Effects of encoding strategy on long-term memory for odours

The effects of various encoding tasks on long-term recognition of odours were examined. Different groups of subjects were instructed (a) to form visual images of the source of the odour, (b) to generate the name of the odour and provide a dictionary-like definition, or (c) to describe a life episode of which the odour reminded them. A no-strategy control was simply told to try to remember the odours for a subsequent recognition test. One week later, subjects performed a yes-no recognition test for the odours. The second and third groups displayed significantly higher recognition than the controls. The visual imagery group did not differ significantly from the control group. The results seem to be accounted for best by dual coding theory.