Recognition and recall of odours: the effects of suppressing visual and verbal encoding processes

This study examines the effects on olfactory recognition and recall of the suppression of visual and verbal encoding processes. Subjects were allocated to one of four experimental conditions (no suppression, visual suppression, verbal suppression, and visual-plus-verbal suppression), presented with 15 target odours, and then tested for free recall or recognition of these odours, both within 10 minutes of presentation and one week later. Recall and recognition performance both showed a significant overall effect for level of suppression, with the 'no-suppression' group performing best in each case. Recognition performance also showed a significant overall effect for time of testing. Methodological problems, and strategies for overcoming them, are discussed.