Arguing about names for things is fun, and arguments
about history are captivating and educational, but, if there is one
thing all four commentaries and I can agree on, it is that what really
matters is how best to move a scientific field forward.
Anthropomorphism Pro or Contra: A Scientific Beauty Contest?
The usefulness of an approach in science is a
difficult beast to capture. Attempts to quantify the fertility of
anthropomorphism can quickly degenerate into something akin to a
scientific beauty contest (at worst) or a matter of counting
publications or citations of protagonists (at best). Blumberg asks
"whether individuals who explicitly engage in anthropomorphism have a
track record of scientific discovery that exceeds those who do not[?]"
and suggests that the "apparent usefulness of anthropomorphism … is an
illusion" (p. 145).
Timberlake broadly concurs with Blumberg and me when
he writes that the "…primary dependence on unshackled anthropomorphism
for our knowledge about other species is not a promising direction for
science to go" (p. 140).
On the other side of the argument, Goodrich and Allen
point out that among the scientists who consider anthropomorphism useful
are several, such as "Bekoff, Burghardt, and de Waal, all of whom have
distinguished records of scientific publication" (p. 147). Goodrich and
Allen characterize mentalistic cognitive scientists as "extremely
thoughtful" (p. 148). Burghardt also sees value in careful critical
anthropomorphism.
I have no desire to argue with the reputations of
pro-anthropomorphs, many of whom have made significant contributions to
our science. It was partially for that reason that I presented a
hypothetical case of anthropomorphic explanation of the "remorseful"
behavior of a dog, rather than a critique of a specific study by a
pro-anthropomorph, in my target article. I was also concerned that
whatever published study I might select could be dismissed by
pro-anthropomorphs as somehow not the right example to have chosen.
However, by outlining an hypothetical example, though I had tried to
make clear that I was only sketching an approach – not actually carrying
out the study – I invited the criticism of Burghardt that I was trying
to explain "the most complex behavior of animals… without formal study
or testing" (p. 137). (Anyone interested in collaborating in a study of
this kind is invited to contact the author.)
I am therefore very grateful to Goodrich and Allen
for identifying, "specific scientific work which makes use of the
attribution of mental states to animals [that] would be worthy of
analysis: for instance de Waal’s experiments on fairness in monkeys
(Brosnan & de Waal, 2003) or the experiments by Hunt, Rutledge, and Gray
(2006) and Weir and Kacelnik (2006) to test the understanding of tools
by New Caledonian crows" (p. 149). I am very happy to consider the
usefulness of anthropomorphic thinking as evidenced in these three
papers.
Brosnan and De Waal (2003) reported that monkeys
demonstrated a sense of "fairness" (or "inequity aversion") when they
rejected a less preferred reward under conditions in which they saw
another monkey receive a more preferred reward for the same effort. This
anthropomorphic claim is undermined however by the fact that the monkeys
were just as likely to refuse the less preferred reward in a control
condition in which the more preferred reward was simply made visible but
without any other monkey present in the experimental room. As I stated
in a previous critique of this experiment:
There can be nothing iniquitous about receiving a
nonpreferred reward if nobody is receiving anything better. In the
[control] condition the monkeys are refusing the nonpreferred reward
simply because they can see that a better reward is potentially
available. This is therefore the most parsimonious explanation for
their refusal to accept the nonpreferred reward when they see
another monkey receive a better reward (Wynne, 2004, p. 140).
By jumping to an anthropomorphic and mentalistic
conclusion, Brosnan and de Waal (2003), failed to establish what
variables might have controlled the behavior of their subjects.
The other two papers nominated by Goodrich and Allen
as exemplifying the usefulness of anthropomorphism are among the latest
reports on the surprisingly sophisticated abilities to construct and use
tools by New Caledonian (NC) crows.
Weir and Kacelnik (2006) presented some novel
problems to a laboratory-housed NC crow ("Betty"), already experienced
in the bending of pieces of wire to extract rewards from tubes. In three
experiments, Betty was given the challenge of obtaining food rewards
from traps through the manufacture of tools out of flexible strips of
aluminum. The traps were familiar to Betty, as was the use of flexible
wire to construct hooks to extract rewards from them (Weir, Chappel, &
Kacelnik, 2002), but the aluminum strips were novel to the bird. The
aluminum differed from wire most crucially in that it is only flexible
in one plane (wire can be bent in any direction). In two of the three
tasks Betty became progressively more successful in bending the aluminum
strips to extract the food reward. One of the two tasks on which she was
successful required the bending inwards of the aluminum strip
(shortening it into a hook); the other required her to straighten out
already bent aluminum (to make a longer probe). On the first task, her
latency to extract food declined across trials; her rate of holding the
tool by the modified end (a more successful strategy than holding the
unmodified end) increased across trials, as did the (human-rated)
quality of the tool. On the second task, Betty only completed four
trials before dying unexpectedly. On the first trial, she squeezed the
aluminum strip in on itself in order to make a tool thin enough to
insert into the tube. Although the experiment had been designed so that
a tool bent in this way would not be long enough to secure the meat,
Betty was somehow able to defeat the apparatus and gain the reward. On
Trial 2, Betty poked unsuccessfully with the unmodified tool and did not
reach the reward. On Trials 3 and 4 she prodded the tube for some time
with the unmodified tool, before pushing the aluminum strip back against
the lip of the tube, thus unbending it and enabling access to the meat.
Betty’s behavior is undoubtedly fascinating. But how
is it to be understood? Weir and Kacelnik (2006) state their aims thus:
"The experiment," they explain, "…addressed three inter-related
questions: 1. What did the subject know about the relationship
between tool shape and success at retrieving the bucket… 2. What did she
understand about the link between modification technique and tool
shape…? 3. To what extent was she aware of the connection between
(1) and (2) above…?" (p. 320: emphasis added). I am not sanguine that we
will ever understand the understanding of another species; nor that we
can know what it knows about, or become aware of the extent to which it
is aware. In any case, Weir and Kacelnik acknowledge that Betty’s
behavior is more parsimoniously comprehended as the result of simpler
processes. They note that she repeatedly mandibulated the aluminum strip
as she had previously treated wire, and she "nearly always attempted to
probe for the bucket [with the unbent strip of aluminum] before
modifying the material" (p. 326). Even when she modified the tool, her
first probes were with the unmodified end. Nonetheless, they feel that
reinforcement learning is unlikely to be an adequate explanation of the
crow’s behavior for two reasons. First, because the acquisition was too
rapid; and second, because "…we suspect it is impossible for a robot
equipped exclusively with associative learning algorithms to solve these
tasks with a similar amount of experience..." (p. 332).
These are very weak grounds to reject parsimony.
Taking their first argument first: In most learning models acquisition
rate is governed by a free parameter. Thus rate of learning cannot
render a learning model invalid. Weir and Kacelnik’s (2006) second
argument to reject reinforcement learning as an explanation of Betty’s
performance is an example of what Dawkins calls the "Argument from
personal incredulity" (Dawkins, 1986). The inconceivability to Weir and
Kacelnik of an associative robot completing the tasks as Betty did is an
extremely weak ground to reject an objective parsimonious explanation of
behavior in favor of a vague mentalistic one.
To be fair to Weir and Kacelnik, they acknowledge
that "…progress might come when we can replace terms such as
understanding (which we feel compelled to maintain for the time being)
by precise hypotheses about the operations the subject makes in the
course of generating solutions to novel problems." (2006, p. 332).
Thus I think they and I are in agreement that the
real question at issue here is: What can these birds do and under what
conditions? But whereas they wish to hang on to an ill-defined
mentalistic anthropomorphic conceptualization, I would break the
fundamental question into smaller operationalizable parts: What are the
stimulus conditions necessary to show these remarkable performances?
What prior histories of experience (both extrinsically reinforced and
not) are required? To ask about "understanding" is to move away from
empirical science towards an approach to animal behavior where we judge
the processes controlling behavior by our intuitive response to what we
see (e.g., "the bending [of the aluminum strip] did not appear
‘deliberate’" (Weir & Kacelnik, 2006, p. 325). This cannot be a route to
an objective understanding.
Hunt et al. (2006) studied the response of
wild-living NC crows to food presented in holes. These holes were
constructed so as to be somewhat deeper than the tools the birds were in
the habit of forming were adequate to extract from. The tools are made
by the birds from locally-growing leaves. Hunt et al. observed that over
several trials of experience with deeper holes, the crows developed the
habit of forming longer leaf tools. Returned to shallower holes they
returned to forming shorter tools. The researchers conclude that the
crows have a default length of tool that they bring to any baited hole.
Trial and error learning is not considered a possible mechanism for the
development of longer tools because that "would have produced random
variation around the average length of first tools [and] not
consistently longer second tools" (p. 314). However Hunt et al. are
unable to distinguish between a previously developed associative
learning rule ("if a tool fails make a longer one," p. 308), and what
they call a "delayed causal inference" (p. 308: an inference based on
perceiving the depth of the hole and inferring the length of tool
required by observation).
Though Goodrich and Allen cite this paper as an
example of anthropomorphism at work, I am not so convinced that Hunt et
al.’s (2006) work suffers from mentalistic anthropomorphism. Though
their language tends towards mentalism at times, they operationalize
their terms adequately to permit experimental test. One can argue with
these specific predictions (why should an associative rule demand tools
a constant extent longer on each trial?), but they are not, in my view,
intrinsically anthropomorphic descriptors of behavior.
Thus two of the three papers nominated by Goodrich
and Allen as examples of the usefulness of attributing mental states to
animals in fact exemplify different ways that mentalistic
anthropomorphism can impede our science (and the third is not
significantly anthropomorphic on my reading). Brosnan and de Waal’s
(2003) mentalistic thinking inhibits them from recognizing that the
performance in their control condition contradicts their anthropomorphic
account. Weir and Kacelnik (2006) can see what their bird is doing, but
nonetheless hang onto vague mentalistic anthropomorphic interpretations
in preference to analyzing the stimuli controlling the bird’s behavior.
In both cases, anthropomorphic thinking has impeded progress in
understanding animal behavior.
Anthropomorphizing the Brain
Although I do not want to stray too far from my remit
– which is animal behavior – I do feel compelled to acknowledge that
Goodrich and Allen are quite correct in identifying that my objection to
mentalistic anthropomorphism could apply to mentalistic explanations in
the cognitive sciences more broadly. Burghardt also criticizes my
approach by drawing attention to the thriving state of the study of the
neural bases of awareness and consciousness in nonhumans as exemplified
by Baars (2005).
Goodrich and Allen feel that they have identified a
weakness in my criticism of anthropomorphism because I would be
dismissing "…all the extremely thoughtful work that has gone into
providing a materialistic underpinning for cognitive science over the
past 50 years…" Furthermore, they argue:
If it is perfectly consistent to think, as many
scientists do, that mental states can be understood in
neurofunctional terms, then Wynne’s complaint comes down to the
dubious claim that we should now throw out mentalistic terms because
they were originally associated with a dualistic worldview (p. 148).
I hope I hesitate with due humility before the
thoughtful work of 50 years of cognitive science. I count many cognitive
scientists among my friends. But there are problems with certain kinds
of mentalistic research done under that banner. It is just as unhelpful
to anthropomorphize the brain – even of a human being – as it is to
anthropomorphize a nonhuman animal.
Bennett and Hacker (2003) – neuroscientist and
philosopher – explore some philosophical confusions in neuroscience in
the "Philosophical foundations of neuroscience." They identify as the "Mereological
fallacy" the error of assigning to the brain the actions and powers of
sentient human beings. Brains do not, "believe," "interpret," "know," or
even "represent information" (all qualities that distinguished
cognitive- and neuro-scientists have ascribed to it). Brains simply have
action potentials and other neurological events which exist at the level
of brains but not, of course, at the level of sentient beings.
Space does not permit a detailed rebuttal of Baars
(2005) but, fundamentally there are two fallacies in the comparative
neuroscience of consciousness. The first is believing that finding
neural activity in a human that correlates with some mental state
constitutes an objective basis for accepting that mental state as a
scientific fact. Neural activity correlates with everything people do:
If people in a brain scanner are found to show particular patterns of
neural activity when thinking of Campbell’s tomato soup this does not
turn "thinking of Campbell’s soup" into a fundamental unit of cognitive
science. Second, the fact that there may be neural events or organs
which correlate with conscious mental activity in the human, and that
similar neural events or organs may be observed in nonhuman species,
does not prove that these other species are capable of conscious
mentation. The brains of other species have evolved to enable them to
solve their own problems of survival and reproduction – we cannot assume
that similar neural activity will produce similar outcomes in diverse
species.
In so far as some cognitive scientists (not all) use mentalistic
terms which are poorly operationalized, they are as unlikely to make progress in an objective science of
human behavior and cognition as mentalistic pro-anthropomorphs are to
make progress in the study of animal behavior and cognition.
It ‘is’ Your Grandfather’s Anthropomorphism
As I outlined in the target article, for some five
decades (until 1976), though comparative psychologists and ethologists
argued about many things, there was a cross-party consensus that
mentalism could not aid the study of animal behavior and cognition.
But anthropomorphism runs deep and seems to require
repeated weeding out. Though the term has only been used to characterize
an approach to animal behavior for the last 150 years, something like
what we now call anthropomorphism can be identified in Aesop’s fables
from the sixth century BC.
Mentalistic anthropomorphism is on the resurgent
again. I take Burghardt’s point that his "critical anthropomorphism" is
not Bekoff’s or de Waal’s (or Romanes’s) anthropomorphism. And I
wholeheartedly agree with Burghardt that the "failure to consider that
other animals have a different world from ours" is a failure with dire
consequences for our science. If the approach I sketched in my
remorseful dog story "is critical anthropomorphism" as Burghardt
states, then we are only arguing about the names for things. I do think
the names for things matter: The name "anthropomorphism" has a seven
century history of standing for an error of thinking (where "big bang"
was only used derisively for about a decade). But it is not as important
as stamping out mentalism and keeping our science objective.
What is wrong with mentalism? Mentalism is bad when
it hides causes inside imaginary structures that cannot be
operationalized in objective observable phenomena. Some mentalism is
just a harmless facon de parler – a use of everyday terms in
order to make one’s descriptions of behavior more colorful and to
communicate with a lay audience. But there is a growing resurgence of ol’
time anthropomorphism: the anthropomorphism of Romanes and (much as it
pains me to say it) Darwin. In just the last month prestigious journals
have reported the development of a "self awareness" in elephants (Plotnik,
de Waal, & Reiss, 2007), and "mental time travel" in corvids (Raby,
Alexis, Dickinson, & Clayton, 2007).
If a science of animal behavior and cognition is to
grow, we have to inhibit our spontaneous deep-seated anthropomorphic
tendencies and grasp the challenge of objective descriptions of
behavior. Ultimately – ironically – this is the only way we will ever
discover higher-level cognitive abilities in animals.
Baars, B. J. (2005). Subjective experience is
probably not limited to humans: The evidence from neurobiology and
behavior. Consciousness and Cognition, 14, 7-21.
Bennet, M. R., & Hacker, P. M. S. (2003).
Philosophical foundations of neuroscience. Oxford, UK: Blackwell
Publishing.
Brosnan, S. F., & de Waal, F. B. M (2003).
Monkeys reject unequal pay. Nature, 425, 297 – 299.
Dawkins, R. (1986). The blind watchmaker.
New York: W. W. Norton & Co.
Hunt, G. R., Rutledge, R. B., & Gray, R. D.
(2006). The right tool for the job: What strategies do wild New
Caledonian crows use? Animal Cognition, 9, 307-316.
Plotnik, J. M., de Waal, F. B. M., & Reiss, D.
(2007). Self-recognition in an Asian elephant. Proceedings of the
National Academy of Sciences, 103, 17053-17057.
Raby, C. R., Alexis, D., Dickinson, M. A., &
Clayton, N. S. (2007). Planning for the future by western
scrub-jays. Nature, 445, 919-921.
Weir, A. A. S., Chappel, J., & Kacelnik, A.
(2002). Shaping of hooks in New Caledonian crows. Science, 297,
981.
Weir, A. A. S., & Kacelnik, A. (2006). A New
Caledonian crow (Corvus moneduloides) creatively re-designs
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9, 317-334.
Wynne, C. D. L. (2004). Fair refusal by capuchin
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