The evolutionary stability of a bi-stable system of emotions and motivations in species with an open-ended capacity for learning

Abstract One of the highest evolutionary achievements is the open-ended capacity for learning. This is the ability to acquire a behavioral repertoire which is specifically tailored to the environmental situation(s) an individual happens to live in. This capacity is best exploited if the individual's behavioral organization causes any surplus of energy to be invested in expanding and refining the repertoire, and adapting it to prevailing circumstances. Adaptations of the repertoire are most likely to have survival value if applicable to emergencies and other situations causing high arousal. Experience and skills are therefore maximizing fitness if acquired, and subsequently used, in arousal-evoking, and often risk involving, situations.

Entering high-arousal situation, either voluntarily or involuntarily, however, may be harmful to the individual if the resulting state of high stress lasts too long to allow proper (neuro-)physiological functioning, or if too much risk is involved. An open-ended learning capacity is therefore maximally adding to survival if paired to two distinct tendencies:

1. a tendency to seek high-arousal evoking situations whenever surplus energy is available; and
2. a tendency to seek arousal reducing situations as soon as an emergency occurs or as soon as the surplus energy is exhausted.

This suggests that a bi-stable "telic/paratelic" system of preferred levels of arousal, as described in Apter & Smith's theory of motivational reversals (Apter, 1982), can be considered an Evolutionary Stable Strategy (E.S.S.), as compared to homeostatic systems of arousal and motivation.

Introduction

One of the most recent evolutionary achievements is an open-ended capacity for learning. This is the ability to acquire a behavioral repertoire which is specifically tailored to the environmental situation(s) an individual happens to live in. It will be argued here that this ability is highly enhanced by a bi-stable organization of motivation as described by Apter & Smith in their "reversal theory"(see Smith & Apter, 1975; Apter, 1976, 1982; Apter & Smith, 1976abc, 1977, 1979; and Apter et al., 1985).

In fact, it will be shown that the predisposition for such a bi-modal antagonist system of emotional and motivational reversals constitutes the basis of behavioral flexibility Pelt (this volume) is referring to. The present paper therefore deals with the dynamic structure of the biological substrate of what may be called "memes" (Dawkins, 1976) or "culturgens" (Lumsden & Wilson, 1981). It deals, so to speak, with the interface between "genes" and "memes", between the "hardware""and the "software", as has occurred in man. Here we will deal with the motivational mechanisms taking care of the acquirement and the selection of "software" at the individual level.