Memory for objects and parts

Performance on whole comparisons of two whole objects was compared to that for partial comparisons of a whole object and a part. In particular,same-different comparisons were measured for sequential displays of two-dimensional line figures. The comparisons were analogous to those in the word priority paradigm (Johnson, 1975). The whole comparisons were found to be more accurate and faster than the partial comparisons. This whole advantage was also found for accuracy using a two-alternative forced-choice procedure. This effect was found for brief displays of a single object and for longer duration displays of two objects. It was also found for three different sets of line figures. In contrast, the whole advantage was not found for unconnected figures. These findings were interpreted in the context of hierarchical representations of objects and parts.     

Glycosylated hemoglobin and psychological adjustment in adolescents with diabetes

The relationships between glycosylated hemoglobin levels as an index of metabolic control, life events occurring in the previous year, and general adjustment in the areas of attitude towards diabetes, independence, peer, school, and family relationships were investigated in 37 adolescents with insulin-dependent diabetes mellitus. The number or type of life events did not show a relationship with metabolic control. As measured by the Sullivan Diabetic Adjustment Scale, diabetic adolescents who were in better metabolic control reported more conflict regarding family relationships and issues of independence than did those in lesser control.     

Eye dominance in a reading clinic population.

Eye dominance tests (24 comparisons) varied markedly in aggreement with each other for 225 consecutive screening evaluation (5 yr. to 55 yr.) in a reading clinic.     

An intelligent experimental station controller for human experimental psychology

The purpose of this paper is to describe the intelligent experimental station controller used in the extensible multiprogramming system for experimental psychology (EMPP) at the University of Washington. The EMPP system is an integrated hardware and software system designed to simplify the development of on-line psychological experiments. An intelligent graphics control system is one of the most important aspects of the system. The controller oversees the operation of eight independent experimental stations, each containing a cathode ray tube (CRT) terminal and a keyboard console. In addition to conventional computer interface functions, the controller contains an extensible hardware character generator which allows dynamic selection of the display character set. This paper describes both the hardware and software features of the system.     

Mechanisms of displacement discrimination with and without perceived movement

A nearby visual reference point improves displacement discrimination. This effect occurs regardless of the delay between successive displays. The delay can be varied from short delays (50 ms), where observers report perceived movement, to long delays (2,000 ms), where observers report no movement. The similarity of reference effects for such different delay conditions was investigated by testing the independence of reference and delay effects. The critical independence property is whether the spatial variables (displacement and separation from the visual reference) combine independently of the temporal variable (delay). This kind of independence did not hold for displacement discrimination at delays of 50 ms and 2,000 ms. A further experiment tested for the independence property at delays of 500 ms and 4,000 ms, where observers reported no perceived movement. For these longer delays, the property was satisfied. These results are discussed using the general concept of a psychophysical mechanism. Such a mechanism combines the effects of several stimulus variables into a single mediating representation. By this analysis, at least two mechanisms must mediate the reference effect on displacement discrimination, one for delays of 200 ms and less and another for delays of 500 ms and more.     

Structural aspects of visual similarity

The hypothesis that visual representations for lines and/or points are independent structural units was tested using similarity judgment and speeded discrimination for pairs of six-segment letter-like figures. The stimuli were constructed such that each of two comparison figures had five segments in common with a standard figure. One figure was similar to the standard in its higher order structure (connectedness and closedness properties), whereas the other differed. The results show that the figures with similar higher order structure were systematically judged more similar to the standard than the figures with different structure. The former were also more difficult to discriminate from standards than the latter, as indicated by both time and error measurements. These effects were less pronounced in sequential than in simultaneous comparisons.     

What makes triangles point: Local and global effects in configurations of ambiguous triangles

Perceived pointing of ambiguous triangles was investigated in three experiments. The results show that the probability of seeing an equilateral triangle point in a given direction is strongly influenced by (a) the direction of the ambiguous alternatives, (b) the orientational characteristics of the configuration of elements surrounding the triangle, and (c) the shape of the surrounding elements. These findings are interpreted as supporting the hypothesis that perceived pointing is determined by perceptual reference frames induced at multiple levels of globality: one for the general visual field, one for the entire configuration, and one for the local elements of the configuration.     

Grounding the figure: Surface attachment influences figure-ground organization

We investigated whether the lower region effect on figure-ground organization (Vecera, Vogel, & Woodman, 2002) would generalize to contextual depth planes in vertical orientations, as is predicted by a theoretical analysis based on the ecological statistics of edges arising from objects that are attached to surfaces of support. Observers viewed left/right ambiguous figure-ground displays that occluded middle sections of four types of contextual inducers: two types of attached, receding, vertical planes (walls) that used linear perspective and/or texture gradients to induce perceived depth and two types of similar trapezoidal control figures that used either uniform color or random texture to reduce or eliminate perceived depth. The results showed a reliable bias toward seeing as “figure” the side of the figure-ground display that was attached to the receding depth plane, but no such bias for the corresponding side in either of the control conditions. The results are interpreted as being consistent with the attachment hypothesis that the lower region cue to figure-ground organization results from ecological biases in edge interpretation that arise when objects are attached to supporting surfaces in the terrestrial gravitational field.