Doing Away with Morgan ' s Canon - SIMON FITZPATRICK
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
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, scientific approach to the study of
animal cognition. In contrast I argue that Morgan’s Canon is unjustified, 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 benefits 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 scientific 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 superficial
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 Sheffield where versions of this paper were presented.
Address for correspondence: Department of Philosophy, University of Sheffield, Arts Tower,
Western Bank, Sheffield, S10 2TN, UK.
Email: s.fitzpatrick@sheffield.ac.uk
Mind & Language, Vol. 23 No. 2 April 2008, pp. 224–246.
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing LtdDoing Away with Morgan’s Canon 225
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 flimsy anecdotal evidence (Boakes,
1984).
2
In particular those associated with the field of ‘cognitive ethology’ (e.g. Griffin, 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 justified by its
proponents (e.g. Newbury, 1954; Griffin, 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 justification 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 justification and that it should not be employed over
zealously.
To date the best discussion of Morgan’s Canon is Elliott Sober’s (1998). Sober finds much
that is wrong in the standard justifications that have been given for Morgan’s Canon, but
nonetheless argues that it should be retained in a significantly 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 sufficiently persuasive case
for abandoning Morgan’s Canon has not yet been made. The principal aim of this paper is
to correct this deficit.
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing Ltd226 S. Fitzpatrick
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 benefits 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 unjustified, 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 first 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 first-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 reflexes, 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 LtdDoing Away with Morgan’s Canon 227
second-order intentionality is a ‘higher’ cognitive process than first-order
intentionality, since possession of second-order intentionality allows an organism
to form mental states whose contents concern other mental states, while possession
of first-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 clarification of ‘higher’ and ‘lower’ in mind, there are still a number
of different ways that Morgan’s principle can be fleshed out. In fact individual
theorists frequently appear to disagree significantly 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 first 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 clarification of ‘higher’ and
‘lower’. While the foregoing remarks are sufficient 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; Griffith, 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 find 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.
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing Ltd228 S. Fitzpatrick
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
butterfly’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 butterfly’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 butterfly’s behaviour: one that attributes a
sophisticated cognitive process to the butterfly (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 LtdDoing Away with Morgan’s Canon 229
considerations that favour the chosen explanation over its rivals. Take the following
example from Custance et al. (1999) who find 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 influence 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 justifications 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 first
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 Ltd230 S. Fitzpatrick
by appeal to simplicity concerns the notoriously difficult 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 justification for preferring simpler theories and many
are sceptical that a plausible justification 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 justification 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 justified 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.
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing LtdDoing Away with Morgan’s Canon 231
• 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 justification 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 justification becomes all the more pressing when we notice
that following Theoretical Conservatism will often conflict 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 Ltd232 S. Fitzpatrick
us that this kind of simplicity must always trump the others when it conflicts
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 difficult 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 LtdDoing Away with Morgan’s Canon 233
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 sufficient justification
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 justified 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 fitness 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
sufficient 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
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing Ltd234 S. Fitzpatrick
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 fitness benefits of having a particular sophisticated
process may outweigh the fitness costs of increases in brain size.
Attempting to give a biological justification 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 justification for
doing so. It might however be suggested that Theoretical Conservatism can
nonetheless be justified 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 sufficient to produce the
same behaviour. Rudimentary conceptual stocks should always be preferred
over sophisticated, human ones. The Canon fires a warning shot at crude
anthropomorphic interpretation (Graham, 1998, pp. 82-83).
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing LtdDoing Away with Morgan’s Canon 235
Graham’s views about the justification 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 justifies the need for a principle
like Theoretical Conservatism.
Unfortunately, this attempted justification 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, specifically
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 sufficient 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 sufficiently supported by the data, it is not clear that we are thereby
justified in endorsing the least cognitively sophisticated explanation available, since
that explanation may not be sufficiently 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 sufficient 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: firstly, Theoretical
Conservatism is complete overkill as a guard against crude anthropomorphism.
There is no justification 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 Ltd236 S. Fitzpatrick
bias built into Theoretical Conservatism. Without sufficient independent
justification, an inclination to accept cognitively unsophisticated explanations of
animal behaviour that are not sufficiently 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 figure-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 figure-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 LtdDoing Away with Morgan’s Canon 237
distance of the food source from the hive, which is encoded in the duration of the
waggle runs through the centre of the figure-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 confirmed
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 firmly 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 deflationary 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 find food sources. Often
bees that do, in fact, use dance information could find 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).
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing Ltd238 S. Fitzpatrick
Moreover when dance information is used it directs the bees to only an approximate
location, with olfaction being used to find the specific location. Bees that attend
to dances also exhibit significant variation in flight-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 first 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
sufficient 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 sufficient, 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 find
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 unjustified, pernicious, and conflicts
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 justified. Morgan’s Canon however
is meant to be a general methodological guideline for explaining animal behaviour.
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing LtdDoing Away with Morgan’s Canon 239
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 suffice (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 superficial 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 Ltd240 S. Fitzpatrick
with some possible deflationary 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 sufficient auxiliary assumptions about the organism’s history of
reinforcement (Dennett, 1983). Such deflationary 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 confirmation bias where a
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing LtdDoing Away with Morgan’s Canon 241
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 scientific 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 scientific 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 significant. 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.
© 2008 The Author
Journal compilation © 2008 Blackwell Publishing LtdYou can also read
