Pain cues and uncertainity as determinants of aggression in a situation involving repeated instigation.

In contrast to the Buss aggression paradigm, a situation was employed in which subjects were given an expanded range of response options and were exposed to instigation throughout their response period. It was found that (a) despite these changes pain cues depressed aggressiveness in the present situation as they generally do in the Buss paradigm, but that this effect only occurred where the subjects' aggression was initially ineffective in changing their target's behavior; (b) situational uncertainity, which is minimal in a Buss-type situation, was related to aggressiveness; (c) subjects tended to match rather than attempt to control the responses of the target; and (d) the present paradigm is capable of isolating a personality variable related to overall aggressiveness. These data are discussed in terms of other recent paid cue studies that deviate from the standard Buss situation. Generally, the findings suggest the potential of increasing the range of situations in which aggression is studied.     

An analysis of the word-superiority effect

It is easier to decide which of two letters was presented tachistoscopically if the critical letter was in a word rather than in a scrambled word. We showed that this word-superiority effect holds just as strongly for pronounceable nonwords as for words, even when the critical letters are constant over all trials. This finding rules out word meaning and familiarity as variables accounting for the effect. In addition, it was found that the superiority of pronounceable stimuli holds for two-letter stimuli as well as four, and it is therefore concluded that the effect is not due to a memory limitation. An explanation of the effect in terms of the use of additional acoustic information is ruled out by showing that the effect was not diminished when the two possible words sounded exactly alike. An experiment using correctly and incorrectly spelled chemical formulas suggested that spelling regularities, regardless of pronounceability per se, account for the superiority effect. Finally, when decisions about two critical letters must be made on each trial, the correlation between being correct on one and on the other is higher for pronounceable stimuli under some conditions.     

The threshold for successiveness

In Experiment 1, three stimuli were presented on each trial; the second and third were simultaneous. Ss said which of the three they saw first and then made a different second guess. Second guesses were correct more often than chance when first guesses were wrong, contradicting the predictions of a psychological moment theory. Psychometric functions are inconsistent with a theory which holds that Ss can order their perceptions and that errors result from lack of correspondence between this order and that of the stimuli. In Experiment 2, two pairs of stimuli, each simultaneous or successive, were presented on each trial, the interval between their onsets varying, and Ss guessed whether each was successive. A moment-like cyclic process affecting the perception of successive stimuli should raise the correlation between responses when both pairs were successive and beginning at the same time; this was not found.     

Suppression of behavior by timeout punishment when suppression results in loss of positive reinforcement

This investigation, using rats as subjects and punishment by timeout for responses maintained on a ratio schedule, sought to determine whether behavior would be suppressed by timeout punishment when such suppression also reduced reinforcement density or frequency. A series of experiments indicated that timeout punishment suppressed responding, with the degree of suppression increasing as a function of the duration of the timeout period. Suppressive effects were found to decrease as a function of increases in deprivation (body weight) and were eliminated when the punished response also was reinforced. It was concluded that timeout can produce aversive effects even when loss of reinforcement results. An alternative interpretation of the findings, based on the effects of extinction periods and delay of reinforcement on chained behavior, was discussed.     

Facilitation and suppression of human loss-avoidance by signaled, unavoidable loss

A 15-sec stimulus followed by unavoidable monetary loss was presented to human subjects who were avoiding loss on a free-operant schedule. As has been observed in studies where shock is the aversive event, initial reactions to the pre-loss stimulus were transient increases in overall and stimulus rates. Unlike shock studies, continued training produced decreased rates, in the presence of the 15-sec stimulus, which were maintained in two of three subjects. Subsequent observations indicated that lowered rates were a function of the subject's rate of avoidance responding, the duration of the stimulus, and the scheduling of avoidable losses. Increasing the duration of the stimulus eliminated lowered rates in the presence of the stimulus and subsequent exposures to conditions which previously produced lowered rates did not result in recovery of the phenomenon. Introduction of the pre-loss stimulus on an extinction baseline (avoidable losses were omitted), however, reinstituted lowered rates. It is proposed that the pre-loss stimulus assumed discriminative control over low rates because responding in the presence of the stimulus was ineffective in avoiding the unavoidable loss. Recovery from lowered rates is attributed to the occurrence of avoidable losses during the stimulus period, and maintenance of lowered rates on the extinction schedule to the omission of such avoidable losses.     

Mathematical Explanation and Epistemology: Please Mind the Gap

This paper draws together two strands in the debate over the existence of mathematical objects. The first strand concerns the notion of extra‐mathematical explanation: the explanation of physical facts, in part, by facts about mathematical objects. The second strand concerns the access problem for platonism: the problem of how to account for knowledge of mathematical objects. I argue for the following conditional: if there are extra‐mathematical explanations, then the core thesis of the access problem is false. This has implications for nominalists and platonists alike. Platonists can make a case for epistemic access to mathematical objects by providing evidence in favour of the existence of extra‐mathematical explanations. Nominalists, by contrast, can use the access problem to cast doubt on the idea that mathematical objects play a substantive role in scientific explanation. 1     

Analog scale,magnitude estimation,and person trade‐off as measures of health utility: biases and their correction

Subjects judged the disutility of health conditions (e.g. blindness) using one of them (e.g. blindness+deafness) as a standard, using three elicitation methods: analog scale (AS, how bad is blindness compared to blindness+deafness?); magnitude estimation (ME, blindness+deafness is how many times as bad as blindness?); and person trade‐off (PTO, how many people cured of blindness is as good as 10 people cured of blindness+deafness?). ME disutilities of the less bad condition were smallest, and AS was highest. Interleaving PTO with ME made PTO more like ME. AS disutilities were inconsistent with direct judgments of differences between pairs of conditions. ME and PTO judgments were internally inconsistent: e.g. the disutility of one‐eye‐blindness relative to blindness+deafness was larger than predicted from comparison of each to blindness. Consistency training reduced inconsistency, increased agreement between AS and PTO, and transferred from one method to the other. The results support the use of consistency checks in utility elicitation. Copyright © 2001 John Wiley & Sons, Ltd.