Jesse E. Purdy

Animal research in psychology. More than meets the eye of the general psychology student.

The general psychology course provides a unique opportunity to present the science of psychology to a wide audience. Informing the general public about the importance of animal research in psychology is especially important given contemporary concerns about animal rights and animal welfare. A study of 8 leading introductory psychology textbooks indicated that with the exception of principles of conditioning and learning, the contributions of animal research to psychology were often not explicitly acknowledged. In addition, major findings from animal research were frequently presented as if they had been obtained with humans. In obscuring the contributions of animal research, introductory psychology textbooks miss the opportunity to ensure that public policy be based on accurate information about the significance of this research to many areas of psychological science.

Sign tracking in cuttlefish (Sepia officinalis).

Two groups of cuttlefish (Sepia officinalis) were used to demonstrate classical conditioning in this species and to determine whether the resulting approach response would be that of sign tracking or goal tracking. For cuttlefish in the paired condition, a flashing light was presented at one end of a long tank followed by food dropped into the center of the tank. For cuttlefish in the unpaired condition, food was dropped into the center of the tank either before or after the flashing-light stimulus. Paired cuttlefish oriented to the light, positioned themselves within striking distance, and occasionally attacked the light. Unpaired cuttlefish showed no reliable response to either stimulus. The results demonstrate that cuttlefish are capable of signal learning and that, under the conditions tested, cuttlefish sign tracked. This study begins a comparative analysis of learning in cuttlefish and offers a possible ecological advantage for sign-tracking behavior.

Prawn-in-a-tube procedure: habituation or associative learning in cuttlefish?

The prawn-in-a-tube procedure (J. B. Messenger, 1973a) has been used almost exclusively to study associative learning in cuttlefish. In two experiments, the authors sought to determine whether the decline in attack responses observed in this procedure was best accounted for by habituation or associative learning. Results of Experiment 1 revealed an asymmetrical stimulus-specificity effect that could be interpreted as either an instance of habituation or of associative learning. Results of Experiment 2 demonstrated that the response decline could not be reversed following the presentation of a dishabituatory stimulus. The combined results of these experiments support the conclusion that the response decline is best viewed as a resulting of associative processes. The authors considered whether the response decline represents extinction or passive avoidance.

Immediate and Long-Term Retention For Pictorial and Verbal Stimuli.

Although nouns of high imagery are generally recalled better than nouns of low imagery, both Palermo and Yuille have shown that retention for the former decreases with time. The present study tested the hypothesis that this decreased effectiveness occurs because images stored in long-term memory are accessible only through their verbal labels. 64 subjects were presented pictures and later asked to draw them or provide one-word descriptions. Other subjects were presented words and asked to recall them or draw representational pictures. Recall was tested immediately and 48 hr. later. Regardless of recall mode, subjects viewing pictures showed significantly greater recall than subjects viewing words, and for all subjects immediate recall was better.

NEW ESTIMATE FOR STORAGE TIME IN SENSORY MEMORY

Sperling in 1960 reported information in sensory storage remained for about one sec. In 1974 Phillips reported that information in sensory storage passed on to short-term visual memory after 100 msec. To distinguish between these alternatives, 55 subjects received 36 trials in which two matrices of letters, familiar shapes, or non-familiar shapes were presented successively in a recognition task. The interstimulus interval varied systematically. Results showed that as the interval increased, performance decreased. Further, memory for letters and familiar shapes was superior. Finally, there were no differences among letters, familiar shapes, and non-familiar shapes at the .25-sec. interval. At the .5-sec. interval, performance for familiar shapes was superior to performance for non-familiar shapes. It was concluded that information transfers to short-term visual storage after .25 sec.

Persistence of a briefly presented visual stimulus in sensory memory

College students were given 12 trials in which two 4 by 4 matrices of letters were presented sequentially, each for 100 msec. On one-half of the trials, the second matrix was the same as the first, and on one-half of the trials, the second matrix differed from the first. Both the interval between the two presentations and the degree of difference between the second matrix and the first were manipulated systematically. Results indicated that when the difference between the second matrix and the first was either large or nonexistent, recognition was good. When the difference between the matrices was small, performance decreased significantly. The interstimulus interval variable was not significant. Results were discussed in terms of Sperling’s (1960) findings and those of Cermak (1971) and Phillips (1974).

Optimal Foraging by Patch and Prey Selection in Thamnophis Sirtalis Similis

Abstract Patch and prey selections by blue-striped garter snakes (Thamnophis sirtalis similis) were examined in a series of simultaneous choice situations. We presented snakes with choices between small or large patches (defined by the size of the bowl in which they foraged) containing either small or large prey fish and recorded subject choices, attacks made, and capture success. T. s. similis appeared to optimize energy investments by discriminating between differing patch and prey characteristics and choosing those situations characterized by the lowest procurement cost. Subjects foraged successfully most often in small patches with large prey, where they also made the fewest mean attacks per fish captured. Choices followed success rates in that T. s. similis selected small patches with large prey most often. Results are discussed in light of foraging optimization in other garter snakes and ectotherms in general.

Contributions to the history of psychology: XCV. Possible relations between theories of evolution and animal learning.

It is proposed that the dominance of continuity learning theory as set against noncontinuity learning theory during the middle third of the 20th century rested importantly on its derivation from Darwins theory of evolution. The kinship is shown in several ways. First, Thorndike and Hull echoed the principle of natural selection in their belief that behaviors underwent gradual modification because acts that were attended steadily by favorable consequences tended to occur with increasing frequency. Second, they denied both nonphysical explanations of behavior and a priori purposes which might guide that behavior. Third, the laws of learning were said to hold for all organisms. It is argued that the continuity approach may have enjoyed success because it was consistent with the Darwinian world view. Had punctualist, rather than gradualist, explanations of evolution come to the fore in the late 19th century, learning theories might have proceeded quite differently with the dominance of noncontinuity approaches.

Danger at the Waterhole

The effects of declining accessibility of water and risk of electric shock on drinking patterns in rats were examined. Rats chose between two conditions to obtain their daily intake of water. In one condition, accessibility of water decreased systematically. In the other condition, water was readily accessible, but responses occasionally were followed by electric shock. Both variables affected drinking patterns similarly. As accessibility to water decreased, the number of drinking bouts initiated decreased but the quantity of water consumed increased. In response to risk of electric shock, the number of drinking bouts decreased but bout size increased. Results are considered in light of findings by Fanselow, Lester, and Helmstetter, (1988), Collier, Hirsch, and Hamlin (1972), and Marwine and Collier (1979).