Development of binocular fixation in human infants

Two experiments measured changes in binocular eye alignment from 1- to 6-month-old human infants. In Experiment 1 changes in binocular eye alignment were recorded from 1, 2, and 3 month olds using corneal photography. A luminous target was moved along the infant's midline at one of two constant speeds. Infants at all three ages showed some evidence of appropriate changes in binocular eye alignment (convergence as the target approached and divergence as the target receded). The likelihood of appropriate convergence and divergence increased with age, as did the ability to respond appropriately to the faster target motion. A measure of convergence lag (further decrease in interpupillary distance after target motion had ended) was obtained for trials on which the target approached the infant. Convergence lag decreased with age and was greater on trials at the faster target speed until 3 months of age. Experiment 2 measured the responses of 3, $\text{4}\text{1}\text{2}$, and 6 month olds as a wedge prism was placed alternately in front of each eye. The prism displaced the image nasally (either 2.5° or 5°), creating inappropriate binocular eye alignment. A refixation eye movement in response to the prism was not present consistently until 6 months of age. Hypotheses as to the mechanism controlling infant binocular eye alignment are discussed with respect both to the present findings and to findings from human adults and animals.     

Differences in the search rate of children and adults in short-term memory

When people recognize a test item as belonging or not belonging to a previously presented set, recognition latency increases with the number of items in the set. Although some evidence suggests otherwise, it is currently held that the rate of this increase is the same for children and adults. In contrast, the present experiments indicated a much slower search rate for second graders (mean age = 7.33 years) than for seventh (mean age = 12.50 years) and twelfth graders (mean age = 17.25 years). Moreover, search rate for second graders was invariant under instructions which did or did not emphasize speed and with presentation of the memory set in either the auditory or visual modality. Experiment II showed that the slow search rate for children was not due to differences in encoding between children and adults.     

Visual-feature and response components in a picture-word interference task with beginning and skilled readers

A series of four experiments is reported in which reaction times for naming line drawings were analyzed as a function of the similarity of the print superimposed on the drawings to the printed label for the drawing. This effect was studied as a function of grade level (ages 6, 8, and 11 years) and, hence, reading experience. The studies were designed to determine more precisely the characteristics of the stage of visual feature analysis of word identification and to examine response competition factors in this interference task. Results indicated that a combination of end letters and word shape was important for word identification and that response articulation was a significant distinct interference component in this task.     

Introtacts as predictors of discrimination performance in kindergarten children

Kindergarten children were given simultaneous discrimination tasks with two irrelevant dimensions varying within settings. Prior to each block of eight feed-back trials, the children were asked to attempt to provide a statement of the solution. The introtacts thus provided were found to have several of the desirable characteristics that have been reported for older children with either introtact or blank-trial probes, but which have not been found previously for kindergarten children with the blank-trial probe. Classification of the children according to the trial block on which they first verbalized the correct relevant dimension was found to account for more than 60% of the total variability in discrimination performance. The introtacts were also used to assign parameters to theoretical prediction equations, with nearly two-thirds of the total variability in discrimination performance accounted for by the theory. Extension of the method to other models is discussed.     

Effects of differential reinforcement and task difficulty on preschoolers' compliance with teacher instructions

Preschool children in day schools were given instructions to complete certain tasks. Four tasks were given of two types and two levels of difficulty. In each condition compliance with at most one instruction (one task) was reinforced. In two similar experiments, with six children, general results were: compliance with easy tasks was maintained without reinforcement when any task compliance was reinforced; compliance for hard tasks remained high only when that specific task was reinforced. Thus, generalization of compliance with instructions varied with task difficulty. The setting and procedure for both studies were designed to reduce possible coercive features of laboratory studies of generalized performance. Results show generalized performance can occur under naturalistic conditions. The effect of effort, as a response characteristic affecting generalized performance, is discussed.     

Children's strategies in producing three-dimensional relationships on a two-dimensional surface

It is a common task to give children a picture containing implicit depth cues and to require them to extract depth information from it. The cues are always selected from the adult repertoire; little is known about children's production of their own cues. In this experiment, 5- to 10-year-old children were required to draw one object behind another in a situation in which adults invariably produce the further object partially occluded by the nearer. The results were an age-related decline in the tendency to segregate the objects and an increase in the tendency to group the objects using partial occlusion, with a cross-over at 8 years. At all ages some children drew one object inside the boundary of the other. It is argued that the results are composed of two tendencies, a gradual mastery of discrete scaling phenomena (e.g., “up” on the page means “further”) within a given style, and a set of decisions to be made between incompatible styles.     

On the ethics of psychological research

Three philosophical positions on the nature of ethics were examined and contrasted within the context of psychological research: (a) teleology, which involves the balancing of the costs and benefits associated with an action as a means of developing general ethical rules; (b) deontology, which involves the rational adherence to rigid, universal rules that hold irrespective of the situation or consequences; and (c) skepticism, which involves denying the ability to apply universal rules and asserting the individuality of moral codes. Two experiments investigated the degree to which judgments of the ethicality of psychological research are affected by the consequences of the research and judge's ethical ideology. Subjects judged experiments that investigated obedience to an authority as generally less moral and more threatening to the participants' dignity and welfare when the proportion of total obedience was high rather than low. The proportion of participants (10 vs 40%) who were described as “psychologically upset” by the research did not affect moral judgments. These results were obtained across two different obedience situations (Milgram's study and a Watergate study) and different subject populations (high school and college students, males and females). As suggested by philosophers, a judge's ethical ideology determined how the perceived benefits and costs of the research were correlated with moral judgments. Teleologists weighed scientific benefits heavily, deontologists weighed participants' costs heavily, and skeptics weighed both heavily.     

Figural emphasis and person perception

Based on Jones and Nisbett's (1972) proposition that actor-observer differences in causal attributions derive from differences in attentional focus, it was hypothesized that observers' focus of attention would influence their causal attributions for an actor's behavior. More specifically, it was predicted that the behavior of an actor who was the focus of attention by virtue of some salient physical attribute would be attributed by observers more to dispositional causes and less to situational causes than would the behavior of a less physically salient actor. The manipulations of physical salience were based upon Gestalt laws of figural emphasis in object perception. They included brightness (Study I), motion (Study II), pattern complexity (Study III), and contextual novelty (Studies IV and V). The results revealed that the salinece of the actors' environments (i.e., the other people present) rather than the salience of the actor him/herself had the most consistent influence on causal attributions. When environmental salience was high, behavior was attributed relatively more situationally than when it was low. Prior research findings are considered in light of the proposition that causal attributions for an actor's behavior vary only with the salience of his/her environment, and additional implications of this phenomenon are suggested. Some ambiguities in the application of Gestalt principles to the perception of people are discussed.     

Perceived objectivity and the effects of evaluative reinforcement upon compliance and self-evaluation in blacks

Two experiments were conducted to investigate the effects of positive and negative reinforcements upon black college students. In the first experiment subjects received either positive or negative reinforcement from a black or a white Evaluator. Behavioral change (compliance) was greater in response to negative reinforcement from a black Evaluator than in response to negative reinforcement from a white Evaluator, while there were no divergent effects of Evaluator's Race upon compliance with positive reinforcement. The same pattern obtained in subjects' self-evaluations. The second experiment offered a test of the hypothesis that the objectivity of black Evaluators was perceived as greater than that of white Evaluators, and that a manipulation aimed at equating the Evaluators on objectivity would attenuate the effects of Evaluator's Race upon compliance and self-evaluation in response to negative reinforcement. These hypotheses were generally supported by the results.     

Control of responding by location of auditory stimuli: adjacency of sound and response.

Four rhesus monkeys were trained to respond on one key when a one-second noise burst was presented through one speaker and to respond on a second key when the noise burst was presented through a second speaker. The acquisition of stimulus control was studied under three conditions, in each of which the relationship between the sound source and the response-key positions varied: an adjacent condition in which the noise burst was presented through the key and a response on this key was reinforced; a reversed-adjacent condition in which the noise burst was presented through one key and responding on the other key was reinforced: and a nonadiacent condition in which responding on the key nearer the sound was reinforced. Under adjacent conditions, stimulus control developed within one or two sessions. Under reversed and nonadjacent conditions, 10 sessions were required for the development of control. The asymptote of correct responding was the same under each condition in all animals.