Motivational Systems in Rats and Monkeys:
Are They Homologous
Methods Page 2


Title/Abstract page

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Introduction
Page 1

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Methods
Pages 2 - 3

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Results
Pages 4 - 5 - 6

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Discussion
Pages 7 - 8 - 9 - 10

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References
Page 11

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Figures
Figures 1 - 2 - 3


The methodologies for the two studies will not be given here in detail since they are being published elsewhere for the rat [Lehman and Adams, 1977] and monkey [Adams and Schoel, submitted for publication]. Instead, the general outlines of methodology will be sketched, and the few differences between the two studies will be stressed.

In the rat study, 40 adult males isolated in 80 X 25-cm wire-mesh cages were the resident rats. Intruder rats, consisting of 40 adult males of a different strain that had been kept under group housing conditions, were placed individually into the home cages of the resident rats. All acts, postures, and vocalizations of the resident and intruder were recorded and later analyzed for the first 10 min of the confrontation. A scoring system for acts and postures was adapted from Grant and Mackintosh [1963]. Acts and postures were considered as a single continuous channel of communication within and between the two animals; all nonrandom (P < 0.001) dyadic sequences of acts and postures, both within each animal and between the two animals, were determined from 2 X 2 tables using chi square or Fisher's exact test for statistical analysis. Vocalizations were considered as a second, independent, discontinuous channel of communication; the association of vocalizations with particular acts and postures was determined from 2 X 2 tables analyzed by the same statistics.

In the monkey study, six socially isolated adult males were used. Their dominance relationships had been observed in previous tests, in which it had been determined that four were always dominant, one was always subordinate, and one was dominant to the most subordinate animal, but was subordinate to the others. Thirty-two tests were conducted in which a subordinate animal was placed first into the test cage, a wire-mesh cage with dimensions of 2.7 X 5.4 X 2.7 m high. The dominant animal was then placed into the test cage and all acts, postures, vocalizations, and facial expressions of both the dominant and the subordinate animal were recorded and later analyzed for the first 5 or 10 min of their confrontations. Twenty-two tests were 5 min in duration and 10 were 10 min in duration. A scoring system for acts, postures, vocalizations, and facial expressions was adapted from Bertrand [1969] and Chevalier-Skolnikoff [1974]. The analysis was the same as that for the rats. Acts and postures were considered as a single continuous channel of communication within and between the two animals; all nonrandom (P < 0.001) dyadic sequences of acts or postures, both within each animal and between the two animals were determined from 2 X 2 tables. Vocalizations and facial expressions were considered as two other independent, discontinuous channels of communication, and their associations with particular acts and postures were determined from 2 X 2 tables.

(Continued on next page)

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