Philosophical Psychology
Vol. 19, No. 1, February 2006, pp. 119 127
Reviews
Decisions, Uncertainty and the Brain: The Science of Neuroeconomics
PAUL GLIMCHER
Cambridge, MA: MIT Press, 2004
395 pages, ISBN: 0262572273 (pbk); $22.00
Most social scientists interested in neuroeconomics tell a story in which attention to
psychological studies of rationality and decision making gave economics a new
degree of psychological realism both in itself and through the responses from
mainstream economics that it stimulated. But these developments told us nothing
about neuropsychological mechanisms until cognitive neuroscience developed a
social dimension. Part of that development was the arrival of neuroeconomics, which
studies the neural basis of economic behavior. The story concludes by looking
forward to a synthesis linking economic theory informed by psychology or
sociology with neuroscience in order to bring us an understanding of the behavior
and biology of more or less rational agents.
Paul Glimcher came to neuroeconomics via oculomotor physiology, and he tells
the story from another perspective, as the introduction of greater formal
sophistication into neuroscience. Glimcher argues that the rational agent of
neoclassical economics is in fact just what s needed to lead the way out of an
impasse that has afflicted neuroscience since its inception. The key idea is that
nervous systems are designed to maximize inclusive biological fitness via maximizing
utility (p. 267). Glimcher s own work demonstrates the scientific progression that
he foresees. While working on the visual system, he came to develop probabilistic
approaches to investigate how monkeys choose to allocate attention. The book covers
a lot of territory, and although philosophers of mind won t find much here to help
with the traditional problems of their subject, there s a lot to think about for
philosophers interested in how the cognitive neurosciences work, as well as other
scholars who want to know more about neuroeconomics and its potential
significance for cognitive psychology more broadly.
The problem Glimcher thinks neuroeconomics can address is that behavioral
neuroscience has been driven by physiology it has discovered brain circuits and
then looked for their function. The program derives from Descartes attempt to
explain all human action as the reflexive response of the central nervous system to
external stimuli. (Philosophers should pause sometimes to remember that Descartes
was, for decades, known as one of the great champions of materialism.) This has been
a bottom-up approach, in which reflex circuits are first understood as anatomical
units and then investigated experimentally. The problem Glimcher sees with this
ISSN 0951-5089 (print)/ISSN 1465-394X (online)/06/01000119-127 ß 2006 Taylor & Francis
DOI: 10.1080/09515080500462438
120 Reviews
method is its failure to ask about the function of behaviors in the overall life of the
organism. Glimcher draws on economics to suggest a rival top-down approach in
which tools from probability and game theory are used to specify the tasks that an
organism has evolved to perform. I ll try to tell the story the way Glimcher tells it,
focusing on what I take to be the big picture. There s a lot of fascinating science in the
book, but I will not go over it in detail.
To explain why contemporary issues have the form they do, Glimcher looks to
their history; the exception, oddly, is neoclassical economics. The history is often
agreeable to read one gets the sensation of touring a well-stocked intellect but the
downsides are that crucial steps in Glimcher s argument keep getting deferred and
some of the history seems irrelevant.
Still more is eccentric, or just hard to follow. For example, Glimcher claims that
Sherrington and Pavlov wanted a mathematically complete model of the organism in
which behavior was to be explained by understanding the relations between reflexes
as akin to the relations between logical constants. This project, he says, was dealt a
dire blow by Gödel s proof of the incompleteness of mathematics (pp. 72 73). But
nothing more than first-order logic seems to be at stake in the discussion of
Sherrington and Pavlov i.e., if any logic is involved at all. None of the extensive
quotations from Sherrington and Pavlov seem to support the claim that they were
modeling reflex theory on mathematical logic. Glimcher does say that the
physiologists just had in mind something similar to what the logicians were doing,
but if the projects were just somehow similar then I don t understand the relevance of
Hilbert and Gödel to the biology (p. 68). The limitations of mathematics are only
significant if the reflex arc tradition was looking to do something that,
mathematically, cannot be done.
This example shows what s wrong with the history, especially in the opening
chapters. It lacks the detail to make Glimcher s historical case convincing. On the
other hand, it has too much detail to merely be a summary of the development of
the issues that Glimcher thinks cognitive neuroscience must now confront. The
exception is his discussion of the experimental tradition in neuroscience from which
he dissents. Here at least you can see what he means, and the history is very
interesting. Another problem is that large philosophical themes like dualism and free
will are clearly intended to be illuminated by the discussion, but nothing is spelled
out. I think Glimcher is mixing up two books. Sometimes it reads as though he s
trying to provide a general, user-friendly but rigorous, introduction to neuroeco-
nomics; and sometimes he seems to be advocating his own particular vision of what
economics can offer neuroscience.
So, what is the positive program which Glimcher advocates in place of the
approach whose history he has investigated? Glimcher assumes that cognition is
modular, without ever really spelling out what he means by that, beyond functional
specification. He thinks that the modules are each designed to solve an adaptive
problem. So the problem naturally arises: how do we analyze the problems the
modules evolved to solve? Evolutionary psychology, which also sees the mind as a
collection of evolved modules, has a notorious answer to this question, which is to try
Philosophical Psychology 121
to understand the life lived by our hunter-gatherer forebears and assume that the
modules are solutions to the problems that they faced. Glimcher takes a different
tack, arguing that mathematical theories of decision making that include probability
theory must form the core of future approaches to understanding the relationship
between behavior and brain (p. 177). Glimcher takes this ahistorical approach to
understanding adaptation because of an overriding commitment to the idea that the
nervous system has evolved to make decisions that maximize inclusive fitness.
Although he doesn t say so, this is reminiscent of Dennett s intentional stance, but
with formal theories of behavior replacing Dennett s intuitive folk psychology as the
basis for predictions. (This makes perfect sense if, as theorists like Jon Elster (1989)
have argued, we should think of rational choice theory as a mathematically
sophisticated development of the underlying structure of folk psychology.) So it s
economics, not evolutionary history, that s the means for defining the problem that
an animal faces or the goal that it should achieve (p. 201).
Now, as Glimcher recognizes, his conception of his project places him squarely
in the recent mainstream of behavioral ecology and biomechanics. Quantitative
optimality analyses for organisms have been around for years, drawing on
engineering to predict things like the optimum structural properties of tubular
bones, as well as game theory to predict behaviors such as intraspecies conflict and
sex ratios. Glimcher uses examples drawn from foraging theory, where optimality
analyses have long been utilized effectively, and Maynard Smith s evolutionary game
theory. His picture is one in which the existing formal methods of behavioral ecology
are extended into the brain via a search for properties of neurons that can be modeled
in economic terms.
Traditional approaches in ecology and population genetics were highly idealized,
assuming that phenotypes could be described game-theoretically as strategies that
one could then model as genotypes. Everyone knew that this picture was only a
simplification people don t play just one strategy all the time and there is no simple
one-one relation between genes and strategies. The picture survived because it made
for tractable models and useful predictions. Glimcher, though, wants to use the
strategy to understand neural mechanisms. He doesn t look for the genes underlying
optimal rational behaviors, but the neurons. And indeed, he argues that he
has discovered neurons in parietal area LIP that compute expected utility, and do
so in the same basic fashion corresponding to traditional canons of rational
choice regardless of whether or not the task at hand involves a predictable
environment. Glimcher thinks this is a very big deal indeed, because he treats the
distinction between predictable and unpredictable behaviors as the distinction
between behaviors that, in the Cartesian tradition, can be understood by assuming
the organism is an automaton, versus those that can only be understood by positing
the soul or free will (p. 337).
Glimcher thinks game theory offers a breakthrough here by showing that a purely
physical organism can engage in unpredictable behavior. He assumes that
hitherto physicalists have argued that a deterministic system must be predictable.
But philosophers have been saying for years that a physically determined system can
122 Reviews
be unpredictable. So I m afraid Glimcher adds nothing to the philosophical debate.
But there are some issues that Glimcher raises at the boundaries of philosophy and
the cognitive and social sciences that are of great interest (and his account of his
experimental work is fascinating on its own). I ll end by mentioning a couple.
Essentially, Glimcher treats utility, which can be computed by the brain, as a proxy
for biological fitness, which cannot. After all, organisms do not strive to maximize
fitness directly. Rather, they look for food, mates, predators, etc. If they manage these
tasks well enough, they leave more descendants. Glimcher s basic idea is that all this
diversity of behavior can be boiled down, at the level of proximate mechanisms, to
the operations of brain systems which compute expected utility. This allows utility
maximization to be used as a general measure of optimality, instead of specific
measures for specific traits. Although many behaviors, especially in other organisms,
might be approachable in this way, it s very unlikely that it can provide a general
approach to human behavior. It might work when it comes to satisfying preferences
(e.g., sex, food) that might have been instilled in us by evolution. But it still seems
implausible in light of stresses that have recently afflicted traditional economic
models of rationality, that the approach can be extended to more complex human
behaviors, where the relevant probabilities may not be ones we are evolved to learn.
There may still be a moral here for the study of complex behavior. Glimcher s
orientation on cognition is taken from David Marr. He borrows from Marr the idea
that we should ask what the goal of a behavior is, how it is to be modeled
computationally, and how it is realized in brain tissue. Yet, the final program does
not seem to be Marrian at all. Rather, it relies on defining the problem in terms of
expected utility theory and then going straight to the neurons connecting,
as Glimcher puts it, behavior and neurophysiology through a mathematical corpus
(p. 319). The middle Marrian level, of cognitive architecture, is not involved. So in so
far as the Marrian picture distinguishes the traditional approach to cognitive science,
I think it fails to fit the picture in neuroeconomics, or indeed social and cognitive
neuroscience more generally. Cognitive psychologists have discovered many
important and fascinating effects, but attempts to uncover an independent layer
of computational generalizations haven t gotten very far, and indeed there s no
consensus when it comes to the computational approach that s needed: classical,
dynamic, and connectionist models all have their constituencies.
Perhaps the lesson to take from neuroeconomics is that we can bypass these
computational controversies. We have increasing knowledge of the brain, and
increasing knowledge of our psychology, including formal economic models that can
be rendered more realistic by experimental and observational input from psychology
and the other social sciences. Both the social sciences (including parts of psychology)
and the neuroscience (including parts of psychology) seem to be more robust than
purely Marrian cognitive psychology. In particular, attempts to provide computa-
tional models of rational processes and their frailties seem to have gone nowhere.
So maybe all we need is the interaction between these two lines of inquiry. Perhaps
the attempt to find a general computational approach independent of the specifics of
the human brain is just misguided. Rather than trying to understand cognition as a
Philosophical Psychology 123
set of abstract computational entities, we should focus on understanding human
behavior and linking it to the neurons. Jerry Fodor has long argued that the relations
between beliefs and utilities could not be understood using computational tools, and
concluded that cognitive science could not, therefore, be done. Fodor s pessimism
was based on his belief that computational models of non-demonstrative inference
were impossible, but doing things Glimcher s way suggests that such models may not
be needed for understanding cognition after all.
Put another way, maybe the three-level approach we got from Marr was over-
complicated, and the future of cognitive science will be social science at the top, brain
science at the bottom, and nothing in between. This is the project that Glimcher
really points us towards, I think, and this book has some fascinating suggestions
about how we might start doing it.
References
Elster, J. (1989). Nuts and bolts for the social sciences. Cambridge, England: Cambridge University
Press.
DOMINIC MURPHY
Division of Humanities and Social Sciences
California Institute of Technology
MC 101-40
Pasadena, CA 91125, USA
Email: murphy@hss.caltech.edu
Early Category and Concept Development: Making Sense of the Blooming,
Buzzing Confusion
DAVID H. RAKISON &LISA M. OAKES
New York: Oxford University Press, 2003
442 pages, ISBN: 0195142934 (hbk); $49.50
At the dawn of modern science, philosophers argued about the age-old question of
whether humans construct reality from their senses or whether reality is shaped by
innate properties of the human mind. Early Category and Concept Development adds
a new perspective to this question using the lens of developmental psychology.
As Francis Bacon suggested, infants and children might offer an interesting test
case for understanding reality through science: They are unspoiled by years of
experience, uncorrupted by false notions (Cranston, 1967, p. 235). One can thus
ask how infants view the world. Do they start with adult-like categories of objects and
events? Or do they construct their categories and concepts of objects and events by
assembling perceptual regularities witnessed through years of experience? In this
superbly edited volume, Rakison and Oakes take us through multiple theoretical
124 Reviews
perspectives and offer a panoramic view of the kind of data that developmental
psychology can add to these questions.
This book continues the philosophical conversation and raises three questions of
interest to modern-day scientists. The first concerns constructivism, and is cast in
terms of concepts and categories: Do infants have a priori conceptual information
that guides the ways in which they see and represent their world, or do they use
perceptual building blocks to construct object and event categories? The second
question concerns the role of language in the development of concepts and
categories: Do conceptual categories guide language learning? Alternatively, does
language invite or shape the way our categories are formed (Waxman, ch. 9)? The
third question raised by Oakes and Rakison (ch. 1) asks whether the methods
used in developmental psychology are sufficient to address the questions being raised.
That is, do the methods employed by psychologists tap into infants existing and
changing knowledge about categories and concepts or do these methods themselves
impose a grid that prompts infants to construct a view of the world online
(Newcombe, Sluzenski, & Huttenlocher, 2005)?
The first eight chapters are devoted to the question of constructivism. That
categorization and conceptualization are central to the human experience is taken as
a given in these chapters. As Oakes and Rakison note,
Forming categories reduces demands on our inherently limited memory storage
and perceptual processes, and without it we would have to remember
independently the same or similar information about each individual member of
a category . . . we would have to remember that a particular Rottweiler has four legs
and so does a particular poodle. (p. 4)
How do these categories and concepts come to shape our experience? Most of the
authors in this volume advocate a bottom-up answer to this question, holding that
infants attend to perceptual elements in the environment and build concepts and
categories through a kind of statistical assessment of the input. Younger (ch. 4), for
example, showed infants of different ages sets of stimuli that were systematically
varied (e.g., by the size of the body, tail, legs, and ears). She asked whether infants
notice experimenter-controlled correlations among these different perceptual
elements. The youngest infants in her studies ( 3 months) noticed only specific
features, while older infants ( 9 10 months) detected correlated features that later
form categories. Quinn s (ch. 3) research presents a similar developmental story.
Infants begin with meager attention to perceptual specifics, only later building
complex categories for spatial concepts (e.g., BETWEEN).
These authors support a perceptual, constructivist view. The infants view of reality
differs significantly from the adults and requires little or no a priori organization
from an innate human mind. While this is attractive from a parsimonious view, it is
not without its critics. First, one can ask whether all percepts are created equal or
whether some are more privileged or more noted than others. This traditional
relevance problem haunts the bottom-up approach, and is one that Rakison (ch. 7)
attempts to address. By way of example, Rakison attempts to solve the relevance
Philosophical Psychology 125
problem by proposing that infants prioritize certain percepts over others (i.e.,
movement of object, object size). There is, then, some organization imposed on
perceptual processes used to construct categories and concepts. Second, some
authors like Mandler (ch. 5) suggest that infants bring more to the table than just the
ability to statistically assemble perceptual information.
Mandler s top-down approach thus stands in stark contrast to that presented by
others in this volume. She advocates that instead of moving from specific percepts to
broad categorizations, development progresses from broad generalizations to specific
instances. She writes:
. . .infants generalize broadly on the basis of abstract conceptualizations first and
only with experience learn to pay attention to perceptual detail . . . even though
infants must use various physical features to tell animals such as dogs and cats
apart, they do not rely on them when they are construing the meaning of an event
and generalizing from it. (p. 115)
The test case for Mandler comes in a design that pits perceptual information against
deeper conceptual information. For example, Mandler might show children that a set
of toy vehicles (e.g., cars) can be associated with a key and that a set of toy animals
(e.g., dogs) can be fed with a bottle. She and her colleagues then ask whether, when
presented with a two perceptually similar toys that cross ontological boundaries,
infants make the proper inductions or generalize by perceptual similarity. Mandler
finds that 14-month-olds will feed a bottle to a bird, but not to a perceptually similar
airplane. She concludes that infants therefore go beyond the surface properties of
objects to induce something about conceptual essences. Gelman s work (ch. 13)
presents similar data to suggest that infants are not driven by perception alone, but
rather that they operate with a richer set of categories and concepts that allow them
to discover deeper order in the world in which they live. For these authors,
conceptual biases drive perceptual organization rather than the other way around
(cf. Rakison, ch. 7).
The first half of the book offers the most interesting discussion of these
foundational issues in psychology and philosophy. It is capped by Cohen s (ch. 8)
very balanced commentary on the question of whether there exists a single
categorization system (i.e., one that relies on perceptual information) or a dual
categorization system (i.e., one that relies on both perceptual and conceptual
information). While he favors the bottom-up perspective on these issues, he also
admits:
it is inevitable that unresolved issues will emerge in a field as active and significant
as infant categorization. What is most exciting is that those issues are generating
empirical questions both within and beyond the traditional realm of infant
categorization research. (p. 207)
While the first half of the book asks how infants interpret reality in a nonlinguistic
world, the second half (ch. 9 16) explores language s role in the development of
categories and concepts. Smith and colleagues (ch. 11) believe that children s early
word learning helps create their category knowledge by making some features of
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objects more salient than other features. For example, children have a bias to extend
names for animate objects to objects of similar shape and texture, and names for
substances to objects of the same material. Waxman (ch. 9) contends that words
serve as an invitation for categorization and heighten attention to common
properties shared by a large number of objects. She suggests that infants first attend
to category-based commonalities when they hear a word (e.g., animal and vehicle)
and only later attend to object properties (e.g., color and texture) and relations. Older
infants move beyond objects to link novel adjectives to specific properties of the
object they see (e.g., purple horse).
The prior papers explore ways in which labels serve as attractors for categories.
Other chapters examine the idea that labels provide rich mental structures for infants
that tap into underlying theories of conceptual organization (e.g., Gelman & Koenig,
ch. 13; Gopnik & Nazzi, ch. 12). According to Gelman and Koenig, language may be
crucial for anchoring kinds (p. 351). Language, then, does more than merely draw
attention to shape or objects. It helps children coalesce multiple sources of
information, including function, ontology, intention, and non-obvious properties as
they form broader categories and concepts that tap into richer conceptual theories.
Linguistic labels become the placeholders for a theory about why two things are
members of the same kind and can be used to make inferences when kind is relevant
to the inference (Markman & Jaswal, ch. 15, p. 400).
In the treatment of both the non-linguistic and linguistic theories of infant
development, this volume represents theoretical divisions in the field and offers
commentary to place these divisions within the broader purview of psychology. The
book also displays a spectrum of different methodologies used in the field of infant
development and demonstrates how these methods often generate different answers
to questions about the bottom-up and top-down nature of category and concept
development. In this sense, the book also serves as a tutorial in burgeoning methods
within a field. The reader will be impressed by the ways in which developmentalists
peer into the mind of the pre-linguistic child. Readers might also wonder about a
hotly debated issue within the field of child psychology: whether the methods used to
examine preexisting categories in infants are themselves responsible for the
organization that we see in early development (Newcombe et al., 2005).
In the end, then, we can ask whether the study of infants helps to resolve deeper
philosophical questions about how humans experience reality. The developmental
literature does offer some interesting data on this question. Minimally, the chapters
in this volume show that infants are able to find constancy in their world and to
detect correlations of perceptual stimuli. The data also demonstrate that infants can
form categories of both objects and events from these more meager perceptual
beginnings. A number of researchers hold that this alone suggests we can now offer a
parsimonious path from perception to conception.
Do infants have more than perceptual atoms to work with? The evidence that
babies seem to be making inductive inferences and generalizations about the objects
and events in their world is interesting and tantalizing. Whether these data are
convincing, the reader must evaluate. Wherever one stands in the theoretical debate,
Philosophical Psychology 127
this clearly written and well-edited book adds to the chorus of opinion that might
inform answers to those questions plaguing the study of reality and its construction.
This book is a must-read for those who study human categorization and
conceptualization. It offers an up-to-date and well-argued compendium of opinion
and research from the finest minds in developmental psychology, and illuminates the
current status of the empiricist-rationalist debate within psychology.
References
Cranston, M. (1967). Francis Bacon. In P. Edwards (Ed.), Encyclopedia philosophy (Vol. 1,
pp. 235 240). New York: Macmillan.
Newcombe, N. S., Sluzenski, J., & Huttenlocher, J. (2005). Preexisting knowledge versus on-line
learning. What do young infants really know about spatial location? Psychological Science, 16,
222 227.
SHANNON M. PRUDEN, KATHY HIRSH-PASEK, &JULIA PARISH
Department of Psychology
Temple University
1701 North 13th Street
Philadelphia, PA 19122-6085, USA
Email: spruden@temple.edu
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