Text representations as reflected in patterns of cognitive distance

Subjects performed a task that involved learning a text and then indicating, for each of a series of pairs of words, whether they belonged to the same sentence of that text. When the principle of argument overlap or causal coherence was the sole integrative factor in a text, negative response times and error rates reflected distances in the network representation predicted by the principle. When the two principles predicted conflicting representations for a text, response times and error rates reflected the predictions of the principle of argument overlap. The results were interpreted as suggesting that network connections predicted by the two principles are both present in the memory representations of texts and that causal connections are recorded at a more abstract level of representation than are argument overlap connections.     

A procedure for the computerized representation and presentation of rotated and reflected stimuli

Psychological experiments in mental rotation and pattern recognition often require the presentation of stimuli in a variety of different orientations. Traditionally these stimuli have been presented with a tachistoscope; however, there are several advantages to using a system that presents such stimuli on a microcomputer. Unfortunately, in a typical experiment of this type, stimuli are presented after several different rotations, reflections, and translations, making the computerized representation of all the different permutations time- and memory-consuming. This paper describes a method of representation, utilizing a modified polar coordinate system, which allows for the efficient storage and transformation of such stimuli.     

Goodness of regularity in dot patterns: global symmetry, local symmetry, and their interactions

Goodness is a classic Gestalt notion defined as salience or perceptual strength of a given pattern. All operational models of goodness have assigned a central role to mirror symmetry but not much attention has been paid to the distinction between global and local mirror symmetry, and their possible interactions. We designed eight different types of dot patterns (all consisting of 80 dots), combining different numbers (0, 1, and 2) and relative orientations (parallel or orthogonal to each other) of local and global axes of symmetry (affecting 50% or 100% of the dots, respectively) at different absolute orientations (vertical and horizontal). Each of 640 trials consisted of a short presentation of a new dot pattern, which subjects had to classify as regular or random. We hypothesised that the overall goodness of patterns is not the simple sum of the amount of regularity present in them but depends on the cooperation and competition between symmetries. The results confirmed our hypothesis, showing that performance in this regularity-detection task did not increase in a linear way when some symmetries were added to other symmetries.     

Visual acuity in children as a function of hue

Ninety-six suburban school children, 7 to 14 years old, were tested, with colored parallel bars as acuity targets, to assess relative effects of hue, age, and intelligence on visual acuity. The main effects of color and age were found to be significant but with no significant interaction. A one-way analysis of variance for each color indicated blue and black acuity improved with age while red did not. Since natural myopia for blue light may have accounted for the effect with blue, a second experiment was undertaken with focusing being introduced as a variable. Focusing eliminated the effect of age, but the color effect remained significant. Lowest resolution thresholds were obtained with black, next red, and blue highest. There was no relationship between acuity and intelligence nor were there any sex differences.     

The role of axes of elongation and symmetry in rotated object naming

Many theorists have postulated that axes of elongation and/or symmetry play an important role in the recognition of objects. In this paper, evidence is presented that mitigates this claim from independent assessments of the effects of axes of elongation or symmetry on the time to name rotated line drawings of common objects. This conclusion was further supported in a stronger test in which both of these variables were orthogonally controlled, the aspect ratio of elongation was manipulated,and only objects that were completely geometrically symmetrical or asymmetrical were used. In all the experiments, objects were named for several blocks to determine the influence of these variables on effects of orientation with practice. Symmetry was found to diminish the effects of orientation after practice in naming the object set, and the effects of the most extreme orientation tested (120 degrees from upright) were diminished when both axes defined the same orientation, relative to when they defined different orientations. Contrary to many theories, these findings relegate the axes of symmetry and elongation to relatively minor roles during object identification.     

Detection of symmetry as a function of angular orientation.

Subjects decided as quickly as possible whether dot patterns were or were not symmetrical about a line. Their decision times were shorter when the line was verticle and increased as the angle between the line and the verticle increased. This orientation function was essentially the same whether or not the subjects knew in advance what the orientation of the line would be. When the subjects tilted their heads, the function shifted in the direction of the head tilt, indicating that it was tied more closely to retinal than to gravitational coordinates. These data can be interpreted to mean that people mentally rotate patterns to a vertical orientation before judging their symmetry. This in turn suggests that the "template" for detecting symmetry may itself be embedded symmetrically in the brain.     

Challenge-control interaction as reflected in sympathetic-adrenal and pituitary-adrenal activity: comparison between the sexes

The relative sensitivity of the sympathetic-adrenal and pituitary-adrenal systems to different psychosocial demands is considered on the basis of experimental data. It is concluded that positive and negative aspects of psychological arousal ("effort" and "distress") are differentially associated with the activity of each of the two systems, effort being related primarily to catecholamine secretion, distress primarily to cortisol secretion. Data are presented to illustrate the role of personal control as a major modulating factor. Controllability tends to reduce the negative aspects and enhance the positive aspects of arousal, thereby changing the balance between sympathetic-adrenal and pituitary-adrenal activity. The neuroendocrine pattern is the same for males and females, but there is a consistent sex difference in that females are less prone than males to respond to achievement demands by increased catecholamine secretion. The relative influence of biological and social factors on this sex difference in reactivity is discussed.     

Visual recognition as a function of stimulus offset asynchrony and duration

The stimuli consisted of two complementary dot patterns that formed a bigram when they were flashed simultaneously; impairment of letter recognition developed when one of the patterns was briefly extended beyond the termination of the other (stimulus offset asynchrony). However, if the ratio of stimulus offset asynchrony to bigram duration remained constant, the probability of a correct recognition response also remained constant as duration varied over a 50- to 100-msec interval. When percent stimulus asynchrony increased, the impairment increased. An interaction between bigram letter position and each of bigram duration and percent stimulus asynchrony was observed with recognition accuracy greater in general for the letter in the left half of the field.