A computerized system for monitoring and controlling intracranial electrical self-stimulation behavior

An automated system for measuring intracranial self-stimulation behavior is described. The system consists of two Commodore 6502 microcomputers interfaced with a constant-current generator and a standard operant chamber. The system hardware allows sine- and square-wave stimulation. Stimulus intensity can be varied in 256 steps between 0 and 100, 0 and 500, or 0 and 1,000 /µA. The system programs, which are written in machine language, allow the control of various schedules of reinforcement, the counting of operant responses and reinforcements, the measurement of interresponse intervals, and the storage of the data on disk. The software is designed for the determination of the threshold of reinforcement, on the basis of the titration of postreinforcement pauses caused by changeover in schedule control between concurrent continuous reinforcement and fixed ratio schedules.     

Hand Test characteristics of severely behavior handicapped children

The Hand Test was administered to 98 severely behavior handicapped (SBH) children and a matched control group of public school children. The withdrawal score and associated variables, indicative of severe psychopathology, differentiated the two groups. In addition, a qualitative analysis of the SBH protocols tentatively suggested a preponderance of four behavioral types that could be described as the underproductive, perseverative, psychotic and impulsive child. Implications of these findings are discussed.     

A simple but powerful theory of the moon illusion

Modification of Restle's theory (1970) explains the moon illusion and related phenomena on the basis of three principles: (1) The apparent sizes of objects are their perceived visual angles. (2) The apparent size of the moon is determined by the ratio of the angular extent of the moon relative to the extents subtended by objects composing the surrounding context, such as the sky and things on the ground. (3) The visual extents subtended by common objects of a constant physical size decrease systematically with increasing distance from the observer. Further development of this theory requires specification of both the components of the surrounding context and their relative importance in determining the apparent size and distance of the moon.     

The spontaneous facial expression of differential positive and negative emotions

This research examines the expression of positive and negative emotions under minimally social conditions. Male and female encoders were covertly videotaped while they viewed and made written ratings of their responses to a number of slides, using a list of emotion terms derived from members of the same subject pool. Results show that, even when the social nature of the situation is reduced to a minimum, the experience of some emotions is reflected on the face, and there is clear evidence for differential expression of certain positive emotions. However, the reduced social nature of the situation removes the usual female encoding advantage, supporting the suggestion that this reflects the operation of display rules. The ability to recognize the minimal expressions in this study is related to both gender and emotion type in ways that may be explained by a socialization hypothesis.I wish to thank Gill Thorpe and Eiko Mori for running the decoding subjects of this study, and Sylvie Collins, Tony Manstead, and two anonymous reviewers for comments on an earlier version of the paper.     

Inductive inference in the limit of empirically adequate theories

Most standard results on structure identification in first order theories depend upon the correctness and completeness (in the limit) of the data, which are provided to the learner. These assumption are essential for the reliability of inductive methods and for their limiting success (convergence to the truth).The paper investigates inductive inference from (possibly) incorrect and incomplete data. It is shown that such methods can be reliable not in the sense of truth approximation, but in the sense that the methods converge to empirically adequate theories, i.e. theories, which are consistent with all data (past and future) and complete with respect to a given complexity class of L-sentences. Adequate theories of bounded complexity can be inferred uniformly and effectively by polynomial-time learning algorithms. Adequate theories of unbounded complexity can be inferred pointwise by less efficient methods.     

Analysis of long-term stress reactions in emergency room patients: An initial study

The psychological stress reactions of 44 family medicine patients who were treated in the emergency room were examined approximately a year after the event. Patients were assessed on several psychological measures, including one for posttraumatic stress disorder (PTSD), and on their perception of how stressful the event was initially and now. Results show continuing stress reactions related to the emergency room event. Three patients endorsed symptoms indicating full PTSD and 13 appeared to have at least partial PTSD. Age appeared to be a factor in the presence of stress symptoms and in degree of perceived communication with the physician.     

Spontaneous decay of response-code activation

Summary Two experiments investigated whether theTwo experiments investigated whether the Simon effect (i. e.., faster responses to spatially corresponding than to noncorresponding stimuli, with stimulus location being irrelevant) is affected by the frequency of noncorrespondence trials. Stimulus discriminability (Experiment 1) and immediate or delayed stimulus formation (Experiment 2) was varied in order to manipulate the temporal relationship between coding of the relevant stimulus information and of stimulus location. As was expected, the Simon effect decreased from high to low discriminability and from immediate- to delayed-stimulus formation. This is consistent with the notion of a gradual decay of location-induced response-code activation. Moreover, the Simon effect decreased with increasing frequency of noncorrespondence trials and was even reversed with higher frequency. This demonstrates strategic preparation of stimulus processing and/or response selection based on irrelevant location information. However, frequency did not modify the interaction between S-R correspondence and stimulus discriminability or stimulus formation, this suggesting that code decay is not a result of a strategy, but an automatic process.