Bertamini Marco, Helmy Mai Salah, Hulleman Johan
Department of Experimental of Psychology, University of Liverpool, Liverpool L69 7ZA, UK.
Q J Exp Psychol (Hove). 2013;66(4):767-85. doi: 10.1080/17470218.2012.717953. Epub 2012 Sep 17.
Visual perception of shape is affected by coding of local convexities and concavities. For instance, a recent study reported that deviations from symmetry carried by convexities were easier to detect than deviations carried by concavities. We removed some confounds and extended this work from a detection of reflection of a contour (i.e., bilateral symmetry), to a detection of repetition of a contour (i.e., translational symmetry). We tested whether any convexity advantage is specific to bilateral symmetry in a two-interval (Experiment 1) and a single-interval (Experiment 2) detection task. In both, we found a convexity advantage only for repetition. When we removed the need to choose which region of the contour to monitor (Experiment 3) the effect disappeared. In a second series of studies, we again used shapes with multiple convex or concave features. Participants performed a change detection task in which only one of the features could change. We did not find any evidence that convexities are special in visual short-term memory, when the to-be-remembered features only changed shape (Experiment 4), when they changed shape and changed from concave to convex and vice versa (Experiment 5), or when these conditions were mixed (Experiment 6). We did find a small advantage for coding convexity as well as concavity over an isolated (and thus ambiguous) contour. The latter is consistent with the known effect of closure on processing of shape. We conclude that convexity plays a role in many perceptual tasks but that it does not have a basic encoding advantage over concavity.
形状的视觉感知受局部凸凹编码的影响。例如，最近一项研究报告称，凸度所携带的对称性偏差比凹度所携带的偏差更容易被检测到。我们消除了一些混淆因素，并将这项工作从轮廓反射（即双侧对称）的检测扩展到轮廓重复（即平移对称）的检测。我们在双间隔（实验1）和单间隔（实验2）检测任务中测试了凸度优势是否特定于双侧对称。在这两个实验中，我们发现仅在重复情况下存在凸度优势。当我们消除选择监测轮廓哪个区域的需求时（实验3），这种效应消失了。在第二项研究系列中，我们再次使用具有多个凸或凹特征的形状。参与者执行了一个变化检测任务，其中只有一个特征可以改变。当要记忆的特征仅改变形状时（实验4）、当它们改变形状并从凹变为凸或反之亦然时（实验5），或者当这些条件混合时（实验6），我们没有发现任何证据表明凸度在视觉短期记忆中具有特殊性。我们确实发现，与孤立（因此模糊）的轮廓相比，编码凸度和凹度具有小的优势。后者与闭合对形状处理的已知效应一致。我们得出结论，凸度在许多感知任务中起作用，但它相对于凹度没有基本的编码优势。
