The effects of sequential presentation and spatial arrangements on the free classification of multidimensional stimuli

Subjects classified sets of eight stimuli, constructed from three binary dimensions, into discrete groups in any way they wished. The stimuli were presented either simultaneously (all atonce) or sequentially (one at a time). When stimuli were presented simultaneously, different spatial arrangements did not produce different classifications. When stimuli were presented sequentially, in some sequential orders the level of each dimension varied at a different position in the sequence. For these orders, Ss tended to use the two levels of the first dimension that varied to classify the stimuli into two groups. But, other orders in which the levels of all dimensions varied on the second stimulus did not influence Ss’ classification. A comparison of sequential and simultaneous presentation showed for sequential presentation: (a) a smaller number of classifications was made using the dimensional structure to classify the stimuli, and (b)of those classifications that were dimensional, fewer dimensions were used to classify the stimuli into groups.