Face processing : the role of dynamic information
This thesis explores the effects of movement on various face processing tasks. In Experiments One to Four, unfamiliar face recognition was investigated using identical numbers of frames in the learning phase; these were viewed as a series of static images, or in moving sequences (using computer animation). There was no additional benefit from studying the moving sequences, but signal detection measurements showed an advantage for using dynamic sequences at test. In Experiments Five and Six, moving and static images of unfamiliar faces were matched for expression or identity. Without prior study, movement only helped in matching the expression. It was proposed that motion provided more effective access to a stored representation of an emotional expression. Brief familiarisation with the faces led to an advantage for dynamic presentations in referring to a stored representation of identity as well as expression. Experiments Seven to Nine explored the suggestion that motion is beneficial when accessinga pre-existingd escription. Significantly more famous faces were recognised in inverted and negated formats when shown in dynamic clips, compared with recognition using static images. This benefit may be through detecting idiosyncratic gesture patterns at test, or extracting spatial and temporal relationships which overlapped the stored kinematic details. Finally, unfamiliar faces were studied as moving or static images; recognition was tested under dynamic or fixed conditions using inverted or negated formats. As there was no difference between moving and static study phases, it was unlikely that idiosyncratic gesture patterns were being detected, so the significant advantage for motion at test seemed due to an overlap with the stored description. However, complex interactions were found, and participants demonstrated bias when viewing motion at test. Future work utilising dynamic image-manipulated displays needs to be undertaken before we fully understand the processing of facial movement.