The inference of covert hypotheses by verbal reports in concept-learning research

A paradigm designed to examine the degree to which verbal reports represent the subject's learning was evaluated using a concept-acquisition task. Specifically, the degree to which hypotheses verbalized during the concept-acquisition procedure represent the covert hypotheses controlling category responding was examined. Subjects were required to make category responses, verbal reports, and sorts and re-sorts (blank-trial probes) of the stimuli at intervals in a reception paradigm. By comparing the sorts made during the acquisition procedure, the re-sorts after a 1-week delay, and the sorts made by subjects who had not participated in the acquisition procedure, it was determined that the verbal reports do not accurately represent the underlying hypothesis-testing process under all conditions. Verbal reports elicited at the beginning of the acquisition procedure and at criterion accurately represented the underlying hypotheses; those elicited at intervening points did not. The ambiguity of the verbal reports was a similar function of acquisition trials.     

Linear programming techniques for multidimensional analysis of preferences

This paper offers a new methodology for analyzing individual differences in preference judgments with regard to a set of stimuli prespecified in a multidimensional attribute space. The individual is modelled as possessing an ideal point denoting his most preferred stimulus location in this space and a set of weights which reveal the relative saliences of the attributes. He prefers those stimuli which are closer to his ideal point (in terms of a weighted Euclidean distance measure). A linear programming model is proposed for external analysisi.e., estimation of the coordinates of his ideal point and the weights (involved in the Euclidean distance measure) by analyzing his paired comparison preference judgments on a set of stimuli, prespecified by their coordinate locations in the multidimensional space. A measure of poorness of fit is developed and the linear programming model minimizes this measure overall possible solutions. The approach is fully nonmetric, extremely flexible, and uses paired comparison judgments directly. The weights can either be constrained nonnegative or left unconstrained. Generalizations of the model to consider ordinal or interval preference data and to allow an orthogonal transformation of the attribute space are discussed. The methodology is extended to perform internal analysis,i.e., to determine the stimuli locations in addition to weights and ideal points by analyzing the preference judgments of all subjects simultaneously. Computational results show that the methodology for external analysis is unbiased—i.e., on an average it recovers the true ideal point and weights. These studies also indicate that the technique performs satisfactorily even when about 20 percent of the paired comparison judgments are incorrectly specified.The authors wish to express their deep appreciation to J. Douglas Carroll and Joseph B. Kruskal for their most valuable comments on an earlier version of this paper.     

Hue discrimination as a function of stimulus luminance

The relation between hue discrimination and stimulus luminance was investigated. It was found that discrimination was best at the highest luminance and deteriorated at the lowest, except in the yellow region.     

Measurement of eye orientation of monkeys during visual discrimination

This paper describes apparatus and procedures for measuring eye orientation in the rhesus monkey without restraining the head. The main components of the apparatus are (a) a helmet on which are mounted the discriminative stimuli and the optical and other devices for obtaining a corneal reflection, (bj a special restraining chair that allows the monkey to respond to pushbuttons in front of him, yet prevents him from reaching the equipment mounted on the helmet, and (c) systems for presenting stimuli, monitoring choice responses, and recording eye orientation, which are controlled by a LINC-8 computer. The initial findings on eye orientation during performance on both a hard and an easy brightness discrimination problem are also presented.     

Visual recognition thresholds and dimensions of word meaning

Tachistoscopic recognition thresholds were obtained for nouns with high or low values on one dimension of meaning while two others were controlled. Frequency, imagery concreteness (I), and meaningfulness (m), were varied in different lists in one experiment, frequency and m in a second, and m alone in a third. Ratings of familiarity were also obtained to supplement frequency as a measure of familiarity. The results showed that ease of visual recognition was most strongly related to frequency and familiarity. Imagery was unrelated to thresholds when familiarity and m were controlled. Meaningfulness showed a small but consistent positive relation to ease of recognition even with the other variables held constant. Except for the puzzling effect of m, the results are consistent with the view that perceptual recognition is primarily dependent upon the familiarity of the target stimulus and not upon associative processes evoked by it.     

Attributions for negative life events and depression: the role of perceived control

Although perceptions of control occupied a central role in the development of learned helplessness theory, recent helplessness research has not considered controllability judgments when relating attributions to depression. Supporting the importance of this construct, the research discussed in this article found evidence that judgments of control interact with other attributions in predicting depression. Specifically, in a prospective study of stress and well-being in adolescence, internal, stable, and global attributions for negative events attributed to uncontrollable causes were found to be positively related to increases in depression (as predicted by the reformulated helplessness theory), but internal and global attributions for negative events attributed to controllable causes were found to be inversely related to increases in depression. The discussion considers the implications of the findings for understanding the nature of the relation between attributions for naturally occurring life events and depression.     

Peer interactions of normal and attention-deficit-disordered boys during free-play,cooperative task,and simulated classroom situations

Groups of 30 ADD-H boys and 90 normal boys were divided into 30 mixed dyads composed of a normal and an ADD-H boy, and 30 normal dyads composed of 2 normal boys. Dyads were videotaped interacting in 15-minute free-play, 15-minute cooperative task, and 15-minute simulated classroom settings. Mixed dyads engaged in more controlling interaction than normal dyads in both free-play and simulated classroom settings. In the simulated classroom, mixed dyads completed fewer math problems and were less compliant with the commands of peers. ADD-H children spent less simulated classroom time on task and scored lower on drawing tasks than normal peers. Older dyads proved less controlling, more compliant with peer commands, more inclined to play and work independently, less active, and more likely to remain on task during the cooperative task and simulated classroom settings. Results suggest that the ADD-H child prompts a more controlling, less cooperative pattern of responses from normal peers.     

Indirectly expressed motivational deficits among arthritic adults

The present experiment examined whether adults suffering from arthritis evidence motivational deficits reflective of a diminished sense of effectiveness in dealing with their environment. Content-coding of imaginative stories revealed that both osteoarthritics and rheumatoid arthritics possess significantly lower levels of achievement and power motivation compared with control subjects. Furthermore, arthritic patients with poor health status, as assessed by the Arthritis Impact Measurement Scales, were found to be especially low in their level of achievement motivation. No differences between arthritics and healthy controls were found when self-report measures of achievement and power motivation were used in place of the thematically coded indices. That is, arthritics reported that their desire to do something better and their desire to influence others was just as strong as that of healthy adults. This suggests that arthritic adults suffer from a motivational deficit that may not be revealed in response to direct questions about their motives or goals.This research was funded by a National Institute of Health Grant (AR 20613) to the Multipurpose Arthritis Center at Boston University and by a fellowship from the Seaver Institute.     

Color name as a function of surround luminance and stimulus duration

A color-naming experiment was performed in which both surround luminance and exposure duration were varied. The data showed substantial effects from these changes; however, none could be interpreted to indicate the presence of a Bezold-Brucke shift or tritanopia.