Information processing apparatus and processing method of information processing apparatus

Abstract

To enable a user to more appropriately understand the contents of digital contents.SOLUTION: An information processing apparatus includes a brain wave acquisition unit that acquires a brain wave of a user who is playing back a digital content for each predetermined time, a brain wave comparison unit that determines whether dissimilarity between a feature amount of a brain wave at a second time after a first time at which playback of the digital content is started and a feature amount of a brain wave at a third time before the second time is less than a dissimilarity threshold value, and an output control unit that selects information related to a position of the digital content corresponding to the third time when the dissimilarity is less than the dissimilarity threshold value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an information processing device and a processing method for the information processing device. [Background technology]

[0002] Research is being conducted on information processing devices and systems that can provide information related to digital content whose playback has been completed. Patent Document 1 describes an electronic book content related information distribution system that can display information related to the digital content whose playback has been completed to a user when the user has completed playback of the digital content of an electronic book. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-158817 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, there are cases where it is desired to help the user better understand the content of the digital content.

[0005] The present disclosure has been made in view of the above, and aims to provide an information processing device and a processing method for the information processing device that enable a user to more appropriately understand the content of digital content. [Means for solving the problem]

[0006] The information processing device according to the present disclosure includes an electroencephalogram acquisition unit that acquires electroencephalograms of a user at predetermined time intervals while playing digital content; an electroencephalogram comparison unit that determines whether the dissimilarity between the electroencephalogram features at a second time after a first time when playback of the digital content started and the electroencephalogram features at a third time before the second time is less than a dissimilarity threshold; and an output control unit that selects information related to the position of the digital content corresponding to the third time if the dissimilarity is less than the dissimilarity threshold.

[0007] A processing method of an information processing device according to the present disclosure includes the steps of acquiring electroencephalograms of a user at predetermined time intervals while playing digital content, determining whether the dissimilarity between the electroencephalogram features at a second time after a first time when playback of the digital content started and the electroencephalogram features at a third time before the second time is less than a dissimilarity threshold, and selecting information related to the position of the digital content corresponding to the third time if the dissimilarity is less than the dissimilarity threshold. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide an information processing device and a processing method for an information processing device that enable a user to more appropriately understand the content of digital content. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating an overview of an information processing apparatus according to the first embodiment. [Figure 2] FIG. 2 is a schematic block diagram of the information processing device according to the first embodiment. [Figure 3] FIG. 3 is a flowchart illustrating a processing flow when setting a bookmark in the information processing device according to the first embodiment. [Figure 4] FIG. 4 is a schematic block diagram of an information processing apparatus according to the second embodiment. [Figure 5]FIG. 5 is a schematic diagram illustrating an example of a semantic space. [Figure 6] FIG. 6 is a flowchart illustrating a processing flow when the information processing device according to the second embodiment outputs related information. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations in which the respective embodiments are combined.

[0011] (First embodiment) (Digital Content) The digital content played back by the information processing device 100 according to this embodiment is various digital data, and may be, for example, data such as e-books, videos, movies, dramas, concert footage, and music. In other words, digital content is information expressed by at least one of moving images, still images, audio, and text information. The digital content in this embodiment is an e-book.

[0012] (Information processing device) The information processing device 100 according to this embodiment is an information processing device that plays digital content. The information processing device 100 may be, for example, a smartphone, a tablet terminal, a desktop PC (Personal Computer), a notebook PC, a mobile phone, a PDA (Personal Digital Assistant), etc. Fig. 1 is a schematic diagram illustrating an overview of the information processing device according to this embodiment.

[0013] The information processing device 100 according to this embodiment, shown in FIG. 1, is a tablet terminal and includes a sensor unit 160 that acquires vital information of a user U. More specifically, the information processing device 100 according to this embodiment acquires vital information of a user U who is playing digital content from the sensor unit 160, calculates information about the digital content based on the acquired vital information, and provides the information about the digital content to the user U. In other words, the information processing device 100 according to this embodiment sets a position in the digital content at which playback will start next for the user U who has paused playback of the digital content, based on the acquired vital information of the user U who is playing the digital content, and presents the set position of the digital content to the user U. Note that a method for setting the position of the digital content at which playback will start next will be described later.

[0014] Next, the configuration of the information processing device 100 according to this embodiment will be described. FIG. 2 is a schematic block diagram of the information processing device according to this embodiment. As shown in FIG. 2, the information processing device 100 according to this embodiment includes an input unit 110, an output unit 120, a storage unit 130, a communication unit 140, a control unit 150, and a sensor unit 160. The input unit 110 is a device that accepts operations by a user U, and may be, for example, a mouse, a keyboard, or a touch panel. The output unit 120 is a device that outputs information, and may be, for example, a touch panel that displays images, a display, or a speaker that outputs audio data.

[0015] The storage unit 130 is a memory that stores the calculation contents of the control unit 150, programs, and various information input by the user U of the information processing device 100 from the input unit 110, and includes at least one of, for example, a main storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), and an external storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The program for the control unit 150 saved in the storage unit 130 may be stored in a recording medium readable by the information processing device 100.

[0016] The communication unit 140 is responsible for transmitting and receiving various types of data to and from external devices via wireless communication or wired communication. In the case of wireless communication, the communication unit 140 may be provided with a communication processing circuit such as a communication antenna, an RF (Radio Frequency) circuit, or a wireless LAN (Local Area Network) card. In the case of wired communication, the communication unit 140 may be provided with, for example, a NIC (Network Interface Card) with a wired LAN terminal, a transmission circuit, or other circuits for communication processing. Note that the communication format of the communication unit 140 according to this embodiment is wireless communication.

[0017] The control unit 150 is a calculation device and includes a calculation circuit such as a CPU (Central Processing Unit). The control unit 150 according to this embodiment includes a content playback unit 151, an electroencephalogram acquisition unit 152, a concentration level calculation unit 153, a start position determination unit 154, and an output control unit 155. The control unit 150 reads and executes a program (software) from the storage unit 130, thereby realizing the content playback unit 151, the electroencephalogram acquisition unit 152, the concentration level calculation unit 153, the start position determination unit 154, and the output control unit 155 and executing the processes. The control unit 150 may execute these processes using a single CPU, or may be provided with multiple CPUs and execute the processes using the multiple CPUs. At least a portion of the content playback unit 151, the electroencephalogram acquisition unit 152, the concentration level calculation unit 153, the start position determination unit 154, and the output control unit 155 may be implemented by hardware.

[0018] The sensor unit 160 is a sensor that measures biometric information of the user U, in other words, vital data. The sensor unit 160 according to this embodiment is an electroencephalography (EEG) sensor that detects brain waves. Specifically, the sensor unit 160 may be an electroencephalography (EEG) device that uses electrodes to detect brain waves generated from weak currents flowing through the brain's neural network. For example, the sensor unit 160 may be implemented as a type that reduces contact resistance between the electrodes and the skin by placing a conductive gel between the user U's skin and the electrodes, or a type that impregnates an electrolyte with a sponge placed between the skin and the electrodes. The sensor unit 160 according to this embodiment is attached to the head of the user U. However, the sensor unit 160 may be located anywhere other than the head of the user U. The brain waves detected by the sensor unit 160 are brain waves that can detect the level of concentration of the user U, and may be, for example, an electrical signal emitted by the user U and having a frequency of 8 Hz to 50 Hz.

[0019] Furthermore, although the sensor unit 160 according to this embodiment is connected to the information processing device 100 via a harness or cable (not shown), the present invention is not limited to this structure. The sensor unit 160 and the information processing device 100 may be separate components, in which case the sensor unit 160 includes a communication unit and transmits detected brain waves to the information processing device 100 via the communication unit.

[0020] (Processing of information processing device) The processing contents of the information processing device 100 will be explained below.

[0021] (Playing content) The content playback unit 151 plays digital content. More specifically, the content playback unit 151 according to this embodiment reads out digital content designated by the user U via the input unit 110 from the storage unit 130 and plays back the read digital content. For example, if the digital content is an e-book, the content playback unit 151 displays the e-book on a display or touch panel, which is the output unit 120. For example, if the digital content is video data, the content playback unit 151 may play back the digital content by causing a speaker, which is the output unit 120, to output the audio of the digital content and by causing a display or touch panel, which is also the output unit 120, to display the video.

[0022] Note that content playback unit 151 is not limited to reading digital content from storage unit 130, and may acquire digital content to be played back by any method. For example, content playback unit 151 may download and acquire digital content stored in a server (not shown) via communication unit 140, and play it back.

[0023] Furthermore, the content playback unit 151 may start playing the read digital content from any position in the digital content. For example, the content playback unit 151 may start playing from the first position of the digital content. Furthermore, if a bookmark indicating the position at which the next playback will start has been set for the digital content by the start position determination unit 154 (described later), the content playback unit 151 may start playing from the position of the set bookmark. If a bookmark has been set for the digital content, the content playback unit 151 according to this embodiment causes the output control unit 155 to display, via the output unit 120, a message asking the user U whether the playback start position should be the first position or the position at which the bookmark has been set. Then, the digital content is played from the start position specified by the user U via the input unit 110. A method for setting a bookmark will be described later.

[0024] (acquiring EEG) The brain wave acquisition unit 152 acquires brain waves of the user U while the digital content is being played. More specifically, the brain wave acquisition unit 152 acquires brain waves of the user U at predetermined time intervals while the digital content is being played, using a sensor unit 160 attached to the user U. The brain wave acquisition unit 152 may arbitrarily set the predetermined time to one second, ten seconds, one minute, or the like. The brain wave acquisition unit 152 may acquire brain waves at predetermined time intervals starting from the predetermined time. The brain wave acquisition unit 152 acquires brain wave information and information on the time when the brain waves were acquired in association with each other. Of the brain waves acquired by the brain wave acquisition unit 152, the brain waves of the user U at a first time (hereinafter referred to as the first time) when the user U started playing the digital content will hereinafter be referred to as the reference brain wave. Here, assuming that user U, who started playing digital content at a first time, experiences a decrease in his / her concentration on the digital content as playback time elapses due to fatigue, user U's concentration on the digital content at the first time can be considered to be at its highest. In other words, the reference electroencephalogram (EEG), which is user U's EEG at the first time, represents the EEG in a state in which user U experiences the highest concentration on the digital content. The "concentration level" here refers to an index indicating user U's level of concentration on the digital content. The degree of decrease in concentration over the course of playback time of the digital content is referred to as the "decrease in concentration level." A state in which this decrease in concentration level is less than a concentration level threshold (described later) indicates that user U is able to maintain concentration on the digital content. Conversely, a state in which the decrease in concentration level is equal to or greater than the concentration level threshold (described later) indicates that user U is lacking concentration on the digital content. It is generally known that the dominant frequency components of a person's EEG change depending on the person's mental state. For example, it is known that the alpha wave (8 Hz to 13 Hz) component of electroencephalograms becomes dominant when a person is concentrating on one thing. The information processing device 100 according to this embodiment focuses on the above-described electroencephalogram characteristics and calculates the degree of decrease in the concentration level of the user U based on the acquired electroencephalogram of the user U. A specific method for calculating the degree of decrease in the concentration level will be described later.

[0025] The electroencephalogram acquiring unit 152 acquires electroencephalograms of the user U at each time instant while the user U is playing digital content, and also acquires reference electroencephalograms, which are the electroencephalograms of the user U at a first time instant. The reference electroencephalograms may be the electroencephalograms of the user U at the first time instant as the reference electroencephalograms, or may be calculated by averaging electroencephalograms acquired over a predetermined period from the first time instant. Specifically, if the digital content is an electronic book, the reference electroencephalograms may be calculated as an average value of the electroencephalograms of the user U acquired from the time the user U starts reading at the first time instant until the user U finishes reading the first few pages. Alternatively, if the digital content is video data, the reference electroencephalograms may be calculated as an average value of the electroencephalograms of the user U acquired over a predetermined period from the first time instant after the user U starts playing the video at the first time instant. The electroencephalogram acquiring unit 152 stores the acquired electroencephalograms of the user U at each time instant in the storage unit 130.

[0026] (Calculate the degree of decrease in concentration) The concentration level calculation unit 153 calculates the degree of decline in the concentration level of the user U at the second time based on a reference electroencephalogram, which is the electroencephalogram of the user U at the first time, and an electroencephalogram of the user U at a second time (hereinafter, the second time) that is later than the first time. In other words, the concentration level calculation unit 153 calculates the degree of decline in the concentration level of the user U at the second time based on the reference electroencephalogram, which is the electroencephalogram at the first time when the user U is in a state of highest concentration on the digital content, and an electroencephalogram at the second time. The method for calculating the degree of decline in the concentration level by the concentration level calculation unit 153 may be any method, but the concentration level calculation unit 153 according to this embodiment calculates the difference between the reference electroencephalogram, which is the electroencephalogram at the first time, and the electroencephalogram at the second time, and calculates a value based on the difference (for example, the difference itself) as the degree of decline in the concentration level of the user U at the second time. The concentration level calculation unit 153 may calculate the difference between a specific component in the reference electroencephalogram, which is the electroencephalogram at the first time, and a specific component in the electroencephalogram at the second time. The concentration level calculation unit 153 may select any component as the specific component in the electroencephalogram. The concentration level calculation unit 153 according to this embodiment takes the difference between alpha wave components, which are known to be dominant when a person is concentrating on one thing, and calculates the difference as the degree of decline in the concentration level of the user U. Alternatively, the concentration level calculation unit 153 may take the ratio between a reference electroencephalogram, which is an electroencephalogram at the first time point, and an electroencephalogram at the second time point, and calculate a value based on the ratio (for example, the ratio itself) as the degree of decline in the concentration level of the user U at the second time point.

[0027] The electroencephalogram of the user U at the second time may be an electroencephalogram acquired at the second time, or may be an electroencephalogram obtained by averaging electroencephalograms acquired over a predetermined period. Specifically, if the digital content is an e-book, the electroencephalogram of the user U at the second time may be an average value of the electroencephalograms from the time when the user U starts reading the page of the e-book that the user U has open at the second time to the time when the user U finishes reading.

[0028] (Set bookmark) The start position determination unit 154 sets a bookmark position, which is the position at which the user U who interrupted the playback of the digital content will start the next playback, based on the degree of decrease in the user U's concentration calculated by the concentration calculation unit 153. The start position determination unit 154 may set the bookmark position in any manner. However, in this embodiment, if the degree of decrease in the concentration at the second time is equal to or greater than the concentration threshold and the difference between the second time and the first time is equal to or greater than the difference threshold, the start position determination unit 154 determines the position of the digital content being played at the second time as the bookmark position, which is the position at which the next playback will start. Here, the concentration threshold is a threshold related to the degree of decrease in the concentration, and the difference threshold is a threshold indicating a predetermined value related to time. In other words, if the degree of decrease in the concentration calculated from the electroencephalogram is equal to or greater than the concentration threshold at the second time, which is equal to or greater than the difference threshold since the first time when the user U started playing the digital content, the start position determination unit 154 determines that the user U lacked concentration on the digital content. Furthermore, the start position determination unit 154 sets the position of the digital content being played back at the second time as the bookmark position, which is the position from which the next playback will start, for the user U who interrupted the playback of the digital content.

[0029] The start position determination unit 154 may store the position of the bookmark in the storage unit 130. Furthermore, if the degree of decrease in the concentration level at the second time is equal to or greater than the concentration level threshold and the difference between the second time and the first time is equal to or greater than the difference threshold, the start position determination unit 154 may select the position of the digital content being played at the second time and store the position in the storage unit 130. Furthermore, if the degree of decrease in the concentration level at the second time is equal to or greater than the concentration level threshold and the difference between the second time and the first time is equal to or greater than the difference threshold, the start position determination unit 154 may select the position of the digital content being played at the second time if the degree of decrease in the concentration level at the second time is equal to or greater than the concentration level threshold. Furthermore, the start position determination unit 154 may select the position of the digital content being played at the second time if the difference between the second time and the first time is equal to or greater than the difference threshold.

[0030] Here, the start position determination unit 154 does not need to determine whether the time difference is equal to or greater than the difference threshold in synchronization with the playback of the content. For example, consider a case where a user plays content over two days. On the first day, the content playback unit 151 plays the content, the electroencephalogram acquisition unit 152 acquires the user's electroencephalogram, the concentration level calculation unit 153 calculates the degree of decline in concentration level, and stores the electroencephalogram or the degree of decline in concentration level together with the time in the storage unit 130, and the start position determination unit 154 does not set a bookmark. On the second day, when the content playback unit 151 attempts to play the content, the start position determination unit 154 determines whether the difference between a first time, which is the time at which the content is to be played, and a second time stored in the storage unit 130 is equal to or greater than the difference threshold. If the difference between the first time and the second time is equal to or greater than the difference threshold, the start position determination unit 154 may set a bookmark at the position of the digital content that was being played at the second time. The start position determination unit 154 may select, as the second time, any of the times at which brain waves or the degree of decline in concentration level are stored in the storage unit 130. The start position determination unit 154 may select, as the second time, any of the times at which brain waves or the degree of decline in concentration level are stored in the storage unit 130, a time different from the first time. Furthermore, when the brain waves or the degree of decline in concentration level and the time are stored in the storage unit 130, the start position determination unit 154 may determine whether or not the difference between the times is equal to or greater than a difference threshold. When the brain waves or the degree of decline in concentration level and the time are stored in the storage unit 130, the start position determination unit 154 may determine whether or not the degree of decline in concentration level at the second time is equal to or greater than a concentration threshold.

[0031] (Setting the concentration threshold) The start position determination unit 154 may set the concentration threshold using any method. For example, the start position determination unit 154 may set the concentration threshold based on the content of the digital content. More specifically, if the digital content is an e-book, the start position determination unit 154 may set the concentration threshold based on the ratio of kanji characters in the text of the e-book, the difficulty level of the kanji characters, and the character density. The kanji ratio here refers to the ratio of the number of kanji characters to the total number of characters used in the e-book. The difficulty level of the kanji characters refers to the ratio of the number of commonly used kanji characters to the total number of kanji characters used in the e-book. A high ratio of commonly used kanji characters lowers the difficulty level of the kanji characters, while a low ratio of commonly used kanji characters raises the difficulty level of the kanji characters. The character density refers to the number of characters per page, calculated by dividing the total number of characters written in the e-book by the total number of pages. The start position determination unit 154 may set the concentration threshold for each page based on the ratio of kanji characters per page of the e-book, the difficulty level of the kanji characters, and the character density.

[0032] The start position determination unit 154 according to this embodiment may set the concentration level threshold to a larger value as the level of difficulty of the digital content increases. For example, the start position determination unit 154 may determine that the level of difficulty increases as the proportion of kanji characters included in the digital content increases. For another example, the start position determination unit 154 may determine that the level of difficulty increases as the level of kanji characters included in the digital content increases. For another example, the start position determination unit 154 may determine that the level of difficulty increases as the density of characters included in the digital content increases. By increasing the concentration level threshold as the level of difficulty increases, it is possible to prevent a bookmark from being set for digital content that is prone to concentration loss, even when concentration has not decreased significantly.

[0033] Furthermore, the start position determination unit 154 may set the concentration level threshold to a smaller value as the difficulty level of the digital content increases. By setting the concentration level threshold to a smaller value as the difficulty level increases, it is possible to quickly detect a decrease in concentration in digital content that is prone to concentration loss and set an appropriate bookmark position. Note that whether the concentration level threshold is increased or decreased as the difficulty level of the digital content increases may be set by the user U depending on the situation.

[0034] Alternatively, the start position determination unit 154 may set the concentration level threshold based on the user U's level of understanding of the digital content. Here, if the digital content is an e-book, and the content of the digital content is easy for the user U and the user U has a high level of understanding of the content, the user U's reading speed of the digital content will be fast. Conversely, if the content of the digital content is difficult for the user U and the user U has a low level of understanding of the content, the user U's reading speed of the digital content will be slow. In other words, the start position determination unit 154 may set the concentration level threshold based on the speed at which the user U reads the digital content. Note that the speed at which the user U reads the digital content may be acquired by any method. For example, the start position determination unit 154 may calculate the speed at which the user U reads the digital content from the time from when the user U starts reading at a first time until the user U stops reading. Alternatively, the start position determination unit 154 may calculate the speed at which the user U reads the digital content from the difference between the time when the user U starts reading and the time when the user U finishes reading. Furthermore, the start position determination unit 154 may calculate the speed at which the user U reads the digital content from, for example, the time it takes for the user U to start reading from a first page at a first time and finish reading up to a second page at a second time. That is, the start position determination unit 154 may calculate the value obtained by dividing the difference between the first page and the second page by the difference between the first time and the second time as the speed at which the user U reads the digital content.

[0035] The start position determination unit 154 according to this embodiment may set the concentration level threshold to a larger value as the user U's understanding of the digital content decreases. For example, the start position determination unit 154 may determine that the slower the speed at which the user U reads through the digital content, the lower the user U's understanding of the digital content. By setting a larger concentration level threshold as the user U's understanding of the digital content decreases in this way, it is possible to prevent a bookmark from being set due to a decrease in concentration even when the user U's concentration has not decreased significantly in digital content in which concentration is likely to decrease.

[0036] Furthermore, the start position determination unit 154 may set the concentration threshold to a smaller value as the user U's understanding of the digital content decreases. In this way, by setting the concentration threshold to a smaller value as the user U's understanding of the digital content decreases, it is possible to quickly detect a decrease in concentration in digital content that is prone to concentration loss and set an appropriate bookmark position. Note that whether the concentration threshold is set to a larger or smaller value as the user U's understanding of the digital content decreases may be set by the user U depending on the situation.

[0037] The start position determination unit 154 sets a concentration threshold based on the content of the digital content and the user U's level of understanding of the digital content, thereby appropriately calculating the position where the user U lacked concentration on the digital content and setting a bookmark at that appropriate position.

[0038] (Output of bookmark location) The output control unit 155 outputs information relating to the position of the bookmark set by the start position determination unit 154 via the output unit 120. The information relating to the position of the bookmark output by the output control unit 155 may be information in any format, and for example, if the digital content is an e-book, the number of the page where the bookmark is set and a message that the digital content will be played from the page where the bookmark is set may be displayed on the display or touch panel that is the output unit 120. Also, for example, if the digital content is video data, a message that the digital content will be played from the position (playback time) of the video where the bookmark is set may be displayed on the display or touch panel that is the output unit 120.

[0039] (Processing flow) Next, a processing flow of this embodiment will be described. FIG. 3 is a flowchart illustrating a processing flow when setting a bookmark in the information processing device according to this embodiment. The content playback unit 151 reads out from the storage unit 130 the digital content specified by the user U via the input unit 110. If the read digital content does not have a bookmark set (step S10; No), the content playback unit 151 plays back the digital content from the initial position of the digital content (step S12). If the read digital content has a bookmark set (step S10; Yes), the content playback unit 151 causes the output control unit 155 to display, via the output unit 120, a message asking the user U whether to start playback from the initial position or the position where the bookmark is set. If the user U has specified the bookmark position as the playback start position (step S14; Yes), the content playback unit 151 plays back the digital content from the bookmark position of the digital content (step S15). In step S14, if the user U specifies the initial position as the position to start playback (step S14; No), the content playback unit 151 plays the digital content from the initial position of the digital content (step S12). When the content playback unit 151 starts playing the digital content from the initial position of the digital content or the position of the bookmark (step S12 or step S15), the brain wave acquisition unit 152 acquires the brain waves of the user U while the digital content is being played (step S16). The brain wave acquisition unit 152 acquires a reference brain wave (step S20) at a first time when the user U starts playing the digital content (step S18; Yes), and acquires the brain waves of the user U for each time at a second time after the first time (step S18; No) (step S21). The concentration level calculation unit 153 calculates the degree of decrease in the concentration level at the second time based on the brain waves of the user U acquired at the second time and the reference brain wave (step S22).If the degree of decrease in the concentration level at the second time calculated by the concentration level calculation unit 153 is less than the concentration level threshold (step S24; No), or if the difference between the second time and the first time is less than the difference threshold (step S26; No), the control unit 150 returns to step S16. Furthermore, if the degree of decrease in the concentration level at the second time calculated by the concentration level calculation unit 153 is equal to or greater than the concentration level threshold (step S24; Yes) and if the difference between the second time and the first time is equal to or greater than the difference threshold (step S26; Yes), the start position determination unit 154 sets the position of the digital content being played at the second time to the position of the bookmark, which is the position from which user U who interrupted the playback of the digital content will start playback next time (step S28), and ends this process. The control unit 150 may repeat the processes from S16 to S28 until playback of the digital content is completed.

[0040] (effect) As described above, the information processing device 100 according to this embodiment includes an electroencephalogram acquisition unit 152 that acquires electroencephalograms at each time of the user U who is playing digital content, a concentration calculation unit 153 that calculates the degree of decrease in the concentration level of the user U at a second time based on a reference electroencephalogram, which is the electroencephalogram of the user U at a first time when the user U started playing the digital content, and an electroencephalogram of the user U at a second time after the first time, and a start position determination unit 154 that sets the position of the digital content that was being played at the second time as the position to start the next playback if the degree of decrease in the concentration level at the second time is equal to or greater than a concentration threshold and the difference between the second time and the first time is equal to or greater than a difference threshold. According to the present disclosure, the position at which the digital content is to be played next can be appropriately set depending on the situation of the user U.

[0041] Furthermore, according to the present disclosure, the information processing device 100 sets the position at which the next playback will start using the degree of decrease in user U's concentration, and can start the next playback from the position at which user U was lacking concentration on the digital content, rather than the position at which user U interrupted the playback of the digital content.

[0042] Furthermore, according to the present disclosure, the information processing device 100 can calculate the degree of decrease in user U's concentration level over time by using a reference electroencephalogram, which is user U's electroencephalogram at a first time when user U starts playing digital content, and user U's electroencephalogram at a second time after the first time.

[0043] Furthermore, according to the present disclosure, the information processing device 100 sets the position of the digital content being played at the second time as the position to start the next playback if the difference between the second time and the first time is equal to or greater than a difference threshold, in addition to the degree of decrease in the concentration level at the second time. This makes it possible to prevent a bookmark from being set at the second time when the user U can regain concentration and play the digital content again even if the user U loses concentration.

[0044] Furthermore, according to the present disclosure, the start position determination unit 154 can set the concentration threshold based on the content of the digital content and the user U's level of understanding of the digital content, thereby appropriately calculating the position where the user U lacked concentration on the digital content and setting the bookmark position at that appropriate position.

[0045] (Second embodiment) Next, a second embodiment will be described. An information processing device 100A according to the second embodiment differs from the first embodiment in that it selects and outputs information related to the position of digital content based on the brain waves of a user U who is playing the digital content. In the second embodiment, components common to the first embodiment are denoted by the same reference numerals and description thereof will be omitted. The second embodiment can be combined with the first embodiment.

[0046] 4 is a schematic block diagram of an information processing device according to this embodiment. The information processing device 100A according to this embodiment further includes an electroencephalogram acquiring unit 152A and an electroencephalogram comparing unit 156, as compared with the information processing device 100 according to the first embodiment.

[0047] (Processing of information processing device) The processing contents of the information processing device 100A will be explained below.

[0048] (acquiring EEG) The electroencephalogram acquisition unit 152A acquires the electroencephalograms of the user U at each time while the digital content is being played back, and stores the acquired electroencephalograms in the storage unit 130. The electroencephalogram acquisition unit 152A according to this embodiment calculates electroencephalogram feature quantities from the electroencephalogram values ​​of the user U. Note that the concentration level calculation unit 153 according to the first embodiment calculates the degree of decrease in concentration level by focusing on the alpha wave component of the electroencephalograms acquired by the electroencephalogram acquisition unit 152, but the electroencephalogram acquisition unit 152A according to this embodiment calculates electroencephalogram feature quantities by taking into account not only the alpha wave component of the acquired electroencephalograms but also other components. More specifically, the electroencephalogram acquisition unit 152A according to this embodiment converts the acquired electroencephalogram values ​​of the user U into values ​​in the coordinate system of the semantic space MS, which will be described later, and stores the converted values ​​in the storage unit 130 as electroencephalogram feature quantities.

[0049] (Semantic Space) FIG. 5 is a schematic diagram illustrating an example of a semantic space. Here, the semantic space MS can be considered a coordinate system with multiple axes (multiple dimensions) that indicates the content of an image. In the example of FIG. 5, the electroencephalogram acquiring unit 152A sets a semantic space MS in which spatial coordinates are expressed by the dimensions of the X-axis, Y-axis, Z-axis, and α-axis. It is generally known that the content recalled by a user U can be inferred from the feature quantities of electroencephalograms. The information processing device 100A according to this embodiment infers the content recalled by the user U from the feature quantities of electroencephalograms by associating the set semantic space MS with the feature quantities of electroencephalograms. Specifically, the electroencephalogram acquiring unit 152A assigns the acquired electroencephalograms of the user U at each time to the coordinate system of the semantic space MS. More specifically, the electroencephalogram acquiring unit 152A converts the acquired electroencephalogram values ​​of the user U at each time into coordinate values ​​corresponding to each axis (each dimension) of the semantic space MS, and assigns and plots them as feature quantities of electroencephalograms in the coordinate system of the semantic space MS. The number and types of dimensions in the semantic space MS may be determined as appropriate, and the method for converting EEG data into coordinates in the semantic space MS may also be determined as appropriate. For example, the average amplitude of each of the following predetermined frequency components of EEG data, namely, α1 wave component (8 Hz to 10 Hz), α2 wave component (11 Hz to 13 Hz), β wave component (14 Hz to 24 Hz), and γ wave component (25 Hz to 50 Hz), may be calculated, and the calculated average amplitude of each component may be set as the coordinate value of each axis in the semantic space MS. Since EEG data are plotted in the semantic space MS in this manner, it is possible to estimate what the user U was thinking when the EEG data was detected based on the values ​​plotted in the semantic space MS (feature quantities of EEG data). Furthermore, plots of two EEG data that represent similar contents and have high similarity (low dissimilarity) will be clustered close to each other in the semantic space MS.

[0050] Specifically, the electroencephalogram acquiring unit 152A assigns the electroencephalogram of the user U at each time when the video is played to the coordinate system of the semantic space MS. FIG. 5 plots the electroencephalogram of the user U at each time when the user U plays digital content. In the example of FIG. 5, plot PP1 is a plot of the electroencephalogram of the user U at the time when motorcycle-related content is played in the digital content and the user U thinks of motorcycles, and plot PP2 is a plot of the electroencephalogram of the user U at the time when car-related content is played in the digital content and the user U thinks of cars. In this case, plots PP1 and PP2 are aggregated in the semantic space MS. Similarly, plot PP3 of the electroencephalogram of the user U at the time when dog-related content is played in the digital content and the user U thinks of dogs, and plot PP4 of the electroencephalogram of the user U at the time when bird-related content is played and the user U thinks of birds, are aggregated in the semantic space MS. Plot PP5 of the electroencephalogram of user U at the time when the landscape image is played is plotted at a position in the semantic space MS that is distant from the other plots PP1 to PP4 described above. In other words, when the contents of multiple digital contents are played back and the contents of the multiple digital contents are related to each other (in the example of FIG. 5, plots PP1 and PP2 are related by the concept of vehicles, and plots PP3 and PP4 are related by the concept of living things), the similarity of the features of the electroencephalograms of multiple users U obtained becomes high.

[0051] Furthermore, for example, if the digital content is an e-book, the electroencephalogram acquisition unit 152A uses a gaze detection sensor (not shown) to detect the reading position of the user U at each time from the gaze of the user U while reading, that is, the words the user U is reading at each time, and acquires the electroencephalogram of the user U corresponding to the words the user U was reading. The acquired electroencephalogram of the user U is then assigned to the coordinate system of the semantic space MS. In this case, in the semantic space MS, plots of the electroencephalogram of the user U at the times when the user U was reading related words are grouped together.

[0052] Note that the method for calculating the feature quantities of the electroencephalogram is not limited to plotting the electroencephalogram in the semantic space MS as described above. The electroencephalogram acquiring unit 152A does not have to plot the values ​​of the electroencephalogram in the semantic space MS. The electroencephalogram acquiring unit 152A may convert the values ​​of the electroencephalogram into coordinate values ​​corresponding to each axis of the semantic space MS and calculate the coordinate values ​​as the feature quantities of the electroencephalogram. Furthermore, the electroencephalogram acquiring unit 152A may, for example, perform a Fourier transform on the acquired electroencephalogram to calculate a power spectrum, which is an intensity distribution for each frequency included in the electroencephalogram, and calculate the calculated power spectrum as the feature quantities of the electroencephalogram.

[0053] (Comparison of EEG) The electroencephalogram comparing unit 156 compares the electroencephalogram of user U at the second time acquired by the electroencephalogram acquiring unit 152 with the electroencephalogram of user U at a third time that is earlier than the second time. More specifically, the electroencephalogram comparing unit 156 calculates the difference between the feature amount of the electroencephalogram of user U at the second time and the feature amount of the electroencephalogram of user U at the third time as the dissimilarity. Then, the electroencephalogram comparing unit 156 determines whether the calculated dissimilarity between the feature amount of the electroencephalogram of user U at the second time and the feature amount of the electroencephalogram of user U at the third time is less than a dissimilarity threshold. Here, the dissimilarity threshold is a threshold that indicates a predetermined value related to the dissimilarity. While any method for this determination may be used, the electroencephalogram comparison unit 156 according to this embodiment calculates the difference between the feature amount (spatial coordinates in the semantic space MS) of the user U's electroencephalogram at the second time and the feature amount (spatial coordinates in the semantic space MS) of the user U's electroencephalogram at a third time, which is earlier than the second time and has already been plotted in the semantic space MS, and determines whether the difference between the spatial coordinates is less than the dissimilarity threshold. Specifically, with reference to FIG. 5 , if the digital content is video data, the electroencephalogram comparison unit 156 assigns spatial coordinates in the semantic space MS based on the feature amount of the electroencephalogram to the electroencephalogram of the user U when an image of a horse was played at the second time, and plots the assigned spatial coordinates in the semantic space MS. The plot CP of the electroencephalogram of the user U when an image of a horse was played at the second time is plotted near plots PP3 and PP4, which share the concept of animals. The electroencephalogram comparison unit 156 then calculates the difference between the plot CP and the other plots, and if there is a plot where the difference between the spatial coordinates is less than the dissimilarity threshold, identifies that plot. Here, the brain waves of user U at the third time may be the brain waves of user U when playing digital content different from the digital content that user U started playing at the first time, or may be the brain waves of user U when playing the same digital content.

[0054] Furthermore, the EEG comparing unit 156 may select, as the third time, from a plurality of times at which EEGs were recorded before the second time. The EEG comparing unit 156 may select, as the third time, from all times at which EEGs were recorded before the second time. The EEG comparing unit 156 may select, as the third time, a predetermined number of times from a plurality of times at which EEGs were recorded before the second time. The storage unit 130 may store the predetermined number. The EEG comparing unit 156 may select times at a time interval equal to a value obtained by dividing the time at which the EEGs were recorded by the predetermined number read from the storage unit 130.

[0055] Furthermore, the electroencephalogram comparing unit 156 may calculate the dissimilarity between two electroencephalograms A and B to be compared in the semantic space MS as the Euclidean distance between the electroencephalograms A and B. That is, the electroencephalogram comparing unit 156 may calculate the dissimilarity between the electroencephalograms A and B as the square root of the sum of the squares of the differences for each dimension. The electroencephalogram comparing unit 156 may calculate the dissimilarity between the electroencephalograms A and B as the sum of the squares of the differences for each dimension.

[0056] (Suggestions for related information) The output control unit 155 according to this embodiment selects related information, which is information related to the location of digital content corresponding to the third time, when the dissimilarity between the feature of the electroencephalogram of the user U at the second time and the feature of the electroencephalogram of the user U at the third time is less than a dissimilarity threshold. The related information is information indicating which digital content, among digital content played by the user U in the past, contains content similar to or related to the content of the digital content being played by the user U at the second time, and at what position in that digital content. Specifically, in this embodiment, the related information is information indicating the location of the digital content being played by the user U at a third time, which is earlier than the second time. Here, if the digital content being played by the user U at the third time is considered to be the related content, the related information can be said to be information related to the location of the related content. The output control unit 155 may output the selected related information in any format. In addition, when the dissimilarity between the electroencephalogram features at the second time and the electroencephalogram features at the third time is less than a dissimilarity threshold, the output control unit 155 may select related information that is information related to the location of the digital content corresponding to the third time, and store the related information in the memory unit 130.

[0057] For example, the output control unit 155 may display a list of related contents on the output unit 120, which is a display or touch panel, as related information for the digital content currently being played, for the user U who is playing the digital content at the second time.

[0058] Alternatively, the output control unit 155 may display a message on the display or touch panel of the output unit 120 asking the user U who is playing the digital content at the second time whether to interrupt the playback of the currently playing digital content and play the related content from the position in the related content that the user U was playing at the third time.

[0059] Note that, prior to the second time, there may be a plurality of times when the dissimilarity of the electroencephalogram feature to the electroencephalogram of the user U at the second time is less than the dissimilarity threshold. Here, among the third times prior to the second time, a third time at which the dissimilarity of the electroencephalogram feature to the electroencephalogram of the user U at the second time is less than the dissimilarity threshold is set as a candidate time. When there are a plurality of candidate times (i.e., when there are a plurality of third times at which the dissimilarity to the electroencephalogram feature at the second time is less than the dissimilarity threshold), the output control unit 155 may select one time from the plurality of candidate times as the target time using any method. Then, the output control unit 155 may select information related to the location of digital content (related content) corresponding to the target time as related information.

[0060] For example, when there are multiple candidate times, the output control unit 155 may select, as the target time, the time at which the electroencephalogram (EEG) acquired at the multiple candidate times exhibits the greatest decrease in concentration. Specifically, the storage unit 130 according to this embodiment stores the degree of decrease in concentration at a third time, which is earlier than the second time, together with the electroencephalogram (EEG) at the third time. The output control unit 155 may select, as the target time, the time at which the electroencephalogram (EEG) acquired at the multiple candidate times exhibits the greatest decrease in concentration. The method for calculating the concentration level at the third time is the same as that in the first embodiment, and therefore a description thereof will be omitted. Furthermore, when there are multiple electroencephalograms at the third time whose dissimilarity with the feature of the user U's electroencephalogram at the second time is less than the dissimilarity threshold, the output control unit 155 may select, as the related information, information related to the location of the digital content corresponding to the third time at which the electroencephalogram (EEG) exhibits the greatest decrease in concentration, among the locations of the digital content corresponding to the third time at which the multiple electroencephalograms were acquired.

[0061] Furthermore, for example, when there are multiple candidate times, the output control unit 155 may select, as the target time, the time at which the position closest to the position at which the digital content is to start was played out from among the multiple candidate times. Furthermore, when there are multiple candidate times, the output control unit 155 may select, as the target time, the time closest to the time at which the digital content is to start out from among the multiple candidate times. Furthermore, when there are multiple electroencephalograms at a third time whose dissimilarity with the feature of the electroencephalogram of the user U at the second time is less than the dissimilarity threshold, the output control unit 155 may select, as the related information, information related to the position closest to the position at which the digital content is to start out from among the positions of the digital content corresponding to the third time at which the multiple electroencephalograms were acquired.

[0062] (Processing flow) Next, the processing flow of this embodiment will be described. FIG. 6 is a flowchart illustrating the processing flow when the information processing device according to this embodiment outputs related information. When the content playback unit 151 starts playing digital content at a first time, the electroencephalogram acquisition unit 152A starts acquiring electroencephalograms of the user U playing the digital content (step S40). The electroencephalogram acquisition unit 152A calculates a feature amount of the electroencephalogram acquired at a second time (step S42). The electroencephalogram comparison unit 156 calculates a dissimilarity between the feature amount of the electroencephalogram of the user U at the second time and the feature amount of the electroencephalogram of the user U acquired at a third time before the second time (step S44). When the electroencephalogram comparison unit 156 determines that the dissimilarity calculated in step S44 is equal to or greater than the dissimilarity threshold (step S46; No), the process returns to step S40. Furthermore, if the electroencephalogram comparing unit 156 determines that the dissimilarity calculated in step S44 is less than the dissimilarity threshold (step S46; Yes), the output control unit 155 selects information related to the position of the digital content corresponding to the third time (step S48) and ends this process. The control unit 150 may repeat the processes from S40 to S48 until the playback of the digital content is completed.

[0063] (effect) As described above, the information processing device 100A according to this embodiment includes an electroencephalogram acquisition unit 152A that acquires electroencephalograms (EEGs) of a user U at each time while the user U is playing digital content; an electroencephalogram comparison unit 156 that determines whether the dissimilarity between the feature of the user U's electroencephalogram at a second time (after a first time when the user U started playing the digital content) and the feature of the user U's electroencephalogram at a third time (before the second time) is less than a dissimilarity threshold; and an output control unit 155 that, if the dissimilarity is less than the dissimilarity threshold, selects and outputs information related to the location of the digital content corresponding to the third time. According to the present disclosure, the user U playing digital content can be made to more appropriately understand the content of the digital content. That is, according to the present disclosure, the content the user is recalling can be identified from the user U's electroencephalogram at the second time, and location information indicating content similar to that content can be presented to the user U. Therefore, the user U can deepen his or her understanding of the content by checking the content at the similar location.

[0064] Furthermore, according to the present disclosure, the information processing device 100A selects information related to the location of digital content corresponding to the third time using the dissimilarity between the electroencephalogram features of the user U at the second time and the electroencephalogram features of the user U at the third time, which is earlier than the second time, and thereby can appropriately select related information that differs for each user U using the dissimilarity between multiple electroencephalogram features that differ for each user U.

[0065] Furthermore, according to the present disclosure, the related information selected and output by the information processing device 100A is selected based on the dissimilarity of multiple electroencephalogram features that the user U cannot control by his or her own will, and therefore the information processing device 100A can also select related information that the user U has previously played but has forgotten.

[0066] Furthermore, according to the present disclosure, the first embodiment and the second embodiment can be combined. The information processing device 100A includes an electroencephalogram acquisition unit 152A that acquires electroencephalograms of a user U at predetermined time intervals while the digital content is being played back, a concentration calculation unit 153 that calculates the degree of decrease in the concentration level of the user U at a second time based on the electroencephalograms at a first time when the playback of the digital content starts and the electroencephalograms at a second time after the first time, and a start position determination unit 154 that selects the position of the digital content being played back at the second time when the degree of decrease in the concentration level at the second time is equal to or greater than a concentration threshold and the difference between the second time and the first time is equal to or greater than a difference threshold. According to the present disclosure, the position at which the digital content is played back can be appropriately set depending on the situation of the user U.

[0067] Moreover, the information processing device 100A according to this embodiment further includes an electroencephalogram comparison unit 156 that determines whether the dissimilarity between the electroencephalogram feature amount acquired by the electroencephalogram acquisition unit 152A at a second time and the electroencephalogram feature amount acquired at a third time earlier than the second time is less than a dissimilarity threshold, and an output control unit 155 that selects information related to the position of digital content corresponding to the third time when the dissimilarity is less than the dissimilarity threshold. According to the present disclosure, it is possible to select information related to the content of the digital content being played for a user U who is playing digital content.

[0068] (Effects of the present disclosure) As described above, the information processing device 100A of the present disclosure includes an electroencephalogram acquisition unit 152 that acquires electroencephalograms of a user U at predetermined time intervals while the user U is playing digital content, an electroencephalogram comparison unit 156 that determines whether the dissimilarity between an electroencephalogram feature amount at a second time after a first time when the user U started playing the digital content and an electroencephalogram feature amount at a third time before the second time is less than a dissimilarity threshold, and an output control unit 155 that selects information related to the position of the digital content corresponding to the third time if the dissimilarity is less than the dissimilarity threshold. According to the present disclosure, the user U playing the digital content can be allowed to understand the content of the digital content more appropriately.

[0069] Furthermore, according to the present disclosure, when there are multiple electroencephalograms at the third time whose dissimilarity with the feature of the electroencephalogram at the second time is less than the dissimilarity threshold, the output control unit 155 selects information related to a position closest to the start position of the digital content from among the positions of the digital content corresponding to the third time when the multiple electroencephalograms were acquired. According to the present disclosure, related information that helps the user U to properly understand the digital content can be made information that is easier for the user to understand.

[0070] According to the present disclosure, the device further includes a concentration calculation unit 153 that calculates the degree of decrease in concentration of user U at the second time based on the electroencephalogram at the first time and the electroencephalogram at the second time, and a start position determination unit 154 that selects the position of the digital content that was being played at the second time when the degree of decrease in concentration at the second time is equal to or greater than a concentration threshold and the difference between the first time and the second time is equal to or greater than a difference threshold. According to the present disclosure, the position at which the digital content is played can be appropriately set depending on the situation of user U.

[0071] According to the present disclosure, the device further includes a concentration calculation unit 153 that calculates the degree of decrease in concentration of the user U at the second time based on the electroencephalogram at the first time and the electroencephalogram at the second time, and when there are multiple electroencephalograms at the third time whose dissimilarity with the feature amount of the electroencephalogram at the second time is less than a dissimilarity threshold, the output control unit 155 selects information related to the position of the digital content corresponding to the third time at which the electroencephalogram with the highest degree of decrease in concentration was acquired among the multiple electroencephalograms. According to the present disclosure, it is possible to select information related to the content of the digital content being played by the user U and related to a position where the user U previously lacked concentration on the digital content.

[0072] A processing method of an information processing device according to the present disclosure includes the steps of acquiring electroencephalograms of a user U at predetermined time intervals while the user U is playing digital content, determining whether a dissimilarity between an electroencephalogram feature at a second time after a first time when the user started playing the digital content and an electroencephalogram feature at a third time before the second time is less than a dissimilarity threshold, and selecting information related to the position of the digital content corresponding to the third time if the dissimilarity is less than the dissimilarity threshold. According to the present disclosure, the user U playing the digital content can be allowed to more appropriately understand the content of the digital content.

[0073] Although the above has been described as processing by the information processing device 100, 100A, in the present disclosure, some of the processing of the information processing device 100, 100A may be processed by an information processing device separate from the information processing device 100, 100A. This separate information processing device may include a communication unit, and the information processing device 100, 100A may receive the results of the processing in the information processing device via the communication unit 140. Furthermore, for example, the information processing device 100, 100A may not include the content playback unit 151, and may not perform processing to play digital content. In this case, for example, the information processing device 100, 100A may output the processing results of the control unit 150 described above (e.g., information related to the position of the bookmark and related information) to the separate information processing device, and the separate information processing device may play the digital content based on the received processing results.

[0074] Although the embodiments of the present invention have been described above, the embodiments are not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is called equivalents. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments. [Explanation of symbols]

[0075] 100 Information processing device U User MS Semantic Space 151 Content playback unit 152 EEG acquisition unit 153 Concentration calculation part 154 Start position determination section 155 Output control section 156 EEG Comparison Unit

Claims

1. an electroencephalogram acquiring unit that acquires electroencephalograms of a user at predetermined time intervals while the digital content is being played; an electroencephalogram comparison unit that determines whether a dissimilarity between the electroencephalogram feature amount at a second time that is later than a first time when playback of the digital content is started and the electroencephalogram feature amount at a third time that is earlier than the second time is less than a dissimilarity threshold; an output control unit that selects information related to a position of the digital content corresponding to the third time when the dissimilarity is less than the dissimilarity threshold. Information processing device.

2. and when there are a plurality of electroencephalograms at the third time point, the dissimilarity of which with respect to the feature amount of the electroencephalogram at the second time point is less than the dissimilarity threshold, the output control unit selects information related to a position closest to a start position of the digital content from among positions of the digital content corresponding to the third time point at which the plurality of electroencephalograms were acquired. The information processing device according to claim 1 .

3. a concentration level calculation unit that calculates a degree of decrease in the concentration level of the user at the second time point based on the electroencephalogram at the first time point and the electroencephalogram at the second time point; a start position determination unit that selects a position of the digital content being played back at the second time when the degree of decrease in the concentration level at the second time is equal to or greater than a concentration level threshold and the difference between the first time and the second time is equal to or greater than a difference threshold.

3. The information processing device according to claim 1.

4. a concentration level calculation unit that calculates a degree of decrease in the concentration level of the user at the second time point based on the electroencephalogram at the first time point and the electroencephalogram at the second time point, and when there are a plurality of electroencephalograms at the third time instant whose dissimilarity with the feature amount of the electroencephalogram at the second time instant is less than the dissimilarity threshold, the output control unit selects, from the plurality of electroencephalograms, information related to the position of the digital content corresponding to the third time instant at which the electroencephalogram with the greatest degree of decrease in the concentration level was acquired. The information processing device according to claim 1 .

5. acquiring an electroencephalogram of a user at predetermined time intervals while the digital content is being played; determining whether a dissimilarity between the electroencephalogram feature amount at a second time that is later than a first time when playback of the digital content is started and the electroencephalogram feature amount at a third time that is earlier than the second time is less than a dissimilarity threshold; and selecting information related to a location of the digital content corresponding to the third time if the dissimilarity is less than the dissimilarity threshold. Processing method of information processing device.

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