Genetic experiments with animal learning: A critical review

Abstract

Abstract:The basic patterns of inheritance of learning ability in animals have been delineated. Summaries of strain differences in learning rate, responses to selective breeding for learning, heritabilities of learning phenotypes, and heterosis and overdominance are presented. In addition, the patterns of inheritance are shown to vary with the early environment.The causes of genetic differences have received much attention, but much of the research is inconclusive. Both general learning ability and task-specific abilities are important, but their relative importance is not known for most learning tasks. Strain differences have been found to vary widely in response to variations in stimulus parameters, motivational levels, temporal spacing of trials, and pharmacological manipulations. However, in only a few cases have strain differences in learning actually been shown to be attributable to differences in sensory capacities, motivation, memory or activity levels. The physiological bases for differences are totally unknown. The pathways of gene action on learning also await discovery.Although some researchers have claimed to study the adaptive value of learning, their exclusive utilization of laboratory populations precludes meaningful interpretation of their results.Several methodological shortcomings of various experiments are considered, and important areas for future research are suggested. Article:Learning is a phenotype which has engaged the interests of numerous researchers seeking genetic bases for behavioral differences. In fact, much of the earliest research identifiable as behavior genetics dealt with some aspect of learning in animals (Bagg, 1916;Yerkes, 1916;Tolman, 1924). Ensuing experimentation was performed primarily by psychologists using genetically ill-defined populations. The rather recent appearance of standardized inbred mouse strains with widespread availability has led to renewed interest in the genetic analysis of learning, as well as other phenotypes. Several sophisticated quantitative genetic tools are now readily available for the study of learning. Examples of the application to learning research of selective breeding, the classical cross, the diallel cross, sib analysis, parent-offspring regression, and single-gene analysis have appeared recently.A central motive for compiling the present review is the author's opinion that the increase in genetic sophistication has not been paralleled by a similar growth in the sophistication of measures of learning. In many studies it appears that learning was selected as a phenotype of convenience and general interest.Similarly, the questions about learning investigated have tended to be simplistic and of little interest to those concerned with the nature of the learning process itself. Many recent studies have raised issues that were presented in the earliest research and therefore have contributed little to progress in the area. This is an unfortunate situation in view of the potential power of genetic techniques to answer important questions abou...

Routine Formation and Flexibility in Social and Non-Social Behaviour of Aggressive and Non-Aggressive Male Mice

“…Some may argue that the difference in response to reversal between SAL and LAL mice is caused by differences in learning ability. It has firmly been established that learning differences between individuals are to a considerable extent due to genetic variation (for review : WAHLSTEN, 1972). Although in our study attack latency has been the only selection criterion, correlated changes in other phenotypes, like for instance learning ability, may also appear through the additive action of common genes.…”

“…However, differences between individuals in level of performance in tasks which involve learning cannot simply be interpreted as individual differences in learning ability. There is abundant evidence that many other factors exert their influence on performance level in a particular task, like sensory capacities and preferences, motivation (e.g., some strains appear to be more highly motivated by hunger than others) or activity (PADEH et al, 1974;WAHLSTEN, 1972). A task for which it has now generally been recognized that differences in performance do not reflect differences in learning abilities is the two-way active shock avoidance task.…”

The photically evoked afterdischarge: Current concepts and potential applications

“…Differences in temperament among rat strains are obvious. Whether or not such differences in temperament can be related to the operation of a single or polygenic factor has been debated (Wahlsten, 1972;Wilcock, 1969). Fleming et a1.…”

Social stress impact on developmental stability of laboratory rat Rattus norvegicus

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