Quantitative Analysis of IRT Variability During the First Training Stages of a Variable-Interval Schedule in Rats

Five rats were reinforced under variable-interval schedules with different average interreinforcement intervals (30 seC., 1 min, 2 min, and 4 min). Each animal was run only two sessions of each schedule. The interresponse times (IRTs) were recorded and analyzed. The autocorrelation function of the IRT series and of the IRT time series (number of responses per time interval) were calculated, and absence of periodicity in the subject’s behavior was demonstrated. Frequency distribution of IRTs showed in all cases a similar shape and could be fitted to a gamma probability density function in 60% of cases with a signification level of .01 (Kolmogorov-Smirnoff test). The frequency distributions of the IRT time series were distributed as a Poisson process with a .05 significance level. These results suggest that during variable-interval schedules the responses of the animal can be modeled as a random process characterized by a gamma distribution, as a first approximation.

     

Scores on the State-Trait Anxiety Inventory for children in a longitudinal study of pubertal Spanish youth.

Changes in scores on the State-Trait Anxiety Inventory for Children for a sample of 534 pubertal adolescents were longitudinally studied over a period of 4 years. Biological development and other variables were investigated. For the 310 boys, A-trait scores decreased significantly with age. The 224 girls showed significantly higher scores than boys in all years of the study. No significant relationship was found between anxiety and pubertal maturity. The year-to-year persistence in symptomatology of anxiety ranged between 55.6% and 66.1% for girls and between 48.5% and 53.1% for boys. Girls showed bi- and tri-annual persistence between 31% and 50%, and boys between 13% and 27%. Neuroticism scores formed the best predictor of A-trait scores. Symptomatology of anxiety is not transient during early adolescence, so personality may provide a risk indicator in the development of anxiety.     

Individual differences in depression,induced mood,and perception of emotionally toned words

The associative network theory of emotion and memory, outlined by Bower (1981), predicts that depressed mood leads to biases which favour the perception of mood-congruent information. In this study, a lexical decision task was used to assess the effects of degree of depression and induced elation and depression on lexical decision times for positive and negative words. Subsequently, subjects were given a recall test for the words presented during the lexical decision task. The results partially offered support for perceptual bias. The data showed that in non-depressed and elation-induced subjects, decision times were differentially affected by hedonic tone. Words of positive nature were responded to significantly faster than were negative words. In mildly depressed and depression-induced, decision times were similar for both types of words (positive and negative). These findings are discussed in relation to the associative network model and a growing amount of empirical research on human emotion and cognition.     

The influence of height and key on the perceptual similarity of transposed melodies

In two experiments, the perceptual similarity between a strong tonal melody and various transpositions was investigated using a paradigm in which listeners compared the perceptual similarity of a melody and its transposition with that of the same melody and another transposition. The paradigm has the advantage that it provides a direct judgment regarding the similarity of transposed melodies. The experimental results indicate that the perceptual similarity of a strong tonal melody and its transposition is mainly determined by two factors: (1) the distance on the height dimension between the original melody and its transposition (pitch distance), and (2) the distance between keys as inferred from the circle of fifths (key distance). The major part of the variance is explained by the factor pitch distance, whereas key distance explains only a small part.     

Suppressing permutations or rigid planar rotations: A remedy against nonoptimal varimax rotations

Varimax rotation consists of iteratively rotating pairs of columns of a matrix to a maximal sum (over columns) of variances of squared elements of the matrix. Without loss of optimality, the two rotated columns can be permuted and/or reflected. Although permutations and reflections are harmless for each planar rotation per se, they can be harmful in Varimax rotation. Specifically, they often give rise to the phenomenon that certain pairs of columns are consistently skipped in the iterative process, whence Varimax will be terminated at a nonstationary point. The skipping phenomenon is demonstrated, and it is shown how to prevent it.The author is obliged to Henk Kiers for commenting on a previous draft.     

Irrational Beliefs, Interpersonal Perception and Marital Adjustment

To test the hypothesis that the major evaluative beliefs postulated by Rational-Emotive Behaviour Therapy are related to marital adjustment, 50 married couples completed the Dyadic Adjustment Scale (DAS) and the Survey of Personal Beliefs (SPB). Significant correlations were found between DAS scores and three subscales (Other directed shoulds, Low frustration tolerance and Self worth) of the SPB. On the interpersonal dimension of assumed similarity, females in the high dyadic adjustment group were better able to predict their spouses' awfulizing, low frustration tolerance and self-worth beliefs than were females in the low adjustment group. However, the present study offers only limited support for the hypothesis that interpersonal perception of irrational evaluative beliefs is related to marital adjustment.     

HUSSERL'S PHENOMENOLOGY AND WEYL'S PREDICTIVISM

In this paper I discuss the version of predicative analysis put forward by Hermann Weyl in Das Kontinuum. I try to establish how much of the underlying motivation for Weyl's position may be due to his acceptance of a phenomenological philosophical perspective. More specifically, I analyze Weyl's philosophical ideas in connexion with the work of Husserl, in particular Logische Untersuchungen} and Ideen .I believe that this interpretation of Weyl can clarify the views on mathematical existence and mathematical intuition which are implicit in Das Kontinuum.     

On Green's best linear composites with a specified structure,and oblique estimates of factor scores

Green solved the problem of least-squares estimation of several criteria subject to the constraint that the estimates have an arbitrary fixed covariance or correlation matrix. In the present paper an omission in Green's proof is discussed and resolved. Furthermore, it is shown that some recently published solutions for estimating oblique factor scores are special cases of Green's solution for the case of fixed covariance matrices.