Do Additional Features Help or Hurt Category Learning? The Curse of Dimensionality in Human Learners

The curse of dimensionality, which has been widely studied in statistics and machine learning, occurs when additional features cause the size of the feature space to grow so quickly that learning classification rules becomes increasingly difficult. How do people overcome the curse of dimensionality when acquiring real‐world categories that have many different features? Here we investigate the possibility that the structure of categories can help. We show that when categories follow a family resemblance structure, people are unaffected by the presence of additional features in learning. However, when categories are based on a single feature, they fall prey to the curse, and having additional irrelevant features hurts performance. We compare and contrast these results to three different computational models to show that a model with limited computational capacity best captures human performance across almost all of the conditions in both experiments.     

Debunking Morality: Lessons from the EAAN Literature

This article explores evolutionary debunking arguments as they arise in metaethics against moral realism and in philosophy of religion against naturalism. Both literatures have independently grappled with the question of which beliefs one may use to respond to a potential defeater. In this article, I show how the literature on the argument against naturalism can help clarify and bring progress to the literature on moral realism with respect to this question. Of note, it will become clear that the objection that the moral realist begs the question, when appealing to the truth of some of her moral beliefs, is unsuccessful.     

Social support and adaptation to stress by the elderly

The first of a two-phase project is reported that examined the prospective effects of stress and social support on the physical and mental health of the elderly. A sample of 50 elderly subjects was assessed at two points in time over a 6-month period. Results indicated that social support was a significant predictor of physical health status, whereas mental health was related to the Stress X Social Support interaction term. These latter results were consistent with the buffering hypothesis, in that high levels of social support served to reduce the negative impact of stress on mental health. Individuals who were in better mental health at the initial assessment experienced fewer stressful events and higher levels of social support over the subsequent 6-month period. The implications of these findings for research and theory regarding the relation between stress and social support are discussed.     

On the nature of perceptual limits in vision

Summary Studies of attention have generally assumed that the principal limit to visual perception involves the capacity to identify a stimulus. Analyses of responses in visual tasks, however, suggest that errors can arise from a loss of position information, as well as a loss of identity information, and that these two types of errors may be affected by different variables. Based on this, we have proposed that the difficult aspect of perception is not that of recognizing the form of the stimulus but rather determining its position relative to other items in the field. To demonstrate this, we conducted a series of experiments on lateral masking that showed that the failure to perceive a parafoveal stimulus surrounded by other items is due to two quite separate components: a loss of identity information induced by the immediately adjacent items and a loss of position information induced by both adjacent and non-adjacent items.This research was supported by grant A-9581 from the Natural Sciences and Engineering Research Council of Canada to the senior author. The first two experiments were reported in a paper to the annual meeting of the Psychonomics Society, San Antonio, 1984     

The relationship between temperament and personality: An exploratory study

Although the terms temperament and personality are often used interchangeably in the literature and clearly are conceptually related, there is little empirical data to illuminate their relationship. In this exploratory study we measured temperament (using the Dimensions of Temperament Survey), and personality (using the Eysenck Personality Questionnaire), in young adolescents and in adults. Some age and sex differences in relationships between the measures and their correlations were found. The temperament dimension of adaptability was clearly related to Eysenck's Extraversion factor and reactivity to Neuroticism in females. More substantial relationships emerged in the adult sample than in the adolescent group, Our data, combined with that of a 1984 Australian study using different techniques, provides substantial support for measurable overlap between some dimensions of temperament derived largely from the developmental literature, and Eysenck's personality theory.     

Affective judgments,common sense,and Zajonc's thesis of independence

Zajonc (1980) argued that, contrary to what is commonly believed, an affective judgment about a stimulus may be independent of the cognitive processes through which we know what that stimulus is. The evidence Zajonc offered (the exposure effect in the absence of recognition) does not entail this claim. An example of the sort of experiment that could do so is offered. When carried out, however, this study indicated the opposite: An affective judgment about a stimulus depended on how it was cognitively interpreted. We argue that what is commonly believed in this area is presumptively correct: Affective judgments about a stimulus depend on whatever information is possessed about that stimulus.     

Month of birth and academic achievement

The degree results of nearly 300,000 British graduates were tabulated by the month of their birth. The number of graduates varied as a function of month of birth. So too, but in a different way, did the quality of their degree results. A number of possible predictors of the results are examined. These analyses suggest that, among those who stay at school until the age of 18, the oldest in their year group are at an advantage but, by the time they graduate from university, the youngest perform best. It is concluded that some intellectually relevant quality peaks between 18 and 21 yr of age and then declines.     

Reviews

S tein , M urray . Jung's Treatment of Christianity: The Psychotherapy of a Religious Tradition
R ycroft , C harles . Psychoanalysis and Beyond
C hasseguet -S mirgel , J anine . The Ego Ideal: A Psychoanalytic Essay on the Malady of the Ideal
R othstein , A rnold . The Narcissistic Pursuit of Perfection