Making sense of feelings

Abstract

Internal feeling states such as pain, hunger, and thirst are widely assumed to be drivers of behaviours essential for homeostasis and animal survival. Call this the 'causal assumption'. It is becoming increasingly apparent that the causal assumption is incompatible with the standard view of motor action in neuroscience. While there is a well-known explanatory gap between neural activity and feelings, there is also a disjuncture in the reverse direction-what role, if any, do feelings play in animals if not to cause behaviour? To deny that feelings cause behaviours might thus seem to presage epiphenomenalism-the idea that subjective experiences, including feelings, are inert, emergent and, on some views, non-physical properties of brain processes. Since epiphenomenalism is antagonistic to fundamental commitments of evolutionary biology, the view developed here challenges the standard view about the function of feelings without denying that feelings have a function. Instead, we introduce the 'sense making sense' hypothesis-the idea that the function of subjective experience is not to cause behaviour, but to explain, in a restricted but still useful sense of 'explanation'. A plausible framework is derived that integrates commonly accepted neural computations to blend motor control, feelings, and explanatory processes to make sense of the way feelings are integrated into our sense of how and why we do and what we do.

Keywords: awareness; neural circuitry; phenomenal consciousness; qualia; subjective experience.

Figure 1

Diagrammatic representation of an input-output brain pathway consisting of an input, a processing module and an output. In the upper pathway, a copy of the input is sent to a forward model that generates a rapid prediction of the output. In the lower pathway, a copy of the output is sent to an inverse model that rapidly predicts the input. The forward and inverse models are trained using an error signal generated by comparing the output prediction and input prediction with the real output or input, respectively

Figure 2

Feelings explain behaviour framework. The underlying premise here is that the conscious brain seeks to explain to itself why it acts in the way it does. A copy of the driving input is sent to a forward model, which predicts the motor command. This predicted motor command is simultaneously entered into both an inverse model and a second forward model. The inverse model outputs the cause of the predicted motor command, which is equivalent to the prediction of the driving input. The second forward model outputs the effect of the motor command which is the predicted sensory feedback arising from the behaviour. Both the predicted driving input and predicted sensory feedback are generated prior to the behaviour and can be fed back into the driving input to rapidly adjust the motor command in real time. The predicted driving input and sensory feedback are what become experienced as conscious feelings. Notably, it is the predicted sensory feedback that contributes specifically to feelings of action. The square dotted line separating conscious and nonconscious processing is illustrative and is not intended to represent the existence of a conscious place in the brain