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Discussions of infant perception and cog-nition have been heating up recently
with some of the major investigators,
such as Renee Baillargeon, MarshallHaith, Andrew Meltzoff, Linda Smith,
and Elizabeth Spelke, engaged in vocal
and written debate at professional meet-ings and in issues of Infant Behavior
and Developmentand Developmental
Science15. What is the fuss about? Muchof it centers on the appropriate level of
richness of interpretation of the evi-
dence, and what kinds of skills and
knowledge can be attributed to infants,based on their performance in experi-
ments conducted with habituationdishabituation and spontaneous-pref-
erence methodologies. In accordancewith traditional constructivist views of
development, infants may be detecting
low-level stimulus variables like bright-ness and frequency, and gradually
learning to organize them by means of
experience (i.e. instruction by the envi-ronment) into more complex mental
structures that eventually attain the
status of representations. From a morenativist perspective, infants may be in-
nately possessive of deep cognitive con-
straints, which in time take the form oftheories that organize domains of
knowledge. The question is whether we
should characterize the infant as beingprimarily perceptual or intelligent.
In The Cradle of Knowledge:Development of Perception in Infancy,
an ambitious book that provides detailed
coverage and thoughtful analyses of theliterature on early perceptual devel-
opment, Philip Kellman and Martha
Arterberry offer the view that neitherthe constructivist nor nativist positions
provide apt descriptions of infant de-
velopment. Kellman and Arterberry es-pouse a different view in which infants
are, at the same time, perceptual and
intelligent because they are guidedthroughout the course of early knowl-
edge acquisition by smart perceptual
mechanisms that have evolved to extracthigher-order stimulus relationships and
produce output representations that
constitute abstract, meaningful descrip-tions of the environment. The authors
note that these descriptions can supportongoing action, but they also can be
stored and recruited for later thought
and action. The rest of cognition suchas memory, categorization, thinking, and
problem solving requires represen-
tations obtained from perceiving (p.283). The perspective is ecological, and
has its origins in the views of the early
Gestaltists, J.J. Gibsons theory of direct
perception, and E.J. Gibsons differenti-
ation model of developmental change,but it also has a modern cognitive-
science flavor (and escapes radicalGibsonianism) by invoking constructs
of mechanism and representation.
I am sympathetic to the views ofKellman and Arterberry, in particular,
to the idea that early knowledge ac-
quisition must proceed from a strongperceptual base. Such an approach to
thinking about cognition in infants is
in accordance with Robert Goldstone
and Larry Barsalous recent attempts toreunite perception and conception in
adults6. I would add that Kellman andArterberrys framework for understand-
ing perceptual development is in somerespects consistent with a form of na-
tivism that is embodied in the neural se-
lectionist views of Jean-Pierre Changeuxand Gerald Edelman. These views imply
that our evolutionary history has en-
dowed the infant with inherent sensi-tivities, perceptual preferences, and in-
formation-processing constraints, as well
as potential knowledge (i.e. categoryrepresentations and their many combi-
nations). Such species-specific biases may
account for the rapid learning observedin many of the experiments described
in this book, but without building in
innate content.Constructivism, too, offers possibil-
ities for learning complex knowledge-structures (e.g. theories) from the rep-
resentational primitives delivered by
perception (although it also needs anumber of initial constraints). For exam-
ple, the new computational analyses by
Denis Mareschal and Yuko Munakata7,8,which utilize recurrent connections to
create dynamic visual memory, may pro-
vide a mechanism for explaining howrepresentations of hidden objects can be
built up from experience with occlusion
events.Given Kellman and Arterberrys ex-
pertise in object and depth perception,
it is not surprising that the book is con-centrated in the domain of vision. But
there is also coverage of auditory per-ception, intermodal correspondence,
and the relation between perception
and action. An early chapter providesbackground on biological development
and sensory constraints, and their likely
perceptual consequences, and might beregarded as required reading for anyone
new to infant perception research. The
initial, penultimate, and final chaptersare the most provocative and offer in-
formed commentary on difficult core
issues such as the nature of perception,
Booksetcetera
443T r e n d s i n C o g n i ti v e S c i e n c e s V o l . 3 , N o . 1 1 , N o v e m b e r 1 9 9 9
The Cradle of Knowledge:Development of Perception inInfancy
by Philip J. Kellman and Martha E. Arterberry, MIT Press/Bradford Books, 1998.
$39.50 (xiv 369 pages) ISBN 0 262 11232 9
the relation between perception and
conception, and the work that remains
to be done to achieve a more completeunderstanding of perception and its
development.
Some readers might find the cover-age in the data-based chapters too de-
tailed for their tastes, but it does demon-
strate how empirical phenomena canvary, sometimes significantly, even with
slight parametric variation. The analysesof disparate experimental findings are
probing, and the authors are generous
in communicating many wise sugges-tions for further studies that might be
useful in resolving current dilemmas.
Within each chapter, periodic summariesof the conclusions that the authors draw
from sets of studies examining a com-
mon issue may prompt readers to ponderthe findings themselves and make their
own assessment of the evidence. Also, as
the book progresses, certain outcomeskeep reappearing (e.g. the importance
of motion information for represen-tation of objects and space), and majorthemes are reviewed (e.g. the develop-
mental primacy of information with the
highest ecological validity). These fea-tures provide an overall cohesiveness to
the presentation.Because there is nothing currently
quite like it, the book is well positioned
to make an immediate and significantimpact on the field of infant cognition,
an area of inquiry that will undoubt-
edly continue as one of the most activewithin cognitive science. Jacques Mehler
and Emmanuel Dupouxs What Infants
Know: The New Cognitive Science of
Early Developmentis already five years
old and has somewhat different em-
pirical and theoretical emphases9. AlanSlaters edited volume, Perceptual
Development: Visual, Auditory, and
Speech Perception in Infancy, is con-
temporary, but multi-authored, and thus
is not in a position to compete in termsof consistency of narration10.
For teaching purposes, Kellman
and Arterberrys book could be benefi-cially coupled with Alison Gopnik and
Andrew Meltzoffs Words, Thoughts, and
Theories11, in a kind of pointcounter-point contrast of bottom-up versus top-
down approaches to early knowledgeacquisition. Another option would be touse the text alongside Peter JusczyksThe Discovery of Spoken Language12,
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inasmuch as a grounding in speech is as
important as a foundation in vision forunderstanding human development.
However used, readers will benefit
from having studied Kellman andArterberrys impressive work.
Paul C. Quinn
Department of Psychology, Brown University,
Providence, RI 02912, USA.
tel: +1 401 863 2727
fax: +1 401 863 1300
e-mail: [email protected]
References
1 Haith, M.M. (1998) Who put the cog in infant
cognition? Is rich interpretation too costly?
Infant Behav. Dev. 21, 167179
2 Meltzoff, A.N. and Moore, M.K. (1998) Object
representation, identity, and the paradox of
early permanence: steps toward a new
framework Infant Behav. Dev. 21, 201235
3 Spelke, E.S. (1998) Nativism, empiricism, and
the origins of knowledge Infant Behav. Dev.
21, 181200
4 Baillargeon, R. (1999) Young infants
expectations about hidden objects: a reply to
three challenges Dev. Sci. 2, 115132
5 Smith, L.B. (1999) Do infants possess innate
knowledge structures? The con side Dev. Sci.
2, 133144
6 Goldstone, R.L. and Barsalou, L.W. (1998)
Reuniting perception and conception
Cognition 65, 231262
7 Mareschal, D., Plunkett, K. and Harris, P.
(1995) Developing object permanence: a
connectionist model, in Proc. 17th Annu.
Conf. Cognit. Sci. Soc. (Moore, J.D. and
Lehman, J.E., eds), pp. 170175, Erlbaum
8 Munakata, Y. et al. (1997) Rethinking infant
knowledge: toward an adaptive process
account of successes and failures in object
permanence tasks Psychol. Rev. 104,
686713
9 Mehler, J. and Dupoux, E. (1994) What
Infants Know: The New Cognitive Science of
Early Development, Blackwell
10 Slater, A., ed. (1998) Perceptual Development:
Visual, Auditory, and Speech Perception in
Infancy, Taylor & Francis
11 Gopnik, A. and Meltzoff, A.N. (1997) Words,
Thoughts, and Theories, MIT Press
12 Jusczyk, P. (1997) The Discovery of Spoken
Language, MIT Press
Booksetcetera
444T r e n d s i n C o g n i ti v e S c i e n c e s V o l . 3 , N o . 1 1 , N o v e m b e r 1 9 9 9
The behavior of central nervous system
neurons depends on a complex interplay
of ionic currents of multiple sources. Thisinterplay determines how the neuron
transforms various inputs into its main
output the action potential. Under-standing the type of computations un-
derlying this inputoutput transfor-
mation often lies beyond the capacity ofour intuitive reasoning because of the
complexity of the interactions involved.
A possible approach to this problem isthat of computational neuroscience,
which integrates biophysical and mor-
phological data in computer models toinvestigate the range of complex oper-
ations taking place in neurons. This ap-
proach has become particularly interest-ing in the last 20 years or so because the
key ionic mechanisms underlying neur-onal operations have been precisely
characterized by in vitro techniques,
thereby allowing computational modelsto address questions in close relationship
to experiments.
A detailed account of this field re-quires an introduction of the basics as
well as the details of the different ionic
mechanisms that determine neuronalbehavior, such as voltage-dependent
currents, synaptic interactions, and so
forth. It also needs a clear explanationof the rationale of the different for-
malisms used for modeling these ionic
currents and how to apply them to in-vestigate specific problems, such as that
of dendritic integration. All these aspectsare treated with a remarkable clarity
by Christoph Koch in this well-written
monograph.Biophysics of Computation is orga-
nized into small chapters, each contain-
ing a relatively stand-alone description
of a specific topic, followed by a briefsummary of one page or so at the end.
The chapters are arranged in a logicalorder, starting with the basics on ionic
currents and cable theory, and consider-
ing successively more complicated issues,such as dendritic integration and spike
initiation. Indeed, one of the attractive
features of the book is that each chaptercan be consulted relatively indepen-
dently. This aspect should be particularly
appreciated by readers already familiarwith the basics, who can therefore skip
those chapters.
Throughout this tour of the field,Koch uses neocortical pyramidal neurons
as an example, and shows us a wide
range of problems that can be investi-gated using computational modeling. As
the author says, this book is not intended
to be a primer for students, because ofthe complexity of the subjects treated,
and also because the basics are relativelysuccinctly overviewed. It is more in-
tended as a reference work for advanced
graduate students and researchers in thefield of computational neuroscience, and
is also an indispensable companion for
anyone seeking to understand moreabout the biophysical interactions that
take place in neurons. Readers interested
in problems related to systems neuro-science, such as learning or sensory per-
ception, might be deceived though,
because these aspects are barely men-tioned here. However, apprehending
these problems necessarily requires a
deep understanding of issues such asdendritic attenuation, interaction of
synaptic inputs with active membranes,or the type of processing performed bydendritic spines. These subjects are
magisterially covered here and, in my
Biophysics of Computation:Information Processing inSingle Neurons
by Christof Koch, Oxford University Press, 1999. 45.00 (xxiii + 552 pages)
ISBN 019 510491 9
opinion, this is one the best overviews
of these topics presently available.On the negative side, one might
criticize the relatively narrow focus ofthe book, which essentially concentrateson single-cell or subcellular behavior,
mostly of cortical pyramidal neurons.
A lot of beautiful biophysically basedmodeling studies have been done at
the network level or at the single-celllevel for other cell types in the nervous
system, and including them would have
broadened the scope of the book. Forexample, the chapter on bursting cells
is surprisingly short although this sub-
ject was intensely studied using com-putational models, and despite the
fact that bursting plays a central role
in both vertebrate and invertebrateneurophysiology.
Fortunately though, these criticisms
do not harm the quality of the presen-tation nor the scientific value of the
work. This book should have an impor-
tant impact in making the biophysicsof neuronal behavior part of the gen-
eral knowledge that any neuroscientist
should have. Many of us would gain alot by reading it.
Alain Destexhe
Department of Physiology,
Laval University, Quebec,
Canada G1K 7P4.tel: +1 418 656 5711
fax: +1 418 656 7898
e-mail: [email protected]
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