Rotating objects to determine orientation, not identity: Evidence from a backward-masking/dual-task procedure

The effects of picture-plane rotations on times taken to name familiar obje cts (RTs) may reflect a process of mental rotation to stored viewpoint-spec ific representations: the rotate-to-recognize hypothesis. Alternatively men tal rotation might be used after stored object representations are activate d by a misoriented stimulus in order to verify a weak or distorted shape pe rcept: the double-checking hypothesis. We tested these two accounts of rota tion effects in object recognition by having subjects verify the orientatio ns (to within 90 degrees and basic-level names of 14-msec, backward-masked depictions of common objects. The stimulus-mask interval (SOA) varied from 14 to 41 msec, permitting interpolation of the SOA required for 75% accurac y (SOA,). Whereas the SOA(c) to verify orientation increased with rotation up to 180 degrees, the SOA(c) to verify identity was briefer and asymptoted at similar to 60 degrees. We therefore reject the rotate-to-recognize hypo thesis, which implies that SOA(c) should increase steadily with rotation in both tasks. Instead, we suggest that upright and near-upright stimuli are matched by a fast direct process and that misoriented stimuli are matched a t a featural level by a slightly slower view-independent process. We also s uggest that rotation effects on RTs reflect a post recognition stage of ori entation verification: the rotate-to-orient hypothesis, a version of double -checking that also ex-plains the well-known reduction in orientation effec ts on RTs when naming repeated objects.