The Nature of Pain: Hedonic Tone, Motivation, and Non-Human Animals is an international, interdisciplinary research project, focused on (i) relations amongst pain, perception, and emotion, and (ii) pain in non-human animals.  It began in January 2012 and runs until 30 June 2013.

Based in the University of Glasgow (Philosophy, School of Humanities), the project's Principal Investigators (PIs) are Dr David Bain and Dr Michael Brady.  The project is part of an overarching programme, Pain and the Nature of Minds, run by the University of Notre Dame and funded by the John Templeton Foundation.

Our research team (see below), including a postdoctoral fellow, comprises philosophers of mind and cognitive science, ethicists, neuroscientists, and veterinary scientists, in Glasgow, Paris, and Oslo.  

To illuminate a number of philosophical issues -- e.g. the problem of evil -- a better understanding of pain is needed. Hence our project seeks to answer two fundamental questions: What is pain’s point? In what sense is pain bad? This requires addressing two of pain’s most obvious but least understood aspects: its unpleasantness and its motivational force (how it drives us to injury-avoiding behaviour). For one might wonder what good pain’s unpleasantness does us. Might we not have had injury-avoidance systems just as effective, but less unpleasant? Addressing these core questions, our project has three strands. How does pain relate to perception, whose role seems informational rather than motivational? How does pain relate to emotional suffering, which is both implicated in and intriguingly parallels physical suffering? And, crucially, how is pain illuminated by comparisons and contrasts between human and non-human pain? 

Project Description
What is pain’s point? In what sense is pain bad? These questions require a better understanding of two of pain’s features: its unpleasantness and the way it drives us to injury-avoiding action. Even if pain is dissociable from these features, as some think pain asymbolia shows, pain’s unpleasantness and motivational force seem tightly linked to each other in interesting ways. So precisely how are they related, and what is their nature? Getting clearer about this will help us evaluate the worry that God or natural selection could have given us—and perhaps did give other animals—systems with all the benefits of pain, but which hurt less. 

Our interdisciplinary approach to these questions has three central strands.

1. Unpleasantness, Motivation, and Perception
Many regard pain as a perceptual system—interoceptive, certainly, but playing a role not unlike exteroceptive senses like vision. But perceptual experiences are sometimes taken to be informative rather than motivational, and so this model can seem to neglect pain’s distinctive nature and role. One major research aim will be to see whether a perceptual model can address this criticism.

To this end, invoking desires, might we think of pains as a kind of perceptual experience we want to cease? Or might we instead capture pains’ motivational force by taking them to be experiences with imperative content, like commands? Another possibility is that the content of pain is action-specifying in the way that perception of a gap’s ‘jumpability’ is sometimes taken to be. Or perhaps pain is akin to a perceptual evaluation of bodily conditions. Moreover, we can ask about the bearing on these questions of the fact that other senses too have hedonic and motivational aspects, such as the awful experience of some smells or tastes, or the pleasures of ‘affective touch’ (hugging or caressing, for example).

Investigating the unpleasant, motivational character of pain—and its relationship to perceptual phenomena—will advance our central objective of understanding pain’s role and badness, and help us to see whether we might have been equipped with a pain system that motivated injury-avoiding behaviour via hedonically neutral perceptions.

2. Pain and Emotion
A second, related pathway to thinking about the badness and motivational role of pain is through pain’s connections with emotion. The amygdala is closely involved in both, for instance; and some aspects of the unpleasantness of pain are emotional, e.g. anxiety (which morphine reduces) about pain’s significance.

Emotion’s involvement in pain makes even more interesting the idea that emotional suffering is arguably an illuminating model for pain. As with pain, the relationship between emotions and perception is complex and controversial. As with pain, emotions exhibit a dual aspect: informative on the one hand, hedonic and motivational on the other. And as with pain, emotions arguably exhibit another duality: descriptive on the one hand; evaluative on the other.

This last point suggests that work on emotion might help answer questions about pain’s badness. If pains evaluate bodily conditions as bad, would this explain why pains are bad? Why should representing something as bad be itself bad? Well, emotions exhibit a similar structure: grief, for example, arguably represents a death as bad while also being itself bad (in certain ways). So philosophical research aimed at explaining the “valence” of emotional responses might also illuminate the badness of pain.

A further link with emotions concerns empathy, which is related to moral virtues and invoked by soul-making theodicies. What is the neural basis of empathy? What is to be made of recent results that empathy worsens the empathetic’s own pain? And what is the relationship between empathising and being in pain?

3. Pain and Animals
Our focus throughout the project will be on both human and non-human pain. Animals variously differ from us, and yet we share similar pain mechanisms and, so some evidence suggests, experience pain similarly. So what do the differences and similarities tell us about the nature of pain? If, in human pain, emotion or evaluation or anticipation is involved, are other animals capable of such things? If so, what form do they take? How does this bear on the role of pain in animals, and the ways in which it is bad for an animal to suffer? A guiding worry above was that we might have had effective pain systems that operated less unpleasantly. What do the various injury-avoidance systems of non-human animals tell us about this worry? In all these ways, then, animals will be a central case as we address our two fundamental questions: What is pain’s point? And in what sense is pain bad?