THE ROLE OF ATTENTION IN THE SHIFT FROM ORIENTATION-DEPENDENT TO ORIENTATION-INVARIANT IDENTIFICATION OF DISORIENTED OBJECTS

In two experiments, the naming of rotated line drawings of natural obj ects was examined after a training phase in which the objects were eit her attended or ignored. In the training phase of Experiment 1, subjec ts were presented with objects in a number of orientations over five r epeated blocks of trails. In the center of each object, seven letters (Xs and Ts, colored red or blue) were presented in rapid succession. H alf the subjects named aloud the rotated object and ignored the changi ng letter display (object-attend). The other half ignored the object a nd counted the number of red Ts, and then used this number to perform a simple multiplication (object-ignore). In the test phase, all subjec ts named the rotated objects. The results showed that in the first blo ck of trials in the training phase, mean naming time in the object-att end condition increased the further an object was rotated from the upr ight. This effect of orientation for attended objects was much reduced in the later presentations of the test phase. In contrast, there was no such benefit of prior presentation observed for the naming of objec ts that had previously been ignored. Instead, a substantial orientatio n effect was shown for the naming of previously ignored objects, which was similar to the orientation effect observed for attended objects n amed in the first block. Similar results were found in Experiment 2, i n which object-attend subjects in training covertly named the objects and then performed a letter count and multiplication task. In both exp eriments, performance on the letter count and multiplication task vari ed with the angle of the ignored object. The results suggest that full attentional resources must be allocated in order for orientation-inva riant representations to be formed and used in the identification of r otated objects.