# Towards Detection of Interest Using Physiological Sensors
## 3 Physiological Patterns and Features of Interest
### EEG and ECG Patterns
Based on the analysis results, the authors considered the combination of waves at 6 and 10 Hz to be associated with \"favorite\", the combination of waves at 11 and 16 Hz with \"dislikeable\" for haptic sense, the combination of waves at 4 and 7 Hz with \"favorite\", the combination of waves at 9 and 14 Hz with \"dislikeable\" and dozing was associated with waves at 5, 6, 9, and 16 Hz. While the study addressed the effects of television commercial, which are normally visual stimuli, the authors did not clarify the meaning or usage of the terms haptic and olfactory senses in the results section. Thus, it is not clear if the combination of waves with these frequencies is related to the type of television commercial product, e.g., those with odor, which triggers the olfactory organs, or if the authors are referring to other uncited studies that they had carried previously. Comparing the results of the questionnaire used by the subjects to rate their interest levels to those obtained using the proposed system yielded an accuracy of 79.6%. [PERSON] and [PERSON] [49] carried out their experiment using the same EEG device described in the above report. The purpose of their study, however, was to detect latent emotions experienced by subjects while watching television commercials. The authors specified these emotions as like, interest, concentration, drowsiness, and stress. The experiment included 100 Japanese television commercials falling into one of two categories: award-winning and non-award-winning. The commercials were randomly ordered and differed between subjects. Both categories contained television commercials of two different lengths: 15 s and 30 s. Questionnaires were used to evaluate the subjects' emotions after they had watched 10 television commercials. One month after viewing the commercials, the subjects were asked to name television commercials that they found memorable. The EEG device \"KANSEI\" was used to calculate percentage values for the aforementioned five emotions (0%: low degree to 100%: high degree) by converting the raw EEG data to a frequency domain spectrum using fast Fourier transform. This study is thus far the only one that investigated the effects of the stimulus length on the subject's emotions while viewing a stimulus. Fifteen-second television commercials induced increases in the subjects' stress levels. In contrast, 30-s commercials decreased the subjects' stress. The authors argue that this is because the 15-s commercials are required to present sufficient information within a limited time, while the 30-s commercials have double the time to create and present emotional content, such as a storyline. The authors found significant correlations for only two emotions out of the five studied (including interest): concentration and stress. Therefore, the study focused on concentration and stress, and did not discuss interest or the other two states (like and drowsiness) in depth. Hence, the significant contribution of this study to the field could be the procedure and experimental design, but not the outcomes or the result. The importance of the correlation between stress and concentration, which led to the exclusion of the other non-significant correlations and their respective emotions, was not clarified. Moreover, since the device was used to perform all the processing, the reliability of the calculations and classifications need to be inspected. [PERSON] et al. [34] examined the applicability of another method used to assess the level of interest. P3 is known to reflect mental workload and attention paid to a task [68]. The authors used this information to extend the work of [PERSON] et al. [69] by using a three-tone oddball task to assess the level of interest in the subjects. In this paradigm, when an interesting or non-interesting video is played (primary task), the subject is asked to simultaneously respond to an occasional presented auditory stimulus. This technique is based on the idea that there is a fixed capacity for attention.