Skip to main content
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 1, Issue 1, 1987

Research Article

Evolution by Process, Not by Consequence: Implications of the New Molecular Genetics on Development and Evolution

There is much in common between comparative psychologyand biological tradition that includes such distinguished figures as poetscientist Goethe, evolutionist Lamarck, embryologist Driesch; andcloser to our time, D'Arcy Thompson, Alfi-ed North Whitehead, JosephNeedham, Richard Goldschmidt and Conrad Waddington. This traditionhas been variously referred to as organized, holist, neovitalist, and soon, though none of the labels are completely accurate. Its chiefconcernis the study of living organization at different levels each with its owndistinctive emphasis. Nevertheless, these people share a passionatecommitment to vital process and a refusal to be seduced by simplisticpseudoexplanations at every turn. The levels of organization apparentin the living world today have emerged in the course of evolution:from molecules and protocells (see Fox, 1984 and refs. therein) toprotists; from the first multicellular organisms to communities ofanimals and plants, and finally to intricate human societies. All theseproducts of evolution coexist and are interdependent because they arepart of one evolutionary process. The key to the survival of our planetlies in a proper appreciation of the continuity which exists among the physicochemical, biological and sociocultural realms. It is from thisperspective of the unity of nature that a biologist like myself maybe encouraged to address psychologists on the implications that recent advances in molecular genetics have on our study of developmentand evolution.

Behavioral Correlates of Cerebellar Ablations in the Teleost, Aquidens Latifrons

The effects of ablation of the corpus, eminentia granularis and valvula of the cerebellum on the performance of optomotor tasks, and the appearance of atypical behavior patterns were studied in the teleost fish Aquidens latifrons . The subjects were observed in their home tanks before and after surgery, and were tested in a modified optomotor apparatus where the drum changed direction of rotation at regular intervals. The corpus cerebellum was ablated totally or partially, bilaterally or unilaterally. In other subjects the eminentia granularis was ablated on the right side or in conjunction with ipsilateral corpus lesions. The valvula was completely ablated in still other subjects with only slight damage to adjacent brain tissue.

When experimentally naive intact fish were given a series of optomotor tests they gradually improved their optomotor performance. After cerebellar operations this improvement was reversed in most of the optomotor measurements as the fish followed the moving stripes much less efficiently. However swimming speed, which we considered a good indicator of motor performance, was unchanged except in 2 out of 13 groups. We concluded that the less efficient optomotor behavior could not be attributed to a direct effect of the lesions on motor processes. The home-tank observations clearly revealed four postoperative motor abnormalities. Oscillatory movements, wobbling and tilting persisted through the tests, but the fourth, lying on the side, a more profound disability, disappeared in all but one subject in a few hours to a few days. The first three abnormal behavior patterns, especially the oscillatory movements, suggest a deficiency in fme motor tasks and support the interpretation that the major function of the cerebellum is described best as the modulation of movement. High levels of tilting and lying on the side in subjects with unilateral lesions maybe caused by an inbalance in motor function. Several alternative or additional functions of the cerebellum suggested by these experiments are evaluated.

Role of Context in Imprinting

Pekin ducklings ( Anas platyrhynckos ) were exposed either to a white or harlequin duck model. When tested for their preferences with both models simultaneously present, the harlequin was more often preferred. If tested in the presence of another strange object (a stuffed barn owl, Tytus alba ), the harlequin-trained ducklings more often deviated from chosing their training model than did the white-trained ducks, i.e., a reversal of effects. Apparently, the context of the test interacts with the characteristics of the model in a way that confounds predictions.

Immediate and Delayed Flavour-Calorie Learning: Can Rats Do It?

Four experiments which investigated the ability of rats to associate the flavour of a food with the later release of calories are reported. In Experiments 1 and 2, which involved immediate reinforcement, rats were trained to discriminate between two flavours (e.g. cinnamon and wintergreen), one of which was mixed with a solution of glucose which provided many calories on some days and the other with a solution of saccharin which did not yield any calories on other days. In subsequent two-bottle tests between the two flavours mixed with the same type of substrate, all rats displayed large shifts in preferences for the flavour previously paired with glucose compared to the second flavour previously paired with saccharin. Experiment 2 further showed that the conditioned effects extinguished very easily. In Experiments 3 and 4, which involved delayed reinforcement, rats were trained to discriminate between the two flavour cues, both dissolved in saccharin, one of which was reinforced with food after a long delay on some days and the other with nothing on other days. In Experiment 3 glucose was delivered after a 30 min. delay whereas in Experiment 4 various kinds of food were used and the delay was reduced to 20 min. In subsequent preference tests between the flavour cues in Experiment 3, only a small, but significant, increase in preference for the paired flavour was detected. Similarly in Experiment 4 some evidence for discrimination learning was again found with glucose, but there was no evidence that rats could associate a flavour with starch solution or solid chow over the 20 min. delay. Overall these results show that rats can easily form flavour-calorie associations under immediate reinforcement conditions but they do so with great difficulty when long delays are involved.

Book Review: Constraints on Sociobiology

Philip Kitcher's Vaulting Ambition: Sociobiology and the Quest for Human Nature