View sensitivity increases for same-shape matches if mismatches show pairs of more similar shapes

Lawson, Bülthoff, and Dumbell (2003) found increased view sensitivity when more similar shapes had to be discriminated. Their sequential picture-picture matching studies showed depth-rotated views of novel, complex, 3-D objects. However, with a similar task and stimuli, Hayward and Williams (2000) found no variation in view sensitivity on same-shape match trials depending on whether similar or dissimilar pairs of shapes were shown on mismatch trials. Thus view sensitivity increases from dissimilar-shape mismatches to similar-shape mismatches to same-shape matches (Lawson et al., 2003). However, view sensitivity may not increase on same-shape matches if those trials are combined with similar-rather than dissimilar-shape mismatches (Hayward & Williams, 2000). The latter result was reexamined here. Matches were view sensitive given even the dissimilar-shape mismatch context. This view sensitivity increased in the medium and especially the hard contexts that showed similar shapes on mismatches. Thus, indirectly increasing shape similarity via mismatch context modulated view-change effects (cf. Hayward & Williams, 2000).