Integration of shape information occurs around closed contours but not across them.

Scenery and complex objects can be reduced to a combination of shapes, so it is pertinent to examine if the integration of information found occurring around simple contours also occurs across them. Baldwin, Schmidtmann, Kingdom, and Hess (2016) investigated this idea using radial frequency (RF) patterns, distributing information around a single contour or across four contours. However, their use of a restricted number of locations for this information may have influenced their results (see Green, Dickinson, & Badcock, 2017). The current study revisits their paradigm using random-phase (spatial uncertainty) presentation of RF patterns with 11 observers. Results provide strong evidence for the integration of information around single contours but not across them. These findings are contrary to the lack of integration found by Baldwin et al. (2016) within a single contour, but do provide support for their suggestion that improvement in performance when adding information to separate RF patterns is a function of probability summation. Similar to Green et al. (2017), it suggests the importance of using random-phase RF patterns when measuring integration.