Abstract
Infant looking-time results (Spelke, 1994) have shown that pre-verbal infants grasp the continuity principle (i.e. that objects cannot pop in and out of existence) and the solidity principle (i.e. that solid objects cannot pass through one-another) from around 3 months of age. Early theories assimilated both by treating solidity as resulting from a single, general principle of object continuity. However, more recent work on primates and older children (Santos, 2004; Keen, 2003) has suggested that children and primates have a greater mastery over continuity than solidity in action-based tasks. One potential explanation for this is that the vision/action system places a higher priority on continuity than solidity in object tracking. Here we tested this hypothesis directly using a novel object detection task. Adult participants viewed short videos depicting an object rolling behind one or two occluding screens. The occluding screen(s) then dropped, revealing the ball in a location either indicative of a continuity/solidity violation or non-violation, and participants were required to indicate the location in which they perceived the ball via keypress within 750ms. Participants were tested in one of two learning conditions: a 75% non-violation condition or a 75% violation condition. Across three experiments, we observed (consistent with our original hypothesis): (1) A larger decrease in accuracy for violations relative to non-violations in the continuity than solidity condition. (2) A consistent three-way interaction between learning condition, physical principle (solidity vs. continuity), and violation. This three-way interaction resulted from the fact that in the 75% violation condition, participants learned to overturn solidity but not continuity based anticipations. Taken together these findings suggest that the visual system indeed places a higher priority on object continuity than solidity, and so offer a potential explanation for some puzzling developmental results.
Meeting abstract presented at VSS 2015