The role of verbal processing in face recognition memory
This dissertation attempts to provide a comprehensive view of the role of verbal processing in face recognition memory by examining some of the neglected issues in two streams of cognitive research, face recognition and verbal overshadowing. Traditionally, research in face recognition focuses on visual and semantic aspects of familiar and unfamiliar face processing, with little acknowledgement of any verbal aspect. By contrast, the verbal overshadowing literature examines the effect of verbal retrieval of unfamiliar face memory on subsequent recognition, with little attention to actual mechanisms underlying processing of these faces. Although both are concerned with our ability to recognise faces, they have proceeded independently as their research focus is diverse. It therefore remains uncertain whether or not face encoding entails verbal processing, and whether or not verbal processing is always detrimental to face recognition. To address these issues, some experimental techniques used in face recognition research were combined with methods from verbal overshadowing research. The first strand of experiments examined configural-visual and featural-verbal processing associations in change recognition tasks. The second strand systematically examined the role of verbal processing in recognition memory by manipulating the degree of verbal involvement during and after encoding. The third strand examined the ‘perceptual expertise’ account of verbal overshadowing in picture recognition memory tasks, involving pictures of familiar and unfamiliar people. The fourth strand directly tested a tentative hypothesis ‘verbal code interference’ to explain verbal overshadowing by manipulating the frequency and time of face verbalisation in line-up identification tasks. The concluding experiment looked at the relation between intentional learning and verbal overshadowing in a recognition memory task using more naturalistic stimuli. The main findings indicate first, that mechanisms underlying face processing appear to be complex, and simple processing associations (configural-visual and featural-verbal processing) cannot be made. Second, face encoding seems to involve some sort of verbal processing which may actually be necessary for successful recognition. Third, post-encoding verbalisation per se does not seem to be the key determiner for recognition impairment. Rather, the interference between verbal representations formed under different contexts seems to harm recognition. Fourth, verbal overshadowing was found only for unfamiliar face picture recognition, but not for familiar face picture recognition, casting a doubt on ‘perceptual expertise account’. Finally, although no clear evidence linking intentional learning and verbal overshadowing was found, intentional learning and verbalisation in combination affected a response pattern. These results were discussed in relation to ongoing debate over causes of the verbal overshadowing effect, which raises an important ecological question as to whether the phenomenon might reflect natural human memory interference.