Abstract
What exactly are the “parts” that make up a whole object, and how and when do parts group? The answer we propose hinges on Emergent Features (EFs), defined as features that (1) are possessed by no individual part but that materialize only from the configuration; and that (2) make the object more salient than its parts. The Configural Superiority Effect (CSE) was used to diagnose EFs in an odd-quadrant visual discrimination task. The CSE is obtained when discrimination between two parts (e.g., a vertical line segment in one quadrant vs. a horizontal in each of the other three) is made faster by adding the same context element to each quadrant (e.g., another vertical). Such a result suggests that adding a second line segment creates EFs that are processed more quickly than are isolated segments. Previous work looking for CSEs with dot and three-line patterns has demonstrated several EFs, including orientation, proximity, and linearity. This experiment focuses on two-line configurations. A portion of the infinite, 8-dimensional space of all possible configurations of two line segments was systematically sampled by varying the x and y coordinates of the second segment, thus sweeping out a 2-dimensional plane through that space. The displays were coded to determine what EF differences arose between the odd quadrant and the other three. RTs were then mapped across this plane and were compared with RTs predicted from the number of EF differences between the odd quadrant and the other three and on the direction of those differences (present vs. absent in odd quadrant). The results show large differences in performance depending on the location of the context segment and demonstrate salient EFs including Parallelism, Connectivity, Intersections, and others.