An Epigenetic Perspective on the Development of Self-Produced Locomotion and Its
Consequences
Author(s): Bennett I. Bertenthal, Joseph J. Campos, Rosanne Kermoian
Source: Current Directions in Psychological Science, Vol. 3, No. 5 (Oct., 1994), pp. 140-145
Published by: Blackwell Publishing on behalf of Association for Psychological Science
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140 VOLUME 3, NUMBER 5,OCTOBER 1994
in our
collected
that
infants
young
laboratory suggest
expect a moving object to stop when
a tall, thin box but not
it encounters
in terms of the patterns described
in
more
the model
and to compare
time lines of
the acquisition
closely
are
that
phenomena
superficially
a short, wide
the
box, even when
in
vol
latter is considerably
larger
ume than the former. We
suspect
distinct but deeply related. Second,
as was alluded to earlier, we are at
tempting to teach infants initial con
cepts and variables to uncover what
events.
Pilot data
that infants are
led by the dominant
vertical axis of the tall box to per
it as a wall-like,
ceive
immovable
the
and hence
categorize
object,
event as an instance of a barrier phe
in contrast,
infants tend
nomenon;
to view the wide box as a movable
and
object,
event as an
phenomenon,
the
hence
categorize
of a collision
resulting in incorrect
instance
predictions.
The foregoing
discussion
high
lighted several types of developmen
that would
be antici
tal sequences
an
in
view
innate-mechanisms
pated
elab
but not (without considerable
in an innate-principles
oration)
view. To gain further insight into the
nature and origins of these develop
mental sequences, we have adopted
a dual research strategy. First, we
are examining
of
the development
of additional
infants' understanding
gap,
(e.g.,
phenomena
physical
and occlusion
containment,
phe
to determine
how easily
nomena)
can be captured
these developments
kinds
many
of observations,
and how
are required for
that the pursuit of
two strategies will eventually
us to specify the nature of the
observations,
learning. We hope
these
allow
learning mechanisms
bring to the task of
the physical
that
infants
learning
about
world.
was
research
Acknowledgments?This
by grants from the Guggenheim
supported
the University
of Illinois Cen
Foundation,
ter for Advanced
Study, and the National
Institute of Child Health
and Human De
Iwould
like to
(HD-21104).
velopment
thank Jerry Dejong,
for his support and
Noam Chom
insight, and Susan Carey,
John
Fischer,
sky, Judy DeLoache,
Cindy
Laura Kotovsky,
Brian Ross, and
Flavell,
comments
Bob Wyer,
for many
helpful
and suggestions.
Notes
1. J. Piaget, The Construction of Reality in the
Child (Basic Books, New York, 1954).
2. E.S. Spelke, Preferential looking methods as
tools for the study of cognition in infancy, inMea
surement of Audition and Vision in the First Year of
An Epigenetic Perspective on the
Development of Self-Produced
Locomotion
Bennett
One
and
I. Bertenthal,
of the most
10. P. Rochat and A. Bullinger, Posture and
functional action in infancy, in Francophone Per
spectives on Structure and Process inMental Devel
opment, A. Vyt, H. Bloch, and M. Bornstein, Eds.
(Erlbaum, Hillsdale, NJ, in press).
11. K.D. Forbus, Qualitative process theory, Ar
tificial Intelligence, 24, 85-168
(1984).
12. This example focused exclusively
on the
size of the cylinder, but what of the distance trav
eled by the bug in each event? It seems likely that
infants encode this information not in quantitative
terms (e.g., "the bug traveled x as opposed
to y
distance"), but rather in qualitative terms, using as
their point of reference the track itself (e.g., "the bug
rolled to the middle of the track"), their own spatial
position (e.g., "the bug stopped in front of me"), or
the brightly decorated back wall of the apparatus
(e.g., "the bug stopped in front of such-and-such
section of the back wall").
epigenetic
development
process
of
involving
self-produced
the
locomotion.
Its Consequences
Joseph J. Campos,
striking charac
human develop
teristics of early
ment is its consistency
and stability.
unifor
Infants show considerable
mity in the nature and timing of new
to
behaviors. A principal contributor
this early uniformity
Postnatal Life, G. Gottlieb and N. Krasnegor, Eds.
(Ablex, Norwood, Nj, 1985).
3. R. Baillargeon, The object concept revisited:
New directions in the investigation of infants' phys
in Visual Perception and Cognition
ical knowledge,
in Infancy, CE. Granrud, Ed. (Erlbaum, Hillsdale,
NJ, 1993).
4. E.S. Spelke, K. Breinlinger, J.Macomber,
and
K. Jacobson, Origins of knowledge,
Psychological
(1992).
Review, 99, 605-632
5. R. Baillargeon,
L. Kotovsky, and A. Need
in in
ham, The acquisition of physical knowledge
in Cognition and
fancy, in Causal Understandings
Culture, G. Lewis, D. Premack, and D. Sperber,
Eds. (Oxford University Press, Oxford,
in press).
6. R. Baillargeon, A model of physical reasoning
in infancy, inAdvances in Infancy Research, Vol. 9,
C. Rovee-Collier
and L. Lipsitt, Eds. (Ablex, Nor
wood, NJ, in press).
7. R. Baillargeon, Physical reasoning in infants,
in The Cognitive Neurosciences,
M.S. Gazzaniga,
Ed. (MIT Press, Cambridge, MA, in press).
8. E.S. Spelke, Physical knowledge
in infancy:
Reflections on Piaget's theory, in The Epig?nesis of
Mind: Essays on Biology and Cognition,
S. Carey
and R. Gelman, Eds. (Erlbaum, Hillsdale, NJ, 1991).
9. A.M. Leslie, ToMM, ToBy, and Agency: Core
architecture and domain specificity,
in Causal Un
derstandings in Cognition and Culture, G. Lewis, D.
Premack, and D. Sperber, Eds. (Oxford University
in press).
Press, Oxford,
is the develop
and Rosanne
Kermoian
ment
of species-typical
behaviors,
as
such
vocalization,
locomotion,
and
These
behaviors
reaching.
ensure a common
set of experiences
with far-reaching
for
consequences
In this article, we
development.
review a specific
of this
example
Published by Cambridge
University
Press
EXTERNAL
VERSUS
SELF-PRODUCEDFORMS
OF EXPERIENCE
The importance of self-produced
is often overlooked
experiences
by
researchers, and, indeed, most stud
ies investigating
early development
focus on the effects of stimulation
from the environment.
A paradig
matic example
is the study of infants'
SCIENCE 141
CURRENTDIRECTIONS INPSYCHOLOGICAL
responses to the social stimulation of
their caretakers. The infant is viewed
as a passive
recipient of environ
and responses
mental
stimulation,
are typically assumed
to be contin
gent on the actions of the caretaker.
is that infants
view
The alternative
are active participants
in learning
and
about self and environment,
they provide through their own ac
tions at least some of the experi
ences necessary
for further growth
In contrast to ex
and development.
forms of stimula
ternally produced
are
tion, these new experiences
to all infants regardless of
available
their rearing environments.
on
focuses
Our own
research
how the onset of crawling, the emer
in
gence of independent mobility,
fluences
development.
subsequent
In most
emerges
infants, crawling
between 6 and 9 months of age, and
in
coincides with numerous changes
sensorimotor
including
intelligence,
new ways
rela
of coding
spatial
new
about
tions,
concepts
objects,
new forms of social communication,
a burgeoning of fear, and the further
Is
of other emotions.1
differentiation
it possible that experiences
provided
are
of crawling
by the emergence
some
to
of
these
related
functionally
other major
changes
developmental
occurring at the same time? During
research conducted
the past decade,
in our respective
labs has shed some
on
answer
to this provoca
the
light
tive question.
Fig. 1. Photograph of infant crawling on the visual cliff.
FEAROF HEIGHTS
During the third quarter of the 1st
in
infants show a dramatic
year,
crease in the intensity and probabil
fear.
ity with which
they express
These changes are so abrupt and so
for survival that it is often
adaptive
fac
assumed that neuromaturational
tors are the principal cause of this
shift. An especially
developmental
case
is made for fear of
compelling
it
is such a biologi
because
heights
cally significant behavior. Although
we do not dispute a contribution
by
neuromaturation,
our
research
sug
of fear of
gests that the development
more
com
is
considerably
heights
plex, and is based on the interplay
is Professor
I. Bertenthal
Bennett
at the University
of
of Psychology
is Pro
Virginia.
Joseph J, Campos
and Director
fessor of Psychology
of the Institute of Human Develop
ment at the University of California
at Berkeley. Rosanne Kermoian
is
at
Assistant Research Psychologist
at
the University
of California
Address
correspondence
Berkeley.
to Bennett
I. Bertenthal,
Depart
ment of Psychology,
Gilmer Hall,
of Virginia, Charlottes
University
VA
22903-2477.
ville,
neuromaturation
between
factors,
comotor
especially
and other
lo
self-produced
experience.
Wariness
of heights is often stud
ied using a "visual cliff." Figure 1
shows a picture of this apparatus,
consists of a large sheet of
glass (8x4 ft) suspended almost 4 ft
above the floor. A narrow board is
placed across the middle,
dividing
the sheet into two sides. On one side
(referred to as the shallow side), a
which
textured
checkerboard
Copyright ?
1994 American
pattern
Psychological
is
Society
placed directly under the glass, so
that it appears as a rigid and support
able surface. On the other side (re
ferred to as the deep side), the tex
tured checkerboard
is placed 4 ft
the glass, so that this side ap
pears as a cliff, or as an apparent
Inmost studies,
infants are
drop-off.
on
the
centerboard
and en
placed
cross
to
to
the
mother,
couraged
below
across
stands alternately
the
or
shallow
sides
of
the
cliff.
deep
Our early observations
testing in
fants on the visual cliff revealed that,
who
of other
contrary to the predictions
not
did
avoid
the
researchers,
they
side
the
(i.e.,
apparent drop
deep
the onset
off) immediately
following
of crawling.
Instead, itwas generally
6 to 8 weeks
the onset of
following
crawling that avoidance was first ob
served.
This
was
observation
subse
in a
quently replicated and extended
series of experiments.2
In one study, crawling and pre
infants were
tested on the
crawling
visual
cliff at the same age (7.3
Infants were
held 3 ft
months).
above the glass surface of the cliff by
an experimenter,
and slowly
low
ered
onto
the surface.
heart
rate
sured and compared
with
descent,
their
During
was
this
mea
their heart
142 VOLUME 3, NUMBER 5, OCTOBER 1994
Ingenrate during a baseline period.
in states
eral, heart rate decelerates
and
of orienting
and attentiveness,
in states of defensiveness
accelerates
or fearfulness.3
infants
Precrawling
showed
I was one inwhich
locomotor experi
ence was manipulated
in a quasi
manner.
A group of
experimental
infants were given 40 hr
precrawling
in their
of locomotor
experience
no
placed
some period of time each day. These
enable
infants to locomote
walkers
in a small seat
them
by supporting
changes
either side of the visual cliff (see Fig.
infants
2). By contrast,
crawling
showed significant cardiac accelera
tion when
lowered onto the deep
no
and
cardiac change when
side,
lowered onto the shallow side.
on
frame
walker
experi
ing infants without
ence was also tested on the visual
means
crawl
definitive.
Logically,
could covary with
ing experience
any number of other developmental
variables that might contribute to the
of fear of heights. The
development
firm sup
cliff. The results provided
that experi
port for the conclusion
ences with
locomo
self-produced
to the development
tion contribute
the
of fear of heights. Specifically,
infants with
group of precrawling
walker experience
showed heart rate
research
of subsequent
challenge
was
to show that the relation be
tween crawling experience
and vi
was
causal
sual-cliff
performance
acceleration
when
lowered onto
the
side of the visual
cliff; the age
deep
matched
control group showed only
a slight deceleratory
shift.
Another study confirmed
that the
To do
correlative.
and not merely
a series of converging
so entailed
experiment
convincing
to a
is attached
that
wheels.
Infants with walker experi
ence were
tested with
the descent
on
An age
the
visual
cliff.
paradigm
matched
control group of precrawl
these results suggested
Although
affected
that crawling
experience
were
fear of heights,
by no
they
experiments.
The most
who
by their caregivers,
them in infant walkers
for
homes
cardiac
significant
as they were
lowered onto
relation between
locomotor experi
ence and fear of heights was
not
In this experiment,
task-specific.
wariness of heights was tested by en
couraging
the deep
infants to locomote
and
cliff. To assess
shallow
sides
across
of
the
the ef
independently
fects of age of onset of crawling and
infants who
experience,
crawling
to
or
at
crawl
8 months
6, 7,
began
of age were
tested after 11 or 41
days of
locomotor experience.
The
an
of
infant
probability
crossing the
as
as
well
the
(or
cliff,
latency
time) to begin
elapsed
crossing,
were
related to crawl
significantly
but not to the age of
ing experience,
onset
of crawling
(see Fig. 3).
together, these results offer
evidence
that crawling
compelling
contributes
experience
significantly
to the development
of fear of
Taken
for this re
heights. The explanation
lation is still not completely
under
we
but
do
know
that
stood,
falling
alone are not sufficient
experiences
to account
for this developmental
shift on the visual cliff. A more plau
sible
interpretation
that active control
is
for this shift
of
locomotion,
unlike passive
locomotion, demands
continuous
updating of one's orien
tation relative to the spatial layout.
This information is provided through
multimodal
such as visual
sources,
CL
SI
LU
(D
z
<
and
<
ce
I
rr
<
LU
X
-i
i
i
i
#?
loe shallow
-B?
- ?
preloc deep
preloc shallow
2
2.5
3.5
SECONDSOF DESCENT
rate
heart
Data
are
in 7.3-month-old
changes
plotted
to
show
infants
as
a function
heart
second-by-second
rate
of
beats
per minute
(BPM).
Loc
=
crawling
infants;
preloc
Published
=
locomotor
changes
descent onto deep and shallow sides of the visual cliff. Heart rate change
using
angular
ac
fants are placed on the deep side of
the visual cliff, because
angular ac
on the retina is scaled to
celeration
i r
1.5
0.5
experience.
of
between
visual
expected
mapping
and vestibular
is vio
information
in
lated. This violation occurs when
loe deep
O?
2. Mean
coding
celeration. With
locomotor experi
in angular accelera
ence, changes
tion detected
by the visual system
are mapped onto analogous
changes
detected
system.
by the vestibular
ensues when
Fear or avoidance
the
3 H
o
Fig.
vestibular
precrawling
by Cambridge
during
is calculated
University
infants.
Press
the distance
of the nearest visible
no such scaling oc
texture, whereas
curs for the vestibular
system.4 As a
consequence,
visual
and vestibular
of self-motion
become
specification
an
aver
and
produce
discrepant,
response
sive, vertiginous
by infants,
CURRENTDIRECTIONS INPSYCHOLOGICAL
SCIENCE 143
location even after they
the toy hidden somewhere
This situation changes around
successful
100
observe
I
LU
O
z
LU
?C
LU
-#?
41 days
loe. exp.
else.
-0?
11 days
loe. exp.
8 to 9 months of age, when
infants
to
correct
show
search for a
begin
displaced object. The temporal cor
80 i
between
this develop
respondence
mental shift in search behavior and
the onset of crawling
led a number
to suggest a causal
of investigators
connection
between
crawling expe
rience and the development
of new
60 1
?
5
40 i
IZ
<
LU
2
search
skills.
Two
this
20
7
6.5
7.5
8
9
8.5
9.5
recent experiments
support
relation.
The first
predicted
study
10
tested
in
infants, precrawling
crawling
and
infants
with
fants,
precrawling
= 8.5
walker experience
(mean age
on
a
series
of hiding tasks
months)
AGE AT TESTING (MONTHS)
corresponding
permanence
100
- 41
LU
i?. ?o
LU
?LU 60 H
Z
Q
O
-0?
days
loe. exp.
11 days
loe. exp.
20
7.5
8.5
9.5
Fig. 3. Results from a visual-cliff experiment testing infantswho began to crawl at 6, 7,
or 8 months of age. The top panel shows the mean latency differences between moving
onto the deep and shallow sides of the visual cliff as a function of both locomotor
(loc.
experience
exp.)
and
age
at
testing.
The
bottom
shows
panel
the
percentage
infants not crossing the deep side of the cliff as a function of locomotor experience
of
and
at testing.
to adults
not unlike what
happens
a
down
from
very high
looking
when
skyscraper.5
It is fairly well estab
ing experience.
infants are rarely
lished that young
in searching for a hidden
successful
a displacement
of
object following
themselves
SPATIALSEARCH
The
object
Hands-and
hiding location was present.
The second study involved a dif
ferent task, but the results were sim
AGE AT TESTING (MONTHS)
another
scale.6
infants.
Infants with
the
crawling
most crawling experience
(9 weeks)
passed tasks that involved searching
for objects hidden in a new, spatially
discriminable
pre
location, whereas
were
not able to
infants
crawling
pass even a task involving a single
hiding location if a second (unused)
6.5
age
to Piaget's
and walker-assisted
knees-crawling
infants passed more
precrawling
items on this scale than did pre
40
LU
?_
hands-and-knees
is
for hidden objects
skill that is linked to crawl
search
or
the object.
the best known
Perhaps
of this def
example
icit is the A-not-B error shown by
infants on Piaget's
object-perma
nence test. In this test, infants con
in a previously
to search
tinue
Copyright ?
1994 American
Psychological
Society
ilar.7 Hands-and-knees-crawling,
in
and precrawling
belly-crawling,
fants (mean age = 7.5 months) were
a toy was
tested on trials in which
hidden in one of two differently col
ored containers placed in front of the
infant. After the hiding was com
pleted, either the infant or the table
was rotated 180? so that the correct
location of the hid
left-versus-right
den toy was reversed. The results re
vealed that crawling experience was
related to search per
systematically
formance
when
the
infant was
but not when
the table was
moved,
rotated (see Table 1). When
the in
fant was
hands-and-knees
rotated,
infants searched the correct
crawling
container more often than predicted
144 VOLUME 3, NUMBER 5, OCTOBER 1994
sponds to a diagonal coupling of the
limbs, inwhich diagonally
opposite
limbs, such as the right arm and left
and 180?
leg, move simultaneously,
Table 1. Number of infants showing correct and incorrect search for hidden
toy on first trial
Search
Correct
Infant
group
Infant-displacement
out of phase with the other pair of
limbs. The development
of this diag
onal pattern is an emergent
process
Incorrect
condition
fueled by the initial experience
of
on hands and knees. Limb
moving
movements
to a diag
corresponding
are rarely observed
onal pattern
the infant de
prior to the time when
sufficient
velops
strength to support
the torso off the ground. By contrast,
a diagonal pattern is observed a little
Precrawling 5 15
Belly crawling 3 7
Hands-and-knees
crawling
13
5
Table-displacement
condition
Precrawling 11 9
Belly crawling 3 7
Hands-and-knees
crawling
10
8
infants
precrawling
by chance,
container
the incorrect
searched
more
often
than predicted
by
infants
and
chance,
belly-crawling
showed a mixed
response.
How
does crawling
to infants'
contribute
experience
searches
for
to
onset
Prior
the
of
hidden objects?
one
lo
infants remain in
crawling,
cation for extended
periods of time.
in
They are thus fairly successful
coding the location of an object with
a body-centered
frame of reference.
onset
in
the
of crawling,
Following
fants are moving much more often,
mates
the experience
of infants fol
onset
the
of
Infants
lowing
crawling.
learn from this experience
that they
must update their spatial code for
the location of an object following a
the
self-displacement.
Apparently,
new search response
that emerges
with crawling experience
does not
immediately
in which
this
would
improve performance.
also
response
THEORGANIZATIONOF
CRAWLINGBEHAVIOR
inefficient for them
and it becomes
to code the location of an object us
frame of refer
ing a body-centered
ence.
to other
generalize
conditions
A
theme high
complementary
the
research is
lighted by
preceding
that all forms of locomotor experi
ence are not equivalent,
and that the
During the initial stages of this
infants are likely to show
transition,
in perfor
much greater variability
we
is
which
what
mance,
exactly
in
with
observed
belly-crawling
it is the
fants. From our perspective,
in performance
greater variability
this time that
that occurs
during
drives the system to a new level of
to
belly crawling
is
espe
crawling
important. This developmen
cially
in com
tal transition shares much
mon with the other shifts reviewed.
The newly emergent
organization.
search strategy no longer relies on a
frame of reference,
body-centered
but instead uses landmarks or some
other strategy, such as visual track
of hands
Indeed, the development
one
offers
and-knees
of the
crawling
clearest examples of how the selec
tion of new behaviors by infants rep
resents an emergent
process based
updating the lo
ing, for continually
an
cation of
object.
It is noteworthy
that search per
formance was
related to locomotor
on the confluence
of multiple organ
ismic and environmental
factors.
In a recently completed
study, we
in the
infant
experience
only
This condition,
rotation condition.
the table-rotation
with
compared
more
condition,
approxi
closely
transition
from
hands-and-knees
assessed
the develop
longitudinally
ment of crawling
in six infants.8 Ki
nematic analyses of interlimb coor
dination
revealed
that the most
corre
movement
stable pattern of
Published by Cambridge
University
Press
more
than 50% of the time just 1 to
2 weeks
after the torso is supported
off the ground (see Fig. 4).
Our interpretation for this finding
is that hands-and-knees
that the torso
quires
re
crawling
remain sup
ported and balanced during forward
are
these requirements
progression;
irrelevant during the preceding
stage
of belly
and creeping.
crawling
Once
infants develop
sufficient
in their arms and legs to
strength
support the torso, they begin to ex
interlimb patterns
plore the various
available
for movement,
such as
one
a
at
limb
time or
moving
only
moving both limbs on the same side
of the body at the same time. Fol
lowing a relatively brief opportunity
to explore the various
interlimb pat
terns
to
available
verge on
because
infants
them,
con
the same diagonal
pattern
it provides
effi
greater
Fig. 4. Mean percentage of time that
limbs are diagonally
coupled during
Data
crawling.
prior
(-2)
to
are
the
plotted
onset
from
of
2 weeks
hands-and
knees crawling through 6 weeks follow
ing (+ 6) the onset of hands-and-knees
crawling.
CURRENTDIRECTIONS INPSYCHOLOGICAL
SCIENCE 145
ciency and stability
alternatives.
Two
than any of the
should
be
points
empha
sized about this developmental
shift.
to
the
transition
hands-and
First,
knees crawling begins with a period
success
in producing
during which
is quite
forward prone progression
This experience
informs
variable.
interlimb
the infant that the previous
no
is
organization
longer adequate
the in
for the new task. Gradually,
fant converges on a new form of in
the
terlimb patterning
representing
most dynamically
stable organiza
tion given the task at hand. Second,
are
these developmental
changes
nor obligatory,
the natural out
neither
prescriptive
but rather represent
come of a system governed by trying
to achieve the most dynamically
ef
It is noteworthy
that
this sequence
of increased variabil
ity followed by greater stability and
is a common
greater generalizability
theme that cuts across many differ
ficient solution.
ent developmental
theories.9
More
of development.
processes
that
over, it confirms our contention
some of the relevant factors contrib
uting to the uniformity of early be
are indeed ex
havioral development
An
for
important goal
is to assess the gen
of our finding to deter
eralizability
mine whether
other forms of self
such as
experiences,
generated
periential.
future research
those produced
by sitting or reach
to the develop
ing, also contribute
mental process.
Second, our findings underscore
the limitations invoked by assuming
a linear model
of development.
Such a model makes
the simplistic
con
that
assumption
performance
tinues to improve at a constant rate
as experience
increases.
Logically,
this prediction
is problematic
be
cause most behaviors
reach an as
level of performance
and
ymptotic
then show no further improvement.
the results from many
Moreover,
are
not
consistent with the
studies
that change occurs at a
expectation
rate. For instance, the de
of a diagonal gait pattern
the onset of hands-and
following
to an
knees crawling
corresponds
constant
velopment
GENERALIZATIONS
ABOUT
DEVELOPMENT
At a specific
level, the findings
from this research program provide
that locomotor
evidence
compelling
is
related to
experience
functionally
the development
of a number of new
forms. At a more general
these
level,
findings lend support to
three
important
generalizations
about the developmental
process.
First and foremost, our research
shows
that some of the
program
most
significant
early experiences
are those produced
by the infant's
own actions. This finding represents
a radical departure
from the tradi
behavioral
tional
actions
perspective
as merely
of viewing
products
these
and not
abrupt nonlinear
a monotonically
change
rather than
func
increasing
is
that
the
ap
experience
such as
plication of linear models,
linear regression, to the study of the
effects
of experience
sometimes
or
incorrect
produces
misleading
tion. Our
results.10
Finally, this research underscores
importance of conceptualizing
from a systems per
development
the
is
spective. Developmental
change
a
cause.
to
attributable
rarely
single
For example,
locomo
self-produced
tor experience
to search
contributes
but so do im
objects,
trunk control, ability to se
and increased vi
actions,
for hidden
proved
quence
Copyright ?
1994 American
Psychological
Society
suai attentiveness.6
It is essential
that
conceptualize
early de
as
to
responsive
velopment
multiple
factors that interrelate and subsume
investigators
coactions.
organism-environment
From
this perspective,
behavioral
re
is
multidetermined,
development
lational, and emergent.
research
Acknowledgments?The
in this review
scribed
National
Institutes
de
was
of
supported
by
Health
Grants
HD16195 and HD23144, and also by a
grant from
MacArthur
nine
Pinto
the John D.
Foundation.
T.
and Catherine
We
thank Jean
for her helpful comments.
Notes
1. A comprehensive
review of these develop
mental changes is presented in B.I. Bertenthal, J.J.
locomo
Campos, and K.C. Barrett, Self-produced
tion: An organizer of emotional, cognitive, and so
in infancy, in Continuities
cial development
and
in Development,
Discontinuities
R.N. Emde and
R.J. Harmon, Eds. (Plenum, New York, 1984).
2. J.J. Campos,
B.I. Bertenthal, and R. Ker
and emotional develop
moian,
Early experience
ment: The emergence of wariness of heights, Psy
(1992).
chological Science, 3, 61-64
3. J.J. Campos, Heart rate: A sensitive tool for
the study of emotional development,
in Develop
mental Psychobiology:
The Significance of Infancy,
L.P. Lipsitt, Ed. (Erlbaum, Hillsdale, NJ, 1976); L.A.
Sroufe and E.Waters, Heart rate as a convergent
measure
in clinical and developmental
research,
Merrill-Palmer Quarterly, 23, 3-27 (1977).
4. T. Brandt, W. Bles, F. Arnold, and T.S.
Kapteyn, Height vertigo and human posture, Ad
vances in Oto-Rhino-Otolaryngology,
89, 88-92
(1979).
5. For more details, see B.I. Bertenthal and J.J.
Campos, A systems approach to the organizing ef
fects of self-produced
locomotion during infancy, in
in Infancy Research, Vol. 6, C. Rovee
Advances
Collier and L. Lipsitt, Eds. (Ablex, Norwood,
NJ,
1990).
6. R. Kermoian and J.J.Campos, Locomotor ex
perience: A facilitator of spatial cognitive develop
ment, Child Development,
59, 908-917
(1988).
7. D.L. Bai and B.I. Bertenthal, Locomotor sta
tus and the development
of spatial search skills,
Child Development,
(1992).
63, 215-226
8. R.L. Freedland and B.I. Bertenthal, Develop
in interlimb coordination: Transi
mental changes
tion to hands-and-knees
crawling, Psychological
(1994).
Science, 5, 26-32
9. G. Edelman, Neural Darwinism
(Basic
Books, New York, 1987); E. Thelen, Evolving and
of leg co
dissolving synergies in the development
in Perspectives on the Coordination of
ordination,
S. Wallace,
Ed. (Elsevier, Amsterdam,
Movement,
1989).
10. B.I. Bertenthal and J.J.Campos, A reexam
inaron of fear and its determinants on the visual
413-417
cliff, Psychophysiology,21,
(1984).