Quantitative and qualitative individual differences in visual comparison processing: are strategies only analytic or holistic?

Forty-two subjects participated in a visual comparison task and then gave retrospective reports about their solution strategy. In order to replicate Cooperʹs (1976, 1982) results, individual RT data were analysed and two distinct patterns emerged: for some subjects, comparison time decreased as similarity between the stimuli decreased, while for the other subjects comparison time remained constant. However, the analysis of verbal reports revealed five strategy groups, hence verbal data did not fit with a dual-route (holistic vs analytic) model. Moreover the five subject groups using different strategies produced different patterns of RTs which were consistent with mean predicted variations for each strategy. It was also found that some strategies were faster than others. Implications for accommodating individual differences into processing models and the usefulness/reliability of RT data and verbal reports as tools for inferring individual strategies are discussed.