Joan S. Girgus

Predictors and consequences of childhood depressive symptoms : a 5-year longitudinal study

A 5-year longitudinal study investigated the interrelationships among childrens experiences of depressive symptoms, negative life events, explanatory style, and helplessness behaviors in social and achievement situations. The results revealed that early in childhood, negative events, but not explanatory style, predicted depressive symptoms; later in childhood, a pessimistic explanatory style emerged as a significant predictor of depressive symptoms, alone and in conjunction with negative events. When children suffered periods of depression, their explanatory styles not only deteriorated but remained pessimistic even after their depression subsided, presumably putting them at risk for future episodes of depression. Some children seem repeatedly prone to depressive symptoms over periods of at least 2 years. Depressed children consistently showed helpless behaviors in social and achievement settings.

Sex differences in depression and explanatory style in children

We report data from the first two years of a longitudinal study of depression, and explanatory style in children. Measures of these variables have been obtained from a group of elementary school children every six months since they were in the third grade. Results show that the boys consistently reported more depressive symptoms than the girls. This was particularly true for symptoms of anhedonia and behavioral disturbance. The boys also showed much more maladaptive explanatory styles than the girls. These results are discussed in light of previous studies of sex differences in childrens attributions. Possible reasons for the expected switch in the sex differences in puberty are also discussed.

Stress exposure and stress generation in child and adolescent depression: a latent trait-state-error approach to longitudinal analyses.

In 2 longitudinal studies of negative life events and depressive symptoms in adolescents (N = 708) and in children (N = 508), latent trait-state-error structural equation models tested both the stress generation hypothesis and the stress exposure hypothesis. Results strongly suggested that self-reports of depressive symptoms reflect the influence of a perfectly stable trait factor as well as a less stable state factor. Support emerged for both the stress generation model and the stress exposure model. When the state depression factor was modeled as predicting stress, support for the stress generation model appeared to increase with age. When the trait depression factor was modeled as the predictor of stress, support for the stress generation model did not vary with the childs age. In both models, support for the stress exposure remained relatively constant across age.

Assimilation and contrast illusions: Differences in plasticity

Three experiments show differences in the plasticity of the contrast and assimilation portions of the Delboeuf, Ebbinghaus, and Ponzo illusions. Contrast illusions show decrement in illusion magnitude with free inspection, whereas assimilation illusions do not. A model to explain both the original distortion and the differential susceptibility of the two classes of illusion to decrement is offered.

Differentiation and decrement in the Mueller-Lyer illusion·

Two experiments were conducted to test the hypothesis that decrement of the Mueller-Lyer illusion with inspection is due to learning to differentiate the test element from the accessory lines. In one experiment, the test element is predifferentiated for the observer by means of configurational variations and in the other by restriction of attention. Although the initial magnitude of the illusion is found to be inversely proportional to the amount of predifferentiation, the slopes of the decrement curves are not affected.

Principles of perceptual organization and spatial distortion: the gestalt illusions

In five interleaved experiments, conducted with 94 observers, it is shown that organization of the visual field according to gestalt principles results in measurable spatial distortions. Using the principles of proximity, similarity, good continuation, and two types of closure, it was found that interior distances (within a perceptual unit or group) are underestimated relative to exterior distances. The relationship between these spatial distortions and the resultant perceptual organization are discussed.

An empirical taxonomy of visual illusions

A classification system for visual-geometric illusions, based upon the interrelationships between behavioral responses to various distortions was created. Forty-five illusion configurations were presented to 221 observers. Factor analysis revealed that there are five classes of illusions. A secondorder analysis revealed that visual distortions are ultimately reducible to two global types of distortions: illlusions of extent and illusions of shape or direction.

A comparison of five methods of illusion measurement

The relative efficiency of five techniques of illusion measurement were tested on parametric variations of the Mueller-Lyer and Ebbinghaus figures. The methods of average error, reproduction, and selection from a graded series all showed significant effects of configurational variations. The subjective scaling techniques each failed to measure adequately changes in illusion magnitude for one illusion configuration. The suitability of the tested measures for group administration is also discussed.

The case for misapplied constancy scaling: depth associations elicited by illusion configurations.

It has been suggested that many visual-geometric illusions arise from inappropriate evocation of size-constancy by depth cues implicit in illusion configurations. Observers gave free association responses while viewing illusion figures. Analysis of these responses provides weak but consistent evidence for the elicitation of depth in the Sander parallelogram, Mueller-Lyer, Zoellner, and Ehrenfels variant of the Ponzo illusion. No evidence for depth is found in the normal form of the Ponzo, Poggendorff, and horizontal-vertical illusions, and the evidence is ambiguous in the Orbison configurations. These results indicate that depth processing may be evoked by some, but not all, classical illusion forms.

The assessment of components involved in illusion formation using a long-term decrement procedure

Available evidence seems to indicate that illusion decrement represents reorganization of cognitive components involved in visual-geometric illusions. Observers viewed one of the two forms of the Mueller-Lyer illusion, containing differential opportunities for peripheral structural interactions, for a 10-min test session on each of 5 successive days. The magnitude of the distortion decreased to a different asymptotic level in each of the two configurations with the form, with more opportunity for structural interactions showing the higher asymptote. Thus, this asymptote probably represents the structural or physiological contribution to the illusory distortion.