Responses to salivary olfactants in relation to dominance of the degu (Octodon degus)

Large amounts of head sniffing and grooming have been associated with social dominance in the degu. This study examined whether salivary olfactants act as cues which could potentially mediate social dominance in 4 male and 8 female adults. Using salivary samples taken from the buccal cavities of partners of predetermined status, no preferences for dominant or submissive stimuli were evident. Comparison of work with the degu and that with other species was made.     

The influence of a conductor and co-performer on auditory-motor synchronisation,temporal prediction,and ancillary entrainment in a musical drumming task

Interpersonal coordination is exemplified in ensemble musicians, who coordinate their actions deliberately in order to achieve temporal synchronisation in their performances. However, musicians also move parts of their bodies unintentionally or spontaneously, sometimes in ways that do not directly produce sound from their instruments. Musicians' movements—intentional or otherwise—provide visual signals to co-performers, which might facilitate temporal synchronisation. In large ensembles, a conductor also provides a visual cue, which has been shown to enhance synchronisation. In the present study, we tested how visual cues from a co-performer and a conductor affect processes of temporal anticipation, synchronisation, and ancillary movements in a sample of primarily non-musicians. We used a dyadic synchronisation drumming task, in which paired participants drummed to the beat of tempo-changing music. We manipulated visual access between partners and a virtual conductor. Results showed that the conductor improved synchronisation with the music, but synchrony with the music did not improve when partners could see each other. Temporal prediction was improved when partners saw the conductor, but not each other. Ancillary movements of the head were more synchronised between partners when they could see each other, and greater ancillary synchrony at beat-related frequencies of movement was associated with greater drumming synchrony. These results suggest that compatible audio-visual cues can improve intentional synchronisation, that ancillary movements are affected by seeing a partner, and that attended vs. incidental visual cues thus have partially dissociable effects on temporal coordination during joint action.     

Evolved sex differences in the number of partners desired? The long and the short of it

Do men seek more short-term mates than women? Buss and Schmitt (1993) showed a pattern of mean difference in the ideal number of sexual partners men and women desired over various time frames. We replicated these mean sex differences (e.g., ideal number over the next 30 years: Ms = 7.69 and 2.78 for men and women, respectively), but in both data sets the sampling distributions were highly skewed. In Study 1, we found few sex differences in medians across time frames (e.g., ideal number over the next 30 years: Mdn = 1 for both men and women). In Study 2, most college men (98.9%) and women (99.2%) said they wanted to settle down with one mutually exclusive sexual partner at some point in their life, ideally within the next 5 years. Neither medians in number of partners desired overall before settling down (replicating Study 1) nor medians in short-term partners desired before settling down (Mdn = 0) differed significantly by gender. Rather, men and women concurred: Short-term mating is not what humans typically seek.     

Decision ecology: Foraging and the ecology of animal decision making

In this article, I review the approach taken by behavioral ecologists to the study of animal foraging behavior and explore connections with general analyses of decision making. I use the example of patch exploitation decisions in this article in order to develop several key points about the properties of naturally occurring foraging decisions. First, I argue that experimental preparations based on binary, mutually exclusive choice are not good models of foraging decisions. Instead, foraging choices have a sequential foreground-background structure, in which one option is in the background of all other options. Second, behavioral ecologists view foraging as a hierarchy of decisions that range from habitat selection to food choice. Finally, data suggest that foraging animals are sensitive to several important trade-offs. These trade-offs include the effects of competitors and group mates, as well as the problem of predator avoidance.     

Behaviorism and mentalism: Is there a third alternative?

Behaviorism and mentalism are commonly considered to be mutually exclusive and conjunctively exhaustive options for the psychological explanation of behavior. Behaviorism and mentalism do differ in their characterization of inner causes of behavior. However, I argue that they are not mutually exclusive on the grounds that they share important foundational assumptions, two of which are the notion of an innerouter split and the notion of control. I go on to argue that mentalism and behaviorism are not conjunctively exhaustive either, on the grounds that dropping these common foundational assumptions results in a distinctively different framework for the explanation of behavior. This third alternative, which is briefly described, is a version of non-individualism.     

Body posture effects on self‐evaluation: A self‐validation approach

Building on the notion of embodied attitudes, we examined how body postures can influence self‐evaluations by affecting thought confidence, a meta‐cognitive process. Specifically, participants were asked to think about and write down their best or worse qualities while they were sitting down with their back erect and pushing their chest out (confident posture) or slouched forward with their back curved (doubtful posture). Then, participants completed a number of measures and reported their self‐evaluations. In line with the self‐validation hypothesis, we predicted and found that the effect of the direction of thoughts (positive/negative) on self‐related attitudes was significantly greater when participants wrote their thoughts in the confident than in the doubtful posture. These postures did not influence the number or quality of thoughts listed, but did have an impact on the confidence with which people held their thoughts. Copyright © 2009 John Wiley & Sons, Ltd.     

A dynamical framework to understand performance trade-offs and interference in dual tasks.

This study demonstrated that the dynamic pattern approach may reconcile resource and outcome conflict theories to explain performance in dual tasks. Participants performed a bimanual coordination task and a reaction time task with different conditions of attentional priority. Results showed a trade-off between pattern variability and reaction time when priority was given to the coordination task. Such a trade-off was indicative of resource allocation. An analysis of perturbation in the bimanual coordination revealed interference, a reputed sign of outcome conflict. Moreover, interference diminished substantially when priority was given to the bimanual task. The coexistence of performance trade-off and outcome conflict suggests that these two phenomena are not mutually exclusive. Rather, both may follow from modifying the coupling between the limbs through attention.     

Sex differences in ambulation and defecation in the degu (Octodon degus)

The degu, a hystricomorph rodent, was studied in both an open-field (OF) and running-wheel testing situation. Of primary interest was whether there would be appparent sex differences in ‘emotionality’ and/or locomotion measures. Unlike domesticated species, females were found to ambulate and defecate more frequently than males in the OF. Both sexes increased their rates of defecation with exposure to the field. The running-wheel data indicatedf that overall males were more active, particularly during the dark phase of the light cycle. The data are examined with respect to similar measures obtained from domesticated laboratory rodents.     

The interplay of attention and bimanual coordination dynamics

Despite their common origin, studies on motor coordination and on attentional load have developed into separate fields of investigation, bringing out findings, methods, and theories which are diverse if not mutually exclusive. Sitting at the intersection of these two fields, this article addresses the issue of behavioral flexibility by investigating how intention modifies the stability of existing patterns of coordination between moving limbs. It addresses the issue, largely ignored until now, of the attentional cost incurred by the central nervous system (CNS) in maintaining a coordination pattern at a given level of stability, in particular under different attentional priority requirements. The experimental paradigm adopted in these studies provides an original mix of a classical measure of attentional load, namely, reaction time, and of a dynamic approach to coordination, most suitable for characterizing the dynamic properties of coordinated behavior and behavioral change. Findings showed that central cost and pattern stability covary, suggesting that bimanual coordination and the attentional activity of the CNS involved in maintaining such a coordination bear on the same underlying dynamics. Such a conclusion provides a strong support to a unified approach to coordination encompassing a conceptualization in terms of information processing and another, more recent framework rooted in self-organization theories and dynamical systems models     

THE REPRESENTATIVENESS OF OBSERVATIONAL SAMPLES OF DIFFERENT DURATIONS

The representativeness of behavioral observation samples with durations of less than the whole time of interest was investigated. A real-time recording system was developed to quantify the behavior of 5 profoundly mentally retarded physically handicapped adult students in an institutional training setting. Behavior was observed using six mutually exclusive and exhaustive categories during 2.5-hr observation sessions. Sample observation sessions with durations ranging from 15 to 135 min were computer simulated from the whole-session (150-min) records. It was found that the representativeness of these samples, when compared to whole-session records, was a function of the relative duration of the behavioral categories and of sample duration. The occurrence of relatively high-duration behaviors (lasting for more than 50% of the session) was estimated to within 20% error by samples of less than 60 min, but low-duration behaviors (1 to 3% of the session) were inadequately quantified even from 135-min samples. Increasing irregularity of bouts of behavior in the low-duration behaviors is suggested as the cause of the functions obtained. Implications of the findings for applied behavior analysis are discussed, with the recommendation that the adequacy of observational session durations be empirically assessed routinely.     

Social influence techniques during marital conflict

The use of social influence techniques was examined in two studies of marital conflict. In each study, couples discussed two issues in counterbalanced order: one in which the husband wanted change and one in which the wife wanted change. Interactions were coded for the use of influence techniques. Evidence from both studies supported a social role explanation, such that roles based on who wanted change predicted the use of influence, whereas gender did not. Secondary hypotheses based on attribution theory and schema theory were also supported. When discussing areas in which they wanted change in partners, spouses made more partner attributions, were more likely to suggest change, and were more likely to explain their partners’behavior than when discussing areas in which their partners wanted change. However, they were more likely to ask questions to clarify the problem when discussing a change their partners wanted in them than when discussing a change they wanted. The importance of considering social structural variables such as social roles in examining conflict interactions is discussed.     

Individual and collective problem-solving in a foraging context in the leaf-cutting ant Atta colombica

In this paper we investigate the flexibility of foraging behavior in the leaf-cutting ant Atta colombica, both at the individual and collective levels, following a change in the physical properties of their environment. We studied in laboratory conditions the changes occurring in foraging behavior when a height constraint was placed 1 cm above part of the trail linking the nest to the foraging area. We found that the size and shape of the fragments of foraging material brought back to the nest were significantly modified when the constraint was placed on the trail: independent of their size, forager ants cut smaller and rounder fragments in the presence of a height constraint than in its absence. This size adjustment does not require any direct sensory feedback because it occurred when the ants cut fragments in the foraging area; no further cutting was done when they encountered the constraint. This points to the existence of a template that ants store and use as a reference to adjust their reach while cutting. Remarkably, despite the decrease in the foraging material brought to the nest per capita the colony was still able to improve its foraging performance by doubling the number of transporters. This study illustrates the flexibility of foraging behavior exhibited by an ant colony. It provides a rare example of insects finding an intelligent solution to a problem occurring in a foraging context, at both the individual and collective levels.     

Impaired body but not face perception in patients with obsessive–compulsive disorder

Background. Empirical evidence involving the processing of social information by patients with obsessive–compulsive disorder (OCD) has been relatively scarce. Our study investigated the perceptual abilities of patients with OCD to recognize human faces and bodies. Method. Fifty‐four drug‐free or drug‐naïve patients with OCD and 42 healthy controls performed discrimination tasks consisting of four types of stimuli: two sets of faces that were manipulated with regard to configuration and features, human bodies, and chairs. The stimuli were presented in upright and upside‐down orientations. Results. Patients with OCD were significantly less accurate in discriminating pairs of bodily postures implying actions. However, we found no significant differences between patient and control groups in the ability to recognize faces and chairs. The inversion effects for bodies and faces were also comparable between the two groups. Conclusions. The current findings suggest that patients with OCD experience difficulty in perceiving static forms of bodily postures, but are able to adequately recognize human faces. Our data indicate a selective deficit in the perception of bodily postures in those with OCD and suggest that this deficit is probably not related to the abnormal configurational processing of social objects.     

Effects of test anxiety, tests, and sleep on children''s performance

This study examined the interrelationship between children's test anxiety, sleep, and performance. The subjects, 239 sixth and seventh graders, responded to questionnaires examining sleep behavior and test anxiety on a day when they had a major exam in school, and on a day when they did not. They also completed a vigilance task on both days. The results showed that partial sleep loss (i.e., under 3 hr) did not adversely influence subjects' performance on the vigilance task or on the actual class exam. However, the results did reveal that test anxiety was negatively related to performance on the class exam.     

Evidence of teaching in atlantic spotted dolphins (Stenella frontalis) by mother dolphins foraging in the presence of their calves

Teaching is a powerful form of social learning, but there is little systematic evidence that it occurs in species other than humans. Using long-term video archives the foraging behaviors by mother Atlantic spotted dolphins (Stenella frontalis) were observed when their calves were present and when their calves were not present, including in the presence of non-calf conspecifics. The nine mothers we observed chased prey significantly longer and made significantly more referential body-orienting movements in the direction of the prey during foraging events when their calves were present than when their calves were not present, regardless of whether they were foraging alone or with another non-calf dolphin. Although further research into the potential consequences for the naïve calves is still warranted, these data based on the maternal foraging behavior are suggestive of teaching as a social-learning mechanism in nonhuman animals.     

Ceding and Succeeding: How the Altruistic Can Benefit from the Selfish in Joint Decisions

We examine how the interplay of two partners’ interpersonal orientations (selfish vs. altruistic) in a decision‐making dyad impacts the extent to which the joint decision matches each partners’ individual a priori preferences. Two experiments, in which we manipulate and measure interpersonal orientations, as well as examine real consumption decisions, demonstrate the benefit of mismatching interpersonal orientations (selfish‐altruistic) in dyadic decisions. Specifically, altruistic and selfish consumers reach joint decisions that better reflect their individual preferences when working with a partner who has the opposite interpersonal orientation (heterogeneous dyad) versus a matching one (homogeneous dyad). Initial evidence suggests that this effect occurs because homogeneous dyads are more prone to engage in negotiation (communication that involves departure from one's initial position to a mutually serving position) than heterogeneous dyads. This leads homogeneous dyads to focus more on equally preferred options than on their own most preferred options, which pushes them further down both partners’ preferences lists. This research contributes to the literature on joint decision making and has important implications for consumer well‐being.     

Romantic Ideals,Fear of Negative Implications,and the Practice of Safe Sex1

The present study examined how young heterosexuals’ beliefs about the power of condom use to destroy their romantic ideals and to lead to negative implications affected both their intentions and their actual behavior of using and discussing the use of condoms with sexual partners. The extra predictive power gained from considering these beliefs, in addition to subjects’ beliefs concerning whether condoms reduced their risk of contracting HIV, was examined within the context of Fishbein and Ajzen's (1975) theory of reasoned action. One-hundred-and-two sexually active heterosexual students participated in the study. At the first wave of data collection, beliefs concerning the potential of condoms to reduce risk, to destroy romance, and to lead to negative implications were assessed, as were norms and intentions. Measures of actual behavior were obtained three months later for both regular and casual/new partners. The results of the study indicated that norms and beliefs concerning the risk-reduction effects of condom use were the primary predictors of intentions to use condoms. Subjects’ beliefs concerning whether condoms destroyed their romantic ideals or led to negative implications did not influence their intentions with casual/new partners, although emotional concerns played a minor role in determining intentions with regular partners. In contrast, these emotional concerns had a major impact in determining actual behavior for all partner types. Although intentions partially predicted behavior, beliefs about reducing risk, destroying romance and fear of negative implications had strong and direct influences on behavior, especially in the case of casual/new partners. Additional analyses revealed gender differences in the determinants of behavior. Females, in contrast to males, were less able to act in accord with their attitudes about using condoms to reduce their risk of contracting HIV, and were also less able to act in conformity with their subjective norms with less well-known partners. Although both males and females were similarly affected by more emotional concerns with new and/or casual partners, gender differences occurred in how these emotional factors affected behavior with regular partners. Implications of the finding that behavior is determined to a large extent by more emotional concerns that are not factored in ahead of time when formulating intent are discussed.     

Risk-sensitive foraging theory and operant psychology.

Hastjarjo, Silberberg, and Hursh (1990) have presented data on the foraging behavior of rats and discussed it in terms of risk-sensitive foraging theory. Because risk-sensitive foraging theory is comprised of several different models, it does not lead to general predictions about when an organism should prefer a foraging option with high variance to a foraging option with low variance. Any comparison of data with the predictions of the theory must be based on an appropriate model. I draw attention to various experiments that are potentially relevant to the results reported by Hastjarjo et al. and show how the time period over which the organism must survive can influence a model's predictions about risk sensitivity.