Biomedical subjects
Publications and source records attributed to S S Rakover.
It is argued that the whole face is more dominant than the individual features. In the case of a jumbled face the external pattern is dominant when a face is upright, whereas the internal pattern is dominant when a face is inverted.
The goal of the present paper is to propose a solution to the 'saliency problem' which has been raised in regard to Rakover and Cahlon's (1989) Catch model for identifying a previously seen target face (Ft). In contrast to real life situations, the Catch model assigned the same weight to different facial dimensions and values. Mathematical proofs, reanalyses of the results of three experiments reported in Rakover and Cahlon, and the analysis of the results of a new experiment show that this proposal expands and improves the Catch model.
"Facial inversion effects" refers to the findings that recognition of inverted faces is less accurate than recognition of upright faces. We now report inversion effects for isolated facial features: forehead, eyes, nose, mouth, and chin. This shows that configurational information extracted from a whole face (i.e., from spatial relationships among the facial features) is not necessary for obtaining the inversion effects. Other factors, such as "upright-orientation," mental rotation, and feature saliency, account for the inversion effects both in a whole face and in its isolated features. We propose a simple formula that satisfactorily predicts the recognition of a whole face and the inversion effects for that face on the basis of its individual features.
The purpose of the present paper is to describe a new technique and a mathematical model--called the "Catch model"--for identifying a face previously seen (i.e., the target face). Both the technique and the model were developed on the basis of the general approach of information processing used with respect to human memory. Subjects were presented with a pair of test faces on each trial. Neither of the test faces was the target face. Their task was to choose from the two test faces the one most similar to the target face. The data furnished by the subjects were used to reconstruct the target face in the following way: At each trial the differentiating values, such as a long nose and blue eyes, of the test face chosen by the subject were recorded. These values were the ones that accounted for the difference between the two test faces. Over the whole run of the test trials, the differentiating values were associated with various frequencies of occurrence. The target face was reconstructed by selecting the differentiating values having the highest frequency of occurrence. Only one differentiating value per facial dimension such as a nose and eyes could be selected. Thus, given that the facial dimension of the nose has three different values consisting of the long, short, and wide varieties of nose, the value chosen would be the one associated with the highest frequency of occurrence. Mathematical derivations show that, given different variations of the proposed technique, the target face will be detected. These derivations were supported by the results of three experiments.
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Fish learned a shuttle avoidance task faster than a lever-bumping task. The latter task was hardly mastered at all. These and other results tend to support the suggestion for functionally similar universal reactions to a conditioned fear-arousing stimulus.
A second visual stimulus, to which no response was required, following a primary one lengthened the reaction time to the first stimulus for 25 college students. Reaction time rose as a function of the increase in the interstimulus interval. Duration time of the second stimulus did not affect this response. These results were found under a condition of stimulus-response certainty.
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