Interactions between the processing of facial identity, emotional expression and facial speech
The experiments investigate the functional relationship between the processing of facial identity, emotional expression and facial speech. They were designed in order to further explore a widely accepted model of parallel, independent face perception components (Bruce and Young, 1986), which has been challenged recently (e.g. Walker et. al., 1995; Yakel et. al., 2000; Schweinberger et. al., 1998; Schweinberger et.al., 1999). In addition to applying a selective attention paradigm (Garner, 1974; 1976), dependencies between face related processes are explored by morphing, a digital graphic editing technique which allows for the selective manipulation of facial dimensions, and by studying the influence of face familiarity on the processing of emotional expression and speechreading. The role of dynamic information for speechreading (lipreading) is acknowledged by investigating the influence of natural facial speech movements on the integration of identity specific talker information and facial speech cues. As for the relationship between the processing of facial identity and emotional expression, overall the results are in line with the notion of independent parallel routes. Recent findings of an "asymmetric interaction" between the two dimensions in the selective attention paradigm, in the sense that facial identity can be processed independently from expression but not vice versa (Schweinberger et. al., 1998; Schweinberger et. al., 1999) could not be unequivocally corroborated. Critical factors for the interpretation of results based on the selective attention paradigm when used with complex stimuli such as faces are outlined and tested empirically. However, the experiments do give evidence that stored facial representations might be less abstract than previously thought and might preserve some information about typical expressions. The results indicate that classifications of unfamiliar faces are not influenced by emotional expression, while familiar faces are recognized fastest for certain expressions.