I t has been found that a number of factors including group size (Cmt~cn, 1946, 1947) environmentM temperature (AsKEw, 1962) and training and handling of experimental animMs (R~rsHToN, STeINBerG and TINSON, 1963) may influence the results of experiments in which the behaviour of animal groups under the influence of drugs is being studied. More recently, LAPIN (1962) has used amphetamine group toxicity tests as a screening procedure for investigating the central effects of drugs on mouse behaviour. I t has been recognised that another factor which influences drug action arises from the interactions of the animals between themselves. H6HN and LASAGNA (1960) at tempted to control this factor in their experiments by grouping their animals. Mice, which were strangers to each other because they had been housed prior to the experiments in different cages, were combined in groups only during the actual experiments. Gn~N~LA~T and OSTE~BE~G (1961) recognised the importance of this factor, and they took precautions in their experiments so that the animals in one cage could not see those in another, tIEIMSTna (1962a, 1962b) has defined this factor as soeiM stimulation, and has shown that the introduction of stranger animals into an experimental situation may alter the behavior, and the action of drugs on the experimental animals. WILSON, (1962) has investigated the effects produced by the introduction of previously isolated normal mice ("rogue mice") into groups of mice subject to audiogenic seizures. In these experiments, unknown and previously isolated rogues were deliberately introduced into stable groups of mice, that is, into groups of mice which had become accustomed to one another by living together in the same container for a period of at least a week. I t was shown that the severity of the seizures was significantly increased, and that this effect depended on the number of rogues which were introduced (WILSON, 1963).
Download Full PDF Version (Non-Commercial Use)