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Open Access Publications from the University of California


The International Journal of Comparative Psychology is sponsored by the International Society for Comparative Psychology. It is a peer-reviewed open-access digital journal that publishes studies on the evolution and development of behavior in all animal species. It accepts research articles and reviews, letters and audiovisual submissions.

Volume 5, Issue 3, 1992

Research Article

Experimental Analysis of the Roles of Siblings Calls After Hatching in Chicks (Gallus domesticus): Comparison with an Artificial Auditory Stimulus

Several recent studies have emphasized the role of the maternal call in the attachment process in young nidifugous birds. Prenatal auditory stimulation (audition of sibling calls or self perception) is a determinant factor in the development of the attractivenessc of the maternal assembly call. However, little is known about the role of sibling calls after hatching. In particular, they may be involved in attraction  between broodmatesx and, in this way, they may compete with the maternal call during the development of attachment. These experiments were designed to test the value of postnatal audition of sibling calls (C). Several groups of chicks were placed in an operant conditioning paradigm in which the instrumental response allowed the birds to receive either auditory, visual raudiovisual stimuli. Results demonstrated that audition of sibling calls is appetitive but, surprisingly,the chicks did not evince a clear-cut choice for this stimulus over audition of a pure tone (T). Moreover, chicks were tested in a choice situation between two audiovisual stimuli. The visual stimulus was the vision of their own image in a mirror (V). In this choice situation between "V + C" and "V + T," chicks did not choose the "V-l-C" stimulus significantly more. Thus, these data, without denying communicative value to sibling calls, support the hypothesis that they do not play an important role in attraction between broodmates and that the main effect of their audition is an activating one.

Effects of Physical Environement and Social Experience on Stimulus Seeking Behaviour and Emotionality in Rats (Rattus norvegius)


influences of the physical and social aspects of the environment on temperament in rats are reported in two experiments. In Experiment One changes in animal behavior due to social isolation and enrichment of the physical environment were studied in rats subjected to experimental conditions when they were 25-30 days old. Enrichment of the physical environment led to decreased need for light stimulation and increased exploratory behavior. Social isolation led to an increase in emotional reactivity. Experiment Twowas analogous to Experiment One, diff"ering only in that 60-70 day-old animals were given the experimental conditions. In this case enriched physical environment and social isolation led to decreased exploratory behavior. Need for light stimulation was aff'ected by the interaction of experimental variables. Need for kinesthetic and tactile stimulation were affected by the social environment. Enrichment of the physical environment also led to a decrease in emotional reactivity in the rats. Our experiments indicate that environmental efl'ects were age-contingent. It is proposed that there is probably a relationship between categories of environment and temperament. Further, our findings draw attention to the possibility of a related evolution of sensory systems and temperamental traits.

Increased Turn Alternation by Woodlice (Porcellio scaber) in Response to a Predatory Spider, Dysdera crocata

The common garden woodlouse (Porcellio scaber) is known to alternate turns (correcting behaviour), but the function of this behaviour is only poorly understood. We investigated Hughes' (1967) hypothesis that this behaviour enables woodlice to escape efficiently from unfavourable environmental conditions by considering the effect of contact with a predator, a potentially unfavourable environmental condition that has not been nvestigated previously. In experiments, woodlice alternated turns more frequently after contact with a known predator of woodlice (Dysdera crocata) than after contact with cotton wool or a nonpredatory arthropod (housefly, Musca domestica).


Courtship Behavior in the Male Guppy (Poecilia reticulata); A Genetic Analysis

Courtship behavior in the male guppy (Poecilia reticulata) was analyzed employing 13 behavioral sequences measured in standardized situations. The stability of these measurements allowed a systematic study of individual differences and of their origins. Factorial analyses lead to two distinguishable main categories of behaviors: one was related to gonopodial swinging; the other to sigmoid display. Variables used to describe gonopodial swinging have only environmental correlates. The additive genetic component was null when estimated by two independent genetic analyses and this result was confirmed by a nonresponse to directional selection. On the contrary, most of the variables used to describe sigmoid display exhibit significant additive genetic components and this was confirmed by the incidence of males exhibiting vs. not exhibiting this behavior in a replicated directional selection. The adaptive significance of the variables is discussed in the light of genetic and observed correlations between the phenotypes.