What Are Emotion Theories About? Aaron Sloman School of Computer Science, The University of Birmingham Birmingham, B29 7LF, UK [email protected] Abstract There is, however, a kind of validation of theories of a type Popper did not (as far as I know) admit as science, This is a set of notes relating to an invited talk at and many scientists do not acknowledge, partly because of the cross-disciplinary workshop on Architectures for Popper’s influence, namely theories about what is possible Modeling Emotion at the AAAI Spring Symposium at (what can occur). Simple logic shows that even a single Stanford University in March 2004. The organisers of the workshop note that work on emotions “is often example validates such a theory. The importance of theories carried out in an ad hoc manner”, and hope to remedy of what is possible and how they are presupposed by the this by focusing on two themes (a) validation of emotion search for laws and regularities which constrain what is models and architectures, and (b) relevance of recent possible, was discussed in Sloman (1978, Ch 2). See also findings from affective neuroscience research. I shall (Boden 1990). In particular, contrary to wide-spread views focus mainly on (a), but in a manner which, I hope is on scientific method, the truth of a statement that something relevant to (b), by addressing the need for conceptual can occur is established by a single example – which could clarification to remove, or at least reduce, the ad- be world-shaking (e.g. the discovery that light of low hocery, both in modelling and in empirical research. In intensity and small wavelength can trigger an electric current particular I try to show how a design-based approach when high intensity large wavelength light fails (the photo- can provide an improved conceptual framework and sharpen empirical questions relating to the study of electric effect), the discovery in 1919 that light from a star mind and brain. From this standpoint it turns out that can be deflected by passing near the sun, or Newton’s earlier what are normally called emotions are a somewhat discovery that white light passing through a prism can be fuzzy subset of a larger class of states and processes split into beams different colours). However, checking that that can arise out of interactions between different the description of the example is correct may be non-trivial, mechanisms in an architecture. What exactly the especially if it requires the use of concepts that are not yet architecture is will determine both the larger class and generally understood or theories that are not yet accepted. the subset, since different architectures support different For present purposes the study of architectures and the classes of states and processes. In order to develop the phenomena they support is part of the study of what can design-based approach we need a good ontology for exist or occur (deep science) and why, rather than an attempt characterising varieties of architectures and the states and processes that can occur in them. At present this to discover any new laws about what happens when or what too is often a matter of much ad-hocery. We propose correlates with what (shallow science). But we need to know steps toward a remedy. what we are talking about. What are we talking about? Validation vs testing It is sometimes forgotten that the question whether a theory It is good to ask how theories can be validated, though I is true or false presupposes an answer to whether it makes would rather ask how they can be tested, and how they can sense at all. All theories use concepts, for these are the be compared, in various dimensions, such as depth, clarity, building blocks of propositions, but insofar as the concepts generality, precision, explanatory power, etc., since most are obscure, confused, or vague, the theories, and even the theories are incomplete, provisional, premature, vague, or questions to which the theories are answers, will be flawed. just false. So validation is rarely to be expected, even when For instance, if our concept of ‘emotion’ is ambiguous then a theory is the best one available and provides a good basis so also will many questions about emotions be ambiguous, for further research, a point that is familiar from the writings e.g. how emotions evolved, what their functions are, of Karl Popper (Popper 1934; Magee 1985), and work of which animals have them, which brain mechanisms produce Lakatos cited by Dean Petters in this symposium. them, what types there are, whether they are needed for intelligence, whether a foetus has them, etc. Copyright c 2004, American Association for Artificial Intelli- Alas, our everyday concept of ‘emotion’ mixes up gence (www.aaai.org). All rights reserved. motivations, attitudes, moods, and other affective states and processes, and is therefore is too deeply flawed to be a useful component of scientific questions and theories for reasons recounted elsewhere.1 But that does not prevent scientists assuming that these concepts can be used to formulate clear, unambiguous scientific questions or theories. For instance, sometimes people who argue that emotions are needed for intelligence are merely defending the truism that motivation is needed for action, and preferences are needed for selecting between options. However, not everyone would call a motive or preference, however important, an emotion. Wishful thinking isn’t science Sometimes over-generalising the notion of ‘emotion’ is related to a desire to argue that emotions are important in ways not previously acknowledged, e.g. that they are a pre- requisite for intelligence. This can be wishful thinking or a trivial truism. If ‘emotion’ is construed so broadly that it Figure 1: The CogAff schema defines a crude first-draft division covers all goals and preferences the claim that emotions are of mechanisms into 9 categories. A particular type of fast, pattern- driven, reactive central mechanism, with inputs from and outputs needed for intelligence is vacuous. On the other hand if it to many other components of the architecture could function as refers more narrowly to the sorts of processes in which one an alarm mechanism able to produce global reorganisation very subsystem interferes with or disrupts the normal functioning quickly. Different sorts of alarm systems can produce different of another, as happens in many of the states in which sorts of emotions, depending on where the inputs come from people are described as being ‘emotional’ then it is false where the outputs go, what kinds of decisions are taken and what that emotions are required for intelligence: on the contrary, kinds of output signals are sent. Slower, longer lasting, more emotions of that sort can get in the way of sensible decisions easily suppressed dispositional mechanisms can produce long term and actions. emotions, such as grief or jealousy. Monica Croucher and I once argued in 1981 that mechanisms required for intelligence in resource-limited robots in fast-changing environments would inevitably We need finer-grained ontologies produce the possibility of emotional states, involving We should not put both (i) a general preference for saving interruption or modulation of one process by another (where effort, and (ii) fear produced by a stampeding herd, in the latter is often a fast and therefore relatively stupid the same conceptual basket when they have so very many process) that detects an urgent need for some change, e.g. differences, including the (relative) permanence of the first using reactive mechanisms labelled ‘alarms’ in Fig. 1. But and the transience of the second. Or rather, we can put them saying that states of type X can occur as a side-effect in a more general basket labelled ‘affect’ which includes of the operation of some mechanism M that is required sub-categories which might be aptly labelled ‘emotion’, for intelligence does not imply that states of type X are ‘desire’, ‘preference’, ‘attitude’, ‘value’, ‘mood’, etc. themselves required for intelligence. Many wishful thinkers I am not claiming that all emotions are short-term (though misinterpreted that paper as claiming that emotions are many emotion theories have that consequence, often not required for intelligence, just as they fail to see the obvious noticed by their proponents). In Wright et al. (1996) we flaw in Damasio’s widely quoted reasoning (1994) from the tried to show, at least in outline, how long-term emotions premiss: Damage to frontal lobes impairs both intelligence such as grief, could exist in the form of dispositions and emotional capabilities to the conclusion Emotions are which only rarely manifest themselves, either because of required for intelligence. A moment’s thought should external triggers (reminders) or because other competing show that two capabilities could presuppose some common attention-grabbers subside. Many states generally regarded mechanisms without either capability being required for the as important human emotions that form the stuff of other. plays, novels and garden-gate gossip are long term largely A research community with too much wishful thinking dispositional states, including jealousy, vengefulness, family does not advance science. Of course, if I have misread such love, obsessive ambition, infatuation, fascination with a people and they are merely proposing the truism (noted by mathematical problem, etc. There are other long term Hume, which needs no empirical evidence) that motivation affective states such as preferences, and attitudes that are and preferences are required for intelligent thought and not normally called emotions. actions then that is another manifestation of the ambiguity Of course, someone who defines an emotion as an of the word ‘emotion’. episodic state in which there are particular sorts of bodily changes or sensed changes in a body state map will not 1E.g.