A revision of the psychological refractory period

A brief review of the major psychological refractory period (PRP) theories reveals that they have lost their original objective, i.e., to explain human information processing under rapid sequential stimulation. Conventional data interpretation has restricted attention to delay of reaction times as a result of interstimulus interval (ISI) variation. This form of data interpretation fails to capture important performance aspects under double-stimulation, e.g., the phenomenon that stimulus complexity affects the processing rate. Effects of stimulus rate and complexity are better analyzed in terms of reaction times as well as interresponse intervals (IRI). If this is done, behavioral phenomena emerge that cannot be explained within the frame of any of the existing PRP theories. To account for these newly revealed phenomena a processing interrupt model is introduced which is based on three major hypotheses: single-channel processor, additive stages, and perceptual interrupt facility.     

Emotion perception explains age-related differences in the perception of social gaffes

Young (<36 years) and older (>59) adults viewed videos in which the same individual committed a faux pas, or acted appropriately, toward his coworkers. Older participants did not discriminate appropriate and inappropriate behaviors as well as young participants. Older participants also scored lower than young participants on an extensive battery of emotion recognition tests, and emotion performance fully mediated age differences in faux pas discrimination. The results provide further evidence for the role of emotion perception in a range of important social deficits.     

Preferential theory revision

Employing a logic program approach, this paper focuses on applying preferential reasoning to theory revision, both by means of preferences among existing theory rules, and by means of preferences on the possible abductive extensions to the theory. And, in particular, how to prefer among plausible abductive explanations justifying observations.     

Measuring the duration of perception

An analysis is presented of ways in which the total duration of perception of transient visual stimuli may be determined by means of psychophysical judgments of the simultaneity (or relative precedence) of two sensory events. This analysis yields a new method for measuring the duration of perception that only requires judgments of the simultaneity of the offset of one visual target with the onset of another (“offset-onset” judgments), and is thus free of differential biases between onset-onset and offset-onset judgments of simultaneity which could be involved in previous measurements. When three or more perceived durations need to be determined, the new method is more efficient than earlier methods; it requires measurement of only one PSE in order to evaluate one response duration as compared to two PSEs per response duration for previous methods. We also describe ways of determining the presence of some kinds of biases and quantitatively evaluating the magnitude of bias in the new method, as well as bias in onset-onset or offset-offset judgments of simultaneity alone; such evaluations of differential bias were not possible for the earlier methods. An experimental example of a bias analysis is described. No significant biasing effects were detected in the measures of perceived duration that were extracted as either retinal location or background luminance was changed, although background luminance itself markedly influenced the values of perceived duration.     

Vowel perception: A neuroradiological localization of the perception of vowels in the human cortex

Whether the perception of vowels takes place in the right or left cerebral hemisphere, or is dependent on bilateral cortical processes, is of importance in our treatment of patients with language deficiencies. To investigate this problem a phonetic test with a series of vowellike stimuli was administered to 68 right-handed adult patients with cerebral lesions, mainly of vascular origin. The results were compared to the results in a control group of 19 speech therapists. Second, a neuroradiologic method was developed in order to visualize the anatomic site of Wernicke's area in the left hemisphere on CT scans. This method formed the basis for an evaluation of the extent and localization of the patients' lesions in Wernicke's area. Of 46 patients with lesions in the left hemisphere, 19 had no perceptual disturbances and 27 had severe perceptual disturbances with lesions predominantly located in Wernicke's area. Twenty-two patients with lesions in the corresponding area in the right hemisphere showed no perceptual disturbances. The results of this investigation appear to indicate that the perception of vowels in right-handed persons is unilaterally located in Wernicke's area in the left hemisphere.     

The independence of size perception and distance perception

Research on distance perception has focused on environmental sources of information, which have been well documented; in contrast, size perception research has focused on familiarity or has relied on distance information. An analysis of these two parallel bodies of work reveals their lack of equivalence. Furthermore, definitions of familiarity need environmental grounding, specifically concerning the amount of size variation among different tokens of an object. To demonstrate the independence of size and distance perception, subjects in two experiments were asked to estimate the sizes of common objects from memory and then to estimate both the sizes and the distances of a subset of such objects displayed in front of them. The experiments found that token variation was a critical variable in the accuracy of size estimations, whether from memory or with vision, and that distance had no impact at all on size perception. Furthermore, when distance information was good, size had no effect on distance estimation; in contrast, at far distances, the distances to token variable or unknown objects were estimated with less accuracy. The results suggest that size perception has been misconceptualized, so that the relevant research to understand its properties has not been undertaken. The size-distance invariance hypothesis was shown to be inadequate for both areas of research.     

Psychophysical features of the transition from pure heat perception to heat pain perception

The psychophysical features of the transition from the pure heat to the heat pain range were studied in 25 healthy subjects (mean age 28.8 years). Thirty short heat stimuli from ?1.6° C to + 1.6° C relative to the pain threshold were applied to the thenar of the left hand with an apparatus containing a Peltier thermode (nine different temperatures at 0.4°C intervals). The subjects rated the sensation intensity on a visual analogue scale. The resulting stimulus/sensation intensity relations could be explained equally well (same goodness of fit) by a model with a power function (PF) and by a model with two linear regression lines (TLR), one for stimulus intensities below and one for those above the pain threshold and intersecting at the pain threshold. The slopes of the TLR model were significantly larger above the pain threshold than below it. The PF model produced exponents between 1.8 and 1.9. We conclude that to describe the transition area, it is sufficient to use simple linear models for both the pure heat and the heat pain ranges.     

Determinants of the perception of choice

Two experiments were conducted to investigate possible determinants of perceived choice. The first experiment employed an observer paradigm and the second employed an actor paradigm. The results of both studies provided evidence for the hypotheses that perceived choice will be greater when there is a small difference in attractiveness between outcome alternatives than when there is a large difference and under conditions of low certainty about the attractiveness of each outcome alternative than under conditions of high certainty. Also, the results of both studies provided some evidence for the hypothesis that the effect of the relative difference in attractiveness upon perceived choice will be greater under conditions of low certainty than under conditions of high certainty. The hypothesis that perceived choice will be less when there is no difference in attractiveness between outcome alternatives than when there is a small difference was not supported by the results of the first experiment but was supported by the results of the second experiment. The hypothesis that perceived choice will be greater the more time a person takes to select an action from possible actions was supported by results of the first experiment but not by those of the second experiment. The results for the relative difference and certainty variables were discussed in terms of a theoretical analysis of perceived choice.     

Alternative revision theories of truth

The Revision Theory of Truth (Gupta/Belnap 93) has been challenged in A. M. Yaqb's recent book The Liar Speaks the Truth. Yaqb suggests some non-trivial changes in the original theory — changing the limit rule — to avoid certain artifacts. In this paper it is shown that the proposed changes are not sufficient, i.e., Yaqb's system also produces artifacts. An alternative solution is proposed and the relation between it and Yaqb's solution is explored.