Dissociating positive and negative influences of verbal processing on the recognition of pictures of faces and objects.

Four experiments investigated the role of verbal processing in the recognition of pictures of faces and objects using an adapted picture recognition memory paradigm. We used: (a) a stimulus-encoding task where participants learned sequentially presented pictures in control, articulatory suppression, and describe conditions and then engaged in an old-new recognition test; and (b) a post stimulus-encoding task where participants learned the stimuli without any secondary task and then either described or not (in the control condition) a single item from memory prior to the recognition test. The main findings were as follows. First, verbalization influenced picture recognition. Second, there were contrasting influences of verbalization on the recognition of faces as compared with objects which were driven by (a) the stage of processing during which verbalization took place (as assessed by the stimulus-encoding and post stimulus-encoding tasks); (b) whether verbalization was sub-vocal (whereby one goes through the motions of speaking but without making any sound) or overt; and (c) stimulus familiarity. During stimulus-encoding there was a double dissociation whereby sub-vocal verbalization interfered with the recognition of faces but not objects whilst overt verbalization benefited the recognition of objects but not faces. In addition, stimulus familiarity provided an independent and beneficial influence on performance. Post stimulus-encoding, overt verbalization interfered with the recognition of both faces and objects and this interference was apparent for unfamiliar but not familiar stimuli. Together these findings extend work on verbalization to picture recognition and place important parameters on stimulus and task constraints, which contribute to contrasting beneficial and detrimental effects of verbalization on recognition memory.