Typicality effects in artificial categories: is there a hemisphere difference?

In category classification tasks, typicality effects are usually found: accuracy and reaction time depend upon distance from a prototype. In this study, subjects learned either verbal or nonverbal dot pattern categories, followed by a lateralized classification task. Comparable typicality effects were found in both reaction time and accuracy across visual fields for both verbal and nonverbal categories. Both hemispheres appeared to use a similarity-to-prototype matching strategy in classification. This indicates that merely having a verbal label does not differentiate classification in the two hemispheres.     

Range and regression, loudness scales, and loudness processing: toward a context-bound psychophysics

How does context affect basic processes of sensory integration and the implicit psychophysical scales that underlie those processes? Five experiments examined how stimulus range and response regression determine characteristics of (a) psychophysical scales for loudness and (b) 3 kinds of intensity summation: binaural loudness summation, summation of loudness between tones widely spaced in frequency, and temporal loudness summation. Context affected the overt loudness scales in that smaller power-function exponents characterized larger versus smaller range of stimulation and characterized magnitude estimation versus magnitude production. More important, however, context simultaneously affected the degree of loudness integration as measured in terms of matching stimulus levels. Thus, stimulus range and scaling procedure influence not only overt response scales, but measures of underlying intensity processing.     

Cholinergic-dopaminergic interactions in cognitive performance

Both acetylcholinergic (ACh) and dopaminergic (DA) systems have been found to be crucial for the maintenance of accurate cognitive performance. In a series of studies examining those aspects of cognitive function revealed by the radial-arm maze, we have found that these two neurotransmitter systems interact in a complex fashion. Choice accuracy deficits in the radial-arm maze can be induced by blockade of either muscarinic- or nicotinic-ACh receptors. The choice accuracy deficit induced by blockade of muscarinic receptors with scopolamine can be reversed by the DA receptor blocker, haloperidol. The specific DA D1 blocker SCH 23390 also has this effect, whereas the specific D2 blocker raclopride does not, implying that it is D1 blockade that is critical for reversing the scopolamine effect. On the other hand, the choice accuracy deficit induced by nicotinic blockade with mecamylamine is potentiated by haloperidol. This effect is also seen with the D2 antagonist raclopride, but not with the D1 antagonist SCH 23390, implying that it is the D2 receptor which is important for the potentiation of the mecamylamine effect. The relevance of the D2 receptor for nicotinic actions on cognitive function is emphasized by the finding that the selective D2 agonist LY 171555 reverses the choice accuracy deficit caused by mecamylamine. Nicotinic and muscarinic blockade are synergistic in the deficit they produce. Antagonist doses subthreshold when given alone produce a pronounced impairment when given together. This latter deficit can be reversed by the D2 agonist LY 171555. These studies have outlined the complex nature of ACh-DA interactions with regard to cognitive function. Possible neural circuits for these interactions are discussed. The effectiveness of these selective DA treatments in reversing cognitive deficits due to ACh underactivation suggests a novel approach to treating cognitive dysfunction in syndromes such as Alzheimer's disease.     

Ethanol-mediated taste aversions and state-dependency in preweanling (16-day-old) rats

Requirements for conditioning of an ethanol-mediated taste aversion in 16-day-old rat pups were examined. Experiment 1 demonstrated that preweanling rats are capable of acquiring, in two trials, an aversion to a 15% sucrose solution when followed by intragastric intubation of a 1.2 g/kg dose of 17% v/v ethanol, but not when followed by a 0.4 g/kg dose. Comparison was with control animals given sucrose followed by an equivalent volume isocaloric Half and Half. When the 0.4 g/kg dose of ethanol preceded sucrose presentation by 30 min (Experiment 2), the aversion was learned, suggesting that the effective delay between the sucrose and the critical consequences of the ethanol had been too long with the former procedure. Expression of the sucrose aversion required, however, the reinstatement of the context of intoxication--state-dependent retention. Finally, the results of Experiment 3B indicated that, in addition to the association between the sucrose and the aversive consequences of alcohol intoxication, the orosensory cues resulting from alcohol's direct elimination, via such processes as respiration and salivation, became associated with the appetitive properties of the sucrose. This was evidenced by a conditioned increase in preference for ethanol odor. Possible age-related differences in the ability to associate stimuli with alcohol's unconditioned consequences, and in state dependency are discussed.     

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.     

Performance objectives in the stance phase of human pathological walking

Permanent disruption of aspects of a highly learned skill such as walking force adaptations to occur to the movement. Firstly the body must determine what factors will guide the formation of the new walking pattern, and secondly that new movement pattern must be learned. Frequently the questionable assumption is made that the performance objectives of the new skill are the same as the original. This work used non-linear optimal control and multiple segment simulation to evaluate the ability of several possible objective functions to predict pathological walking patterns. These predictions were then also compared to the results from normal walking. Preliminary results indicate the performance objectives of pathological gaits may be quite different from those of normals. Some support was also provided for the existence of simultaneous multiple performance objectives in complex movements.     

The internal clock: evidence for a temporal oscillator underlying time perception with some estimates of its characteristic frequency

Evidence for the proposition that human time perception is determined by an internal clock is largely indirect. It would strengthen the case for this hypothesis if a model for the internal clock were available from which predictions could be derived and tested, and if the basic parameter of such a model, the frequency at which the clock runs, could be estimated. A model for an internal temporal pacemaker is briefly described and its properties are explored by computer simulation. Results are obtained that provide a basis for predicting that, under appropriate conditions, interference between an imposed rhythm and the frequency of a temporal oscillator may cause perturbations in temporal judgment which are related to the characteristic frequency of that oscillator. Experimental data are reported which appear to demonstrate such an interference pattern. These results allow some estimates of the characteristic frequency of the temporal oscillator to be obtained.     

Regression analyses of repeated measures data in cognitive research

Repeated measures designs involving nonorthogonal variables are being used with increasing frequency in cognitive psychology. Researchers usually analyze the data from such designs inappropriately, probably because the designs are not discussed in standard textbooks on regression. Two commonly used approaches to analyzing repeated measures designs are considered in this article. It is argued that both approaches use inappropriate error terms for testing the effects of independent variables. A more appropriate analysis is presented, and two alternative computational procedures for the analysis are illustrated.     

Men's heterosocial skill and attitudes toward women as predictors of verbal sexual coercion and forceful rape

This study assessed whether men's heterosocial skill and attitudes toward women are related to verbal and physical sexual coercion in a nonincarcerated population. We predicted that heterosocially skilled men would be more likely than unskilled men to have engaged in verbal sexual coercion, whereas unskilled men would be more likely than skilled men to have engaged in physical sexual coercion (i.e., forceful rape). We expected an interaction, with this pattern holding only for men who accepted traditional gender roles or male sexual dominance; men who did not accept these attitudes were expected to be unlikely to have engaged in either verbal or physical coercion. To identify sexually coercive men, we administered questionnaires to 1152 male introductory psychology students. They completed anonymous self-report measures of (a) heterosocial skill, (b) attitudes toward women, and (c) involvement with verbal and physical sexual coercion. Results showed that heterosocially skilled men were more likely than unskilled men to have engaged in verbal sexual coercion, but heterosocial skill was unrelated to forceful rape. Men who accepted traditional gender roles or male sexual dominance were more likely than other men to have engaged in both verbal sexual coercion and forceful rape. There were no interactions. Theoretical issues and treatment implications are discussed.The authors wish to thank Gayla Goolsby, Trudi Zaplac, Diane Collinge, Shelley Davis, Gina Benedicto, and DiAnne Poehl. This paper is based on the second author's Senior Honors Thesis, done as part of the Texas A&M University Undergraduate Fellows Program, which provided funding.     

Ms. and the manager: A tale of two stereotypes

Recent research on the Ms. stereotype suggests a potentially important exception to the strong link between gender and managerial stereotypes observed in the 1970s. Specifically, we hypothesized that a woman who prefers “Ms.” as her title of address would be seen by perceivers of both sexes as more similar in the “requisite” traits of a successful, middle manager than would a woman who prefers a traditional title of address for herself. These hypotheses were tested by having respondents rate a “successful, middle manager” or other stimulus persons varying in titles of address, sex, and marital status. Correlational analyses of respondents' ratings of stimulus persons yielded strong support for the hypotheses. That is, a woman preferring Ms. as her title of address was seen by adult perceivers of both sexes as possessing the “requisite” personality characteristics of a successful, middle manager; whereas a traditionally titled woman was not. Implications of these findings are discussed.