The linear regression line as a judgmental aid in visual analysis of serially dependent A-B time-series data

The purpose of this study was to investigate the effects of different types and magnitudes of serial dependence (first-order moving average and autoregression) and of linear regression lines within experimental phases on the agreement between results of visual and results of statistical data analyses. The stimulus material consisted of computer-simulated A-B-design data graphs. The time series were generated with a constant variance, varying degrees of treatment effects (changes in level), five conditions of serial dependency, and with or without linear regression lines. The material was presented to three groups of student raters (n₁=52, n₂=14, n₃=17) who rated the treatment effect in the graphs on a five-point scale. These ratings were compared with statistical results (time-series analyses). Each group had to interpret 70 graphs, 35 of which had regression lines. Data were analyzed by means of two three-factor and one four-factor ANOVA and by graphic display. The linear regression lines generally enhanced the agreement between the raters' estimations and the statistical results. Serial dependency also increased the agreement between the two analysis methods. However, with strong autoregression processes in the data, the raters tended to overestimate treatment effects relative to time-series analysis.Parts of this study were presented at the World Congress on Behavior Therapy, Washington, DC, December 11, 1983. The authors wish to express their appreciation to Christoph Bonk and Willi Ecker for their extensive collaboration in data analysis and for their assistance in carrying out the study.     

INDIVIDUALITY IN PLANNING: MEANING PATTERNS OF PLANNING STYLES

The study dealt with the particular contents subjects apply in a cognitive task. The hypotheses were that the frequency of specific contents would be related to the subject's information processing tendencies assessed in terms of the meaning system (Kreitler and Kreitler), that each content variable would be related to a pattern of meaning variables and that in some cases these patterns would resemble in structural features those related to personality traits, particularly cognitive traits. The subjects, 50 undergraduates of both genders, were administered in separate sessions a standard meaning questionnaire, assessing tendencies to use the meaning variables, and 10 planning tasks, coded in terms of eight conceptually-based variables (categories of contents, e.g., emotional, quantitative) and five factorially-based variables (defined on the basis of a factor-analysis of all responses, e.g., concern for aesthetics and external appearance, formal administrative arrangements). The findings showed that each content variable was related to a particular pattern of meaning variables providing insight into its cognitive dynamics. Six conceptually-based variables were related to patterns similar to those related to traits, not only cognitive. Discussion focuses on implications for the study of contents and of traits.     

Buffer effects and threshold effects: An alternative interpretation of nonlinearities in the relationship between social support,stress, and depression

The common interpretation of statistical interactions of global measures of social support and stress in their effects on depression (the "buffer effect" of social support) as reflecting interactive processes within individuals was examined. It was argued that its adequacy depends on incorrect assumptions about the distribution of depressive symptoms within individuals over time and/or different levels of psychosocial adversity. With hypothetical data sets generated under the assumption of a threshold effect in the development of depression and of additive, rather than interactive, effects of social support and stress, it was demonstrated that spurious "buffer effects" of social support can appear in analyses of cross-sectional data. Methodological and substantive implications are discussed, and strategies for study design and data analysis are proposed that allow to assess whether empirical deviations from linearity are more adequately interpreted as a buffer or as a threshold effect.     

The perception of foreground and background as derived from structural information theory

Subjects were instructed to order stimuli, consisting of a white and a black part, in accordance with the perceived foreground-strength of the white (or black) part. It appeared that this task can be carried out consistently. The order is explained on the basis of Structural Information Theory. It is argued that this task involves central processes, and that the strength depends on the preference for an interpretation, in which the white (black) part is a foreground on a black (white) background, with respect to the opposed interpretation in which the white (black) part is the background and the black (white) part is foreground.     

Visually perceived motion in depth resulting from proximal changes. I

According to a model for form and motion perception proposed by Johansson (1964), every two-dimensional change in the proximal stimulation is projected out as a motion in depth. The amount of perceived depth motion can then be predicted from the projective relationship between the proximal change and the projected motion. This prediction was tested in a series of experiments by using squares that continuously changed their sizes as stimuli, and measuring perceived distance of motion in depth. The obtained relationship between perceived and predicted distance of motion was curvilinear for all Ss. Furthermore, the majority of the Ss underestimated the motion systematically, the remainder overestimated it. Thus, the prediction given in the model could not be verified. However, an alternative projective relation based on the assumption that a fixed proportion of the change is not projected out as a motion but perceived as a change of size agreed quite well with the data, both with distance judgments and with judgments of perceived change of size.     

Adaptation to field displacement during head movement unrelated to the constancy of visual direction

Adaptation to vertical field displacements dependent on head turning about a vertical axis was demonstrated under two conditions, rapid training with 100 head movements and 1-h-long training with continuous head turning. The effect of rapid training was measured with the slant estimation method. Adaptation after the longer training was ascertained by comparing the uncertainty ranges for apparent target immobility before and after the adaptation period. Adaptation to field displacements in directions parallel to the plane of the head rotation obtained under corresponding conditions was also measured and found to be somewhat greater than adaptation to vertical field displacements. The result of work by Wallach and Frey that adaptation to field displacement in the direction with the head rotation is greater than to displacement against it was corroborated. While the previous result had, been obtained with rapid adaptation and with the slant estimation method, we confirmed it with 1-h training and by measuring the uncertainty ranges before and after the adaptation period.     

EFFECTS OF CONTINGENCYAND CONTRAST CONTEXTS ON THE COGNITION OF WORDS: A study of stereoscopic rivalry

R ommetveit , R., T och , H. & S vendsen , D. Effects of contingency and contrast contexts on the cognition of words. A study of stereoscopic rivalry. Scad r. Psychol ., 1968, 9, 138–144.—Two typographically very similar words (like 'hell' and 'tell') were presented in a binocular rivalry situation, each appearing after a contrast context (e.g. 'heaven') or a contingency context (e.g. 'devil') had been presented to both eyes. Context effect was then assessed in terms of the frequency with which the context-relevant word was reported as seen. The effect of contrast compared with contingency context was weak when context and test words were presented consecutively, but strong when the context stimulus appeared above the rivalry pair on the same stereogram.