The effect of object alignment on the representation of depth in young children's drawings.

Light and Humphreys (1981, Journal of Experimental Child Psychology, 31, 521-530) provided evidence that young children's drawings, despite infrequently showing view-specific occlusion, do systematically reflect spatial relations within an array. The present research tested the hypothesis that young children's preferences for canonical "best views" interact with array-faithful tendencies to increase early uses of occlusion. Forty-three children between 4 and 7 years of age drew arrays like Light and Humphreys' end-to-end alignments, with end-on views of objects in depth, and arrays aligned side-to-side, with canonical side-views of objects in depth. Significantly fewer single-object, view-specific occlusions were produced for end-to-end than for side-to-side alignments. Nevertheless, the former reveal that more children are able to use the vertical dimension to depict multiple objects in depth. Other comparisons suggest an interaction in multiple-object depictions of canonicality with spatial dimension and graphic complexity.     

Difference and ratio information in children's and adults' memory representations.

A study was made of the choice reaction times of 8-, 10-, 12-year-olds and adults in order to investigate whether length information stored in memory was coded to preserve numerical relations between stimuli. Subjects learned unique line length-color associations and were later presented with pairs of colors and were instructed to choose the color that had been associated with the longer line. For all age groups, choice reaction times were related to both differences and ratios. These results were interpreted as supporting the analog theory of representation.     

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.     

Effects of Response Set on the Infrequent Response Index of the Strong Interest Inventory

Associations of two different response sets on the Infrequent Response Index of the Strong Interest Inventory (SII) were examined. In one, participants responded to each item randomly; in the other, participants deliberately misrepresented their responses. The finding of scores higher than those proposed in the SII manual for the Infrequent Response Index suggests an alternative interpretation of this critical index.     

Career Aspirations of Pregnant Teens

This study examined the career aspirations of pregnant teens enrolled in a program designed to minimize their chances of dropping out of high school. The teens completed a demographic data form that included questions on their career aspirations. The data were coded by Holland type using the Dictionary of Holland Occupational Codes. Trends were discussed in light of the future labor market and critical need for career counseling for this at-risk population.     

An "Epidemic" Model of Adolescent Cigarette Smoking

The prevalence of regular smoking increases rapidly during adolescence. We applied modeling methods from the study of epidemic infectious disease to smoking behavior. Our "epidemic" models dealt with the process of transition among four states: nonsmoker (susceptible), trier (exposed), regular smoker (infected), and ex-smoker (recovered). The best fitting model was one in which the transition from nonsmoker to trier was a social contagion process where nonsmokers contacted either triers or regular smokers. All other transitions were treated as constant rate processes in which a constant proportion of eligible individuals made the transition in a given year. The recursive equation model embodying these assumptions was able to predict accurately the proportion of adolescents in each state in Grades 6–11. Our results support a "stage" model of smoking, suggesting that different psychological and physiological processes are involved in the initiation of smoking than in developing a habit of regular smoking. A possible sex difference was found in the non-contact transition between trier and smoker states, with the transition being more probable in females than in males.     

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.     

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.     

Self-report, peer-report, and teacher-report measures of childhood depression: an analysis by item.

We explored the low correlation among different types of childhood depression measures at the item level. The items from the Children's Depression Inventory (CDI), Peer Nomination Inventory of Depression (PNID), and the Child Behavior Checklist-Teacher Report Form (CBCL-T) were combined, and both first- and second-order factor analyses were conducted. Results indicate that self-report, peer-report, and teacher-report assessments of depression measure generally uncorrelated constructs. Second-order analysis suggests that depression as a global construct is being measured to some degree by items from all three instruments. Canonical analysis was employed to identify items that best predicted CDI, PNID, and CBL-T summary scores simultaneously. Also, the relationship between specific items with similar content was investigated. Results from these analyses generally supported a conclusion that the three types of measures yield scores that are primarily independent and that the use of summary scores is not masking stronger relationships within measures. These findings have implications for clinical practice and construct elaboration.