Temporal Integration Effect In Facial Expression Perception

There are two different views on the underlying cognitive mechanisms of facial expression perception. They diverge at whether identifying a facial expression is based on the holistic information or the local information. The current consensus in facial identity research is that the facial expression perception is based on the whole processing, where configural features are particularly important for facial expression recognition. We refer to this view as the whole-based model. However, a few views suggest that the facial expression is represented and indentified in terms of their individual parts, or features (e.g., eye, nose, and mouth shape, etc.). We refer to this view as the part-based model. There is no consensus in the current perceptual representation of facial expression. The possible view is that there exist two processes in face or facial expression recognition according to the different designs and stimuli the researchers used. However, the paradigm is single in facial expression studies, which research design has focused on spatial integration, where the stimulus processed by the participants is presented within a visual window. There is no study from temporal integration viewpoint to examine the perceptual representation of facial expression, where the stimuli are presented at the different visual windows.It is a very value for us to examine whether participants can identify the facial expression If the whole facial expression are segmented into a few of parts and presented at the different visual windows. The present study aims to investigate the characteristics and time boundaries of facial expression temporal integration, meanwhile, the factors that effected on the processes of facial expression temporal integration are also examined. The design paradigm used in the study is the stimulus onset asynchrony, and the materials are three essential facial expressions (happiness, angry, sadness).Research One aims to investigate the characteristics and time course of facial expression temporal integration through three experiments. Experiment 1 and 3 manipulated the intervals between three main parts (eye, nose, and mouth) of facial expression to examine the time course of facial expression temporal integration; Experiment 2 manipulated the presentation time of three parts to examine the processes of facial expression temporal integration. The results showed that temporal integration is prevalent processes in facial expression perception, as long as the intervals between the facial expression parts and the presentation time of facial expression parts were short enough, and the three separate parts can be held in a short-term store while the separate parts were combined into a meaningful whole representation, that is the temporal integration occurred. Additionally, the temporal integration effects are different in different experimental conditions, and the effects in temporal integration in different facial expressions were also differed.Research, Two aims to investigate whether the feature of facial expression parts influenced on the temporal integration effects from research one through two experiments. Experiment 4 manipulated the presentation time of every part of facial expression to examine the role of eye part, nose part, and mouth part in temporal integration; Experiment 5 manipulated the different stimulus combinations of three parts to examine whether temporal integration in facial expression perception requires three parts to be presented completely. The results showed that the influence of different features on temporal integration effects was different. Of three facial expression parts, eye and mouth features played important role in temporal integration, as long as the presentation time of the separate part was shorter than 400ms the integration process occurred easily. Furthermore, it was not necessary for three expression parts to be presented completely to form a whole representation in facial expression temporal integration.Research Three aims to investigate whether the spatial relation of three facial expression parts influenced on the temporal integration effects from research one and research two through one experiment. Experiment 6 manipulated presentation location and stimulus order of three facial expression parts to examine the effect of spatial relation on temporal integration. The results showed that spatial relation didn’t result in significant difference in temporal integration performance, which indicated that temporal integration was a process in which separated sequential stimuli were organized and processed newly in our cognitive system to form a whole representation rather than a process in which sequential stimuli were close to one another. But the role of spatial relation needs further confirmation. Additionally, the results of experiment 6 provided a replication of research one and two in temporal integration performance of different facial expression.According to the results of study, a cognitive mechanism, memory system possible, was needed by which temporally separated sequential stimuli that presented at different visual windows were combined into a meaningful whole. Because of very short time boundaries of temporal integration and past experience, we deduced that iconic memory and long-term memory was engaged in the processes of facial expression temporal integration. The study examines firstly temporal integration effect in facial expression perception, and under conditions of this research, the main findings are as follows: (1) The facial expression perception was holistic-based model, which depended on configural representation formed by temporal integration. As long as whole information destroyed, it was difficult for participants to identify facial expression; (2) Temporal integration performance of facial expression was affected by many factors, of which, intervals, presentation time, and stimulus features played an important role, which leaded to uncertain time boundaries of facial expression temporal integration; (3) It was not necessary for three expression parts to be presented completely to finish temporal integration task in facial expression perception, as long as the important features, such as eye and mouth, were presented, temporal integration occurred. Iconic memory and long-term memory played an important role in facial expression temporal integration.