What is rotated in mental rotation?

Examined which of the 2 strategies--image rotation and frame rotation--transpires in a mental rotation task and whether the choice of strategy may be affected by experimental conditions. Two hypotheses regarding mental rotation were contrasted. The 1st hypothesis posits that if Ss rotate each stimulus image to the upright (the image rotation hypothesis), then response time should depend solely on the extent of angular deviation from the upright. The 2nd hypothesis posits that if Ss rotate their frame of reference to match that of the disoriented stimulus (the frame rotation hypothesis), then response time should vary with the angular deviation between the current stimulus and the preceding stimulus. In 4 experiments with a total of 56 Ss, 1 involving normal and reflected letters (Exp I) and the other 3 involving lexical decisions on Hebrew letter strings (Exps II and III), much stronger evidence for the image rotation hypothesis was found, though weak but systematic effects of frame rotation were also obtained. Increased likelihood that the same orientation would be repeated (Exp IV) did not yield any stronger frame rotation effects. Also there was no indication of consistent individual differences in the preference for the frame rotation strategy (Exp III). Additional findings pertinent to the application of the mental rotation paradigm to word recognition are discussed. (23 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).