An infrared system for the detection of a pigeon''s pecks at alphanumeric characters on a TV screen: the dependency of letter detection on the predictability of one letter by another.

Three pigeons pecked at letters of the alphabet and at the symbol "?" displayed on a computer-driven cathode ray screen. A 4 by 4 matrix of infrared emitting and detecting diodes and associated circuitry identified the location of a pigeon''s responses to the screen. Responses at the target letter T were probabilistically reinforced with food whenever T appeared in a string of three letters in the middle of the screen. Responses at the symbol "?" appearing below this string were probabilistically reinforced whenever T did not appear. The letter F anywhere in the three-character string either strongly predicted the occurrence of the target letter T, in two conditions, or predicted its nonoccurrence, in a third. This manipulation of the frequency with which the familiar letter F predicted T was shown to change the function relating probability of a correct peck at the symbol "?" to the number of Fs in the string. This effect may be interpreted as an instance of the phenomenon where an organism''s acquired knowledge changes what it sees.     

Discriminated interresponse times: role of autoshaped responses.

When discriminated interresponse-time (IRT) procedures have been used to assess preference relations among temporally extended operants, deviations from matching have been obtained. Using a yoked-control procedure, the present study found that key pecking in a discriminated IRT procedure has two sources of strength--that arising from the response-reinforcer contingency that is explicitly arranged, and that arising from a stimulus-reinforcer contingency that is a by-product of the explicitly arranged contingency. The key pecking of all lead birds, and that of 3 of the 4 birds exposed to a yoked autoshaping procedure, was controlled by the keylight that signaled the lead birds' criterion IRTs. Because stimulus control of key pecking by the keylight, whether autoshaped or discriminative, fosters deviations from matching, the discriminated IRT procedure does not provide an appropriate basis for conclusions about preference relations among IRTs.     

Hippocampal stimulation disrupts spatial working memory even 8 h after acquisition

The present experiment used hippocampal stimulation to determine the temporal gradient of consolidation of spatial working memory. Rats were trained to perform a spatial working memory task on a radial maze with 12 arms. Each rat went to the ends of 6 arms to obtain a food reward. After 8 h, the rat chose among all the arms to find the ones not previously chosen (and consequently still having food). During some test sessions, the hippocampus was stimulated electrically either at a current level just high enough to produce an electrophysiological seizure, or at a current level below this seizure threshold. Stimulation occurred at one of five intervals (0 to 8 h) following the completion of the first six choices. During other test sessions, the hippocampus was not stimulated. After seizure stimulation, the number of retroactive errors (returning to arms chosen prior to stimulation) increased at all delay intervals; the number of proactive errors (returning to arms chosen after stimulation) increased only with the delay of 8 h. Subthreshold stimulation had no influence on either type of error. These results indicate that normal hippocampal function is required for the maintenance of spatial information in working memory, and that the time course of consolidation of this information is significantly greater than that seen in other types of memory, or consolidation may not take place at all.     

“Snips and snails and puppy dog tails”: Gender of agent,recipient, and observer as determinants of perceptions of discipline

This study examined the role of gender of observer, parent, and child on judgments of the severity, appropriateness, and consequences of various forms of discipline. Young adults read stories describing a disciplinary encounter between parent and child and made required judgments. Consistent gender differences emerged. Females judged the discipline more harshly than males, rating it as more severe, more abusive, less appropriate, and more likely to result in emotional harm. Discipline of daughters was judged to be harsher than identical treatment of sons, particularly when the discipline was administered by the father. The implications of differential judgments are discussed.     

A longitudinal comparison of couples with sex-typical and non-sex-typical orientations to intimacy

The present study was designed to investigate the relationship experience of males and females who do not conform to sex-typical orientations to intimacy. One hundred sixty-three couples' and 88 nondating singles' (total N=414) responses to the Relationship World Index—Version 2 (RWI-2) were analyzed via discriminant analysis to determine if subjects' sex could be predicted accurately upon the basis of their RWI-2 scores. One discriminant function was found which was significant by the Wilks' lambda test [x²(60)=140.57, p<.001]; the procedure correctly classified 76% of the respondents. Those who were classified correctly were considered sex-typical and the remaining 24% of the sample was considered non-sex-typical in their orientations to intimacy. Additional analyses using data from a 6-month longitudinal study located qualities which significantly distinguished sex-typical from non-sex-typical subjects and couples in which at least one member was non-sex-typical from couples in which both members were classified as sex-typical.     

A paradoxical prediction from locus of control

Individual differences in attribution have been little researched. Beliefs about locus of control have been taken to be stable and important differences between people. They may provide some of the background assumptions on which people base their explanations of actions, especially insofar as these explanations imply that the cause of an action was within the agent or his environment, and that the action was or was not under the agent's control. Respondents were therefore asked to fill in Rotter and Levenson locus of control questionnaires and to provide explanations or ask questions about several actions. It was hypothesized that internals would be inclined to go for explanations which were personal and implied high control, while externals would not. However, what emerged was the paradoxical finding that internals provided explanations which implied that the causes of the actions lay outside the agent, while externals provided ones which implied that the causes lay within. This result is discussed in terms of the difference between actions and outcomes, and the possibility that an important difference between people may be in the rigidity and simplicity of their beliefs about causality.     

The pathological left-handedness syndrome

A clinical syndrome of pathological left-handedness (PLH) is proposed to identify the pattern of correlative changes in lateral development associated with early brain injury in some manifest left-handers. This syndrome is believed to be caused by a hemispheric lesion that is predominantly left-sided (or bilateral asymmetric), which onsets before Age 6, and which encroaches upon the critical speech zones of the frontotemporal/frontoparietal cortex. The pattern of changes may include any or all of the following features: shifts in manual dominance, trophic changes in the extremities, transfer of hemispheric speech, and/or intrahemispheric reorganization of visuospatial cognitive functions. Although some of these correlates of PLH have long been known, they have not been recognized as an interrelated pattern of traits that constitute a clinical syndrome. Identification of these individuals, all manifest left-handers, will be shown to have implications for diagnosis/remediation and for models of recovery of function.