These results confirm our previous finding that an odor paired with sucrose
subsequently smells sweeter (Stevenson et al., 1995). This occurs even under
conditions where the experiment was administered by five different experimenters
under blind conditions. More importantly, the change in sweetness
ratings on which this conclusion is based cannot result from some form of
stimulus exposure effect, since no such change was observed for the waterpaired
control odor which received equal exposure.
With regard to the issue of awareness, the results replicated the finding
ODOR-SWEETNESS LEARNING 121
reported by Stevenson et al. (1995) that subjects classified as aware did not
perform differently from those categorized as unaware. However, the recognition
test used in Experiment 1 is open to the criticisms that it might lack
sensitivity and that the testing conditions differed from those where learning
took place (see Shanks & St. John, 1994). These were some of the points
addressed by Experiment 2.