Abstract
Figure assignment arises from competition for ownership of an edge. Cues on the same side of an edge cooperate; cues on opposite sides compete. The time taken to determine figure assignment increases as the competition increases. Past experience is among the relevant figural cues (e.g., Peterson et al., 1991). Peterson and Lampignano(2003) found that a single view of a novel shape is sufficient for past experience to enter into the cross-edge competition when the edge is next seen. Their observers decided whether two small closed shapes shown one above another on prime trials were the same or different. The shapes had 1 complex vertical edge and 3 straight edges. On experimental probe trials, the complex edge was repeated from one of the prime shapes, but now, the small, closed shape lay on the opposite side of the complex edge. For control probe trials, a novel complex edge was used. Responses times were longer for experimental than control probe trials, reflecting competition from memory for where the figure lay relative to the edge on prime trials. We report experiments testing whether competition from past experience is evident if just a portion of a complex edge is repeated on probe trials. In Exp. 1 observers viewed two prime shapes and made a same-different response. On the next, probe trial they performed the same task with shapes half as tall as the prime shapes. On experimental trials, either the top or the bottom half of the prime's complex edge was repeated; on control trials, novel edges were used. Results showed that competition from these partial configurations affected figure assignment, p < .01. Exp. 2 was a conceptual replication of Exp. 1, p < .05. Now, on the prime trial a single shape was briefly presented and required no responses from observers. These results indicate that past experience effects are mediated by partial configurations, not holistic structural descriptions.