Staying in bounds: A critical role of closure for object files

Abstract

As we move around the world, and the world around us, we must continually track objects as being the same entities from one moment to the next. But, over what sorts of entities can such ‘object persistence’ be computed? Previous work with adults and infants has shown that one of the most important principles for determining objecthood is cohesion: objects must have and maintain a unified boundary. For example, rarely do real objects suddenly split in two. But what happens if that boundary does not exist in the first place? Here we directly explore one particular aspect of cohesion; the role of closure: must objects have a continuous, single boundary? We examined this by contrasting objects defined by illusory contours (i.e., a Kanizsa square) with objects defined by physical contours. While both conditions involve subjective objects, only one adheres to the principle of closure. We explored the effects of closure on ‘object file’ representations by measuring ‘object specific preview benefits’ (OSPBs) wherein a preview of information on an object leads to a speeded response when that information later reappears on the same object (compared to when it reappears on a different object), beyond display-wide priming. A significant OSPB was found for objects defined by physical contours, but not for objects defined by illusory contours (and the conditions were significantly different from one another). This suggests that closure, per se, may play an especially important role in object persistence.