Human Impulsivity and Choice: A Challenge to Traditional Operant Methodology

“Impulsivity” refers to the choice of an immediate, small reinforcer over a delayed, large reinforcer. Traditional operant methods (single-subject designs, free-operant choice procedures) have frequently been used to study impulsivity in nonhuman subjects but, curiously, have not been applied to humans. Data are reported replicating and extending previous results obtained with an alternative paradigm using a group-statistical design and discrete-trials choice procedure. Adults chose between schedules differing in delay and/or amount of reinforcement, the reinforcer being slides of entertainment and sports personalities. Delay was defined as the interval between a choice response and onset of a slide, amount as the duration of viewing time. Some participants exhibited impulsivity even though such behavior reduced total viewing time. All participants exhibited impulsivity when this behavior increased total viewing time and was thus adaptive. Traditional operant methods may be ineffective in producing the maladaptive form of impulsivity.

     

Estimating the standard errors of rotated factor loadings by jackknifing

The jackknife by groups and modifications of the jackknife by groups are used to estimate standard errors of rotated factor loadings for selected populations in common factor model maximum likelihood factor analysis. Simulations are performed in whicht-statistics based upon these jackknife estimates of the standard errors are computed. The validity of thet-statistics and their associated confidence intervals is assessed. Methods are given through which the computational efficiency of the jackknife may be greatly enhanced in the factor analysis model.Computing assistance was obtained from the Health Sciences Computing Facility, UCLA, sponsored by NIH Special Research Resources Grant RR-3.The author wishes to thank his doctoral committee co-chairmen, Drs James W. Frane and Robert I. Jennrich, UCLA, for their contributions to this research.     

Sex-role stereotypes and requisite management characteristics: A current replication

A mailed survey was conducted to determine differential stereotypes concerning Men, Women, and Successful Managers. A moderately high degree of similarity was found between stereotypes of Men and Managers, but none between Men and Women nor Women and Managers for male respondents. Female respondents perceived a moderately high similarity between Men and Managers and a slight degree of similarity between Women and both Men and Managers.     

Asymmetry of visual interference

This research studies lateral interference among items in the visual field under conditions in which central cognitive factors such as attention and memory limitations are eliminated or controlled for. Under these conditions lateral masking is still found, and it is still asymmetrical (peripheral items interfere with recognition of central items more than central with peripheral). These experiments therefore add to the evidence that both lateral interference and the asymmetry of interference have a component that does not result from cognitive strategies. The experiments also add to the evidence that the asymmetry effect at the sensory level can be attributed to the falloff in acuity from the center to the periphery of the retina, since the mean eccentricity of the target-mask cluster is more peripheral with a peripheral mask than with a central mask. The hypothesis is advanced that the asymmetry effect, as well as lateral interference itself, at the sensory level results from the grouping of target and mask into a single Gestalt-like configuration. The final experiment in the series supports this hypothesis     

On the distinction between physical and psychological stressors

The distinction between physical and psychological stressors is reviewed, including some implications for anxiety research. The relationships among anxiety states, anxiety traits, and type of stressor are complex and can be influenced by such factors as the preciseness by which the stressor is identified, how it is measured, and the coping mechanisms available to deal with the stress. The choice of appropriate state and trait anxiety measures is crucial when assessing the differential impact of physical and psychological stressors.     

Physiological response and task performance in like- and cross-sex competition

The relationship between a subject's sex and his or her behavior in a competitive situation was examined. Male and female subjects completed three tasks, first by themselves and then against either a male or female competitor. A 2×2 design (sex of the subject × sex of the competitor) was thereby created. The dependent measures were the subject's performance and his or her heart rate during each task. Since the relationship between a subject's sex and competitive behavior was expected to be situationally specific, three different kinds of tasks were used: anagram, perceptual-motor, and arithmetical. Results were not consistent with predictions based on Horner's fear of success model (1968). Competition with either sex was found to increase performance level in both sexes on all three tasks. The only sex-related effect found to be consistent across tasks was that both male and female subjects had a greater increase in heart rate when competing against a male than when competing against a female. This heart rate increase was interpreted as an indicator of increased anxiety or arousal.This research was supported by a University of Pittsburgh, Faculty of Arts and Sciences research grant to the second author. The assistance of H. DeGood, L. Paul, and T. Rusiewicz in collection of the data presented here is gratefully acknowledged.     

LABSIM: A data-driven simulation program for instruction in research design and statistics

LABSIM is a general-purpose FORTRAN program that simulates the collection of data from laboratory experiments. Student-specified parameters are employed in a multiple-regression model that allows manipulation or control of up to 10 potential independent variables. Variables may be discrete (up to eight levels), continuous, or range (e.g., IQ). Raw scores may be generated for up to six groups, optionally accompanied by statistical analyses for simple between- or within-subjects designs or for factorial designs, including mixed factorial designs. Seventeen models (content areas) are currently available. As contrasted with other simulation programs, LABSIM models are exceptionally easy to design and implement; no computer expertise is required. Summary data automatically collected by LABSIM indicate a high success rate and extensive use of the program beyond course requirements. The current version of LABSIM is available in either batch or interactive form. A newer version that allows the simultaneous manipulation of up to three independent variables will be available soon.     

Mapclus: A mathematical programming approach to fitting the adclus model

We present a new algorithm, MAPCLUS (MAthematicalProgrammingCLUStering), for fitting the Shepard-Arabie ADCLUS (forADditiveCLUStering) model. MAPCLUS utilizes an alternating least squares method combined with a mathematical programming optimization procedure based on a penalty function approach, to impose discrete (0,1) constraints on parameters defining cluster membership. This procedure is supplemented by several other numerical techniques (notably a heuristically based combinatorial optimization procedure) to provide an efficient general-purpose computer implemented algorithm for obtaining ADCLUS representations. MAPCLUS is illustrated with an application to one of the examples given by Shepard and Arabie using the older ADCLUS procedure. The MAPCLUS solution uses half as many clusters to achieve nearly the same level of goodness-of-fit. Finally, we consider an extension of the present approach to fitting a three-way generalization of the ADCLUS model, called INDCLUS (INdividualDifferencesCLUStering).We are indebted to Scott A. Boorman, W. K. Estes, J. A. Hartigan, Lawrence J. Hubert, Carol L. Krumhansl, Joseph B. Kruskal, Sandra Pruzansky, Roger N. Shepard, Edward J. Shoben, Sigfrid D. Soli, and Amos Tversky for helpful discussions of this work, as well as the anonymous referees for their suggestions and corrections on an earlier version of this paper. We are also grateful to Pamela Baker and Dan C. Knutson for technical assistance. The research reported here was supported in part by LEAA Grant 78-NI-AX-0142 and NSF Grants SOC76-24512 and SOC76-24394.     

Reactions to internal and external criticism of outgroups: social convention in the intergroup sensitivity effect

Recent research has documented the intergroup sensitivity effect (ISE) whereby people respond more favorably to internal versus external criticism of their group. The present studies examine the reactions of bystanders who do not belong to the criticized group and whose reactions are therefore more likely to be informed by social conventions than by defensiveness. Studies 1 and 2 presented British participants with criticisms of Australians, manipulating their ostensible source. These British bystanders exhibited the ISE, responding more favorably to the speaker and comments when the critic was Australian rather than non-Australian. These responses were driven by the perceived motives of speakers rather than their level of experience with the group (Study 2). Study 3 provides direct evidence that internal criticism is more conventionally acceptable than is external criticism.