Doing Away with Morgan 'S Canon

Doing Away with Morgan’ s Canon SIMON FITZPATRICK

Abstract: Morgan’ s Canon is a very widely endorsed methodological principle in animal psychology, believed to be vital for a rigorous, scientifi c approach to the study of animal cognition. In contrast I argue that Morgan’ s Canon is unjustifi ed, pernicious and unnecessary. I identify two main versions of the Canon and show that they both suffer from very serious problems. I then suggest an alternative methodological principle that captures all of the genuine methodological benefi ts that Morgan ’ s Canon can bring but suffers from none of its problems.

1. Introduction

Morgan’ s Canon is a very widely endorsed methodological principle in animal psychology. Proposed at the end of the 19th century by the British comparative psychologist Conwy Lloyd Morgan, it states that:

In no case may we interpret an action as the outcome of the exercise of a higher psychical faculty, if it can be interpreted as the outcome of the exercise of one which stands lower in the psychological scale (Morgan, 1894, p. 53).

This principle has played a central role in subsequent scientiﬁ c and philosophical work into the nature of non-human animal minds. So central in fact that it has been described as ‘ possibly the most important single sentence in the history of the study of animal behaviour’ ( Galef, 1996, p. 9; cited in Radick, 2000, p. 3). Morgan’ s Canon has attained this eminent status because it has been seen as a necessary component of a suitably rigorous approach to explaining animal behaviour. According to a recent textbook, ‘ Morgan’ s Canon … has enabled us to approach the analysis of behaviour sensibly and to avoid the superﬁ cial anthropomorphism which led to many absurdities in the past ’ ( Manning and Dawkins, 1998, p. 295). One of the classic past ‘ absurdities’ referred to here is the case of ‘ Clever Hans’ , the early 20th century horse that was reputed to be able to answer arithmetical questions via a language of hoof-tapping and head-shaking.

Thanks to George Botterill, Paul Faulkner, David Liggins, Peter Lipton, Robert Lurz, Gregory Radick and two anonymous referees for Mind & Language for helpful discussion and comments on earlier versions of this paper. Particular thanks go to Stephen Laurence who provided invaluable feedback on several draft versions. Thanks also to audiences at the Universities of Leeds, Oxford and Sheffi eld where versions of this paper were presented. Address for correspondence: Department of Philosophy, University of Sheffi eld, Arts Tower, Western Bank, Sheffi eld, S10 2TN, UK. Email: s.fi tzpatrick@sheffi eld.ac.uk

Hans’ abilities were acclaimed in many circles, until an investigation led by Otto Pfungst eventually showed that Hans had merely been responding to subtle visual cues unintentionally provided by the audience. Though the original formulation of Morgan ’ s Canon predates the Clever Hans debacle, this famous case of mistaken attribution of sophisticated cognitive capacities to an animal is now presented as the paradigm illustration of why Morgan’ s Canon should be adhered to. It is deemed to be the necessary antidote for the methodological errors that this and other early work in animal psychology fell prey to.1 Morgan’ s Canon is thus seen as a major landmark in the professionalisation of animal psychology, helping ‘ to separate science from its merely anecdotal and anthropomorphising ancestors and neighbours’ (Wilder, 1996, p. 38). Support for Morgan ’ s Canon, though not completely universal,2 is still extremely widespread in modern discussions about animal minds. Indeed most psychologists and philosophers simply take Morgan’ s Canon for granted: it is assumed to be self- evidently reasonable, requiring no detailed defence or explication. The aim of this paper is to investigate whether Morgan ’ s Canon is in fact a good methodological principle. My conclusion will be an emphatic no . I will argue that far from being the antidote to the methodological problems facing animal psychology and for cases like Clever Hans, Morgan ’ s Canon has been, and remains, a persistent impediment to progress. Consequently, Morgan’ s Canon ought to be abandoned. 3

1 Morgan formulated his Canon in response to early Darwinian comparative psychologists ( Darwin, 1871; Romanes, 1882) who had made very bold claims about the psychological capacities of animals on the basis of what he saw as fl imsy anecdotal evidence (Boakes, 1984). 2 In particular those associated with the fi eld of ‘ cognitive ethology’ (e.g. Griffi n, 1976; Allen and Bekoff, 1997; Tomasello and Call, 1997) are much less likely to express support for Morgan’ s Canon and some have been openly critical of the principle. 3 Though Morgan’ s Canon has not received the critical attention it deserves, this is not to say that Morgan’ s Canon has received no critical attention at all. Previous commentators have criticised aspects of the way that Morgan’ s Canon has been employed and justifi ed by its proponents (e.g. Newbury, 1954; Griffi n, 1976; Costall, 1993; Wilder, 1996; Sober, 1998; Thomas, 1998; de Waal, 1999). In particular, commentators have noted that the Canon has often served as a convenient justifi cation for a priori resistance to attributions of mental states to animals, especially in the hands of behaviourists. Nonetheless most critical commentators have claimed that Morgan ’ s Canon is necessary for a rigorous animal psychology, arguing that we just need to be clearer about its justifi cation and that it should not be employed over zealously. To date the best discussion of Morgan’ s Canon is Elliott Sober’ s (1998). Sober fi nds much that is wrong in the standard justifi cations that have been given for Morgan’ s Canon, but nonetheless argues that it should be retained in a signifi cantly revised form. The present paper owes much to Sober ’ s, but I will argue that we should go considerably further than Sober: Morgan’ s Canon should not be revised, but rather abandoned altogether (for discussion of Sober’ s views see fn. 10 and fn. 14 below). This rejectionist view is certainly not without precedents (e.g. Walker, 1983; Fodor, 1999), but a suffi ciently persuasive case for abandoning Morgan’ s Canon has not yet been made. The principal aim of this paper is to correct this defi cit.

A key component of my case for abandoning Morgan’ s Canon will be the claim that it is completely unnecessary for combating crude anthropomorphism in animal psychology, the key function that the Canon is taken to serve. I will show that there is an alternative and much more plausible principle to Morgan’ s Canon that captures all of the genuine methodological beneﬁ ts that the Canon can bring, but suffers from none of its problems. Importantly, this principle places no special constraints on ‘ higher’ explanations of animal behaviour. Thus I will argue that animal psychologists have persistently over-interpreted the appropriate methodological lessons to be learnt from cases like Clever Hans. In so doing they have endorsed methodological principles that are unjustiﬁ ed, pernicious and unnecessary . In short animal psychology ought to do away with Morgan’ s Canon.

2. What is Morgan’ s Canon?

Before we can begin to evaluate Morgan’ s Canon, we fi rst need to be clear about what Morgan’ s Canon actually says. One thing in particular that we need to be clear about is the distinction between ‘ higher’ and ‘ lower’ ‘ psychical faculties’ . Morgan himself was vague about what he meant by these terms and about the nature of the ‘ psychological scale’ . Subsequent theorists have done little to clarify these notions. Nonetheless, I think that we can identify what seems to be the dominant modern view of how ‘ higher’ and ‘ lower’ are to be interpreted in Morgan’ s principle (see also Dewsbury, 1984). 4 Modern theorists generally seem to take these terms to refer to the relative sophistication of the cognitive processes that are postulated by rival explanations for animal behaviour. A cognitive process is ‘ higher’ on the psychological scale than another cognitive process if it is more sophisticated, and ‘ lower’ on the scale if it ’ s less sophisticated. Likewise for explanations of animal behaviour: for example, an explanation that attributes second-order intentionality to an animal will be ‘ higher’ than an explanation that attributes only fi rst-order intentionality, an explanation that attributes capacities for deliberation or practical reasoning will be ‘ higher’ than an explanation that attributes only conditioned responses or innate refl exes, and an explanation that attributes any sort of cognitive process will be considered ‘ higher’ than an explanation that attributes no cognitive processes, and so on. Here in each case the ‘ higher’ explanation attributes cognitive processes to the animal that are generally regarded as more sophisticated than those attributed by the ‘ lower’ explanation. I take the relevant notion of ‘ sophistication’ here to be broadly functional, so that a higher cognitive process is one that endows the animal with more elaborate cognitive capacities than does a lower process. That is why, for example,

4 I emphasise that my focus in this paper is on how Morgan’ s Canon is read by modern animal psychologists and not on how Morgan himself intended it to be read, for which see Costall, 1993; Radick, 2000.

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd Doing Away with Morgan’ s Canon 2 2 7 second-order intentionality is a ‘ higher’ cognitive process than ﬁ rst-order intentionality, since possession of second-order intentionality allows an organism to form mental states whose contents concern other mental states, while possession of ﬁ rst-order intentionality does not. It is the addition of this extra cognitive capacity that makes second-order intentionality a more sophisticated and hence ‘ higher’ cognitive process. Note that the distinction between a ‘ higher’ cognitive process and a ‘ lower’ one may often be one of degree rather than kind and also relative to the point of comparison —so cognitive process X may be higher than process Y but lower than process Z, depending on how they compare to each other in terms of relative cognitive sophistication.5 Thus on what I take to be the dominant current interpretation of ‘ higher’ and ‘ lower’ , Morgan’ s Canon can be rephrased as the principle that:

In no case may we interpret an action as the outcome of the exercise of a more sophisticated psychological faculty, if it can be interpreted as the outcome of the exercise of one which is less sophisticated .

Morgan’ s Canon is thus to be understood as a principle for guiding attributions of different degrees of cognitive sophistication to animals. This is how I will be using the terms ‘ higher’ and ‘ lower’ in what follows.6 With this clarifi cation of ‘ higher’ and ‘ lower’ in mind, there are still a number of different ways that Morgan ’ s principle can be fl eshed out. In fact individual theorists frequently appear to disagree signifi cantly on what this supposedly foundational principle tells us to do. In what follows I will argue that there are two main versions of Morgan’ s Canon in the modern literature. The fi rst should be familiar from other critical discussions of Morgan ’ s Canon. The second has not been discussed by other commentators, but is one of the main ways in which modern theorists interpret the Canon. 7

5 Note also that it need not be necessary for a cognitive process to be considered higher than another that it entails all the cognitive capacities that come with possessing the lower process (as is the case with higher-order intentionality). 6 This is by no means intended to be a completely adequate clarifi cation of ‘ higher’ and ‘ lower’ . While the foregoing remarks are suffi cient for the purposes of what I want to say in this paper, anyone who wants to defend Morgan’ s Canon will need to provide a much more detailed account of the notion of ‘ cognitive sophistication’ than I have done here. 7 I will not be discussing various behaviourist readings of Morgan’ s Canon. Behaviourists often used the Canon to justify a prohibition on positing cognitive processes when explaining animal behaviour (e.g. Skinner, 1938, p. 4; Griffi th, 1943 , p. 332), arguing that a ‘ lower’ behaviourist explanation in terms of associative conditioning could be produced for any animal behaviour and so ‘ higher’ cognitive explanations should be ignored. It is important to note that this has probably been the dominant way of interpreting Morgan’ s Canon over the course of its history (Costall, 1993). Though one can still fi nd behaviouristic readings of the Canon in the literature, most animal psychologists now tend to interpret the Canon differently, at least partly due to widespread recognition of the inadequacy of behaviourist explanations for a great many animal behaviours.

3. Morgan’ s Canon qua Theoretical Conservatism

By far the most popular reading of Morgan’ s Canon in the modern literature can be expressed as the following principle, which I refer to as ‘ Theoretical Conservatism’ :

Theoretical Conservatism : in any case where we are given the choice between competing explanations for animal behaviour that are consistent with the data we should choose the explanation that attributes to the animal the least sophisticated cognitive process(es).

This reading of Morgan’ s Canon is apparent in the following quotations:

Lloyd Morgan ’ s canon seems applicable today. If alternative explanations appear truly equal, the simpler is to be preferred until data require postulation of more complex processes (Dewsbury, 1973, p. 9).

Modern ethologists accept the Canon… as counselling parsimony in attributing cognitive capacities to animals when explaining their behaviour. When they are truly explanatory, explanations in terms of noncognitive factors … are preferable over explanations in terms of cognitive capacities … ; and explanations in terms of lower-order cognitive capacities … , again, when truly explanatory, are preferable over explanations in terms of higher-order abilities … (Wilder, 1996, pp. 33-34).

This recommendation is known as ‘ Morgan’ s Canon’ or ‘ principle of parsimony’ … The parsimony principle would favour an explanation [of a butterﬂ y’ s orientation towards a source of light] in terms of the action of a preprogrammed mechanism (called ‘ tropism’ ) that attracts the insect toward lighted spots, rather than an interpretation invoking, for example the butterﬂ y’ s curiosity (Vauclair, 1996, p. 3).

Theoretical Conservatism dictates that whenever there is a difference in the relative sophistication of the cognitive processes postulated by rival explanations for animal behaviour, we should choose the one that posits the least sophisticated cognitive processes . For example in the quote from Vauclair (1996) we are given the choice between two rival explanations for the butterﬂ y ’ s behaviour: one that attributes a sophisticated cognitive process to the butterﬂ y (curiosity) and one that attributes a much less sophisticated process (a tropism). Theoretical Conservatism instructs us to choose the latter, less cognitively sophisticated, explanation. This reading of Morgan’ s Canon, gives rise to one of the most striking features of the Canon ’ s role in animal psychology: it is routinely used to justify less cognitively sophisticated explanations of animal behaviour. Often Morgan’ s Canon is used defend such explanations even in the absence of any independent

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd Doing Away with Morgan’ s Canon 2 2 9 considerations that favour the chosen explanation over its rivals. Take the following example from Custance et al. (1999) who ﬁ nd themselves with data that is equivocal between rival explanations for the results of a social learning task in capuchin monkeys:

… it is at present impossible for us to categorically distinguish between simple imitation and object movement reenactment. Object movement reenactment involves visual-visual matching, and in this respect it may be less cognitively complex than imitation, which requires cross-modal visual-motor matching … If we apply Morgan ’ s Canon, it seems necessary, on the basis of the present evidence, to interpret the monkeys ’ behaviour in terms of object movement reenactment rather than imitation (Custance et al. , 1999, p. 21).

The authors concede that they have no empirical reason to prefer one explanation to the other; Morgan’ s Canon is then invoked as the tiebreaker, used to decide in favour of the lower explanation even though the data fails to distinguish it from the rival higher explanation. On the most widespread reading of Morgan ’ s Canon in the modern literature then, Morgan’ s Canon amounts to an inference principle that can be used to decide between competing explanations of animal behaviour. This reading has had a far- reaching inﬂ uence in debates in animal psychology: time and again theorists have used Morgan’ s Canon to justify substantive claims about the nature of animal minds. In the rest of this section I will turn a critical eye on this reading of Morgan ’ s Canon qua Theoretical Conservatism. I will raise four fundamental problems, which show that this principle ought to be rejected.

3.1 Problem 1: Simplicity Considerations Tell Against, Not For, Theoretical Conservatism When justiﬁ cations are offered for Morgan ’ s Canon the most popular is to appeal to simplicity (or parsimony). 8 In fact, the Canon is widely seen as merely the application of the general principle that in science one should, given the choice, choose the simpler of two or more competing explanations. This is because it is seen as instructing us to choose the simpler of two or more competing psychological explanations for an animal’ s behaviour. Connecting Morgan’ s Canon to simplicity clearly gives it a substantial degree of authority for animal psychologists, with the result that few have been prepared to question the dialectical usage to which the Canon has been put. However the ﬁ rst and most obvious problem with the attempt to justify Theoretical Conservatism

8 Following most philosophers of science I take parsimony to be kind of simplicity rather than a distinct theoretical virtue in its own right.

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd 230 S. Fitzpatrick by appeal to simplicity concerns the notoriously diffi cult issue of why we should prefer simpler theories. That scientists do often exhibit preferences for simpler theories is not to be doubted, but the legitimacy of such preferences is far from self-evident. Despite considerable effort, philosophers of science have failed to elucidate a plausible general justifi cation for preferring simpler theories and many are sceptical that a plausible justifi cation can ever be found. Some commentators have criticised Morgan’ s Canon on just these grounds. Steven Walker (1983) for instance calls for the rejection of Morgan’ s Canon on the grounds that we shouldn’ t grant the assumption that we should prefer simpler theories, particularly when we are concerned with complex biological systems produced by messy evolutionary processes. While Walker and other commentators are quite right to raise concerns about the justifi cation for preferences for simplicity in psychological theories, there is another more fundamental issue concerning the relationship between Morgan’ s Canon and simplicity: is it in fact a simplicity principle at all ? There are some grounds for scepticism here. Firstly, contrary to the opinion of many of its proponents, Morgan ’ s Canon cannot be connected to principles of parsimony. As Elliott Sober (1998) has noted, properly speaking theories are parsimonious if they posit fewer things (e.g. fewer entities, or kinds of entities). Morgan’ s Canon, however, asks us to prefer theories that posit processes that come lower in the hierarchy of cognitive sophistication rather than theories that posit fewer things. Consequently, Morgan’ s Canon cannot be properly regarded as a parsimony principle. Secondly, Sober and others have pointed out that Morgan himself did not think that his Canon could be justifi ed by appeal to simplicity. Not only did Morgan reject the idea that simplicity was an appropriate criterion for theory choice in science, he also argued that the simplest explanation for an animal’ s behaviour is the most anthropomorphic one ( Morgan, 1894, pp. 53-54). It is generally simpler to explain animal behaviour in the same terms as we would were the behaviour to be exhibited by a human. These observations have led some commentators to argue that Morgan ’ s Canon is not a simplicity principle and hence cannot be defended by appeal to the idea that simplicity is a theoretical virtue ( Newbury, 1954; Sober, 1998; Thomas, 1998). This seems too quick however. Morgan’ s Canon could be a simplicity principle of sorts . There are, after all, many respects in which psychological theories can be seen as simple, and positing less sophisticated cognitive processes might be considered one such respect. But that said, if we grant that Theoretical Conservatism is a simplicity principle, it should be recognized that it is only one of a great many similar simplicity principles that we might seek to apply in animal psychology. Consider for example:

• Ontological Parsimony: given the choice we should adopt the explanation that posits the fewest total number of cognitive processes. • Iteration Parsimony: given the choice we should adopt the explanation that requires the fewest number of iterations of the processes postulated.

• Memory Parsimony: given the choice we should adopt the explanation that places the smallest burden upon the animal’ s memory. • Parsimony of Evolutionary Change: given the choice we should adopt the explanation that entails the fewest number of evolutionary changes in order to explain the behaviour observed and the behaviour of other organisms. • Parsimony of Explanations: given the choice we should utilise similar psychological explanations for similar behaviour.

These principles are no less instances of simplicity principles than Theoretical Conservatism. Each invites us to maximise a certain kind of theoretical simplicity, just as Theoretical Conservatism does. Now the question arises: why should we prefer Theoretical Conservatism to any of these alternative principles and many other similar principles that could be formulated? The justifi cation for Theoretical Conservatism must go over and above a vague appeal to ‘ simplicity’ being a general theoretical virtue since it tells us to pursue only one limited kind of simplicity in theories, not simplicity generally. The need for further justifi cation becomes all the more pressing when we notice that following Theoretical Conservatism will often confl ict with these alternative simplicity principles. For example:

• Given a choice between an explanation that posits a single higher cognitive process and an explanation that posits many lower processes, the principle of Ontological Parsimony would tell us to choose the higher explanation whereas Theoretical Conservatism would tell us to adopt the lower one ( Sober, 1998). • Given a choice between an explanation for animal learning that postulates a sophisticated innate learning faculty and an explanation that postulates less sophisticated associative learning processes that require remembering a great many associative connections between stimuli, the principle of Memory Parsimony would tell us to choose the higher explanation whereas Theoretical Conservatism would tell us to adopt the lower one. • Given a choice between higher and lower explanations for behaviour in a species that is very similar to behaviour in a very closely related species that we know to be the product of the sophisticated process postulated by the higher explanation, the principle of Parsimony of Evolutionary Change would instruct us to prefer the higher explanation. This is so long as it enabled us to explain the emergence of this behaviour in both species through the evolution of a single novel psychological mechanism in a common ancestor rather than through the independent evolution of two novel mechanisms (de Waal, 1999). In contrast Theoretical Conservatism would instruct us to adopt the lower explanation.

The problem here is that in addition to singling out only one way that psychological theories might be considered simple or complex, Theoretical Conservatism tells

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd 232 S. Fitzpatrick us that this kind of simplicity must always trump the others when it conﬂ icts with them. But it seems clear that these other sorts of simplicity should be taken into account, at least in some circumstances, and also that they should sometimes trump the kind of simplicity that is pursued by Theoretical Conservatism. For instance, appeals to various kinds of evolutionary parsimony— such as parsimony with respect to evolutionary change —do seem to be well motivated in some cases, particularly when we consider very closely related species ( Sober, 2000 ). We can easily imagine cases where this kind of simplicity should carry much more force than Theoretical Conservatism and lead us to favour more cognitively sophisticated explanations. The same holds for other sorts of simplicity like those mentioned above. The upshot of this is that simplicity considerations in fact give us good reason to reject Theoretical Conservatism. In so far as simplicity is relevant to theory choice in animal psychology it seems clear that different kinds of simplicity ought to be weighted differently in different contexts and none should trump any of the others in all circumstances. So no blanket preference for any single type of simplicity should be legislated. But that is exactly what Theoretical Conservatism does when it tells us to adopt the least cognitively sophisticated explanation of animal behaviour. Consequently, simplicity considerations tell against, not for Theoretical Conservatism. 9 An advocate of Morgan’ s Canon might suggest that we should read an ‘ other things being equal ’ clause into Theoretical Conservatism. This would allow that various other kinds of simplicity (and other) considerations could be taken into account. Theoretical Conservatism wouldn’ t always trump these other considerations but would rather come into play only when they are irrelevant or equally supportive of the rival explanations. Unfortunately this response won’ t work. Firstly, I don’ t think that this is faithful to the way that Morgan’ s Canon is understood and used by animal psychologists. In fact, as the restatements of Morgan’ s Canon cited in this paper demonstrate, Morgan ’ s Canon is usually seen as the methodological principle that should apply when we are faced with equivocal empirical data— other considerations are not normally given a look in. The more fundamental problem with this response however is that other things are unlikely to ever be equal. ‘ Simplicity’ is such a multifaceted notion that there will almost always be some respect in which a higher explanation will be simpler than a rival lower explanation. Nor is it typically the case that relevant background theories

9 There of course remain difﬁ cult epistemological questions about why any kind of simplicity should ever be taken into account when deciding between rival psychological theories. I am sympathetic to the view endorsed by Elliott Sober (1988) that when simplicity matters in choosing between rival theories it matters for reasons connected to local background theory, rather than due to any general epistemic virtue of simplicity. This kind of account I think allows us to explain the diversity of features of theories that have been seen as contributing to their simplicity and why some kinds of simplicity seem to matter in some cases but clearly do not matter in others (Fitzpatrick, 2006).

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd Doing Away with Morgan’ s Canon 2 3 3 play out equally with respect to rival theories. This means that inserting a ‘ other things being equal’ clause will totally emasculate Theoretical Conservatism, rendering it impotent in the vast majority of cases where have a choice between higher and lower explanations. In sum, not only does an appeal to simplicity fail to provide sufﬁ cient justiﬁ cation for Theoretical Conservatism, a closer inspection of the relationship between this principle and principles of simplicity positively undermines Theoretical Conservatism.

3.2 Problem 2: Biological Considerations Cut Both Ways It has sometimes been suggested that Morgan ’ s Canon qua Theoretical Conservatism can be justiﬁ ed on evolutionary or biological grounds (e.g. Ghiselin, 1983). Prima facie there do seem to be some biological motivations to favour less cognitively sophisticated explanations of animal behaviour. For example:

• Evolvability constraints: there is an upper bound on the sophistication of cognitive processes that we can realistically entertain for any animal species and some sophisticated processes may require onerous evolutionary conditions that are unlikely to be met in the ecological niches that many species occupy. • Phylogenetic constraints: if all the close relatives of a particular species lack the sophisticated cognitive process in question then we might reasonably err on the side of conservativeness and not attribute the process to that species. • Brute facts of physiology : we can only pack so much cognitive sophistication into the brains of neurologically simple creatures. • Fitness considerations: large brains are metabolically costly and pose particular problems for animals that give birth to their young. Thus in so far as the evolution of more sophisticated cognitive processes requires increases in brain size there may be ﬁ tness costs limiting the chances that such processes will evolve.

Such considerations may quite reasonably motivate us to be conservative in our cognitive attributions to some species in some cases. However it is clearly not sufﬁ cient to justify Theoretical Conservatism that it is sometimes reasonable to prefer lower over higher. Morgan ’ s Canon is a general methodological principle that applies across the board and it is not remotely plausible to suggest that biological considerations dictate that for all animals in all cases, we should choose the explanation that posits the least sophisticated cognitive processes consistent with the data. Indeed, what reasonable biological motivations there are for preferring lower cognitive processes in some cases provide equally compelling grounds for claiming that such preferences are not reasonable in all cases. For example:

• Evolvability constraints: if an animal species does occupy an ecological niche that meets the conditions for the evolution of a particular sophisticated

cognitive process then we should be proportionately more inclined towards generosity in attributing that process to that species. • Phylogenetic constraints: if all the close relatives of a particular species possess the sophisticated cognitive process in question then we might reasonably err on the side of generosity in attributing the process to that species. • Brute facts of physiology: we can pack much more cognitive sophistication into neurologically complex creatures. • Fitness considerations: the fi tness benefi ts of having a particular sophisticated process may outweigh the fi tness costs of increases in brain size.

Attempting to give a biological justiﬁ cation for Theoretical Conservatism thus seems distinctly unpromising. Moreover, we have uncovered good reasons for rejecting Theoretical Conservatism as a general principle, since what reasonable biological motivations there may be for preferring lower over higher in some cases, also indicate that it will not be plausible to prefer lower over higher in all cases. This further reinforces the claims made with respect to simplicity considerations in section 3.1, since it seems that it is often background biological considerations that do the work in motivating many of the simplicity considerations mentioned earlier— especially various kinds of evolutionary parsimony. Such biological considerations, which may often come into play when assessing the plausibility of rival explanations, tell against a decision rule that instructs us to always prefer the least cognitively sophisticated explanation consistent with the data.

3.3 Problem 3: Replacing One Bias With Another The forgoing problems show that Theoretical Conservatism will often lead us to the wrong conclusions— favouring less cognitively sophisticated explanations of animal behaviour in circumstances where we have no evidential justiﬁ cation for doing so. It might however be suggested that Theoretical Conservatism can nonetheless be justiﬁ ed on other, non-evidential, grounds. In the following passage, the philosopher George Graham makes an appeal to the problem of crude anthropomorphism:

The main idea behind the Canon is that when animal behaviour can be explained by reference to either sophisticated or unsophisticated belief networks, the unsophisticated should be preferred. Why? The short answer is that observing Morgan’ s Canon helps to resist slippage into crude anthropomorphism. When von Osten ascribed sophisticated beliefs to Hans he projected his own human intelligence onto the horse. But Morgan’ s Canon chides that before endorsing human projection, one must seek to discover whether a lower or less complex belief network is sufﬁ cient to produce the same behaviour. Rudimentary conceptual stocks should always be preferred over sophisticated, human ones. The Canon ﬁ res a warning shot at crude anthropomorphic interpretation (Graham, 1998, pp. 82-83).

Graham’ s views about the justifi cation for Morgan ’ s Canon are widely shared (e.g. Wilder, 1996; Karin-D’ Arcy, 2005). As was noted earlier, the Canon is seen as guarding the methodological integrity of animal psychology by combating the danger of crude anthropomorphism. For many, this justifi es the need for a principle like Theoretical Conservatism. Unfortunately, this attempted justifi cation for Theoretical Conservatism also doesn’ t work and, once again, in fact reveals strong motivations to reject this principle. To see this we need to be clearer about what the problem with crude anthropomorphism is, and what Theoretical Conservatism tells us to do in response. Though the term ‘ anthropomorphism’ is often used as a term of abuse in the literature, as a technical term it refers to the attribution of human traits, specifi cally human psychological traits, to non-humans. This, in itself, is not a mistake, since humans surely do share many psychological traits with other species— obvious examples include perceptual abilities like vision and hearing. Thus it is not anthropomorphism per se but crude anthropomorphism that is the mistake. The problem of crude anthropomorphism in animal psychology is manifested in the tendency exhibited by some theorists and lay people to attribute human psychological characteristics to non-human animals without suffi cient evidential support for doing so. That is, when there are reasonable alternative non- anthropomorphic explanations that are equally well, or better, supported by the available evidence. As a response to this problem, Theoretical Conservatism instructs us to endorse the least cognitively sophisticated explanation available for an animal’ s behaviour. This is meant to counter-balance any bias we might have towards more cognitively sophisticated explanations. However if the worry about crude anthropomorphism is that it is not suffi ciently supported by the data, it is not clear that we are thereby justifi ed in endorsing the least cognitively sophisticated explanation available, since that explanation may not be suffi ciently supported by the data either. After all, we could instead simply be agnostic about which of the competing explanations is correct in the absence of suffi cient evidence either way —withholding endorsement from both an anthropomorphic explanation and an alternative non-anthropomorphic explanation. This agnostic alternative helps to reveal another way of interpreting Morgan’ s Canon that does not involve commitment to choosing lower over higher given the choice, which will be discussed in section 4. It also helps to pave the way toward the replacement principle for Morgan’ s Canon that I will offer in section 5. But for the moment the key points I want to make are these: fi rstly, Theoretical Conservatism is complete overkill as a guard against crude anthropomorphism. There is no justifi cation for simply replacing one bias (towards accepting cognitively sophisticated anthropomorphic explanations) with another (towards accepting cognitively unsophisticated explanations that may be equally ill supported by the data) (Sober, 1998). Secondly, and more fundamentally, if crude anthropomorphism is an error and ought to be rejected then by exactly the same reasoning so should the

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd 236 S. Fitzpatrick bias built into Theoretical Conservatism. Without suffi cient independent justifi cation, an inclination to accept cognitively unsophisticated explanations of animal behaviour that are not suffi ciently well supported by the data, is surely just as much an error as crude anthropomorphism. Hence, for the same reasons that a blanket bias towards anthropomorphic explanations ought to be rejected, Theoretical Conservatism ought to be rejected as well.

3.4 Problem 4: The Pernicious Impact of Theoretical Conservatism Perhaps the most serious problem for Theoretical Conservatism is its pernicious implications for research in animal psychology. Consider the following sort of research strategy, which I call the ‘ Scaling Up Strategy’ :

Scaling Up Strategy: In any given area of research into animal behaviour, the working hypothesis should always be the least cognitively sophisticated explanation consistent with the available data.

This strategy is a very natural correlate to Theoretical Conservatism. If one is committed to endorsing the least cognitively sophisticated explanation consistent with the available data, then it is natural for this explanation to be set as the working hypothesis and the subject of one’ s investigative efforts. Legislating Theoretical Conservatism, and hence, in effect, the Scaling Up Strategy, as part of the basic methodology of animal psychology is bound to have pernicious consequences. There are many examples from the recent history of animal psychology of highly successful research strategies where the least cognitively sophisticated explanation consistent with the data was not the working hypothesis and indeed where progress was achieved in large part because of this. Theoretical Conservatism, via the Scaling Up Strategy, would therefore undermine these research strategies. Though many examples could be cited here, I will illustrate this claim with the case of the discovery of the famous honeybee dance language. In 1946 Karl von Frisch proposed the remarkable hypothesis that foraging honey bees communicate information about the location of resources such as food to their hive-mates via two different kinds of dance that they perform on the surface of the honey-comb ( von Frisch, 1967; Gould and Gould, 1995; Dyer, 2002 ). One of these dances is the ‘ round’ dance, which is used if the food source is close to the hive. It alerts the other bees that the forager has found a good food source and is designed to encourage the bees to attend to the odour that the forager exudes. On leaving the hive the recruited bees then use their sensitive olfactory mechanisms to search for this odour. However if the food source is a relatively long way from the hive a more elaborate ‘ waggle dance’ is used. This dance, which takes a ﬁ gure-of- eight shape, employing both waggling and sounds, conveys three pieces of information: 1) the direction of the food source from the hive, which is encoded in the angle of the waggle movements through the centre of the ﬁ gure-of-eight relative to the vertical, representing the angle from the position of the sun; 2) the

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd Doing Away with Morgan’ s Canon 2 3 7 distance of the food source from the hive, which is encoded in the duration of the waggle runs through the centre of the fi gure-of-eight along with the accompanying sounds; and 3) the quality of the food source, which is encoded in the relative vigour of the dance. Von Frisch’ s discovery was revolutionary, fundamentally challenging the commonsense view that insects are very simple creatures with little or no interesting cognitive capacity. In spite of much initial resistance and a further bout of controversy in the 1960s and 70s, the dance language is now one of the most well confi rmed hypotheses in the study of animal behaviour (Dyer, 2002; Riley et al. , 2005). This is a clear case where a research strategy quite different to the Scaling Up Strategy was followed and led to great success. It is notable that from the very beginning von Frisch’ s hypothesising was fi rmly latched onto communication as an important component of honeybee foraging behaviour. He began studying honeybee foraging in order to vindicate his conviction that bees had colour-vision. After making some initial observations about the patterns of foraging that came out of his colour discrimination experiments— such as the fact that bees seemed to preferentially arrive at feeding stations that had previously been visited by other members of the colony— he began to speculate about the possibility of communication between the bees (von Frisch, 1973 ). It was at this point that he discovered the dances and immediately hypothesised that these might be a medium of communication. He then set about attempting to decode them, a project that took several decades to complete. But there were certainly less cognitively sophisticated explanations available for von Frisch’ s early observations. One such explanation is the ‘ olfaction hypothesis’ that critics of von Frisch later endorsed in the 1960s ( Wenner, 1971, 2002 ). On this hypothesis it is supposed that bees don ’ t communicate at all: they are simply conditioned to record and search for the odours emitted by returning foragers; dancing is an irrelevant physiological artefact that plays no functional role whatsoever. Von Frisch was well aware of this alternative defl ationary hypothesis early on (Wenner, 2002) and so by pursuing communication as his working hypothesis from the outset, rather than the olfaction hypothesis, von Frisch plainly rejected the Scaling Up Strategy. Von Frisch ’ s approach was clearly successful but, more than this, I suggest that his implicit rejection of the Scaling Up Strategy and hence Theoretical Conservatism, was instrumental in this success, to the extent it is highly unlikely that the dance language would have been discovered if this strategy had been strictly adhered to. The reason for this is that discovering such an unusual communication system in an organism as versatile the honeybee is only likely if one is actively looking for it. Honeybee navigation is extremely adaptable. Bees use several different mechanisms including dance information and olfaction to fi nd food sources. Often bees that do, in fact, use dance information could fi nd the food source by olfaction alone, and when food sources are abundant and odours particularly strong bees don’ t dance at all, or just ignore dance information ( Gould and Gould, 1995).

Moreover when dance information is used it directs the bees to only an approximate location, with olfaction being used to fi nd the specifi c location. Bees that attend to dances also exhibit signifi cant variation in fl ight-times in getting to the location ( Riley et al. , 2005). In short, the effects of other variables mean that the precise role of communicated information is buried deep in the foraging behaviour, not readily visible on a fi rst analysis of what the bees seem to be doing. My claim then is that the subtlety and unusualness of honey bee communication is such that if von Frisch had adhered to Theoretical Conservatism and the Scaling Up Strategy, some version of the olfaction hypothesis probably would have looked entirely suffi cient to explain honey bee foraging; and consequently, it is unlikely that the dance language of bees would have been discovered. This, I think, aptly highlights the dangers of Morgan’ s Canon qua Theoretical Conservatism. In many instances unless one is prepared to speculate far beyond the current data, to seriously entertain hypotheses involving more sophisticated cognitive processes when less sophisticated ones seem suffi cient, it is unlikely that one will ever uncover such subtle and surprising capacities as the dance language. One will simply not have any idea of what to look for. The lesson to be learnt here is that theorists should be free to investigate whatever hypotheses they fi nd most reasonable. The restrictions on investigation imposed by the Scaling Up Strategy would not only hinder research programmes such as von Frisch ’ s that have been enormously successful, but would also increase the probability that theorists completely overlook or simply ignore potentially productive avenues of research. Hence given that legislating Theoretical Conservatism as guiding principle will, more often than not, also lead to legislating the Scaling Up Strategy, we have another strong motivation for rejecting Theoretical Conservatism. In summary, Theoretical Conservatism is unjustifi ed, pernicious, and confl icts with a variety of plausible background biological and simplicity considerations, and thus clearly ought to be rejected.10

10 Sober (1998) is also sceptical about Morgan ’ s Canon qua Theoretical Conservatism. In its place he proposes what he takes to be a revised version of the Canon, which states that we can infer that an animal does not possess a higher cognitive process H if we routinely fail to observe an animal performing BH , which we would expect from an animal that possessed H but not from one that only possessed a lower process L. While I accept that there may be some cases in which this kind of inference is appropriate, Sober’ s Canon is highly problematic as a general principle. This is because it is often far from clear what sorts of behaviour we should expect from an animal endowed with a particular cognitive process and one’ s initial intuitions about how particular cognitive capacities will show themselves in behaviour may be extremely wide of the mark. The honey bee dance language is a case in point. Accordingly, Sober ’s Canon is likely to have the same sort of pernicious consequences as Theoretical Conservatism, and thus ought to be rejected as well. It is also worth noting that Sober ’ s Canon is not really a version of Morgan ’ s Canon in any case. As Sober admits, it only applies in certain cases where we fail to observe a particular kind of behaviour from the animal. At best then, it is a reconstruction of how some of the inferences made by appeal to Morgan’ s Canon might be justiﬁ ed. Morgan ’ s Canon however is meant to be a general methodological guideline for explaining animal behaviour.

4. Morgan’ s Canon qua Special Methodological Restraint

We have eliminated what I take to be the dominant reading of Morgan ’ s Canon in the modern literature. But there is another way of reading Morgan ’ s Canon that needs to be examined. In order to honour Morgan’ s stated principle, does one need to endorse the available ‘ lower’ explanation? One could instead be agnostic and merely withhold endorsement from the higher explanation. This agnostic construal has not been discussed by previous commentators, but if anything it seems to be a more natural way of reading Morgan’ s original formulation since this doesn’ t explicitly say that we should endorse the lower explanation. Moreover it is possible to read a slightly weaker sort of principle than Theoretical Conservatism into many of the restatements of Morgan’ s Canon in the modern literature. One does have to be careful here: it is not always clear whether theorists that seemingly endorse a weaker version of Morgan’ s Canon do actually have a weaker principle in mind. Nonetheless, it does seem that many theorists read Morgan’ s Canon as recommending a special sort of methodological restraint when theorising about the cognitive capacities of animals. Consider the following quotations:

One must be cautious about inferring complex cognitive processes when simpler explanations will sufﬁ ce (Zabel et al. , 1992, p. 129, my emphasis). … we must not abandon Morgan’ s canon. For example, we should not accept the idea that honey-bees have such capacities before eliminating every other possibility (Manning and Dawkins, 1998, p. 297, my emphasis). … at a minimum, Morgan was suggesting that we should not trust psychological explanations of behaviour unless we are convinced that those explanations are indispensable— that is to say, unless we are convinced that the behaviour in question cannot be explained in nonpsychological terms (Bermúdez, 2003, p. 7, my emphasis)

These restatements of Morgan’ s Canon are all consistent with a weaker agnostic version of the Canon. Prima facie such a version of Morgan’ s Canon would also seem to be much more plausible than Theoretical Conservatism. But how exactly should we formulate this version of Morgan’ s Canon? The use of expressions such as ‘ every other possibility’ (Manning and Dawkins) and ‘ indispensable’ (Bermúdez) in the above quotations suggest that Morgan’ s Canon might be read as the following sort of principle: Special Methodological Restraint (modal) : we should withhold endorsement from an explanation of animal behaviour that attributes sophisticated cognitive processes to the animal if it is possible to explain the behaviour in terms of less sophisticated processes. Though this principle has some superﬁ cial plausibility, a closer inspection reveals that it places far too severe a constraint on researchers. One can always come up

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd 240 S. Fitzpatrick with some possible defl ationary explanation for any putatively intelligent behaviour. In principle one can formulate an explanation in terms of associative conditioning for any suite of behaviour, including any suite of human behaviour, if one can generate suffi cient auxiliary assumptions about the organism’ s history of reinforcement (Dennett, 1983). Such defl ationary explanations are always possible, though they will often be extremely implausible. This version of Special Methodological Restraint is thus a recipe for methodological paralysis. It imposes a completely unrealistic constraint on researchers. One can never show that it is impossible to explain animal behaviour in lower terms, even in cases where the evidence does strongly support a higher explanation. Another, perhaps more charitable, way of reading the earlier quoted statements is this: Special Methodological Restraint (evidential) : we should be especially restrained in our endorsement of explanations of animal behaviour that attribute sophisticated cognitive processes. Before endorsing them we must show that such explanations are supported by particularly strong evidence. On the face of it, this looks like a much more plausible way of interpreting Morgan’ s Canon. It does not demand that there be no possible explanation whatsoever for the behaviour observed in terms of lower processes, rather it demands that we need to provide a particularly strong case for the endorsement of higher processes. Prima facie this also seems like an appropriate response to the problem of crude anthropomorphism: we can guard against the mistaken projection of sophisticated human cognitive processes onto animals if we demand that such attributions face a particularly strong evidential test. Nonetheless I suggest that such a view is extremely problematic. One problem lies in what it actually means to say that higher explanations ought to be supported by ‘ particularly strong evidence’ . There is a danger that the evidential bar may be set so high that cognitively sophisticated explanations are never accepted, even when they are warranted. Putting this worry aside, the core problem is justifying the asymmetry —the ‘ special’ in ‘ Special Methodological Restraint’ . Why should a special burden of proof be placed on advocates of sophisticated cognitive processes? Why shouldn ’ t it be equally incumbent on advocates of less cognitively sophisticated explanations that they remain agnostic until their hypotheses pass an equally strong evidential test? This brings us to the crux of the problems with Morgan ’ s Canon since this asymmetry is a fundamental property of all versions of the Canon. Clearly, the key argument for endorsing such an asymmetry is that it is required to meet the primary function of Morgan ’ s Canon, which is to guard against crude anthropomorphism. Yet if, as I argued earlier, the error of crude anthropomorphism is the failure to consider alternative non-human-like explanations that are consistent with the data and ought to have been reasonably considered, then it is in principle no different from the crude anthropocentric failure to consider reasonable human-like explanations, or the crude mechanomorphic failure to consider reasonable non- mechanistic explanations, or the error manifested in the confi rmation bias where a

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd Doing Away with Morgan’ s Canon 2 4 1 theorist fails to view any alternative explanation as worth considering. At the root of all of these problems is essentially the same evaluative error: failing to recognise that the evidence supports some reasonable alternative explanation at least as well. I am not claiming that there is no problem with crude anthropomorphism in animal psychology. Rather I am claiming that what problems there are with crude anthropomorphism are not peculiarly different from those presented by other sorts of evaluative error that animal psychologists can fall prey to. A likely reply is that even if there may be no in principle difference between crude anthropomorphism and these other sorts of errors, in practice it is of much more concern because humans are much more likely to fall prey to it. Our folk- psychology, it is often claimed, endows us with a fundamental anthropomorphic bias. I don’ t doubt that many humans do have a propensity to anthropomorphise, but I fail to see this as any more of a serious challenge to scientifi c methodology than the non-folk-psychological biases of many animal psychologists. There are a host of examples from 20th century animal psychology of cases where cognitively sophisticated explanations for animal behaviour were simply ignored. Consider for example that many of the conditioning experiments with rats and pigeons that were taken to support behaviouristic conclusions are now seen as providing good evidence for positing cognitive processes in these species ( Gallistel, 1990). Indeed if one wants to assess the relative damage done to actual scientifi c practice there is no contest between institutionalised behaviourism and Clever Hans (Fodor, 1999). The idea that all organisms are bundles of acquired stimulus-response connections emerged around the same time as Clever Hans. It went on to dominate animal psychology for most of the 20th century, and was a colossal evaluative error ill supported by evidence available even in the early part of that century. 11 The asymmetry built into Morgan ’ s Canon is therefore deeply pernicious. It encourages an obsession with anthropomorphism, perpetuating the view that no evaluative errors can be made with attributions of less sophisticated processes to animals or the view that such errors are less signifi cant. But animal psychology can and has been wrong about the psychological capacities of animals in a myriad of different ways and there is no reason to believe that these errors have been any less serious or any less prevalent than those due to crude anthropomorphism. The evidential version of Special Methodological Restraint is as plausible as Morgan’ s Canon gets, but it still ought to be rejected, because the root methodological asymmetry in Morgan’ s Canon ought to be rejected. 12

11 I do not want to suggest that nothing good came from the behaviourist movement. Many behaviourists did make very important contributions, in particular laying the foundations for modern learning theory. 12 An anonymous reviewer has suggested an alternative account of the role of Morgan’ s Canon: rather than being a substantive methodological principle to be applied by investigators, it is merely an exhortation to students to be cautious when attributing cognitive processes to animals. While I am sympathetic to the idea that Morgan’ s Canon is often more rhetoric than anything else, for reasons that have been indicated in the text, I do not think that it is in any way an appropriate principle to inculcate in students.

5. Evidentialism

Proponents of Morgan ’ s Canon sometimes talk as if it is the only thing that stands between us and blindly accepting any explanation of animal behaviour— as though if we were to reject it there would be nothing to stop animal psychology from falling back into quaint 19th century anecdotalism or uncritically accepting a ‘ Disneyfi ed ’ image of animals. I suggest that the reason that these sorts of sentiments are taken seriously is that no adequate alternative to Morgan’ s Canon has been articulated in the literature. In this section I will present just such an alternative. The principle that I will articulate avoids all of the problems that I have identifi ed for the various readings of the Canon and better captures what ought to distinguish a rigorous scientifi c animal psychology from non-scientifi c approaches. The principle is, to a fi rst approximation, the following:

Evidentialism: in no case should we endorse an explanation of animal behaviour in terms of cognitive process X on the basis of the available evidence if that evidence gives us no reason to prefer it to an alternative explanation in terms of a different cognitive process Y— whether this be lower or higher on the ‘ psychical scale ’ .

Evidentialism is essentially a special case of one of the most fundamental constraints on scientiﬁ c explanation, which is that we can only assert that a particular explanation is the one that is best supported by the available evidence if we can show that there is no reasonable alternative explanation that is at least as well supported by that evidence. In order to be epistemically warranted in endorsing a particular explanation of animal behaviour— whatever its place on the ‘ psychical scale’ —on the basis of the available evidence, we have to show that it provides differential support for that explanation relative to alternative explanations— whatever their place on the ‘ psychical scale’ .13 As ‘ evidence’ here I include, alongside experimental results and observations of behaviour, whatever background considerations that should inﬂ uence judgements about the plausibility of rival explanations. This could include for example, background evolutionary / biological considerations, results from previous studies, and any other relevant considerations that could reasonably be considered as evidence for one sort of explanation or another.

13 The notion of ‘ epistemic warrant’ here carries with it no particular commitments about the nature of epistemic warrant in general. It is speciﬁ cally related to what one is justiﬁ ed in believing on the basis of the evidence . Evidentialism thus does not stake a claim on the issue of whether there are non-evidential aspects to epistemic warrant (my use of the term ‘ evidentialism’ here is thus somewhat different from the way it is sometimes used in epistemology). Note also that Evidentialism does not preclude theorists from taking attitudes towards hypotheses other than full endorsement or belief— e.g. provisionally adopting a hypothesis as a working hypothesis.

Evidentialism treats higher and lower explanations entirely equally, enshrining no methodological bias or weighting in favour of either sort of explanation. It is incumbent on animal psychologists to consider all potential explanations for animal behaviour and, in the absence of differential evidence, to treat higher and lower explanations as equally as possible. Consequently Evidentialism avoids the problems that face the various versions of Morgan ’ s Canon since these all stem from the methodological asymmetry that is built into the Canon. For instance, the problems with Theoretical Conservatism stem from that fact it enshrines a blanket bias towards endorsing lower explanations. This bias is extremely diffi cult to justify and often confl icts with other considerations (such as simplicity considerations [Problem 1 above] and background biological considerations [Problem 2 above]) that are taken into account when deciding between rival explanations; it is just as objectionable as any bias towards endorsing anthropomorphic explanations (Problem 3 above) and, via the associated Scaling Up Strategy, is also likely to have highly pernicious practical consequences by restricting the kinds of research strategies that can be adopted (Problem 4 above). Similarly, the problems with Special Methodological Restraint stem from the fact that it places an asymmetric and unjustifi ed burden of proof specifi cally on higher explanations. All of these problems fall away if we adopt Evidentialism because it tells us to be totally even handed towards higher and lower explanations, and— in the absence of other independent considerations— just to go where the evidence takes us. Evidentialism also demonstrates that Morgan’ s Canon is totally unnecessary for combating crude anthropomorphism in animal psychology. In the case of Clever Hans for instance, it is claimed that Hans’ trainer, von Osten, ignored the possibility that Hans’ seemingly intelligent behaviour was merely the product of features of the experiment. The alleged crude anthropomorphism here lies in the fact that a reasonable lower explanation for Hans’ behaviour— subtle cuing effects from the audience— was available and was in fact better supported by the available evidence but was ignored. Morgan’ s Canon— on all the readings discussed in this paper— would restrain von Osten in this situation and this would indeed be a genuine methodological benefi t. But Evidentialism would achieve exactly the same result and without bringing along with it the additional and pernicious methodological baggage that Morgan’ s Canon would bring. Evidentialism would not allow von Osten to proclaim that Hans ’ behaviour was genuinely indicative of human-like intelligence given the availability of Pfungst’ s alternative explanation. It is however worth noting that the actual historical details mean that this case is not in fact a clear example of crude anthropomorphism at all. The key problem in this case was that the subtle observer-subject interactions that Pfungst eventually discovered were completely unknown to animal researchers at the time and clearly unknown to von Osten. Proponents of Morgan’ s Canon often claim that if von Osten had adhered to Morgan’ s precept this episode would not have occurred. But Morgan ’ s Canon by itself would have made no difference to this case since before Pfungst came along to all intents and purposes there was no reasonable

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd 244 S. Fitzpatrick lower explanation for Hans’ behaviour. Given the knowledge available to von Osten at the time Morgan’ s Canon thus would have instructed us to endorse von Osten’ s account of Clever Hans! Evidentialism of course would have done no better in preventing Clever Hans, but this just goes to show, what should have been obvious in any case, that despite the best of intentions, unexpected diffi culties can arise in investigating animal behaviour. No reasonable methodological principle can solve these diffi culties at a stroke. Sure Morgan’ s Canon would have told us to look for alternative lower explanations, but it took hard work and above all scientifi c imagination and ingenuity on the part of Pfungst to discover the truth behind Clever Hans, not simply adherence to a canon of method. Nonetheless if we assume that Pfungst ’ s explanation had been available to von Osten, Evidentialism would have suffi ced to restrain us from endorsing von Osten ’ s claims about Hans’ abilities. In this situation Evidentialism would be at least as good as Morgan ’ s Canon in preventing crude anthropomorphism. Indeed that is the case for any genuine case of crude anthropomorphism, since all such cases are instances where a particular (anthropomorphic) explanation of animal behaviour is endorsed on the basis of evidence that supports some alternative (non- anthropomorphic) explanation at least as well. Evidentialism is also greatly superior in helping to characterise what distinguishes a rigorous scientifi c animal psychology from non-scientifi c approaches to animal minds. This is because animal psychology would be just as lacking in methodological rigor if, without independent justifi cation, it saw fi t to endorse lower explanations for animal behaviour when there are alternative higher explanations at least as well supported by the evidence. What really distinguishes scientifi c animal psychology from non-scientifi c approaches is not accepting the least cognitively sophisticated explanation consistent with the data, or demanding that there be no possible less cognitively sophisticated explanation for the behaviour, or demanding that cognitively sophisticated explanations be particularly strongly supported. Rather it is sensitivity to the possibility of there being many alternative explanations for animal behaviour of varying degrees of cognitive sophistication and awareness of the fact that it is incumbent on those that engage in the science of animal psychology to provide differential evidential support for their chosen hypothesis— whatever the place on the ‘ psychical scale’ —over alternatives. 14 Seeing Morgan’ s Canon as the key distinguishing mark of a rigorous scientifi c animal psychology is thus to both over-interpret the appropriate methodological response to genuine cases of crude anthropomorphism and to mischaracterise the

14 Since writing this paper I have discovered that in more recent work Sober (2005) has made a similar point: ‘ It is desirable that we avoid the type-1 error of mistaken anthropomorphism, but it also is desirable that we avoid the type-2 error of mistaken anthropodenial. However, the best way to minimize the risk of both types of error is not to embrace an a priori prejudice. The only prophylactic we need is empiricism’ (Sober, 2005, p. 97). Thanks to an anonymous reviewer for bringing this to my attention.

© 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd Doing Away with Morgan’ s Canon 2 4 5 essential nature of the problem. All we need is a principle like Evidentialism. Consequently, we should do away with Morgan’ s Canon.

Department of Philosophy University of Shefﬁ eld

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