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PubMed1990

Oral contraceptive administration, interfemale relationships, and sexual behavior in Macaca fascicularis.

The effects of oral contraceptive administration on the social relationships of adult female cynomolgus monkeys (Macaca fascicularis) were examined. Ten females were administered ethinyl estradiol/ethynodiol diacetate (Demulen), 10 were administered ethinyl estradiol/norgestrel (Ovral), and 10 served as a control group. The monkeys lived in social groups of 5 females each, and patterns of social interaction and social status were recorded. Interfemale relationships were also observed when a vasectomized male was placed in each social group for 50 min, once/week. During the latter observations, preliminary data on the effects of oral contraceptive treatment on sexual interaction were also collected. In the absence of the male, interfemale agonistic interactions and time spent alone were influenced by social status but not by oral contraceptive treatment. Time spent in passive body contact, an affiliative state, was reduced by Ovral treatment. In the presence of the male, dominant females aggressively interfered with the sexual interactions of subordinates. This aggression resulted in the termination of a greater proportion of the sexual interactions of subordinates than dominants in the control group only, indicating suppression of this type of interaction by oral contraceptive treatment. Other effects included a decreased frequency of ejaculation with Ovral-treated females. These results suggest that oral contraceptives may suppress certain types of female agonistic behavior (e.g., in the context of mate competition) and some oral contraceptives may interfere with sexual activity. More broadly, these findings indicate that intrasexual competition for access to mates may occur in females as well as males.

Aggression↗
PubMed1982

Behavioral effects of intracerebroventricularly administered neurohypophyseal hormone analogs in mice.

The neurohypophyseal hormones oxytocin and vasopressin evoke characteristic behavioral changes after intracerebroventricular injection in mice. These included the induction of excessive grooming and scratching in an unrestricted environment and of escape behavior in stressful situations. The structure-activity relations of 33 neurohypophyseal hormones and hormone analogs in the induction of these behavioral changes were examined. The results demonstrate that these effects generally parallel the vasoconstrictory effects of th peptides. It is suggested that the behavioral effects are mediated by a receptor that is closely related biochemically to the vasopressin receptors in blood vessels. They are not related to the long-term effects of neurohypophyseal hormones on learned behavior. A competitive antagonist of the short-term behavioral effects of these peptides is described. This analog also antagonizes some of the hormonal effects of vasopressin and related peptides.

Animals↗
PubMed1996

Cattell's 16 PF and PSY inventory: relationship between personality traits and behavioral responses in patients with acute myocardial infarction.

The aim of this study was to investigate the relationships between personality and behavioral responses in patients with acute myocardial infarction. In a first step, a new instrument (PSY Inventory) for assessment of six behavioral characteristics (Sense of Responsibility, Energy and Competitiveness, Obsessive Behavior, Anger and Hostility, Stress-related Disturbances, Time Urgency) was developed by using factor analysis on intercorrelations of responses from 524 subjects of the general population. Internal consistency reliability for each of the PSY subscales was estimated by Cronbach alpha coefficients. In a second step, the PSY Inventory was administered with the Cattell 16 PF Questionnaire to 838 patients affected by acute myocardial infarction. Significant correlations although relatively low in magnitude for PSY Inventory subscales and certain scales of the Cattell 16 PF were found. With factor analysis on 22 variables (including the six PSY Inventory subscales and the 16 scales of the Cattell 16 PF), five second-order factors were identified, namely, Extraversion, Neurotic Anxiety, Superego Strength, Pathemia, and Neurotic Hostility. While a Pathemia Factor (characterized by sensitivity, imagination, and self-sufficiency) was factorially independent of scales of the PSY Inventory, Extraversion, Neurotic Anxiety, Superego Strength, and Neurotic Hostility Factors were composed of the PSY Inventory scales and Cattell 16 PF scales combined. These relationships would reflect the concordance of internal constructs for behavioral measures of the PSY Inventory and those of personality traits of the 16 PF Questionnaire in patients with acute myocardial infarction.

Adaptation, Psychological↗
PubMedDate not supplied

[The role of inversions in adaptation and speciation].

Studies concerning the effect of population-specific inversions on mating behavior of Drosophila lummei Hackman showed that competitiveness of males carrying the inversion for mating with females without the inversion significantly decreases, independently from the location of inversions in chromosomes and the origin of studied strains. Crossing of the competing males with the female carrying the population-specific inversion showed that the competitiveness of males with the inversion in their genome increases in a series of crosses but, nevertheless, remains lower than that of males without the inversion. Hence, it can be suggested that population-specific inversions can be involved in prezygotic isolation of specific forms during the species divergence.

Adaptation, Physiological↗
PubMed1997

The role of contextual and personal factors in children's risk taking.

The primary aims of the present studies were to (a) add to the sparse developmental database on risk taking and (b) conduct initial tests of a self-regulation model (SRM) of risk taking. According to the SRM, inappropriate risk taking is associated with overconfidence, falling prey to dysregulating influences (e.g., impulsivity, peer presence, etc.), and an insensitivity to outcomes. Experiment 1 tested these proposals by assessing the effects of peer presence and 4 personal factors on the risk taking of 3rd, 5th, and 7th graders. Results generally supported the predictions of the SRM. In Experiment 2, the SRM gained further support from the finding that 5 variables correlated with risk taking in 4th, 6th, and 8th graders: ability beliefs, a preference for thrill seeking, peer nomination, competitiveness, and interest. The discussion focuses on the meaning of age and gender differences in risk-taking as well as the interventional implications of the SRM.

Age Factors↗
PubMed1999

Influence of competitive adsorption on flocculation and rheology of high-pressure-treated milk protein-stabilized emulsions.

The effect of high-pressure treatment (HPT) on the droplet-size distribution and small-deformation rheology of oil-in-water emulsions containing beta-lactoglobulin and a nonionic surfactant or sodium caseinate has been investigated at neutral pH. Addition of Tween 20 (polyoxyethylenesorbitan monolaurate) to a beta-lactoglobulin-stabilized emulsion results in competitive displacement of the adsorbed globular protein film and, following HPT, the formation of a less flocculated emulsion. The age of the beta-lactoglobulin-stabilized emulsion prior to addition of sodium caseinate influences the competitive adsorption behavior. The strengthening of the beta-lactoglobulin layer with time makes it more resistant to disruption by sodium caseinate. The level of pressure-induced flocculation of beta-lactoglobulin-coated oil droplets depends on the intensity of processing conditions and on the degree of interfacial displacement. In contrast, beta-lactoglobulin added after emulsification appears to show little evidence of competitive adsorption behavior at the caseinate oil-water interface. Changes in the rheological properties of these latter systems following HPT can be attributed to pressure-induced denaturation and gelation of beta-lactoglobulin in the continuous phase of the emulsion.

Adsorption↗
PubMed2000

Coaches' expectations and beliefs regarding benefits of youth sport participation.

Although many have investigated why children participate in sport, little is known about what adults expect children to gain from participation. The present purpose was to examine coaches' expectations of what children should gain from participation in sport and the extent to which coaches believe that these expectations are actually fulfilled. Participants included 109 youth sport coaches who completed a survey packet consisting of a demographic information questionnaire and the Ohio Sport Satisfaction Index. Analysis indicated coaches ranked the variables of having fun, learning life skills, being part of a team, developing confidence, and the excitement of competition as the most important outcomes for the youth they coach. Generally, coaches believe that their expectations are being fulfilled. Coaches' sex and years of coaching were not significantly related to any of the criterion variables in the present study.

Adult↗
PubMed1992

Copulatory behavior, reproduction, and sperm competition in two strains of male rats.

Long-Evans males fathered 72% of the offspring when one Long-Evans and one F344 male mated repeatedly with the same female throughout her estrus. When each male was restricted to one ejaculation and the second male was allowed to begin mating immediately following the first male's ejaculation, the second male left more offspring in each strain. However, the proportion was significantly greater for Long-Evans males. In contrast, there were no strain differences in either number of pregnancies or litter size in noncompetitive matings limited to two ejaculations, the minimal number required to induce pregnancy. The only consistent behavioral differences were the greater number of intromissions performed with shorter latencies by F344 males, differences that cannot readily be used to explain their reduced success. It was hypothesized that the two strains may differ in the adequacy of penile reflexes used to form, set, or dislodge sperm plugs.

Animals↗
PubMed1994

Studying complex decision making in natural settings: using a head-mounted video camera to study competitive orienteering.

Head-mounted video recording is described as a potentially powerful method for studying decision making in natural settings. Most alternative data-collection procedures are intrusive and disruptive of the decision-making processes involved while conventional video-recording procedures are either impractical or impossible. As a severe test of the robustness of the methodology we studied the decision making of 6 experienced orienteers who carried a head-mounted light-weight video camera as they navigated, running as fast as possible, around a set of control points in a forest. Use of the Wilcoxon matched-pairs signed-ranks test indicated that compared with free recall, video-assisted recall evoked (a) significantly greater experiential immersion in the recall, (b) significantly more specific recollections of navigation-related thoughts and feelings, (c) significantly more realizations of map and terrain features and aspects of running speed which were not noticed at the time of actual competition, and (d) significantly greater insight into specific navigational errors and the intrusion of distracting thoughts into the decision-making process. Potential applications of the technique in (a) the environments of emergency services, (b) therapeutic contexts, (c) education and training, and (d) sports psychology are discussed.

Adolescent↗
PubMed1977

Competition for meat between chimpanzees and baboons of the Gombe National Park.

Both chimpanzees (Pan troglodytes) and baboons (Papio anubis) at the Gombe National Park in Western Tanzania are know to catch and eat meat. There are five occasions recorded when chimpanzees were seen to seize prey from baboons and five other occasions when there was evidence strongly suggesting that an appropriation had taken place. This paper describes these observations.

Animals↗
PubMed1984

Males and the advantage of sex.

Most sexual populations are at a two-fold disadvantage to parthenogenetic populations. This is because males are produced in equal numbers to females and males contribute virtually no food supplies to the zygote. Females therefore "waste their energy" in the production of sons. Parthenogenetic females produce only daughters and therefore have a two-fold advantage. It is argued that female choice (of males) and male: male competition can reduce mutational loads and this may compensate for the two-fold disadvantage of males. The Haldane mutation load principle indicates a load of 2mu, where mu is the mutation rate per gamete. Female choice and male: male competition are capable of reducing this substantially. The effect is greatest with mildly deleterious mutations and is therefore dependent on the fitness of the mutations. This is in contrast to the Haldane principle load which is determined by the mutation rate only. As most mutations appear to be mildly deleterious the load in many sexual populations may be substantially below that indicated by the Haldane principle.

Animals↗
PubMed2002

Expectations of pediatric sport participation among pediatricians, patients, and parents.

As the number of pediatric and adolescent athletes involved in competitive sports continues to grow, and as the competitors in youth sports trend toward a "win at all costs" mentality, pediatricians are increasingly being asked to provide sports medicine treatment and counseling for athletic children. This article outlines the demographic changes in the pediatric and adolescent athlete population in the United States and explains how the pediatrician can become a more effective caregiver to the athletic patient.

Adolescent↗
PubMed1998

The effects of competition and motor reprogramming on visuomotor selection in unilateral neglect.

Patients with unilateral neglect following right hemisphere damage may have difficulty in moving towards contralesional targets. To test the hypothesis that this impairment arises from competing motor programs triggered by irrelevant ipsilesional stimuli, we examined 16 right hemisphere patients, eight with left visual neglect and eight without, in addition to eight healthy control subjects. In experiment 1 subjects performed sequences of movements using their right hand to targets on the contralesional or ipsilesional side of the responding limb. The locations of successive targets in each sequence were either predictable or unpredictable. In separate blocks of trials, targets appeared either alone or with a simultaneous distractor located at the immediately preceding target location. Neglect patients were significantly slower to execute movements to contralesional targets, but only for unpredictable movements and in the presence of a concurrent ipsilesional distractor. In contrast, healthy controls and right hemisphere patients without neglect showed no directional asymmetries of movement execution. In experiment 2 subjects were required to interrupt a predictable, reciprocating sequence of leftward and rightward movements in order to move to an occasional, unpredictable target that occurred either in the direction opposite to that expected, or in the same direction but twice the extent. Neglect patients were significantly slower in reprogramming the direction and extent of movements towards contralesional versus ipsilesional targets, and they also made significantly more errors when executing such movements. Right hemisphere patients without neglect showed a similar bias in reprogramming direction (but not extent) for contralesional targets, whereas healthy controls showed no directional asymmetry in either condition. On the basis of these findings we propose that neglect involves a competitive bias in favour of motor programs for actions directed towards ipsilesional versus contralesional events. We suggest that programming errors and increased latencies for contralesional movements arise because the damaged right hemisphere can no longer effectively inhibit the release of inappropriate motor programs towards ipsilesional events.

Aged↗
PubMed1996

What they want and what they get: the social goals of boys with ADHD and comparison boys.

Twenty-seven boys diagnosed with attention-deficit hyperactivity disorder (ADHD) and 18 comparison boys participated in a competitive tetradic interaction task. Boys were individually interviewed before the game about their goals for the interaction, and adult observers inferred boys' social goals from videotapes of the interaction. Social acceptance was determined by combining positive and negative sociometric nominations collected through individual interviews at the end of the summer research program in which the interaction was held. In their self-reports, ADHD-high aggressive boys prioritized trouble-seeking and fun at the expense of rules to a greater extent than did both ADHD-low aggressive and comparison boys. Observers judged ADHD-high aggressive boys to seek attention more strongly and seek fairness less strongly than of the other two groups. Self-reported goals of defiance and cooperation predicted boys' end-of-program social standing, even with interactional behaviors and subgroup status controlled statistically. Observer-inferred goals were differentially associated with social acceptance for ADHD and comparison boys, suggesting discontinuities in peer interaction processes. Differentiation of goals from behavior and the integral role of children's goals in peer acceptance are discussed.

Aggression↗
PubMed1991

Popular and aggressive boys' initial social interaction patterns in cooperative and competitive settings.

Thirty-two third- and fourth-grade popular and aggressive boys were observed individually attempting to enter a game being played by a mixed-status unfamiliar-peer dyad in both competitive and cooperative game settings. Consistent with previous findings, popular entry children were accepted more readily into the game situation than were aggressive children. Popular children tended to approach the situations using more prosocial questions while their aggressive peers tended to use demands. More differences in entry strategies were noted in the competitive than in the cooperative game setting. While most entry children directed their first entry bid toward the aggressive game host, they reported having liked the popular game host best when the game was finished. Additionally, the quality of game interactions was observed to become more positive following a popular child's entry, while becoming more negative following an aggressive child's entry. The results are discussed in terms of leadership roles and implications for both assessment and intervention settings and strategies.

Aggression↗
PubMed2003

Female sex pheromone-mediated effects on behavior and consequences of male competition in the shore crab (Carcinus maenas).

Exposure to receptive female pheromone elicits guarding behavior in shore crab males (Carcinus maenas), but little is known about the effects of sex pheromone on male competition or if the female plays an active role in mate choice. This study examined whether female pheromone enhanced agonistic behavior between males and what effects visual and chemical cues had on the rules and costs of such contests. We also investigated whether females exhibit a preference for males in terms of size. Under laboratory conditions, solitary male shore crabs engaged males who already had possession of a female. The visual and chemical presence of a receptive female had an impact on contest rules and costs. Fights were costly in terms of duration and of sustaining injury with either one or both crabs incurring injury in 40% of fights. To investigate the metabolic consequences of fighting over a perceived sexual resource (chemical cue only), fights were staged between pairs of size-matched males in the presence of water containing the female sex pheromone, water in which males had been kept, and untreated seawater. The duration and intensity of contests were greater when staged in the presence of the female pheromone compared with the two other treatments. Crabs that fought in the presence of female sex pheromone also had a greater accumulation of L-lactate and a reduction of glycogen stores. Fights were less costly in terms of injury with a single chemical cue compared with enhanced costs with a multiple sexual cue. The importance of female choice was determined by presenting postmolt females with different sized males. Males were kept in a fixed position, and the majority of females approached and performed courtship behavior to the largest males, demonstrating that females may be selective in terms of size.

Aggression↗
PubMed1994

Behavioral profiles of adult rats in a difficult food supply social situation, related to certain early behavioral features.

Behavioral profiles of male rats were defined in nine intralitter groups of six individuals at various stages of their development: (a) at pup stage in individual situations (uncomfortable positions) and social situations (removal away from the mother), and (b) at adult stage in a difficult food supply social situation (complete immersion of the food access way). The male population was split into two sets, both at pup stage (the most and the least swift and efficient of each group to overcome uncomfortable situations), and at adult stage (carriers and noncarriers of food in each group tested). Our results showed an important relation between these pup and adult behavioral profiles: the swiftest and most efficient individuals of a group at pup stage adopted more often a food carrier behavioral profile at adult stage. Assumptions about the predictive value of some behavioral features of a young rat in regard to its adult behavioral profile are discussed.

Aging↗