Ventral scent marking in Meriones unguiculatus may contribute to thermoregulation

Three experiments were conducted with adult male Meriones unguiculatus in an attempt to demonstrate that ventral scent marking can act to transfer body heat to the object marked. Experiment 1 showed that surgical removal of the ventral gland pad reduced the amount of heat transferred by 50%, even though intact and glandless animals did not differ in the average frequency of scent marking. Experiment 2 demonstrated that the difference in heat transfer due to the presence or absence of the scent pad was not due to differential pressure applied to the substrate during marking. Experiment 3 showed that the pattern of ventral hair spread that occurs as an animal moves over an object is different between intact and glandless animals but that this difference does not account for the difference in heat transfer. It is suggested that heat transfer to the environment with ventral scent marking may increase thermoregulatory competence and also may function to volatilize sebum used in chemocommunication.     

Color discrimination on Mangaia

Bornstein’s hypothesis that there is a loss of color discrimination in tropical areas was not supported in earlier research in the Cook Islands. Using a more sensitive color vision test (the Farnsworth-Munsell 100-Hue Test), a loss of color discrimination in the red-purple and blue-green regions of the spectrum was found. The lack of sex differences in this color discrimination loss supports a physiological rather than a genetic explanation of the observed decrement.     

On the impact of human operant research: Asymmetrical patterns of cross-citation between human and nonhuman research

Reactions to published accounts of research with human subjects, as well as research with nonhuman subjects, were assessed by examining citations in several samples of empirical articles in the Journal of the Experimental Analysis of Behavior. A stable, asymmetrical pattern emerged: Nonhuman research was cited in both human and nonhuman articles, but human research was cited primarily in human articles. Thus, human operant research appears to have had little influence on the nonhuman research which constitutes the bulk of the experimental analysis of behavior. Interpretation of this lack of impact depends on the functions one envisions for human research, several of which are discussed.     

Responsiveness to estrous chemostimuli in male rats (Rattus norvegicus) of different ages

Previous findings indicate that Norway rats (Rattus norvegicus) respond differentially to estrous chemostimuli in early infancy and that adult male sexual responsiveness to such chemostimuli depends on infantile experience with suckling odors (Fillion & Blass, in press). The development of behavioral responsiveness to estrous chemostimuli in male rats from late infancy to adulthood was examined in this study. Preweanling, adolescent, and adult males were observed for 20 min in the presence of an anesthetized estrous or an anesthetized diestrous female. This was, for adolescent and adult subjects, the first heterosexual encounter since weaning. Rats in each age-group responded differentially according to female state, but in distinct, age-related ways. Preweanling spent more time investigating the female's body if she was estrous. Adults expressed the same affinity but by more focused investigation directed perivaginally. Adolescents showed no female-directed bias but groomed themselves more if the female was estrous. These data identify developmental continuities and discontinuities in male rat behavior toward sexually receptive females.     

Social dominance, reproduction, and release of the maturation-delaying chemosignal in the urine of female house mice (Mus musculus)

Five experiments were performed to investigate the effects of social status in groups of female mice on reproduction and on the release or urinary chemosignals that accelerate or delay the onset of sexual maturation in young females. Treatment of young female mice with urine from bottom-ranking mice in groups of 5 adult females resulted in delays in puberty comparable to those produced by treatment with urine pooled from females housed at moderate to high densities. Treatment of young females with urine from top-ranking females from the same groups resulted in ages for puberty not different from those of control females treated with water. There was an interaction between the social rank of a female and the stages of the estrous cycle with respect to the presence in the urine of chemosignals from grouping that delay puberty and estrus that accelerate puberty. Within groups of 5 adult mice, top-ranking females were in estrus more frequently than bottom-ranking females. Individually caged adult females treated with urine from top-ranking females were in estrus more frequently than females treated with urine from bottom-ranking females. When grouped females were separated into individual cages and mated, there was differential reproductive success: More top-ranking females conceived and bore litters than bottom-ranking females. Bottom-ranking females produced more female pups, relative to top- and middle-ranking females.     

Achromatic color categories

Sternheim and Boynton’s (1966) continuous judgmental color-naming technique was used to assess the elemental nature of achromatic colors. Results from three subjects indicate that the names “black” and “white” are necessary and sufficient to describe achromatic test lights associated with the name “gray.” On the basis of the criteria that establishes a color as elemental, black and white were confirmed as elemental, whereas gray was not. These findings support the assumption of various opponent processing models that there are only two elemental achromatic sensations. In addition, the results support Hering’s (1920) view that black and white differ from the paired-chromatic opponent colors in that they are not mutually exclusive.     

Young children's attention to dyadic conversation as modified by sociometric status

Forty-eight American children, 12 popular and 12 rejected children from Grades 3 and 6, were paired with same-sex friends and nonfriends on an interactive task. Children were videotaped and their interactions judged for the amount and type of attention each child in the dyad gave to each other and the conversation. Main dependent measures included mutual engagements, acknowledgement of the partner, getting the attention of the partner, attention to the conversation, and social impact of the utterances. Both rejected and popular children attended to the conversation and the partner, but rejected children appeared to overattend in several ways. The interactions of rejected children and their matches involved more mutual engagements, conversational initiators, facilitators, terminators, and nonverbal attention-getting devices. Sex and developmental effects were also found.