Conservation acquisition, maintenance, and generalization by mentally retarded children using equality-rule training.

To teach conservation to mildly retarded, preoperational preadolescents (9 to 12 years old), a number-representational system was used to mediate the invariance of quantity as part of "equality-rule" training. Before viewing a perceptually misleading configuration of either two equal quantities or two unequal quantities entailing the dimensions of number or length, participants learned that equality involved the assignment of two identical numbers and inequality the assignment of two different numbers. These numbers were then applied to the actual quantities and became the basis for rule statements that were rehearsed, memorized, and subject-generated each time the quantities were transformed into a new configuration. Following equality training, correct judgments and verbal justifications of conservation were high (M greater than or equal to 85%) during both immediate and delayed post-tests and for near-generalization (number and length) and far-generalization (weight, liquid substance, and solid substance) tasks. In contrast, the post-test levels of comparable participants given learning-set (LS) training, LS plus verbal-rule training (a combination of statements about identity, negation, and compensation), or no training at all were substantially and significantly lower. Equality training is of theoretical and practical interest because of its potential to teach a symbolic representational rule that directly and meaningfully articulates the quantitative properties of objects and counteracts the overreliance on task-specific and faulty perceptual cues inherent in the conservation task.     

Some perceptual and cognitive factors in mirror tracing: their limits.

Three mirror tracing experiments were conducted to investigate the connection between perception and motor behavior. In the first experiment, some subjects traced a hex-maze, other subjects traced a hex-maze after observing a model trace, others traced a hex-maze after reading instructions on mirror images, and others traced a hex-maze after having observed a model and heard the instructions. There were no significant differences between the groups' error scores, but their time scores differed significantly, although not always in the predicted direction. In Experiment 2, the subjects were to trace selected letters of the alphabet. Error scores for the second experiment did not differ much from those for the first experiment. In Experiment 3, the experimenter gave each subject commands for the correct directions of movement, using the subject's body as a frame-of-reference. There was little improvement in motor performance. These results suggest that the visual information presented in the mirror captured the subjects' attention and blocked their motor tracing program.     

Exposed eye area (EEA) in the expression of various emotions.

Exposed eye area (EEA) was measured in photographs of Indian adults who modeled six emotions--happiness, sadness, fear, anger, surprise, and disgust--as well as a neutral expression. The data were analyzed with a 2 x 6 (Eyes x Emotions) factorial analysis of covariance (ANCOVA). EEA for neutral expression was used as the covariate measure. The EEAs of the two eyes did not differ significantly during the expression of emotion. The EEAs for fear and surprise were significantly larger, and the EEA for disgust was significantly smaller than those for either other emotions or neutral expression.     

The valuing process: A study of favorite songs and the inner experience of persons diagnosed with schizophrenia

Since valuing is a process grounded in the organizational tendency of human behavior, the characteristics of a highly valued object should reflect the experience of the individual who selects it. This research compared the favorite songs of fourteen individuals diagnosed with schizophrenia to their inner experience as assessed in a standard interview. Many relationships were revealed between the two, often pertaining to important issues identified in theories of schizophrenia. Results may have therapeutic applications and shed light on processes through which psychological difficulties persist.     

Social support, depressed mood, and adjustment to stress: a genetic epidemiologic investigation.

A survey of 821 same-sex female twin pairs from a population-based registry assessed 8 dimensions of social support and social integration. Twin analyses documented significant common environmental influences on 5 of these 8 measures and significant genetic influences on 5 of the 8. A decomposition of the multiplicative association between support and a measure of stressful life experiences in predicting depressed mood--an association typically interpreted as providing evidence for a stress-buffering effect of social support--shows clearly that it is the environmental and genetic factors that cause support, rather than support itself, that buffer the effects of stress on mood in most cases. We discuss the implications of this result for future research on the relationship between social support and psychopathology.     

Coordination of knowledge in communication: effects of speakers' assumptions about what others know.

Two pairs of studies examined effects of perspective taking in communication, using a 2-stage methodology that first obtained people's estimates of the recognizability to others of specific stimuli (public figures and everyday objects) and then examined the effects of these estimates on message formulation in a referential communication task. Ss were good at estimating stimulus identifiability but were biased in the direction of their own knowledge. The amount of information in a referring expression varied inversely with the perceived likelihood that addresses could identify the target stimulus. However, effects were less strong than anticipated. Although communicators do take others' knowledge into account, the extent to which they do so involves a trade-off with other sorts of information in the communicative situation.     

Information feedback and the learning multiple-degree-of-freedom activities

The influence of information feedback on the learning of a multiple-degree-of-freedom activity, the overhand throw, was investigated. During learning, feedback was presented in the form of knowledge of results, knowledge of performance, knowledge of performance with attention-focusing cues, or knowledge of performance with error-correcting transitional information. Across 12 practice sessions, performance was assessed with respect to both throwing distance and throwing form. Subjects provided with knowledge of performance along with transitional information demonstrated significant gains in throwing distance, compared with subjects receiving knowledge of performance or knowledge of results alone. Movement form ratings followed the same trend. Providing learners with cues to focus their attention on the relevant aspects of knowledge of performance or directly providing transitional information was a better aid to the acquisition of throwing form than providing knowledge of results or knowledge of performance alone. These results support the hypothesis that knowledge of results may not be the most potent form of feedback in multiple-degree-of-freedom activities and that knowledge of performance, when combined with additional information, can lead to significant gains in skill acquisition.     

Evidence for an error deadzone in compensatory tracking

Humans and monkeys show intermittent arm movements while tracking moving targets. This intermittency has been explained by postulating either a psychological refractory period after each movement and/or an error deadzone, an area surrounding the target within which movements are not initiated. We present a technique to detect and quantify the size of this deadzone, using a compensatory tracking paradigm that distinguishes it from a psychological refractory period. An artificial deadzone of variable size was added around a visual target displayed on a computer screen. While the subject was within this area, he received visual feedback that showed him to be directly on target. The presence of this artificial deadzone could affect tracking performance only if it exceeded the size of his intrinsic deadzone. Therefore, the size of artificial deadzone at which performance began to be affected revealed the size of the intrinsic deadzone. Measured at the subjects' eye, the deadzone was found to vary between 0.06 and 0.38 degrees, depending on the tracking task and viewing conditions; on the screen, this range was 1.3 mm to 3.3 mm. It increased with increasing speed of the target, with increasing viewing distance, and when the amplitude of the movement required was reduced. However, the deadzone size was not significantly correlated with the subjects' level of performance. We conclude that an intrinsic deadzone exists during compensatory tracking, and we suggest that its size is set by a cognitive process not simply related to the difficulty of the tracking task.     

Recovery of Locomotion in Monkeys With Spinal Cord Lesions

This study reanalyzes kinematically (via film) the pre- and postoperative locomotor behavior of 4 of the 10 monkeys with partial spinal cord lesions (T8) briefly described by Eidelberg, Walden, and Nguyen (1981). The behavior of the remaining 6 monkeys is qualitatively described. The analysis reveals that 5 of the animals initially exhibited unilateral hind limb stepping. Hind and forelimb cycle durations often differed postoperatively; the hind limbs commonly showed increased values, whereas forelimb cycle durations were reduced: ipsilateral interlimb phase values were usually inconsistent. A review of prior studies of primate spinal cord lesions indicates that sparing of the ventrolateral quadrant may not be essential for locomotor recovery (cf. Eidelberg, Walden, & Nguyen, 1981). Furthermore, this review as well as the kinematic analysis indicates that primates with very significant spinal lesions can stilI exhibit locomotor movements. Thus, although the primate's spinal cord seems less able than other mammals' to readily organize locomotor movements (Eidelberg, Walden, & Nguyen, 1981), the total absence of stepping in primates with completely transected cords is unexpected and warrants further research.