On the evolution and optimality of mood States.
Moods can be regarded as fluctuating dispositions to make positive and negative evaluations. Developing an evolutionary approach to mood as an adaptive process, we consider the structure and function of such states in guiding behavioural decisions regarding the acquisition of resources and the avoidance of harm in different circumstances. We use a drift diffusion model of decision making to consider the information required by individuals to optimise decisions between two alternatives, such as whether to approach or withdraw from a stimulus that may be life enhancing or life threatening. We show that two dimensions of variation (expectation and preparedness) are sufficient for such optimal decisions to be made. These two dispositional dimensions enable individuals to maximize the overall benefits of behavioural decisions by modulating both the choice made (e.g., approach/withdraw) and decision speed. Such a structure is compatible with circumplex models of subjectively experienced mood and core affect, and provides testable hypotheses concerning the relationships that occur between valence and arousal components of mood in differing ecological niches. The paper is therefore a useful step toward being able to predict moods (and the effect of moods) using an optimality approach.
School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
Pete C
PC
Trimmer
Division of Animal Health and Husbandry, Langford House, Langford, Bristol BS40 5DU, UK.
Elizabeth S
ES
Paul
Division of Animal Health and Husbandry, Langford House, Langford, Bristol BS40 5DU, UK.
Mike T
MT
Mendl
School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK.
John M
JM
McNamara
School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
Alasdair I
AI
Houston
circumplex; core affect; drift diffusion model; emotion; mood; optimal decision making