Roy B. Mefferd

Repetitive psychometric measures: handedness and performance

Many investigators have reported that right-handed people perform most motor tasks better, faster, and with relatively fewer errors than do the left-handed. We found slight differences in performance on only three of the tests of the Repetitive Psychometric Measures battery—SO, SC, and FC. Some of the difference in performance may be alleviated by minor changes in instruction for left-handed Ss.

Systematic Alterations of the Apparent Centers of Lines.

Predictable stimulus-bound alterations in the apparent centers of lines were used to discriminate behavioral differences in bisection. 2 dimensions of individual differences were demonstrated in bisection that appeared to be related to cognitive control mechanisms: the well-known basic tendency for the upper segment of lines to be overestimated, and the relative influence on the apparent centers exerted by the stimulus-effects. The roles on these of minor modifications in the stimulus and of secondary factors such as practice, eye and hand dominance, sex, etc., were examined. A more basic effect was noted when the lines were bisected in a horizontal orientation—there was almost no correlation between Ss performance with vertical vs horizontal lines. Even though the two main effects noted above were still present, their measures did not correlate with those of the vertical bisection. The implications of this are discussed.

Perception of depth in rotating objects: 4. Fluctuating stereokinetic perceptual variants.

There are a variety of stereokinetic percepts that fluctuate suddenly and unpredictably. On first viewing their sequence is predictable (Phase 1), but later it becomes unpredictable (Phase 2). A given percept results from the interplay of three independent visual systems: (1) the near-far mechanism (perspective reversals), (2) the one object-multiple object mechanism (degree of perceptual organization), and (3) the anchor point mechanism (apparent location of the axis of rotation). It was hypothesized that these fluctuating phenomena result from the operation of a basic system for repetitively sampling and pre-processing information on orientation, perceptual organization, and location of the axis of rotation and that a steady-state apparent-depth mechanism stabilizes the systems.

PERCEPTION OF DEPTH IN ROTATING OBJECTS: 1. STEREOKINESIS AND THE VERTICAL-HORIZONTAL ILLUSION

Os viewed under extreme reduction conditions either a rod or an ellipse as it rotated slowly (5 rpm) in the frontoparallel plane. They reported seeing a sequence of percepts of the luminous stimulus starting with veridical rotation, then expansion-contraction, and/or advance-retreat and finally ending with apparent rotation in a plane oblique to O. The percepts were the same with either monocular or binocular regard and with the head tilted 90° to the side. In the latter case, the apparent plane of rotation shifted with the head position showing that the visual field determined the effect. This stereo-kinetic effect was related to the vertical-horizontal illusion and was explained in terms of the asymmetry of the visual field.

Influence of early formal reading training on commonality of word associations in children and adults

Commonalities of word associations of children and adults were examined as a function of the elementary school grade level at which the words are formally introduced in reading training. Word introduction was found to produce associative changes in children which were reflected in the associations of adults.

FLUCTUATIONS IN PERCEPTUAL ORGANIZATION AND ORIENTATION AND PERCEPTION OF APPARENT MOVEMENT

Three main percepts of a static flat stimulus were reported, one veridical and two with apparent internal depth but which varied in the degree of perceptual organization. In one of these, the entire stimulus formed a single perceptual unit which “reversed” perspective as a unit in a fashion similar to a Necker cube. This percept elicited no reports of apparent movement, but the other percept did. In the latter, the offset central section formed one perceptual unit that was blurred, and the sharp, distinct parts on either side of it formed another unit. The central unit underwent figure-ground reversals, while the adjacent slats of both elements “changed” orientation independently. The changes in apparent position accompanying the latter fluctuations were often perceived as being due to movement of the central section in the frontal plane.

Perceptual fluctuations involving orientation and organization.

Fluctuations in perceptual organization of stimuli (three drawings) were compared with those involving depth (i.e., perspective reversals of a Necker cube). Both types of fluctuations occurred apparently in exactly the same fashion even though each had different consequences for the percept. It was suggested that the fluctuations are the result of the mode of operation of a basic system for processing optical data.

The differentiation of escape and avoidance behavior in two thalamic areas in the cat

Abstract Four cats were trained to hurdle a barrier to avoid a grid shock. When either electrode of a pair, one positioned in the nucleus centralis medialis (NCM) and the other in a lateral (VPL) nucleus of the thalamus, were used to stimulate these nuclei for the first time after the grid training all cats responded with avoidance. Repeated stimulation of the NCM led to increases in the rate of avoidance, but the converse happened with the VPL nucleus. Extinction and retraining first with one, then the other of the electrodes in all cats established that this effect was general. The results demonstrate that specific sensory nuclei (represented by the VPL nucleus) provide only cue function while nonspecific nuclei (i.e., the NCM) provide both cue and response maintenance functions.

ORDER EFFECTS IN CONCOMITANT ATTRIBUTE JUDGMENTS (SHAPE AND SIZE)

This experiment was designed to determine whether judgment of one stimulus attribute would exert an influence on the judgment of a second attribute as a function of the relative phenomenal strength of the two attributes. One group of Ss was instructed to judge the apparent shape of a Necker cube and then to judge the apparent relative size of its two faces. Another group made the size-judgment first, then the shape-judgment. For most Ss, the two judgments were not independent and were influenced by which of the attributes was judged first.

Multiple Development in one Dimension of Thin-Layer Chromatograms of Urinary Amino Acids

Abstract Multiple development in the same direction of thin-layer cellulose chromatograms with n-butanol-acetic acid-water (60:20:20) yielded resolution of 20 ninhydrin-positive spots. The resulting spots were quantitatively estimated by visual comparison with standards.