Antonucci G, Fanzon D, Spinelli D, Zoccolotti P
Institute of Psychology, University of Cagliari, Italy.
Perception. 1995;24(10):1119-30. doi: 10.1068/p241119.
In two studies the effect of the distance between the tip of the rod and the frame sides (gap) in the rod-and-frame (RF) illusion was examined and the effect of a full-square condition was compared with that of two different frame amputations. In both studies, there were more rod-setting errors in the direction of the tilt of the inducing figure with a small gap than with a large one. These findings are consistent with the idea that in the case of small gap size local interactions contribute to determining the RF illusion. The actual length of the rod was varied in order to keep the gap constant across different frame tilts; therefore these findings cannot be due to the co-variation between gap size and frame tilt which is typical of standard apparatuses. The effect of frame amputations was compared to the full-square condition. According to Wenderoth and Beh, amputations that maintain the two orthogonal contours of the square produce the typical angular function of the RF illusion. This prediction was confirmed in both studies. However, results indicate that the full square has a stronger illusory effect in the case of a small degree of tilt of the inducing stimulus, irrespective of gap size. It is suggested that this 'square superiority' effect is related to global, not local, mechanisms. To pursue Wenderoth and Beh's observations, amputations close to the vertical meridian were used in one experiment and those close to the horizontal meridian in the second experiment. Contrary to predictions, these conditions produced overlapping results.
在两项研究中，对杆框（RF）错觉中杆尖与框架边缘之间的距离（间隙）的影响进行了检验，并将全正方形条件的影响与两种不同框架截断的影响进行了比较。在两项研究中，间隙较小时，诱导图形倾斜方向上的杆设置误差比间隙较大时更多。这些发现与以下观点一致，即在间隙尺寸较小的情况下，局部相互作用有助于确定RF错觉。改变杆的实际长度，以便在不同的框架倾斜度下保持间隙恒定；因此，这些发现不可能归因于间隙尺寸与框架倾斜度之间的协变，而这在标准仪器中是典型的。将框架截断的影响与全正方形条件进行了比较。根据温德罗斯和贝赫的观点，保持正方形两条正交轮廓的截断会产生RF错觉的典型角度函数。这一预测在两项研究中均得到证实。然而，结果表明，无论间隙大小如何，在诱导刺激倾斜度较小的情况下，全正方形具有更强的错觉效应。有人认为，这种“正方形优势”效应与全局而非局部机制有关。为了探究温德罗斯和贝赫的观察结果，在一项实验中使用了靠近垂直子午线的截断，在第二项实验中使用了靠近水平子午线的截断。与预测相反，这些条件产生了重叠的结果。
