The factor-gene basis of emotionality

This paper presents the empirical and theoretical evidence in support of the factor-gene model of emotionality. The theory views the expression of emotion as a product of the interaction between cognition and affect, where cognition and affect are each defined as complex systems whose wholistic functioning (cognition interprets inputs and affect controls arousal level) follows the principles of systems and information-processing theory and whose components are identified via factor analysis. On the basis of the empirical identification of factors at the 1st, 2nd, and 3rd strata, it has been hypothesized that the factors in each domain (33 cognitive factors and 31 affective factors) are hierarchically organized. The empirical research also indicates a significant hereditary effect for 31% of the factors in the cognitive domain and for 83% of the factors in the affective domain. The most pervasive experimental finding concerning the mode of inheritance is that each factor is polygenically determined. Furthermore, in the affective domain there is a range of dominance effects, depending on the class of factors. That is, factors related to escape and avoidance are governed by complete or overdominance, and some of them (e.g., escape) also manifest directional dominance, whereas factors related to undifferentiated arousal (e.g., autonomic balance) manifest either partial dominance or an intermediate form of inheritance. In brief, the factor-gene model is a multiple factor model at both the behavioral (i.e., the factors identified by factor analysis) and genetic (i.e., many genes accounting for each behavioral factor) levels. Futhermore, factors and genes are linked via a variety of unspecified, intervening (and to date unknown) psychobiological mechanisms.The experimental aspects of the author's research summarized in this review were supported by grants from the National Research Council of Canada, and the theoretical aspects were supported by grants from the Canada Council.