Three experiments involving a parallel-line figure are reported. In the first and second experiments, the Tolansky version of the Poggendorff illusion, apparent inexact bisection of the space between two lines by a third line, was shown to occur with both dots and lines in combination and with three dots. The effect with three dots on the parallels was as great as that with three lines intersecting the parallels. In the third experiment, a variant of the conventional Poggendorff illusion, apparent misalignment of vertical collinear lines, was also shown to occur with dot-line combinations and dots and to be as great with two dots as with two lines. The occurrence of both versions ofthe illusion to the same degree with dots on the parallels as with lines intersecting them serves to rule out explanations of apparent displacement based on changes in the apparent orientation of lines and the apparent size of angles. The Poggendorff and Tolansky effects with only dots also raises questions about explanations couched in terms of depth processing. These questions are discussed and an alternative explanation in terms of a compromise between objective and figure-relative bisection and alignment is tentatively suggested.The original version of the Poggendorff illusion in which two collinear obliques separated by a pair ofparallels appear displaced from their physical alignment is shown in Figure 1A. The upper-right oblique appears to be too high on the right parallel to be aligned with the lower-left oblique on the left parallel. This effect has been variously attributed to optically induced distortion in the region of the intersections (Chiang, 1968;Glass, 1970

Kanizsa's (1979) explanation of illusory contours in terms of amodal completion of perceptually incomplete elements was examined in five experiments by varying the elements partly delineating the corners and sides of a rectangle. The results from magnitude estimation of contour strength showed that (1) incomplete corner elements consistently resulted in stronger illusory contours than did complete elements, although contours nevertheless always occurred with the latter, (2) contours were always stronger with side elements than without but were not always reliably different in strength when the side elements were parts of an incomplete form, (3) incomplete octagons and slightly different but complete elements resulted in contours of the same strength, (4) the larger of two incomplete comer elements resulted in stronger contours, and (5) incomplete irregular elements resulted in stronger contours than did complete irregular ones, although weak contours again occurred with the latter. Together, the data do not strongly support the view that perceptual completion of incomplete figural elements is the basis of illusory contours. An alternative interpretation in terms of the spreading of induced contrast to partially delineated borders is proposed. It is suggested that apparent overlay occurring independently of perceptual completion enhances these borders and so strengthens the illusory contours.

The purpose of this paper is twofold: to highlight the increased focus on corporate governance responsibility for managing employees’ psychological health, and to present an argument for a systemic approach to prevention of occupational stress. The paper commences with a brief description of the problem posed by occupational stress as a threat to organisational effectiveness. It then discusses the types of currently observed organisational responses to this issue and the extent to which they are shaped by beliefs about occupational stress. There are two fundamental approaches to dealing with work stress, one aimed at the individual and the other, at the organisation. The more comprehensive approaches have been increasingly reported to be more effective. The argument for a systemic approach to its prevention is then developed, in line with the risk management framework currently being adopted by Government jurisdictions governing Occupational Health and Safety in Australia and New Zealand. As the stress issue is now couched in health and safety terms, it is a moral and legal duty of the Board to satisfy itself that it is effectively addressed.

An illusory contour along a partially delineated border in the form of an apparent 'outside' corner due to perspective was as strong as one along a similarly delineated border in the form of an edge due to overlay. An illusory contour along a border in the form of an apparent 'inside' corner, due probably to both perspective and overlay, was stronger than either. These outcomes suggest that apparent stratification from overlay is not necessary for the occurrence of illusory contours. They also accord with the view that apparent depth due to overlay or to perspective is equally effective in rendering partially delineated borders more prominent and, in consequence, the illusory contours that form along them stronger.

In its original form, the Morinaga illusion is the apparent misalignment of the physically aligned apexes of oppositely facing angles. Recently, the effect has been shown to occur also with similarly arranged lines, squares, and small circles (Day, Bellamy, & Norman, 1983). With larger circles similar in size to the angles, lines, and squares, the effect was negligible. The two experiments reported here were designed to ascertain whether the effect occurs with larger circles. The display, response mode, and method of measurement were different from those used earlier.The results indicate that the illusion, although small and relatively unstable, does occur with circles of about the same dimensions as the angles, lines, and squares of the earlier experiments.In Figure 1, the upper and lower angles are located on one side of a vertical axis, and the central angles on the other. Although the apexes of both sets of three angles are aligned in vertical axes, they appear to be misaligned. The upper and lower apexes in each set appear to be too far inward relative to the configuration, and the central apexes too far outward. This apparent misalignment is the Morinaga illusion in its original form (Morinaga, 1941 ;Morinaga & Ikeda , 1965).The direction of apparent misalignment in Figure 1 is opposite to that expected for the Muller-Lyer illusion of extent that is also present in the figure. The horizontal extent between the upper and lower pairs of apexes appears greater than that between the central pair. This suggests that the upper and lower apexes would appear to be displaced outward rather than inward and the central apexes inward rather than outward. Because the direction of apparent displacement from alignment does not accord with expectations for the Mliller-Lyer illusion, the effect has been referred to as the Morinaga paradox (Morinaga & Ikeda , 1965;Restle, 1976). However, it is to be noted that apparent misalignment occurs independently of the Muller-Lyer illusion ; the three apexes on one side of the figure exhibit the illusion in the absence of the three on the other side (Day , Bellamy, & Norman , 1983;Restle, 1976).In a recent investigation , Day, Bellamy, and Norman (1983) showed that the Morinaga effect also occurred when three straight lines or three squares were arranged asymmetrically on either side of an axis, as in Figure 1. With lines, the aligned end points appeared to be misaligned, and with squares , the aligned sides appeared to be misaligned. The apparent misalignment of line ends was about the same in magnitude as that of right-angleThe authors' mailing address is: Department of Psychology, Monash University, Clayton , Victo ria 3168 , Australia.> < Figure 1. The Morinaga misalignment illusion. The aligned apexes of the three angles appear to be misaligned with the central apex apparently too far outward and the upper and lower apexes too far inward relative to the figure. apexes, whereas that of the sides ofsquares was markedly less. The results with circles' were inconsistent. With relat...