Gender recognition from point-light walkers

Point-light displays of human gait provide information sufficient to recognize the gender of a walker and are taken as evidence of the exquisite tuning of the visual system to biological motion. The authors revisit this topic with the goals of quantifying human efficiency at gender recognition. To achieve this, the authors first derive an ideal observer for gender recognition on the basis of center of moment (J. E. Cutting, D. R. Proffitt, & L. T. Kozlowski, 1978) and, with the use of anthropometric data from various populations, show optimal recognition of approximately 79% correct. Next, they perform a meta-analysis of 21 experiments examining gender recognition, obtaining accuracies of 66% correct for a side view and 71% for other views. Finally, results of the meta-analysis and the ideal observer are combined to obtain estimates of human efficiency at gender recognition of 26% for the side view and 47% for other views.     

The role of anticipation and intention in the learning of effects of self-performed actions

The anticipative learning model for acquiring action-effect relations states that the acquisition of action-effect relations depends on processes that are part of action planning, in particular the anticipation of possible effects. Experiment 1 shows that response planning is indeed crucial for the learning of response effects. In this experiment distractors (tones) were presented either during response preparation or in the time interval between response execution and the presentation of a response effect. Response-effect learning was impaired when the distractors were presented during response preparation. The finding is consistent with the assumption that the distractors impaired the anticipation of potential effects and therefore reduced effect learning. In Experiment 2 all responses had two effects. Participants were instructed to produce one of the effects. Under this condition, response-effect learning was only found for the instructed effect, not for the non-instructed effect. The two experiments thus support the view that response-effect learning is selective and depends on the anticipation of potential effects during response planning. The results are discussed in terms of a model that explains both the learning of response-effect relations and the use of these effects for action control within the same theoretical framework.     

Performance of an unpleasant task: Effects of over- vs under-payment on perception of adequacy of rewards and task attractiveness

Subjects who came to an experiment expecting to receive a moderate amount of money for performing a task were then told, either before or after performing it, that their pay would be higher than, equal to, or less than they had expected. When the actual payment was announced after the task was performed, subjects' evaluations of the task increased with the amount they were paid; however, they estimated a higher rate of pay to be appropriate if they received either more or less than they expected than if they received what they expected. When the actual payment was announced before the task was performed (and before subjects made their decision to perform it), a different pattern emerged. Subjects rated the task more attractive when they were offered either more or less than the expected amount, while their judgments of the appropriateness of the pay offered increased with the amount of the offer. Implications of the results for incentive and dissonance theories as well as self-perception and equity theories are discussed.     

The effect of negative feedback about oneself and cost of information on preferences for information about the source of this feedback

The present paper reports an experiment in which different amounts of negative self-discrepant information were induced and its effects on information seeking were tested. In addition, the monetary cost of the information available was manipulated. Subjects received fictitious intelligence test results that were negatively discrepant from their self-evaluation. They were then given the opportunity to choose among several articles containing information that either derogated intelligence tests (test-disparaging information) or argued for their validity (test-supporting information). The relative preference for test-disparaging over test-supporting information increased with feedback discrepancy up to a point, but then decreased as this discrepancy became more extreme. The relative preference in reading desirability for test-disparaging over test-supporting articles was also higher when the information cost money than when it did not. In addition, the difference between the desire for the two types of information was greater under cost than under no cost conditions, particularly at the extreme levels of feedback discrepancy.     

Philosophy and politics: On Fred Dallmayr's “Critical Encounters”

This is the slightly revised text of a paper given at the annual meetings of the Society for Phenomenology and the Human Sciences held at Duquesne University, Pittsburgh, Pennsylvania, 14 October 1989.     

Natural categorization through multiple feature learning in pigeons

Recently (Troje, Huber, Loidolt, Aust, & Fieder 1999), we found that pigeons discriminated between large sets of photorealistic frontal images of human faces on the basis of sex. This ability was predominantly based on information contained in the visual texture of those images rather than in their configural properties. The pigeons could learn the distinction even when differences of shape and average intensity were completely removed. Here, we proved more specifically the pigeons' flexibility and efficiency to utilize the class-distinguishing information contained in complex natural classes. First, we used principal component as well as discriminant function analysis in order to determine which aspects of the male and female images could support successful categorization. We then conducted various tests involving systematic transformations and reduction of the feature content to examine whether or not the pigeons' categorization behaviour comes under the control of categorylevel feature dimensions-that is, those stimulus aspects that most accurately divide the stimulus classes into the experimenter-defined categories of 'Male' and 'Female'. Enhanced classification ability in the presence of impoverished test faces that varied only along one of the first three principal components provided evidence that the pigeons used these class-distinguishing stimulus aspects as a basis for generalization to new instances.