Multiple anchoring of category rating scales

A psychophysical experiment compared the effects of two different kinds of anchoring upon category ratings of the sizes of squares: (1) single anchoring in which the same square was presented on every anchoring trial, and (2) multiple anchoring in which squares of different sizes were presented on anchoring trials. Subjects did not rate the anchors, only those squares presented on alternate trials as the series stimuli. The major finding was that the two kinds of anchoring have similar effects. As with the single anchor, the multiple anchor establishes a new endpoint for the scale of judgment. The previously demonstrated relationship of increasing and then decreasing contrast as a function of the remoteness of the single anchor (Sarris, 1967, 1976) was found also for multiple anchoring.     

Gestalt Issues in Modern Neuroscience

We present select examples of how visual phenomena can serve as tools to uncoverbrain mechanisms. Specifically, receptive field organization is proposed as a Gestalt-like neural mechanism of perceptual organization. Appropriate phenomena, such as brightness and orientation contrast, subjective contours, filling-in, and aperture-viewed motion, allow for a quantitative comparison between receptive fields and their psychophysical counterparts, perceptive fields. Phenomenology might thus be extended from the study of perceptual qualities to their transphenomenal substrates, including memory functions. In conclusion, classic issues of Gestalt psychology can now be related to modern “Gestalt psychophysics” and neuroscience.     

Max Wertheimer on seen motion: Theory and evidence

Summary Max Wertheimer, the chief founder of an experimentally based Gestalt psychology, conducted his pioneering studies in motion perception on new theoretical grounds. Since the influence of this approach may be greater in today's cognitive psychology than it has ever been during the half-century of introspectionism and radical behaviorism, it is appropriate to review the actual roots of Wertheimer's (1912) seminal publication and his continuing research on apparent and real motion perception in the light of past and recent work. Illustrative examples, especially of Wertheimer's early research, are provided in this paper. The implications of his experimentation and biopsychological theorizing are still of major interest for present psychological inquiry. Nevertheless, the need for more future systematic comparative research on motion perception must be emphasized. The Epilogue of this paper examines why important parts of Wertheimer's experimental contributions to psychology may have been underrated or neglected by many contemporary psychologists.Some of the issues dealt with here are treated at length in a three-part laudatio (Sarris, 1987a, b, 1988a). When this article was prepared for print, its original title, Max Wertheimer on Seen Motion: The Significance of Sound Experimentation for Present and Future Research, as presented at the Wertheimer Memorial Symposium, was changed to the present title. Under the present title, a brief version of this paper was presented at the APA Convention, New Orleans, Louisiana, USA, August 11–15, 1989.I am grateful for the comments and cooperative help provided by Carl F. Graumann, Michael W. von Grünau, Eckart Scheerer, and Michael Wertheimer.     

An experimental test of two mathematical models applied to the size-weight illusion.

Two quantitative models, which make different quantitative predictions for the amount of the size-weight illusion, were tested according to the psychophysical methods employed by the respective authors (magnitude estimation versus category ratings). Both models with their corresponding method were supported. This causes uncertainty over Anderson's chaim that the validity of both a model and the applied scale used is sufficiently test by the socalled joint testing procedure.     

Anchor effects and figural aftereffects: a comparative psychophysical investigation.

Perceptual contrast effect was studied from two points of view, as a special anchor effect and as a special figural aftereffect. Two experiments were conducted to investigate the influence of stimulus onset asynchrony on contrast and assimilation effects, induced and measured by different psychophysical methods. Stimuli were circular beams of light projected on screens (Delboef type of illusion). When anchor and series stimuli were shown and the latter were judged by means of a rating scale, stimulus onset asychrony had no substantial influence on the contrast effect (Exp. I). When the constant method was applied, however, the asynchrony altered the shape of the contrast effect considerably (Exp. II).