The biparental care system of the California mouse, Peromyscus californicus

Most knowledge of parent-offspring relations in mammals is derived from studies of mother-infant interactions. Male parental care has been less well studied. We explored maternal and paternal behavior of the California mouse, Peromyscus californicus. Six pairs of parents and their young were videotaped continuously for 12 hours/day, on alternate days from Days 1 to 31 postpartum. Males exhibit all parental activities and to the same extent as displayed by mothers, except lactation. Male parental behavior begins on the day of birth. Mothers and fathers spend substantial and equivalent amounts of time in the nest and in physical contact with pups throughout lactation. Males devote more time than females to licking pups, although females engage in more pup anogenital licking. Mothers nurse for at least 4 weeks, and fathers and mothers both build nests and carry young. The biparental care system of Peromyscus californicus affords an opportunity to develop a broader, more complete view of parent-offspring relations.     

Learning in mature mice (Peromyscus leucopus) subjected to deep hypothermia as neonates

In certain species of nonhibernating rodents, although young nestlings cease breathing and heart action when their body temperature is lowered to near freezing, the nestlings need only be rewarmed to recover. This remarkable capacity for immediate recovery has been known many years, but long-range consequences of deep neonatal hypothermia have never before been investigated. Mice (Peromyscus leucopus) that had been exposed to four 2.5-hr episodes of deep (2-4 degrees C) hypothermia when 4-10 days old were later compared with littermate controls in their performance on two learning tasks. The two groups did not differ in their acquisition or extinction of a lithium-induced learned taste aversion to sucrose. Nor did they differ in learning to find a hidden platform in a swimming pool. Thus in a nonhibernating rodent species, deep hypothermia experienced neonatally--unlike similar hypothermia administered in adulthood--seems not to induce deficits in subsequent learning capabilities. The resistance of neonates to damage probably represents an adaptation, for their modest thermoregulatory abilities render them vulnerable to deep hypothermia in frigid environments.     

Comment on Cameron and Cameron (2002): "children of homosexual parents report childhood difficulties"

Cameron and Cameron's reanalysis of published data in 2002 indicates children being raised in a home environment with at least one homosexual parent report some negative consequences. However, a closer look at the information presented suggests (especially in the absence of control groups) that the negative consequences documented do not constitute major psychological trauma. Rather, they are more in the nature of the teasing and bullying that plagues any child who comes from a home that may be atypical in any fashion.     

Novelty-induced opioid analgesia in deer mice (Peromyscus maniculatus): sex and population differences

Exposure to a new environment elicited significant, naloxone (1.0 mg/kg) reversible analgesic responses in three different populations of deer mice; Peromyscus maniculatus artemisiae from the mainland, and P. m. angustus and P. m. triangularis from small marine islands. In all cases male deer mice displayed significantly greater levels of analgesia than females. In addition, the levels of analgesia were significantly greater in the insular than in the mainland populations. These results indicate that there are substantial sex and population differences in the novelty-induced analgesia displayed by natural and laboratory populations of deer mice.     

Aprendiendo de La Vida (Learning from Life): Development of a Radionovela to Promote Preventive Health Care Utilization among Indigenous Farmworkers from Mexico Living in California

Journal of Medical Humanities - Mixtecs and Zapotecs, originating from the Oaxaca area in Mexico, are among the largest indigenous groups of workers in California. Many adults in this community...     

The myth of "ecological dyslexia": a reply to Pontius (1984)

Ways in which Pontius' rejoinder to the criticisms raised earlier about her 1982 study of white and Aboriginal Australians fall short of success are enumerated.     

Matching and oddity relational learning by pigeons (<Emphasis Type="Italic">Columba livia</Emphasis>): transfer from color to shape

Relational learning, as opposed to perceptual learning, is based on the abstract properties of the stimuli. Although at present there is no doubt that pigeons are capable of relational behavior, this study aims to further disclose the conditions under which it occurs. Pigeons were trained in an outdoor cage on a matching-to-sample or an oddity-from-sample task, with colored cardboard stimuli presented horizontally. The apparatus involved three sliding lids on which the stimuli were drawn and which, when displaced, revealed the reinforcement. The lids were either adjacent to each other or somewhat separated. Training sessions involved two colors, and test sessions six different colors (same dimension test), or six different shapes (different dimension test). One group of birds trained under the ‘adjacent’ condition failed when tested with new stimuli, but succeeded in both dimension tests after training under the ‘separate’ condition. Two other groups of birds succeeded in all tests after training under the latter condition. These results show that depending on procedural details, pigeons are or are not able to transfer from one visual dimension to another, thus extending previous related findings.     

Short-term early exposure to pups alters infanticide in adulthood in male but not in female wild house mice (Mus domesticus)

Male and female wild house mice (Mus domesticus) were allowed to remain in the cage of their parents until 30-35 days of age. When a second litter was delivered, the first litter was exposed to the younger pups for 2-10 days. In adulthood the male and female mice that had been exposed to pups as juveniles and an additional group that had cohabitated with their parents for the same length of time but were not exposed to pups were tested for infanticidal behavior. The frequency of infanticide by the adult female mice was not significantly different (55% vs. 70%, respectively). In contrast, the adult males that were exposed to pups as juveniles were significantly less likely to kill young in adulthood when compared with males that were not similarly exposed (35% vs. 80%, respectively). These data further demonstrate the strong influence of experience on the expression of infanticide by male mice and its relative unimportance to the expression of female infanticide.     

Learning to walk is still an "old" problem: a reply to Zelazo (1983)

Zelazo (1983) proposes that two cognitive prerequisites are necessary for the development of locomotion: The conversion of neo-natal reflexive stepping into instrumental behavior and a shift from stereotypical to relational play. I argue that these cognitive assumptions are unnecessary. The disappearance of neo-natal stepping can be explained as a result of increasing leg mass, and the retention of this reflex with practice may be simply an exercise effect. Comparative and evolutionary evidence suggests that locomotion is not associated with abstract reasoning ability. Learning to walk is a complex, gradual process of maturation of motivation, the integration of subcortical pattern-generating centers with the neural substrate for control of posture and balance, and important changes in body proportions and bone and muscle strength. The control of walking is likely the province of mechanism phylogenetically more primitive than the human cerebral cortex. There is no need to invoke cortical explanations when more simple ones are sufficient.     

Reaction to Compton and Metheny (2000): "assessment of grade inflation in higher education"

Comparison of grades awarded to all students in all courses at SUNY Geneseo in Spring 1990 and Spring 2000 shows a significant overall increase and a fairly stable pattern of grading practices across departments that resembles the pattern reported by Compton and Metheny in 2000 and other investigators.     

Efficacy of the program "Testas's (mis)adventures" to promote the deep approach to learning

This paper provides information about the efficacy of a tutorial training program intended to enhance elementary fifth graders' study processes and foster their deep approaches to learning. The program "Testas's (mis)adventures" consists of a set of books in which Testas, a typical student, reveals and reflects upon his life experiences during school years. These life stories are nothing but an opportunity to present and train a wide range of learning strategies and self-regulatory processes, designed to insure students' deeper preparation for present and future learning challenges. The program has been developed along a school year, in a one hour weekly tutorial sessions. The training program had a semi-experimental design, included an experimental group (n=50) and a control one (n=50), and used pre- and posttest measures (learning strategies' declarative knowledge, learning approaches and academic achievement). Data suggest that the students enrolled in the training program, comparing with students in the control group, showed a significant improvement in their declarative knowledge of learning strategies and in their deep approach to learning, consequently lowering their use of a surface approach. In spite of this, in what concerns to academic achievement, no statistically significant differences have been found.     

Odor-aversion learning in neonate rat pups: the role of duration of exposure to an odor

Five experiments employed 2- and 10-day-old rat pups to examine the ontogeny of odor-aversion learning. When duration of exposure to the to-be-conditioned odor stimulus (CS) was long, Experiments 1 and 2 demonstrated substantial and similar aversions across the two ages regardless of whether the toxin unconditioned stimulus (US) occurred simultaneously with, immediately before, immediately after, or some time after the CS. These experiments, therefore, did not support the claim of Rudy and Cheatle (Ontogeny of Learning and Memory. Hillsdale, N.J.: Erlbaum (1979) ) that the 2-day old pup suffers a deficit in its learning about the relation between successively presented events. The remaining experiments showed, however, that the 2-day-old pups did not acquire an aversion to a briefly presented CS, that the failure to condition this CS was not due to its overshadowing by contextual cues, and that the 10-day-old pup did acquire an aversion to that CS. The experiments have revealed, therefore, that there are age-related differences in the rat pup's ability to learn about the relation between a briefly-presented CS and the effects of a US.