• DOI:10.1111/j.1749-6632.1969.tb12980.x
• Corpus ID: 42323956

PSYCHOGENETICS OF EMOTIONALITY IN THE RAT *

@article{Broadhurst1969PSYCHOGENETICSOE,
  title={PSYCHOGENETICS OF EMOTIONALITY IN THE RAT *},
  author={Peter Lovell Broadhurst},
  journal={Annals of the New York Academy of Sciences},
  year={1969},
  volume={159}
}

• P. L. Broadhurst
• Published 1 July 1969
• Psychology
• Annals of the New York Academy of Sciences

The open-field test has played a long and honorable part in the relatively short history of comparative psychology, having now been in use for as much as 35 years. It is clear that, on the basis of recent work, it has now reached the status of one of the few widely used, relatively standardized instruments in animal psychology, the need for which has long been evident, but which has rarely been achieved. Thus, along with the Skinner box, escape-avoidance conditioning, and some of the standardized maze patterns, the open-field test can usually be relied upon to give results that may be replicated among different laboratories. Credit for this development belongs, primarily, to Calvin S. Hall, who, basing himself on some collaborative work with Ballachey (1932), initiated a series of studies of methodological and substantive importance (see Broadhurst, 1960, for a review of this work). Hall, along with other contemporary workers (e.g., Yoshioka, 1932 and Stone, 1932), was primarily interested in defecation in the open field as a measure of emotionality in the rat. He was not the first to study emotional elimination in this way and, indeed, Stone (1932) also used a 5 f t X 6 f t open field in which, inter alia, he observed defecation responses as a measure of “wildness,” but it was Hall’s sustained work that ultimately led to the widespread use of the test which we see today. In particular, his genetic selection study for strains characteristically high or low in emotional elimination was especially important and the use of his emotional and nonemotional strains of rats had implications which were not always obvious, as Jones and Fennel1 ( 1965) have shown. Thus, it seems that from the first this test has been associated with the study of genetic variables in behavior, and this association was confirmed by the replication of Hall’s study, based on a restandardization of his open-field test and carried out in London in the 1950’s, which gave rise to the establishment of the Maudsley Reactive and Nonreactive strains of rats (Broadhurst, 1960, 1962). There seem to be two main reasons for this association. First, the nature of the defecation response itself, which is essentially innate and, therefore, needs no prior training to emerge, although this does not, of course, mean that it is not susceptible to the modifying effects of environmental influences experienced by the rat, and, second, the test itself is, in consequence, relatively short and simple to administer. This leads to an economy of time and effort essential with the large numbers associated with breeding studies of any kind in which the quantitative nature of almost all behavioral variation demands a biometrical and statistical approach. Such an approach cannot be carried out with the relatively small numbers characteristic of classical genetical techniques involving simple Mendelian ratios. SELECTION AS A PSYCHOGENETIC METHOD