William M. Miley

Strength of aggressive display in Siamese fighting fish (Betta splendens) toward a conspecific, an alien species (Macropodus opercularis), and a mirror image as affected by prior conspecific visual experience.

Siamese fighting fish (Betta splendens) were provided with 10 days of visual experience with other conspecifics or were visually isolated from them for 10 days. Bettas were then allowed to display aggressively toward the following stimuli: a conspecific, an alien species (Macropodus opercularis), and a mirror image. Differences between intraspecific and interspecific displays depended on the response measure used. Isolated bettas displayed more frequently to conspecifics than did the visually experienced bettas, and more so than any other group. Visually experienced bettas showed longer latencies to conspecifics than did isolated bettas. However, there were no differences in the other response measures (duration of display and time to absence of responding for 15 min) in any of the stimulus conditions. Whether there are differences between intraspecific aggression, interspecific aggression, and aggression toward a mirror image may depend on the response measures used and the procedures leading up to behavioral testing.

Prenatal stimulation and postnatal testosterone affects infanticide in female rats

Prenatal handling, prenatal stress, and early postnatal exogeneous testosterone were examined in female rats for their effects on rat pup-killing and pup retrieval. During each of the last 5 days of pregnancy. Long-Evans rats received either 3 minutes of handling, 45 minutes of restraint and intense illumination or remained untouched. Half of the offspring of each group received testosterone from Day 1 after birth to Day 30. In adulthood, animals that received handling prenatally and testosterone postnatally killed pups more rapidly than any other group and a larger proportion did so than in the control groups. Animals not manipulated at any time retrieved pups more rapidly and a larger proportion did so than the combined other groups. The study suggests that prenatal handling interacts with testosterone presented immediately postnatally to increase infanticide in female rats. A variety of perinatal manipulations seem to suppress pup retrieval.

Rat-pup killing and maternal behavior in male Long-Evans rats: Prenatal stimulation and postnatal testosterone

During each of the last 5 days of pregnancy, Long-Evans rats received one of the following conditions: 45 min of restraint and intense illumination, 3 min of handling, 3 min of restraint and.1 mg of androstenedione, and 3 min of restraint and.1 ml sesame oil. Half of the offspring of each group received testosterone postnatally. In adulthood, the handled group’s offspring killed many pups with or without exogenous testosterone; the other offspring killed many only with testosterone. More animals that received androstenedione prenatally and testosterone postnatally killed pups than animals that received either oil or 45 min of restraint and intense illumination prenatally and testosterone postnatally. A subsequent manipulation found that fewer prenatally unhandled animals killed than the prenatally handled animals in this experiment. These prenatally unhandled animals required less time to retrieve pups (and more of them did so) than did any of the other groups.

Prenatal stress suppresses hunger-induced rat-pup killing in Long-Evans rats

During each of the last 5 days of pregnancy, Long-Evans and Wister rats received 45 min of whole-body restraint and intense illumination. When they were 87 days old, they were placed on complete food deprivation until Day 90. At this time, all animals were tested with 1-day-old rat pups and adult mice (Mus musculus). The stress procedure suppressed the level of rat-pup killing induced by the food deprivation in the Long-Evans rats. The 3 days of food deprivation did not induce rat-pup killing in the other groups or mouse killing in any of the groups.

Correlations among Executive Function Scales and Positive Psychological Attributes in College Students

Scores on executive function scales were correlated with scores on attributes of positive psychology. Values were positive among gratitude, satisfaction, and the executive function scales of motivational drive, empathy, and strategic planning. If replicated and extended, such data may predict academic success in college students as in 13- to 14-yr.-olds.

Discriminative control of interspecific killing in hungry and satiated rats

Hungry and satiated killer Long-Evans rats were exposed to two species of prey, mice and frogs. Experiment 1 demonstrated that the rats learned to discriminate between prey when attacks upon one of the prey were punished by electric shocks and attacks upon the alternative were not punished. Thus, killing of the “dangerous” prey was suppressed, while killing of the alternative, “safe” prey continued. However, in Experiment 2—in which the consequences of killing the prey differed in that one was allowed to be eaten following a kill but the other was not—no evidence of discriminative attack resulted. Hungry and satiated rats did not differ in their responsiveness toward prey as objects of attack, but hungry killers were more responsive to prey as food, thus demonstrating a dissociation of killing and eating control.

Self-Awareness And Altruism

The concept of altruism is defined and distinguished from other social interactions. Contrasting theories on the evolution and maintenance of altruism in natural populations are discussed. Many biologists argue against group selection and altruism espoused by Wynne-Edwards. Many behaviors that seem to be altruistic can be interpreted more parsimoniously by natural selection principles. Kin selection, kin-group selection, and reciprocal altruism are principles advanced to explain behaviors thought to be altruistic. Humans, chimpanzees, and orangutans have self-identity, and this capacity may allow organisms to transcend natural selection models of altruism.

Effects of d-amphetamine and pilocarpine on the mouse-killing response of hungry and satiated rats

Two experiments examined some relationships between feeding schedule and two psychoactive drugs on the mouse-killing response in rats. Experiment 1 showed that the combination of a high dose of d-amphetamine (2.00 mg/kg) and food satiation effectively suppresses killing while either factor alone does not. Experiment 2 showed that the combination of a high dose of pilocarpine (30 mg/kg) and food deprivation induces a considerable percentage of Sprague-Dawley rats to kill mice while either variable alone does not.

Effects of Combining Pilocarpine, D-Amphetamine, and Either a Free Feeding Schedule or Cyclic Food Deprivation on Mouse Killing by Rats

The combination of a drug which suppresses mouse killing by rats (d-amphetamine) , a drug which activates mouse killing (pilocarpine), and either ad-lib food or a 24-hour cyclic food deprivation schedule were examined for their effects on the mouse-killing response by rats (N = 53). Results showed that the presence of d-amphetamine prevented the activating effects of pilocarpine in rats with a fairly high killing propensity regardless of whether they were on the ad-lib food or the deprivation schedule. The study suggests that a drug which affects both eating behavior and mouse killing is more effective in determining behavioral outcomes than a drug which affects only mouse killing.

Effect of arousal by social isolation, grouping, and d-amphetamine on inter-male aggression in mice (Mus musculus).

24 adult male Swiss-Webster mice were randomly assigned to one of four equal experimental groups: a socially isolated group (8 days) which received a high dose of d-amphetamine prior to testing, a socially isolated group which received distilled water prior to testing, a social group of six (8 days) which received a high dose of d-amphetamine prior to testing, and a social group of six which received distilled water prior to testing. In the tests in which experimental animals were paired with stimulus animals which had their olfactory bulbs removed, inter-male aggression occurred even in the absence of aggressive retaliation by the stimulus animals. This suggests mutual arousal is sufficient to initiate and maintain biting attacks, aggressive retaliation is not necessary. Also, extremely high arousal in experimental mice induced by d-amphetamine and social isolation completely suppressed inter-male aggression whereas neither variable did so alone.