Quantify The Impact Of Information And Emotional Faces On Time Perception - Cognitive-behavioral And Erp Study

Representing temporal information is an important and fundamental function of human brain, it is also a necessary cognitive processing in our daily life, which including the temporal experience from microseconds, to milliseconds, to seconds and the above related circadian timing or sleep-wake cycle. Among these, the temporal perception in the range of hundreds of milliseconds to seconds is very crucial to many aspects of daily life, such as speech recognition, music perception and skilled motor control, even just wait an upcoming event.Similar to space and quantity, time is one of fundamental dimensions of our external world. Previous researches demonstrated a close relationship between numerical and spatial magnitudes. Number can be represented as "mental number line", and influence many spatial cognitive tasks, which indicated that a common representation may be exist between representing spatial and numerical magnitudes. However, can this type of influence be extended to temporal dimension? Do mutual influence and common representation also exist between temporal and non-temporal dimensions? Up to now, these questions cannot be investigated deeply.In the first study, we investigated whether the estimation of temporal duration could be influenced by the magnitude information of the stimuli that were used to mark the events. Stimuli used included dots (more or less), square (big or small), luminance (high or low) and digits (large or small). Subjects were required to judge which one of two stimuli was presented for longer (or shorter) duration, or which one of two intervals defined by three sequential stimuli was longer. In Task A, subjects performed faster and more accurately when a "small" stimulus (e.g., digit 1) was presented for a shorter duration and a "large" stimulus (e.g., digit 8) was presented for a longer duration (congruent condition). In Task B, subjects also performed better when the shorter interval was defined by two stimuli with "smaller" difference (e.g., digits 8 and 9) and the longer interval was defined by two stimuli with "large" difference (e.g., digits 2 and 9). The difference of Task C and Task B lies in random dots rather than fix crossing during the interval. The influence disappeared for all of conditions except for luminance variation. These results suggest that estimation of temporal duration share some components with representation of magnitudes in non-temporal dimensions. The result of this research has been accepted by Journal of Vision for publication.EEG can monitor the real-time brain activation with high temporal resolution. CNV is a special wave that can reflect the processing of temporal information on line. In the second study, we addressed the underlying mechanism of the above mentioned influence. Participants compared a pair of durations defined by two Arabic digits in a hundreds of milliseconds range, and performed similar to the first study. Event-Related Potentials (ERP) results showed that the primary Contingent Negative Variation (CNV), the secondary CNV and the N1 components, which reflect the orientation of selective temporal attention, were all more negative for the small digits condition than those for large ones. Combining the neurophysiologic evidences with the behavioral results, we suggested that digits could modulate performance of temporal comparison at the relatively early stage of perceptual processing, and selective temporal attention might play an important role in this modulation. Depending upon numeric magnitudes, digits might orientate temporal attention to longer or shorter temporal point respectively, and the resulting temporal expectation influenced accuracy of subjective temporal comparison.Besides the fundamental magnitude information, emotional information is also believed to influence temporal perception. However, the influence is often contacted by attention, individual difference and personal traits in tasks of active perceiving time. In the third study, subjects made a 1-back emotional face task with three types of emotion: happy, fear and neutral while they listened to a series of auditory stimuli simultaneously. 80% of auditory interval is standard with 800 ms, and 20% of auditory interval is deviant with 400, 600, 1000 and 1200 ms. MMN reflected the ability of perceiving change perception that including frequency and temporal variation. ERP results showed that the amplitude and peak latency of MMN were both modulated by the degree of deviant and type of emotion, fearful face significantly decrease the amplitude of MMN. In addition, N1 and P2 evoked by auditory stimuli can interact between emotional types and two smaller interval deviants. These results suggested that emotional face can influence time perception significantly even though they did not perceiving time actively.