Binocular fusion: A test of the suppression theory

Binocular fusion may be due to interocular inhibitory suppression, an hypothesis difficult to evaluate by phenomenal inspection. A test probe method (reaction time to a light pulse) was used to measure visual sensitivity during binocular rivalry and fusion. The absence of inhibitory effects during fusion fails to support the suppression theory of fusion.     

Binocular fusion and contour suppression

Data from three separate investigations are presented to support the conclusion that suppression of visual contours occurs during binocular fusion of identical figures. These data are discussed in relation to examples of confirming and disconfirming results of other investigators.     

Binocular single vision achieved by fusion and suppression

The occurrences of fusion and suppression were determined from stereograms which produced two retinal images located at equal distances but in opposite directions from the fovea. Subjects reported whether the dichoptic stimulus appeared single or not, and if single whether it appeared in the center of the visual field. The report of centrality is predicted by the fusion theory of single vision and that of noncentrality by the suppression theory. Experiment 1, with eight subjects, showed that for small disparities perceived singleness was the percept predicted by the fusion theory; for larger disparities, the percepts could sometimes be predicted by the fusion theory and other times by the suppression theory. Experiment 2, with 16 subjects, showed that with larger stimuli the percept predicted by the fusion theory is more likely to occur. Experiment 3, with four subjects, showed that the centrality was reported when the stimuli were presented for 100 msec. This result provided support for our interpretation that the centrality reports in Experiments 1 and 2 were not due to fixation error and suppression.     

A test of the neo-behaviouristic theory of extinction

A test between Moltz's and Deutsch's theory of extinction was devised. Animals were trained to go to the same goal-box via two different paths. Then they were divided into two groups. The first found the goal-box empty, the second found the entrance into the goal-box blocked. The choices of the animals on the next trial were observed. The results are those predicted by Deutsch.     

A test of the melioration theory of matching

Melioration theory entails that matching in concurrent schedules occurs because the subjects equalize the local reinforcement rates (reinforcers received for each alternative divided by the time allocated to each alternative). The role of local reinforcement rates was tested by using multiple schedules in which one component involved an alternative with a high absolute rate of reinforcement and a low local reinforcement rate while the second component involved an alternative with a low absolute rate and a high local rate. These alternatives were then presented simultaneously in probe trials to determine preference between them. Contrary to melioration, the absolute rate of reinforcement, not the local rate, was the controlling variable.     

A test of the gravity lens theory.

Naito and Cole [1994, in Contributions to Mathematical Psychology: Psychometrics and Methodology Eds G H Fischer and D Laming (New York: Springer)] provide a configuration which they describe as the Gravity Lens illusion. In this configuration, four small dots are presented in proximity to four large disks, and one is asked to compare the slope of an imaginary line which connects one pair of dots with the slope of a line which connects the other pair. In fact the slopes are the same, i.e. their axes are parallel, but because of the positioning of the large disks they appear to be at different orientations. Naito and Cole propose that the perceptual bias is analogous to the effects of gravity on the metrics of physical space, such that mental projections in the vicinity of a disk (or an open circle) are distorted just as the path of light is bent as it passes a massive body such as a star. Here we provide a simple test of this concept by having subjects judge alignments of dots which lie near tangents to a circle. Subjects were asked to project straight lines through pairs of stimulus dots, selecting and marking points in open space which were collinear with each pair. As would be predicted by the Gravity Lens theory, the locations selected by subjects were displaced from straight lines. However, the error magnitudes were substantially larger for judgments of dot pairs which had an oblique alignment, as compared with dot pairs which were aligned with a cardinal axis. This differential of effect as a function of stimulus orientation is not predicted by the gravity concept.     

A meta-analytic test of intergroup contact theory

The present article presents a meta-analytic test of intergroup contact theory. With 713 independent samples from 515 studies, the meta-analysis finds that intergroup contact typically reduces intergroup prejudice. Multiple tests indicate that this finding appears not to result from either participant selection or publication biases, and the more rigorous studies yield larger mean effects. These contact effects typically generalize to the entire outgroup, and they emerge across a broad range of outgroup targets and contact settings. Similar patterns also emerge for samples with racial or ethnic targets and samples with other targets. This result suggests that contact theory, devised originally for racial and ethnic encounters, can be extended to other groups. A global indicator of Allport's optimal contact conditions demonstrates that contact under these conditions typically leads to even greater reduction in prejudice. Closer examination demonstrates that these conditions are best conceptualized as an interrelated bundle rather than as independent factors. Further, the meta-analytic findings indicate that these conditions are not essential for prejudice reduction. Hence, future work should focus on negative factors that prevent intergroup contact from diminishing prejudice as well as the development of a more comprehensive theory of intergroup contact.     

Information search and the effects of failure: A test of complexity theory

The effects of increasing failure and the structural complexity of decision-making teams on four aspects of information search and utilization were examined. Twenty-four structurally homogeneous dyads and 12 unselected control dyads served as Ss in a complex experimental simulation running for six 30-min periods. Information load was held constant at 7 inputs per period. The proportion of failure inputs was sequentially increased from 1:7 in period 1 through 6:7 in period 6. Dyads in the control condition were not exposed to failure. It was found that structurally simple Ss engaged in more delegated information search than complex Ss. Self-initiated information search initially increased, then remained fairly constant at higher proportions of failure. Contrary to expectations, no differences were found between simple and complex Ss in self-initiated search. Complex dyads exceeded simple dyads on two measures of information utilization. The number of search moves used in integrative decisions produced an inverted U-shaped curve with optimal levels at moderate proportions of failure. Efficiency of information utilization showed a general decrease as failure increased. The data produced limited support for complexity theory and did support, where applicable, the information search theories of Lanzetta and Feather.     

Experimental test of the prospect theory value function: A stochastic dominance approach

According to prospect theory, individuals are risk averse regarding gains but risk seeking regarding losses, implying an S-shaped value function. The S-shaped value function hypothesis is based on experiments in which subjects are asked to choose separately between alternatives with either only positive or only negative outcomes, alternatives which rarely exist in the capital market. In addition, the S-shaped findings may be biased by the “certainty effect” and by probability distortion. In this paper we employ the recently developed prospect stochastic dominance criterion to test the prospect theory S-shaped value function hypothesis with mixed outcomes and with no “certainty effect.” Assuming that subjects do not distort moderate probabilities, we strongly reject the prospect theory S-shaped value function, with at least 76–86% of the choices being inconsistent with such preferences. When possible subjective probability distortions are taken into account, we find that at least 50–66% of the choices are inconsistent with an S-shaped value function.     

Laterality effects in risk preference: A test of portfolio theory

A central assumption in portfolio theory of risk preference is that for games with expected value constant the preference ordering of an individual should exhibit a single peaked preference function. This assumption was tested by determining the level of stochastic transitivity satisfied by triples of pairwise preference proportions among eight gambles. In only a small percentage of cases were the predicted levels of stochastic transitivity not satisfied. It was concluded that the results provided strong support for portfolio theory.     

Psychoticism and perceptual processing speed: A test of Robinson's theory

Robinson has argued that bias in the process of knowledge acquisition can give rise to either a differentiated or an integrated learning style. Individuals high on the personality dimension of psychoticism are said to have a differentiated learning style that manifests in superior performance on cognitive tasks that require differentiation of the elements or parts of immediate perceptual experience. To test this theory, 106 undergraduate students aged between 18 and 31 completed the Eysenck Personality Questionnaire—Revised, along with two computer‐based measures of visual processing speed: reaction time (RT) and inspection time (IT). In accord with Robinson's theory, psychoticism scores were found to be inversely related to both mean RT and IT. Moreover, multiple regression analyses indicated that the relationship between psychoticism scores and the two processing speed measures was independent of any age or gender effects. It is recommended that future research examine the relationship between psychoticism, and both poles of Robinson's differentiation versus integration dimension.     

Response mode and choice consistency: A test of unfolding theory

Coombs, Donnell, and Kirk (1978. Journal of Experimental Psychology, 4, 497–512), in a study of risk preferences, collected data using both pick $\text{1}\text{3}$ and reject $\text{1}\text{3}$ response modes. Although the preference orders derived from the two response modes were identical, the pick data contained a greater number of inconsistencies than the reject data. In the present study, predictions were derived from unfolding theory (Coombs, 1964. A theory of data. New York: Wiley) regarding the relative consistency of pick and reject response modes. An experiment performed as a test of these predictions supported the unfolding model suggesting that differences in inconsistency between response modes could be attributed to the fineness of the grid of working midpoints imposed upon the choice process by the response mode.     

A direct test of the original version of regret theory

This paper reports on a direct experimental test of the original version of Regret Theory using a total of 64 subjects in three groups. The experiment, which was run on PCs, was designed to elicit from subjects' responses the two key elements in this theory: namely the basic utility function, and the regret/rejoicing function. It was also designed to provide a quick direct test of the implications of the theory. We found that the evidence refuted this original version of Regret Theory.     

A critical test of the failure-to-engage theory of task switching

When people switch between two tasks, their performance on each is worse than when they perform that task in isolation. One theory of this “switch cost” is the failure-to-engage (FTE) theory, which posits that observed responses are a simple mixture of prepared and unprepared response strategies. The probability that participants use prepared processes can be manipulated experimentally (e.g., by changing preparation time). The FTE theory is a binary mixture model and therefore makes a strong prediction about the existence of fixed points in response time distributions. We found evidence contradicting this prediction, using data from 20 participants in a standard task-switching paradigm. In this article, we examine reasons for the failure of the FTE theory, and we demonstrate that a generalized version of FTE theory accommodates our data.     

A simple duality principle in test theory

It is demonstrated that theorems in test theory have corresponding dual theorems which are obtained by exchanging true scores and error scores, as well as reliability coefficients and their complements, in both the hypothesis and the conclusion. A formula that does not conform to the principle cannot be an identity in the test-theory model, but must be based on additional assumptions in the hypothesis tht perhaps are not immediately apparent. The usefulness of this principle is indicated, and its origin in the mathematical formalism underlying the theory is discussed.     

A brief introduction to unified test theory

This article introduces McDonald's unified treatment of test theory, which merges the major contributions of Spearman (True Score Theory and Common Factor Theory) with aspects of Item Response Theory. The fundamentals are first presented. followed by elaboration of selected aspects of the treatment. An SAS program is given that estimates relevant parameters.