Vertebrate decision making leads to the interdependence of behaviour and wellbeing

Animal behaviour is commonly modelled by fitness-based optimization or individual-based simulation. Each has limitations: the premises for fitness-maximizing modelling are violated in most ecological and sociobiological settings while individual-based modelling generally does not include an evolutionary approach to behaviour. We propose a new approach focusing on the bodily mechanisms that vertebrates (and some other animals) use when making behavioural decisions. Our hypothesis is that decision making in vertebrates is a two-step process where emotion (a cognitive mechanism that for a while may become a state controlling the body and driving behaviour) is the common currency: (1) determining through competition among emotions the organism's current priority and (2) choosing the behaviour that maximizes imagined near-future emotional wellbeing, aided by episodic-like memory. Animals with subjective experience use awareness of their strongest emotional need to concentrate attention, which is a higher level of agency than the unconscious robustness mechanisms in all life forms. Furthermore, animals with imagination-based prediction maximize emotional wellbeing in their decision making. That is, evolution started out without a goal, but from it, animals that live for short-term wellbeing emerged. We show that wellbeing and other mechanisms of organismal robustness can be used in a new class of models that is broadly applicable to animals in natural and artificial settings. This modelling approach can make novel predictions about the links between wellbeing, behaviour and function. • Optimality modelling assumes that the gene pool is adapted to current conditions. • Behaviour and wellbeing are deeply intertwined in vertebrate evolution. • Vertebrate decision making maximizes imagined near-future emotional wellbeing. • Wellbeing and behaviour can be modelled from ancestral robustness mechanisms.