The Journal of General Psychology

ISSN: 0022-1309 (Print) 1940-0888 (Online) Journal homepage: http://www.tandfonline.com/loi/vgen20

Successive Spatial Discrimination Reversals in the Prairie Dog Roy E. Cain & Richard H. Carlson To cite this article: Roy E. Cain & Richard H. Carlson (1975) Successive Spatial Discrimination Reversals in the Prairie Dog, The Journal of General Psychology, 92:2, 267-272, DOI: 10.1080/00221309.1975.9710853 To link to this article: http://dx.doi.org/10.1080/00221309.1975.9710853

Published online: 06 Jul 2010.

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Date: 05 November 2015, At: 18:39

The Journal of General Psychology, 1975,92, 267-272.

SUCCESSIVE SPATIAL DISCRIMINATION REVERSALS I N T H E PRAIRIE DOG*l

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Texas Tech University

ROY E. CAIN AND RICHARDH. CARLSON SUMMARY Six prairie dogs (Cynomys ludovicianus) were given reversal training on a spatial discrimination reversal task in a Wisconsin General Test Apparatus (WGTA). As with many other species, more errors occurred on the first reversal problem than during acquisition of the original discrimination. However, performance improved over training until each S eventually reversed after a single nonreinforced error. Initial findings indicate that prairie dogs perform at high levels in discrimination learning experiments and could be valuable subjects for psychological research.

A.

INTRODUCTION

Prairie, dogs are diurnal sciurids which are uncommon subjects for psychological research. However, various authors ( 1, 5 , 12) have suggested that these animals are useful for laboratory study. Maintenance needs for prairie dogs are minimal, and wild-caught animals are easily tamed. Research with brain stimulation ( 6 ) and drugs2 indicates a possible use for prairie dogs in the area of physiological psychology. Carlson and Kott (7) have published a stereotaxic atlas of the forebrain of the prairie dog and point out that these animals offer “unique opportunities for behavioral research” (p. 321). Boice and Witter (4) have explored the possibility of using prairie dogs for conventional operant conditioning experiments but had difficulty with motivational variables. Cain and Carlson ( 5 ) , however, encountered no difficulty motivating prairie dogs to perform in a modified Wisconsin General Test Apparatus (WGTA) ; these authors found prairie dogs adept at solving color discrimination problems. King ( 12) has pointed out that the prairie dog’s communication system involves at least 10 classes of vocalizations, and that these animals display social behavior comparable

* Received in the Editorial Office, Provincetown, Massachusetts, on May 15, 1974. Copyright, 1975, by The Journal Press. 1 This research was supported by NIMH Grant No. 1 R03 MH17236-01 MSH as part of Predoctoral Fellowship No. 5 501 MH45.273-02 awarded to the first author. 2 Unpublished data by the authors. 267

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in coniplexity to that of many higher animals. Anthony and Foreman ( 2 ) report that “the feeding behavior, initiation of barks, ‘nuzzling’ or nosecontact frequency, general exploratory activity, and learning capacity suggest the presence of a very highly integrated social hierarchy in these forms, which becomes established early in the development and has obvious adaptive significance” (2, p. 245). These field and laboratory studies suggest that the prairie dog may represent a relatively advanced rodent species suitable for psychological research. One method commonly used for analyzing species differences in learning ability is the successive discrimination reversal task (3 ). When confronted with a series of reversals of the same discrimination habit, rats ( 9 ) , cats (8), opposums ( 1 l ) , bats ( l o ) , and other animals (14) generally improve in performance as the number of reversals is increased. Some of these animals are capable of reversing after a single error ( 9 ) . The purpose of the present study was to evaluate the performance of prairie dogs on a series of reversals to a spatial discrimination task. B.

METHODS

1. Subjects The Ss were six experimentally naive Black-tailed prairie dogs, three males and three females of the species Cynomys ludovicianus. They were live-trapped in Lubbock, Texas, and estimated to be 6 mos to 1 yr of age. All Ss were housed individually in primate cages ( 2 ft x 2 ft x 2 f t ) and maintained on a diet of Purina Lab Chow with water available in standard rodent drinking tubes. Prior to training all Ss were brought down to 80% ad lib. weight (Mean = 1030 gm), and during training Ss were maintained on a 23-hr feeding schedule. 2.

Apparatus

The apparatus consisted of a modified WGTA. One side of the device contained twin right arid left Plexiglas panels, each of which covered an opening leading to a circular foodwell. A vertically sliding opaque guillotine door separated S from the stimulus panels between trials. Except for two white stimulus panels, the entire device was painted a flat gray. Olfactory cues were controlled by placing food behind both foodwells, and all tests were conducted under a masking noise. 3. Procedure Prior to testing, Ss received several days of pretraining in which they were shaped to open the stimulus panels to uncover a foodwell containing

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ROY E. CAIN A N D RICHARD H. CARLSON

2 69

a Noyes food pellet (97 mg) . Ss were first rewarded on both sides and then randomly rewarded to either side. Each S then received 10 free-choice trials to test for position preferences. (No strong position preferences were noted.) On the first training trial neither position was reinforced; on subsequent trials the initially nonpreferred side was rewarded. All Ss received 20 noncorrection trials each day with an intertrial interval of approximately 15-20 sec. Criterion was set at 18/20 correct responses for each problem. Each S received one problem per day until criterion was reached, then the problem was reversed the following day. Thus, the two positions became alternately correct as criterion was attained. Each 5’ completed 18 reversals.

C. RESULTS Figure 1 shows the mean number of errors and standard deviations for both original acquisition (Reversal 0) and reversal learning. A t test for repeated measures revealed a significant difference between the first three reversals and last three reversals ( t 9.38, df = 17, p = .001, one-tailed). All Ss improved over the series of reversal tasks, eventually reversing after a single nonreinforced trial. In each case more errors were made on the first reversal than during acquisition of the original discrimination. All prairie dogs achieved single-error reversals by the 14th problem, and two Ss achieved this level of performance after five reversals. Table 1 indicates the number of days (sessions) required to learn each reversal. Again the first reversal required the greatest number of sessions to learn, followed by a gradual decrease over days. Ry the ninth problem, all 5’s achieved criterion within a single daily session.

D. DISCUSSION The present results demonstrate that wild-caught prairie dogs are ahle to achieve single-error reversals on successive discrimination reversal tasks. Although somewhat less docile than laboratory rats, prairie dogs rapidly adapt to a laboratory setting and perform well in a WGTA. Differences in testing procedures make direct comparisons with other species difficult, but few rodents learn to reverse after a single error as rapidly as prairie dogs. Warren ( 13) has pointed out that spatial discrimination reversal learning is facilitated when brightness is confounded with position cues. Laboratory rats, for example, achieve single-error reversals when both brightness and position cues are relevant (9). Only position served as a cue in the present experiment, however. Boice and Witter (4) tested prairie dogs on several schedules of reinforcement in an operant chamber using water as a reinforcer and on a dou-

2 70

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FIGURE 1 FUNCTION OF REVERSAL TRAINING FOR SIX PRAIRIE DOGS

ble alternation task in a maze using sunflower seed reinforcers. Competing behaviors and motivational problems resulted in poor performance on both tasks. Boice and Witter reported that prairie dogs were unable to solve the first alternation task in over 500 trials, and that “periods of consistent performance gave little hope that the dogs could learn the alternation problem” (4, p. 288). Consistency of performance might also be expected to interfere with reversal learning; however, no such difficulty occurred in the WGTA. Perhaps the use of a percentage body weight criterion in the pres-

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ROY E. CAIN A N D RICHARD H. CARLSON

TABLE 1 DAYSTO LEARNING CRITERION Days to criterion Reversal

Original Subject learning

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ent study alleviated some of the motivational problems encountered by Boice and Witter. The present study indicates that prairie dogs may indeed perform at high levels in learning experiments, although the present authors agree with Boice and Witter (4) that these rodents are not likely to replace the laboratory rat. However, prairie dogs do offer certain advantages over rats in some areas of research. Notably, prairie dogs are diurnal, possess excellent visual acuity, and have color vision, thereby providing for a variety of opportunities for research in discrimination learning and perception. These rodents are also highly sociable creatures with a well developed communication system and are capable of complex social interactions. The breeding habits of prairie dogs, however, have both advantages and disadvantages. Since these animals breed once a year, both sexes may be used on behavioral tasks with a minimal interference from hormonal changes. On the other hand, a single breeding season, paired with a greater need for space and nesting, restricts breeding in the laboratory. In the final analysis, prairie dogs should prove interesting subjects for behavioral research. Certainly these animals should be included among the species studied in a comparative psychology of learning. REFERENCES ANTHONY,A. Behavior patterns in a laboratory colony of prairie dogs, Cynomys ludovicianus. J . Mammal., 1955, 36, 67-78. ANTHONY,A., & FOREMAN, D . Observations on the reproductive cycle of the black tailed prairie dog (Cynomys 1udovicianu.s). Physiol. Zool., 1951, 24, 242-248. BITTERMAN, M. E. Phyletic differences in learning. Amer. Psychologist, 1965, 20, 396-410.

BOICE,R., 81 WITTER,J. A. Motivating prairie dogs. Psychon. Sci., 1970, 20, 287289.

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CAIN, R . E., & CARLSON,R. H. Evidence for color vision in the prairie dog (Cynomys ludovicianus) . Psychon. Sci., 1968, 13, 185-186. C. P., & CARLSON,R. H. Habituation of electrically induced 6. CAIN, R. E., SKRIVER, readiness to gnaw. Science, 1971, 173, 262-264. 7 . CARLSON, R. H., & KOTT,J. N. The forebrain of the prairie dog (Cynomys ludo5.

vicianus) in stereotaxic coordinates. Acta Anutom., 1970, 77, 32 1-340.

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11.

12.

13.

CRONHOLM, J. N., WARREN,J. M., & HARA,K. Distribution of training and reversal learning by cats. J . Genet. Psychol., 1960, 96, 105-113. DUFORT,R. H., GUTMAN,N., & KIMBLE,G . A. One-trial discrimination reversal in the white rat. J . Comp. Physiol. Psychol., 1953, 47, 248-249. ELJJNS,S. R., & MASTERSON, F. A. Successive spatial discrimination reversals in the hat. Psychon. Sci., 1971, 25, 265-266. JAMES,W. T. A study of visual. discrimination in the oppossum. J . Genet. Psychol., 1960, 97, 127-130. KING, J. A. Social behavior, social organization, and population dynamics in a black-tailed prairie dog town in the Black Hills of South Dakota. Contrib. Lab. Vert. Biol., 1955, 67, 1-123. WARREN, J. M. Oddity learning set in a cat, J . Comp. Physiol. Psychol., 1960, 53, 433-434.

. The comparative psychology of learning. Ann. Rev. Psychol.,

14. 95-118.

Department of Behavioral Sciences Pan American University . Edinburg, Texas 78539

1965,

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