Calling song signals and temporal preference functions in the cricket Teleogryllus leo.

The acoustic display of many cricket species consists of trains of pulses (chirps) with intermittent pauses. Here, we investigated the temporal cues that females of the cricket Teleogryllus leo used to detect a pulse and a chirp pattern on two different time scales. For both patterns, females accepted a wide range of combinations that covered the respective pulse and chirp parameters in the songs of males. In tests with a continuous series of pulses at different modulation frequencies, the transfer function of pattern discrimination was also determined. Females exhibited two ranges of high response scores indicating two temporal filters with an inhibitory interaction. For the modulation frequency of the pulse pattern, the peak of the preference function was rather sharply tuned and at a lower pulse rate than produced by males. These results show that the combined output of both filters did not increase selectivity, but rather enlarged the accepted range of signals.

Influence of phenytoin and phenobarbital on the disposition of a single oral dose of clonazepam.

Clonazepam (CZP) was measured in the plasma of eight subjects for 48 hr after a 0.03-mg/kg oral dose. After pretreatment for 19 days with phenytoin (DPH, 4.3 mg/kg/day), plasma CZP concentrations were determined in the same subjects after another 0.03 mg/kg oral dose of CZP. The same protocol was followed in eight additional subjects using phenobarbital (PB, 1.4 mg/kg/day) instead of DPH. DPH pretreatment lowered mean plasma CZP concentration in 8 of the 12 time points. DPH pretreatment increased CZP clearance by 46% to 58% and decreased CZP half-life (t1/2) by 31%. Both changes were statistically significant. After PB pretreatment the mean plasma CZP concentration was lowered by an average of 11%, but the decrease was statistically significant for only 1 of the 12 time points. PB decreased mean CZP t1/2 by 11% and increased CZP clearance by 19% to 24%, but only the increase in clearance was statistically significant. Both DPH and PB increased CZP clearances and decreased the areas under the plasma concentration-time curves without altering the volumes of distribution. This observation is consistent with induction of CZP metabolism. The overall effect of DPH (4.3 mg/kg/day) was greater than the effect of PB (1.4 mg/kg/day). Neither the DPH or PB had a significant effect on the extent of CZP protein binding.

Right-sided facial asymmetry in infant emotional expression.

In normal adults, emotional expressions tend to be more intense on the left side of the face, while in preschool-age children, no significant bias in facial asymmetry has been found. We examined facial asymmetries during smiling and distress in 59 infants studied longitudinally at 6.5, 10 and 13.5 months of age. In these infants, asymmetric expressions showed a bias toward greater intensity on the right side of the face. The study of infant facial expression may provide clues to the maturation of the cortical control of emotional responses.

Prediction of steady-state plasma levels of amitriptyline and nortriptyline from a single dose 24 hr. level in depressed patients.

Amitriptyline and nortriptyline plasma levels were measured in depressed outpatients 24 hours after a single dose of amitriptyline and following chronic dosing to steady state. Plasma levels of amitriptyline and nortriptyline measured after the single dose correlated highly with steady state plasma levels. Full use as a test to rapidly place patients on a "therapeutic" dosage of drug will need to await a clear delineation of the relationship between blood levels and clinical response for amitriptyline.

Exploring the biology of socialization.

How will the social sciences take advantage of the revolution that has taken place in biology during the past two decades? Over the last fifteen years, neuroimaging has allowed the study of human cognition and emotion within psychology to achieve close alliances with biology through the development of cognitive and affective neuroscience. There is little doubt that a similar alliance between psychology and biology will occur in the domain of human brain development. In principle, understanding how the human brain is organized by experience (epigenetic rules) and how societies instruct their young could produce a link between natural and social science. The late David C. McClelland sought methods to base the social sciences on psychological ideas. McClelland sought to connect the values of achievement and power as coded from children's readers and popular ballads to societal economic growth and conflict. These efforts lacked knowledge of brain mechanisms of memory and attention and an understanding of the role of experience in organizing brain circuitry. Understanding of cognitive and brain systems related to knowledge and action may allow a new approach to forging connections between individual minds and social behavior.

Temperament and the development of personality.

We present a psychobiological approach to personality development, incorporating developmental principles outlined by R. B. Cairns (1979). We review individual differences in temperament and ask how a temperamental approach to personality might be congruent with these complex and flexible principles. We then illustrate the nature of temperamental processes by considering several developmental topics. We first consider the interaction of infant distress-proneness and maternal behavior in the development of attachment. We then describe the development of self-regulatory mechanisms, emphasizing development of conscience, aggression, and mastery motivation. Finally, we briefly review mechanisms of temperament and environment interaction, illustrating these processes through variable developmental pathways for risk of adolescent and adult psychopathology. Throughout, we stress the idea that temperamental models of personality development are dynamic, interactive, and fit well with Cairns's developmental principles.

Use of categorical and individuating information in making inferences about personality.

In three experiments, we explored the effects of categorical information (stereotypes) and case information (traits or behaviors) on judgments about an individual's characteristics. Subjects judged a target person's aggressiveness on the basis of a description containing both a broad social category and specific case information. In Experiment 1, the description included (a) a category that was either weakly or strongly related to aggressiveness and (b) a behavior that was unrelated, moderately diagnostic, or highly diagnostic of aggressiveness. Trait inferences were a function of both the stereotypic and the behavioral information. A single behavior was not sufficient to override the category effect. In Experiment 2, temporally consistent behaviors were presented as case information; under these conditions, category information had no effect on trait judgements. This finding was extended in Experiment 3 in which subjects predicted behaviors on the basis of the target person's sex and a moderately diagnostic trait.

In-group-out-group differences in the perceived efficacy of coercion and conciliation in resolving social conflict.

In-group and out-group members were predicted to differ in the judged efficacy of coercion and conciliation as social influence strategies, with coercion perceived as relatively more effective than conciliation by outgroup rather than ingroup members. In Experiment 1, all subjects read a description of a conflict between two hypothetical nations, with half of the subjects taking the perspective of the defense minister of one nation and half the perspective of the other. Each nation was developing weapons that increased rather than decreased the likelihood of war. Each subject was asked to consider the effectiveness of an array of social influence strategies, varying in degree of coercive or conciliatory tone, that could modify the actions of either their own or the other country. The prediction was confirmed, both by indexes of rated effectiveness and by a ranking of effectiveness. In Experiment 2, the perspective-taking manipulation was weakened by merely asking subjects to imagine that they were citizens of one country or the other. Experiment 2 replicated the basic findings of Experiment 1. The implications of these results for international conflict, with particular reference to the arms race, are discussed.

Inferring category attributes from exemplar attributes: geometric shapes and social categories.

Three experiments tested the hypothesis that judgments about the attributes of categories are disproportionately based on the characteristics of exemplars that best fit the category. In the first 2 experiments, subjects were presented with good and bad exemplars of categories with defining attributes (rectangles, triangles, pentagons, and ellipses) in which different colors were arbitrarily paired with the good and poor examples. In both experiments, subjects erroneously judged the colors paired with the good exemplars as more frequent than colors paired with the poor exemplars. A third experiment, using social categories, examined whether attributes associated with a single category member were more likely to generalize to the category as a whole for prototypical than for nonprototypical category members. Subjects were presented with information about individual fraternity members who varied in prototypicality, and the tendency to infer a target behavior (liberal vs. conservative voting behavior) from the individual fraternity member to the fraternity as a whole increased with the prototypicality of the category member. Implications for the contact hypothesis, category-exemplar relations, and belief stability are discussed.

Contrast and accentuation effects in category learning.

This study examines the accentuation of perceived intercategory differences. In Experiment 1, 2 sets of trait adjectives were presented--a neutral set and a set of either favorable traits or unfavorable traits. Ss estimated the mean favorability of each set. The mean favorability of the neutral set was then increased or decreased by adding new traits. As predicted, the estimated mean favorability of the neutral set changed more when the set became more distinct from a contextual set than when it became more similar. In Experiment 2, estimated category means were displaced away from each other (contrast effect), and they moved even farther apart when new information increased the variability of trait favorability (accentuation effect). This change was illusory because the actual category means remained constant. Experiment 3, in which trait adjectives described members of 2 novel groups, replicated Experiment 2. The relevance of contrast and accentuation effects to the development and maintenance of differentiated intergroup perceptions is discussed.

Arousal, affect, and attention as components of temperament.

Contemporary models of human temperament have been based on the general constructs of arousal, emotion, and self-regulation. In order to more precisely investigate these constructs, they were theoretically decomposed into 19 subconstructs, and homogeneous scales were developed to assess them. The scales were constructed through an item-selection technique that maximized internal consistency and minimized conceptual overlap. Correlational and factor analyses suggested that arousal can be usefully assessed in terms of its central, autonomic, and motor components. The emotions of sadness, relief, and low-intensity pleasure were most closely related to the measures of central arousal. Emotions of fear, frustration, discomfort, and high-intensity pleasure were more closely related to measures of attentional control. We discuss these findings in terms of the functional relations between arousal, emotion, and attention.

Category learning and change: differences in sensitivity to information that enhances or reduces intercategory distinctions.

We examined the amenability of abstractions of categories to new and relevant information. In Experiment 1, Ss formed impressions of 2 sets of numbers by periodically estimating the cumulative means of each set. During the 1st half of the procedure, the 2 means were mathematically stable. During the 2nd half of the procedure, the mean of 1 set was modified and the mean of the other set remained unchanged. We predicted and found that the resultant estimates for the modified category changed more when the mean difference between the 2 categories was enhanced than when it was reduced. Experiment 2 suggested that the accentuation effect results from a 2-stage process of category learning (Stage 1) and category change (Stage 2). Experiment 3 replicated the effect with person categories. The relevance of category accentuation is discussed with respect to the modifiability of social beliefs.

Self-anchoring and differentiation processes in the minimal group setting.

In-group favoritism in the minimal group setting was hypothesized to be a function of 2 processes: a tendency to base in-group judgments on the self (self-anchoring) and a tendency to assume 1 group to be opposite of the other (differentiation). In the first 3 experiments, in which the order of rating the self and target group was varied, was categorized and uncategorized participants were given trait information about 1 group and were asked to estimate the level of those traits in the other group. In-group judges tended to base group ratings on the self, whereas out-group and uncategorized judges inferred the 2 groups to be opposite of one another. Experiment 4 attempted to directly assess the direction of inference between self and in-group by giving feedback about self or in-group on unfamiliar dimensions and found that participants were more willing to generalize from self to in-group than from in-group to self.

Subtyping versus subgrouping processes in stereotype representation.

Participants were instructed to organize information about group members either by distinguishing stereotype-consistent from stereotype-inconsistent individuals (subtyping instructions), by dividing the individuals into multiple groups on the basis of similarities and differences (subgrouping instructions), or with no explicit organizing instructions. Participants given the subtyping instructions showed greater perceived stereotypicality and homogeneity and perceived a greater difference in how typical the confirming versus disconfirming group members were, relative to subgroup participants. Study 2 demonstrated natural variation among participants in the perceived atypicality of the disconfirming relative to confirming individuals when learning about a gay activist group. Atypicality predicted perceptions of this group, even when prejudice and strength of stereotyping toward gays as a whole were statistically controlled.

Temperament and personality: origins and outcomes.

This article reviews how a temperament approach emphasizing biological and developmental processes can integrate constructs from subdisciplines of psychology to further the study of personality. Basic measurement strategies and findings in the investigation of temperament in infancy and childhood are reviewed. These include linkage of temperament dimensions with basic affective-motivational and attentional systems, including positive affect/approach, fear, frustration/anger, and effortful control. Contributions of biological models that may support these processes are then reviewed. Research indicating how a temperament approach can lead researchers of social and personality development to investigate important person-environment interactions is also discussed. Lastly, adult research suggesting links between temperament dispositions and the Big Five personality factors is described.

Associative storage and retrieval processes in person memory.

In this article, a general associative storage and retrieval theory of person memory is proposed, and seven experiments that test various aspects of the theory are reported. Experiment 1 investigated memory for behavioral information that is congruent with, incongruent with, or irrelevant to a prior impression. The results indicated that incongruent events are best recalled and irrelevant events are most poorly recalled. Experiment 2 replicated this effect and demonstrated that there are systematic individual differences that are consistent with the general nomothetic model proposed. The results of Experiment 3 indicated that, relative to a baseline condition, adding incongruent items to the list increases the probability of recalling congruent items but has no effect on the recall of irrelevant items. Both effects are predicted by the model. Experiment 4 provided support for the retrieval assumptions of the theory by demonstrating that there is a systematic order in which various types of items are recalled, as well as consistent differences in interresponse times. Experiments 5 and 6 demonstrated that the model is relevant to situations in which data driven, as well as conceptually driven, processes are involved. Finally, Experiment 7 examined a special case in which the theory predicts greater recall of congruent than incongruent behavioral events. The results of all seven experiments provide converging evidence for a general theory of person memory, and they have implications for a number of issues related to the study of person memory and social judgment.

Development of the functional visual field.

Andries Sanders' dissertation examined selective mechanisms in the functional visual field, and much of his work since has been concerned with the stages that underlie visual information processing particularly while making saccades. We argue that the study of orienting in the functional visual field is timely because it deals with the relation of covert attention shifts, eye movements and head movements to their underlying neurology. In our paper we develop a method to study learning of sequences at all ages from infants to adults. Our studies focus on how learning influences anticipatory eye movements. We examined the learning of unambiguous and context dependent sequences by 4-, 10-, and 18-month-old infants and undergraduates. We found clear learning of unambiguous sequences at 4 months, but learning of context dependent associations was found only in 18-month-olds and in adults. We hypothesize that the learning of unambiguous sequences by 4-month-olds reflects maturation of a basal ganglia-parietal circuit related to adult implicit learning, while the learning of context dependent sequences requires development of frontal structures underlying more general attentional abilities.

Development of orienting to locations and objects in human infants.

Two experiments investigated preference for orienting to novel locations and novel objects in young infants. Adults and infants of six months and older show a propensity to orient to locations that have not recently been inspected (inhibition of return). Preference for novel locations undergoes development. We show that, similar to adults, its development is related to the ability to program eye movements to attended locations. This preference appears to emerge as infants gain the ability to program eye movements to target locations. Experiment 1 demonstrates that three-month-olds show inhibition of return for 10 degrees target eccentricities, but not for 30 degrees target eccentricities. In a second experiment, three- and six-month-old infants oriented to 10 degrees targets that varied in location and object identity. Infants of both ages strongly preferred orienting to novel objects at novel locations. At three months, the preference for novel objects was equal to the preference for novel locations, while at six months a tendency to prefer novel objects over novel locations emerged. Overall, the findings support separate development of these two forms of novelty preference, and suggest that novel location preferences (inhibition of return) relates closely to the eye movement system. The findings are discussed in relation to issues concerning development, physiology, and cognition.