ArticlePDF Available

Independent development of the Reach and the Grasp in spontaneous self-touching by human infants in the first 6 months

Authors:
Article

Independent development of the Reach and the Grasp in spontaneous self-touching by human infants in the first 6 months

Abstract and Figures

The Dual Visuomotor Channel Theory proposes that visually guided reaching is a composite of two movements, a Reach that advances the hand to contact the target and a Grasp that shapes the digits for target purchase. The theory is supported by biometric analyses of adult reaching, evolutionary contrasts, and differential developmental patterns for the Reach and the Grasp in visually guided reaching in human infants. The present ethological study asked whether there is evidence for a dissociated development for the Reach and the Grasp in nonvisual hand use in very early infancy. The study documents a rich array of spontaneous self-touching behavior in infants during the first six months of life and subjects the movements to analyses of body target, contact type, and Grasp. Video recordings were made of resting alert infants biweekly from birth to 6 months. In younger infants, self-touching targets included the head and trunk. As infants aged, targets became more caudal including the hips, legs, and feet. In younger infants hand contact was mainly made with the dorsum of the hand, but as infants aged contacts included palmar and eventually grasp and manipulatory contacts with the body and clothes. The relative incidence of caudal contacts and palmar contacts increased concurrently and were significantly correlated throughout the period of study. In contrast, developmental increases in self grasping emerged a few weeks after the increases observed in caudal and palmar contacts. The behavioral and temporal pattern of these spontaneous self-touching movements suggest that the Reach, in which the hand extends to make a palmar self-contact, and the Grasp, in which the digits close and make manipulatory movements, have partially independent developmental profiles. The results additionally suggest that self-touching behavior is an important developmental phase that allows for the coordination of the Reach and the Grasp prior to their use under visual guidance.
Content may be subject to copyright.
ORIGINAL RESEARCH ARTICLE
published: 08 January 2015
doi: 10.3389/fpsyg.2014.01526
Independent development of the Reach and the Grasp in
spontaneous self-touching by human infants in the first 6
months
Brittany L. Thomas , Jenni M. Karl and Ian Q. Whishaw*
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
Edited by:
Daniela Corbetta, University of
Tennessee, USA
Reviewed by:
Joshua L. Williams, Armstrong
Atlantic State University, USA
Anjana Bhat, University of
Connecticut, USA
*Correspondence:
Ian Q. Whishaw, Department of
Neuroscience, University of
Lethbridge, 4401 University Drive,
Lethbridge, AB T1K 3M4, Canada
e-mail: whishaw@uleth.ca
The Dual Visuomotor Channel Theory proposes that visually guided reaching is a
composite of two movements, a Reach that advances the hand to contact the target and
a Grasp that shapes the digits for target purchase. The theory is supported by biometric
analyses of adult reaching, evolutionary contrasts, and differential developmental patterns
for the Reach and the Grasp in visually guided reaching in human infants. The present
ethological study asked whether there is evidence for a dissociated development for the
Reach and the Grasp in nonvisual hand use in very early infancy. The study documents
a rich array of spontaneous self-touching behavior in infants during the first 6 months
of life and subjected the Reach movements to an analysis in relation to body target,
contact type, and Grasp. Video recordings were made of resting alert infants biweekly
from birth to 6 months. In younger infants, self-touching targets included the head and
trunk. As infants aged, targets became more caudal and included the hips, then legs, and
eventually the feet. In younger infants hand contact was mainly made with the dorsum of
the hand, but as infants aged, contacts included palmar contacts and eventually grasp and
manipulation contacts with the body and clothes. The relative incidence of caudal contacts
and palmar contacts increased concurrently and were significantly correlated throughout
the period of study. Developmental increases in self-grasping contacts occurred a few
weeks after the increase in caudal and palmar contacts. The behavioral and temporal
pattern of these spontaneous self-touching movements suggest that the Reach, in which
the hand extends to make a palmar self-contact, and the Grasp, in which the digits close
and make manipulatory movements, have partially independent developmental profiles.
The results additionally suggest that self-touching behavior is an important developmental
phase that allows the coordination of the Reach and the Grasp prior to and concurrent with
their use under visual guidance.
Keywords: reach, grasp, prehension, self-touch, sensorimotor development, development of reaching,
development of grasping
INTRODUCTION
The Dual Visuomotor Channel theory proposes that visually
guided reaching consists of two movements, the Reach and the
Grasp, each mediated by separate visuomotor pathways from
occipital to parietofrontal neocortex (Arbib, 1981; Jeannerod,
1981, 1999; Rizzolatti et al., 1998; Tanné-Gariépy et al., 2002;
Culham and Valyear, 2006; Cavina-Pratesi et al., 2010; Filimon,
2010; Karl and Whishaw, 2013). The Reach transports and orients
the hand in relation to the extrinsic (location) features of a target
while the Grasp opens, shapes, and closes the hand for target pur-
chase in relation to the intrinsic (size, shape) features of the target.
Visual fixation of a target from movement onset to target contact
integrates the Reach and the Grasp into a seamless act (de Bruin
et al., 2008; Sacrey and Whishaw, 2012). In a number of situations
in which online vision is not available to guide reaching, the Reach
and the Grasp can become uncoupled, each becoming directed
by somatosensory guidance. Proprioception guides the Reach to
locate the target whereas the Grasp is initiated from informa-
tion obtained after the target is touched (Karl et al., 2012a; Karl
and Whishaw, 2013; Hall et al., 2014). Visually guided reach-
ing is likely accomplished through the same parietofrontal Reach
and Grasp pathways that mediate somatosensory guided reach-
ing (Dijkerman and de Haan, 2007; Fiehler et al., 2009; Fiehler
and Rösler, 2010; Karl et al., 2012b). In short, anatomical, elec-
trophysiological, brain imaging and behavioral evidence provide
support for the idea that reaching consists of two movements,
the Reach and the Grasp, which can be configured in various
ways depending upon the availability of sensory guidance from
different sensory systems.
At the present time, little is known about how the Reach
and the Grasp become integrated as a seamless visually guided
act but it is reasonable to suppose that development in infancy
plays a formative role. A number of prereach and pregrasp move-
ments displayed by infants at different stages of development can
www.frontiersin.org January 2015 | Volume 5 | Article 1526 |1
Thomas et al. Development of infant self-contacts
be viewed as supporting the idea that the Reach and the Grasp
have independent developmental origins. Prior to the onset of
visually guided reaching, prereach movements include first ori-
enting the eyes and head to a visual target (Greenman, 1963;
Kremenitzer et al., 1979; von Hofsten and Rosander, 1997), then
reaching for an object with the mouth by thrusting the head for-
ward and flexing the abdominals (Foroud and Whishaw, 2012),
and eventually swiping at a visual target with a fisted or open
hand (White et al., 1964; von Hofsten, 1982, 1984). Pregrasp
movements include orienting the hand to, and closing the fingers
on, an object that contacts the hand (Twitchell, 1965), perform-
ing spontaneous hand and grip configurations during vacuous
hand babbling (Wallace and Whishaw, 2003), and manipulating
objects (Lobo et al., 2014). Some prereach and pregrasp move-
ments likely begin in utero (Myowa-Yamakoshi and Takeshita,
2006). The descriptions of these prereach and pregrasp move-
ments indicate that they are not only made in relation to visual
stimuli but they are importantly associated with somatosensory
stimulation derived from hand contact with a target (Lockman
et al., 1984; Newell et al., 1993; Corbetta et al., 2014).
One prediction of the Dual Visuomotor Channel theory of
reaching is that development should feature independence in the
maturation of the Reach and the Grasp. Indeed, a number of
previous lines of investigation have noted that reaching without
grasping occurs at an earlier developmental age than reaching
with grasping (Von Hofsten and Lindhagen, 1979; von Hofsten,
1984; Savelsbergh and van der Kamp, 1994; Wimmers et al.,
1998a,b). Nevertheless, there are divergent predictions related
to the significance of the independence of behaviors described
as reaching and grasping. For example, catastrophe theory pro-
poses that during development, reaching gives way to grasping
and that the transition point or cusp is associated with enabling
morphological changes such as those of hand size, arm size,
and torso strength (Wimmers et al., 1998a,b). In contrast, Dual
Visuomotor Channel theory would favor the idea that the Reach
and Grasp remain independent but that development also fosters
conditions in which they can be combined, as occurs when the
Reach and the Grasp are integrated together under online visual
or somatosensory guidance (Karl and Whishaw, 2013; Corbetta
et al., 2014).
Many of the studies that have investigated infant reaching
havefocusedonvisuallyguidedreachingandsohaveused
older infants that display visually guided reaching and grasp-
ing. Somatosensory guided reaching has received less study (but
see Corbetta et al., 2014). The present study was prompted by
the observation by Wallace and Whishaw (2003) that at approx-
imately 4 months of age there is a decrease in the spontaneous
vacuous arm and hand movements made by infants that is seem-
ingly replaced by self-grasping of the body and clothing. These
self-grasping movements have not received experimental anal-
ysis and we hypothesized that they could provide insights into
the development of infant reaching behavior and the organiza-
tion of visuomotor systems. First, they would indicate whether
there is a phase of somatosensory-related reaching/grasping that
precedes and/or is integrated with the onset of visually guided
reaching. Second, the analysis of these movements could pro-
vide further support for the theory that the Reach and the Grasp
are behaviorally independent but can be integrated through
experience. Third, analysis of these movements could test the
notion that the Reach and the Grasp are supported by at least
partially independent neural channels. The present ethological
study was therefore directed toward characterizing self-touching
behavior in developing human infants over the first 6 months
of life.
An important feature of the analysis included determining the
relationship between infant age, the location of hand contact,
and the type of hand-to-body contact. Accordingly, self-touching
movements were coded in relation to the part of the hand that
contacted the body (i.e., Dorsum—side or back of the hand, or
Palmar—digit surface and palm) and the location on the body
at which the contact was made (i.e., Rostral—head or torso, or
Caudal—legs or feet). In addition, any self-grasping movement
with a digit or number of digits on the body or clothes was also
documented. Video recordings of the infants were made across
the first 6 months of life because this time period includes the
age at which self-grasping movements have been documented
and precedes the age at which visually guided reaching becomes a
frequent infant activity.
MATERIALS AND METHODS
RESEARCH PARTICIPANTS
Forty-two normal, full term infants (21 boys and 21 girls)
participated in the study. None of the infants had sensory or
motor impairments. The initial observations were made within
a few days of birth and filming sessions ended when the infants
were approximately 24 weeks old (Wallace and Whishaw, 2003).
This period precedes the age at which visually guided reaching
becomes pronounced.
Infants were recruited from acquaintances of the authors, pri-
vate day homes, the University of Lethbridge Daycare, and a
local Montessori preschool (Sacrey et al., 2012). The daycare,
preschool, and day homes provided the age of the child in weeks
to the experimenters. Informed consent was obtained from the
parent(s) prior to their child participating in the study. The
University of Lethbridge Human Subjects Research Committee
approved the study. All parents were naïve to the purpose and
hypothesis of the study.
VIDEO RECORDING
Participants were recorded using a Sony Hi8 video camera, a Sony
MiniDV video camera, or a Casio Exilim digital camera. All Hi8
and MiniDV tapes were converted to digital formats. The scor-
ers analyzed the video recordings using slow-motion playback on
QuickTime Player 7.
FILMING PROCEDURE
For filming, the infants were either lying on their back or sitting
in baby seats, with the older infants usually supported in a baby
seat or sometimes supported by a parent (see Lobo and Galloway,
2013,Figure 2 for illustration of infant supported in baby seat).
The seating arrangement was in part determined by parental
transport preference. Nevertheless, because Savelsbergh and van
der Kamp (1994) have found that body orientation to gravity
influences early infant reaching, as does the location of target
Frontiers in Psychology | Developmental Psychology January 2015 | Volume 5 | Article 1526 |2
Thomas et al. Development of infant self-contacts
objects relative to the upper and lower visual fields, every attempt
was made to maintain a relatively constant body orientation for
the participants across the study period.
The infants were required to be unencumbered by long cuffs
that covered the hands or blankets that covered their hands, body,
or legs. The infants were filmed from a front view in such a
way that the entire infant was visible. This necessitated plac-
ing the camera above infants that were lying on their back and
before infants that were sitting. The infants did not have toys or
other objects present that would otherwise distract them from
spontaneous activity.
DATA COLLECTION
At least 10 min duration of spontaneous activity was filmed
for an infant on each filming session. At each sampling age,
between 8 and 10 infants comprise the final data set. Some of the
infants were available for repeated filming (n=4 for all sessions),
whereas others were filmed at only a few time points. There were
no obvious differences in the data obtained from infants that were
repeatedly filmed and those that were filmed only once. The sam-
ples were taken as close as possible to the 2 week interval markers
(i.e., when the infant was exactly 2 weeks old, 4 weeks old, etc.) as
long as the infants were alert during these recordings.
SCORING
The actions of both hands were coded separately. Because no
differences in the frequencies of the types of movements were
found between the two hands, the results from the two hands
were combined for analyses. The infants made a large number
of arm and hand movements during the recording sessions, but
only punctuate contacts by the hand with the body were subject
to analysis. Hand contacts were classified according to contact
location (Rostral or Caudal body contacts) and hand posture
(Dorsum, Palmar, or Grasp contacts).
1. Rostral vs. Caudal Body Contacts. Rostral contacts
(Figures 1A,B) were any self-contacts by a hand to the head,
trunk, arm, or other hand. Caudal contacts (Figures 1C,D)
were any self-contacts by a hand to the hips, upper leg, lower
leg, or feet.
2. Dorsum vs. Palmar. Dorsum contacts (Figures 2A,B)wereany
self-contact with the dorsal aspect of the hand, including the
back of the digits or the sides of the hand. Hand shapes could
include a fist shape, a semi-closed hand with the thumb often
tucked under or over the fingers, or an open hand. Palmar
contacts (Figures 2C,D) were any self-contact with the Palmar
aspect of the hand, including the fingertips, the palm, or the
ventral sides of the hand. Hand shapes could include a partially
open hand in which only the Palmar digit tips were in contact,
or a more open hand in which the digits, palm, or digits and
palm were in contact.
3. Grasp contacts. Grasp contacts (Figures 2E,F)weredenedas
the closing of one or more of the digits around the infant’s
body or clothing (Wallace and Whishaw, 2003). These Grasps
included pre-precision grasps, in which only one or a few digits
were involved in grasping, and whole hand Grasps, in which
FIGURE 1 | Location of body contact. Left. Rostral contact on (A) the
head, (B) the trunk. Right: Caudal contact on (C) leg and (D) foot.
all digits were involved. A note was also made with respect to
whether a grasped target was manipulated after grasping.
For each sampling period for each infant, the first 40 instances
of self-touching behavior were documented, irrespective of which
hand was used. The duration of the positioning of each hand
movement was not noted, but most contacts were discrete in that
the contact was broken shortly after it was made. One investiga-
tor (BLT) scored all of the behavior while two other investigators
(JMK, LAL) scored samples of behavior in order to establish rater
reliability. Inter-rater reliability for whether the hand contacted
the body, whether contact was Rostral or Caudal, and whether
contact was Dorsum, Palmar, or Grasp exceeded 95% agreement
between the raters.
STATISTICAL ANALYSIS
The frequency of body contacts and hand posture contacts, as a
function of infant age, were subject to statistical analyses using the
computer program SPSS (v. 21.0.0.0). To accommodate uneven
data points across infants, results were evaluated using repeated-
measures mixed linear models (MLM; Verbeke, 2009; Heck et al.,
2014). Age (0, 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 weeks) served
as the within-subjects factor. A p-value of 0.05 was considered
significant.
RESULTS
From birth through 6 months of age, infants displayed many
spontaneous contacts of the hands with the body. The ethogram
in Figure 3 illustrates a sample of the hand shapes/body loca-
tion for the first 10 contacts made by infants at three different
www.frontiersin.org January 2015 | Volume 5 | Article 1526 |3
Thomas et al. Development of infant self-contacts
FIGURE 2 | Hand posture during contact with the body. Left: Dorsum
contacts, (A) contact with the back of the digits with the hand closed, (B)
contact with the back of the digits with the hand semiclosed. Middle: Palmar
contact, (C) contact with the digit pads and partially open hand, (D) contact
with the fully open hand. Right: Grasp contacts, (E) pre-precision grasp
between the thumb and side of the index finger, (F) wholehandgrasp.
FIGURE 3 | Sample coding of the ethogram illustrating some of
the hand shapes/body location of the first 10 contacts made
by one infant at three different ages (1, 3, and 6 months).
(1) Hand: R, right; L, left; (2) Hand Shape: C, closed; SC,
semi-closed; FT, fingertips; O, open; (3) Location: H, head; T, torso;
Le, legs; F, feet.
ages. Note that these samples were collected in an average of
21 s of observation time at each age (10–39 s). There was no evi-
dence for differences in the location or hand posture of contacts
according to hand or sex. Thus, sex and hand were compiled in
the results. Infants ages 20, 22, and 24 weeks were also combined
for this analysis, as behavioral results were asymptotic for these
ages. Overall, the results show that there is a developmental transi-
tion from Rostral to Caudal contacts, a developmental transition
from Dorsum to Palmar contacts, and a developmental point at
approximately 16 weeks of age at which infants show an increased
proportion of Grasp contacts.
ROSTRAL vs. CAUDAL BODY CONTACTS
Figure 4 illustrates the percent of hand-to-body contacts to the
Caudal portions of the body (legs and feet) as a function of
age (Video 1). In the earliest weeks, the infants mainly made
contacts to the Rostral region of the body, including the head,
torso, arms and hands. Rostral hand-to-body contacts were
restricted to the areas of the body within immediate proxim-
ityofthehand.Andso,foranarmthatwaslargelyflexed
at the elbow, contact was made with the head or torso. At
approximately 12 weeks of age onwards, increased numbers of
contacts were made with Caudal regions of the body (includ-
ing the hips, legs and eventually the feet). Caudal hand-to-body
contacts began with contacts to the hips and upper thighs, and
expanded toward the knees and feet at approximately 20 weeks
of age. Hand-to-body contacts with the knees and feet fre-
quently involved bending of the knees and bringing the feet up
toward the torso, especially when the infant was lying on his or
her back.
Frontiers in Psychology | Developmental Psychology January 2015 | Volume 5 | Article 1526 |4
Thomas et al. Development of infant self-contacts
FIGURE 4 | Caudal body contacts. Percent (mean and standard error) of
contacts with the hand on the Caudal portions of the body (legs and feet)
relative to all contacts as a function of age.
In sum, Caudal contacts began to occur with increasing fre-
quency at approximately 14 weeks of age, progressing from con-
tacts with the head and trunk to contacts with the hips, legs, and
feet. Thus, as a proportion of all body contacts, Caudal contacts
increased as a function of age as indicated by a repeated measures
MLM for Caudal contacts that gave a significant effect of Age
[F(10,13.037) =5.633, p<0.01]. Post-hoc comparisons revealed
that, compared to 0 weeks of age, the percentage of Caudal con-
tacts was significantly increased at 14 (p<0.05), 16 (p<0.05),
18 (p<0.01), and 20+ (p<0.001) weeks of age.
DORSUM vs. PALMAR CONTACTS
Figure 5 illustrates the percent of Palmar contacts as a func-
tion of age. In the earlier weeks, the infants mainly contacted
the body using the Dorsum of the hand, with a high frequency
of self-contacts made with a fist, progressing to Dorsum con-
tacts with a semi-closed hand, including contacts with the back
of the fingers and the side of the hand. Duration of hand-to-
body contact length was brief, marked mainly by contact and
release (Video 2). At 8–12 weeks, hand-to-body contacts become
increasingly exploratory with increased contact duration, digit
manipulation, and movement. By 12 weeks Hand-to-body con-
tacts were increasingly made with the Palmar aspect of the hand
and became more complex, often involving rotation of the hand
at contact, dragging the palm or fingertips along the surface of the
body, and dynamic and complex hand shaping sequences.
In sum, Palmar contacts began to occur with increasing fre-
quency at approximately 12 weeks of age, progressing from con-
tacts with the pads of the fingertips, to dynamic contacts with the
open palm. As a proportion of all body contacts, Palmar con-
tacts increased as a function of age as indicated by a repeated
FIGURE 5 | Palmar body contacts. Percent (mean and standard error) of
Palmar contacts (contact with the digit pads or palm) relative to all contacts
as a function of age.
MLM for Palmar contacts that gave a significant effect of Age
[F(10,20.125) =7.092, p<0.001]. Post-hoc comparisons revealed
that, compared to 0 weeks of age, the percentage of Palmar
contacts was significantly increased at 12 (p<0.05), 14 (p<
0.05), 16 (p<0.001), 18 (p<0.001), and 20+ (p<0.001) weeks
of age.
GRASP CONTACTS
Figure 6 illustrates that the incidence of Grasps as a percentage
of all hand contacts was low in infants aged 0–14 weeks and
then increased at 16–20 weeks. The self-directed preGrasps that
occurred within the first week of infancy continued to occur at
a relatively low frequency across the 24 weeks of study whereas
whole hand Grasps became prominent at 16 weeks of age. As a
proportion of all body contacts, Grasp contacts increased as a
function of age as indicated by a repeated MLM for Grasp con-
tacts that gave a significant effect of Age [F(10,10.547) =3.935,
p<0.05]. Post-hoc comparisons revealed that, compared to 0
weeks of age, the percentage of Grasp contacts was significantly
increased at 16 (p<0.05), 18 (p<0.05), and 20+(p<0.05)
weeks of age.
DEVELOPMENTAL PATTERNS
Normalized regression curves for Caudal, Palmar, and Grasp
contacts are shown in Figure 7. Spearman’s correlations gave a
significant Caudal vs. Palmar Rho =0.806 (p=0.005), a signif-
icant Palmar vs. Grasp Rho =0.770 (p=0.009), but no Caudal
vs. Grasp Rho =0.503 (p=0.138). The regression curves suggest
that increases in Caudal and Palmar contacts are of a comparable
magnitude and follow a similar developmental time course. By
contrast, the regression curve for Grasps is reduced and shifted to
www.frontiersin.org January 2015 | Volume 5 | Article 1526 |5
Thomas et al. Development of infant self-contacts
FIGURE 6 | Grasp body contacts. Percent (mean and standard error) of
Grasp contacts (pre-precision or whole hand) relative to all contacts as a
functions of age.
the right, indicating that the incidence of Grasps did not become
prominent until somewhat later. These relations are also reflected
by follow-up tests described in the Dorsum-Palmer, Rostral-
Caudal, and Grasp sections above. The significant relationship
between Grasp and Palmar is likely due to the fact that a Grasp
is dependent upon a Palmar contact.
DISCUSSION
Therearetwonovelcontributionsofthisstudy.First,itwasfound
that otherwise resting infants in the first 6 months of life made
many, almost continuous, forelimb movements that resulted in
hand contacts with the body. These contacts eventually included
grasping and manipulating the body and clothes in all regions of
the body. Thus, self-touching behavior in infants is revealed to be
a behavior in which infants can practice reaching, and perhaps
additionally acquire body awareness in relation to a hand-related
schema. Second, the analysis of self-touching movements suggests
that advancing the hand to different body targets and contacting
the body with the digit tips and palm represent an early devel-
opmental phase of the Reach whereas grasping the body and
clothes and performing manipulatory movements represent an
early phase of the Grasp. Because Reach activities developmentally
preceded Grasp activities, the results suggest some independence
of the two movements. Taken together with previous work show-
ing that infants do not need to view their own hand in order
to transport it to a target (Clifton et al., 1993; Corbetta, 2010),
the timing and the sophistication of hand contacts with the body
observed in the present study suggest that reaching undergoes
substantial preparedness under the auspices of proprioception
and touch prior to and in concert with the emergence of visually
guided reaching.
FIGURE 7 | First order polynomial regression illustrating the
developmental profile of hand-to-body Palmar contacts, contacts to
the Caudal region of the body, and Grasps. Note the differences
between Palmar/Caudal contacts and Grasps.
It is important to note that the present study was primarily
directed toward describing self-touching hand movements and
secondarily at assessing the idea that during development there
is some independence in the display of reaching and grasping
movements as has been suggested in studies largely directed
toward visually guided reaching (Von Hofsten and Lindhagen,
1979; Trevarathen, 1982; von Hofsten, 1984; Savelsbergh and van
der Kamp, 1994; Wimmers et al., 1998a,b). Thus, although it is
obvious that the spontaneous activity that we have observed is
likely the result of interactions between nervous system devel-
opment, morphological development of the body, the posture of
the infants during testing, and the life history of the experimen-
tal subjects (Savelsbergh and van der Kamp, 1994; Thelen and
Spencer, 1998; Heathcock et al., 2004; Lobo et al., 2014; Soska
and Adolph, 2014), there was no intent in the present study to
distinguish between these contributing factors. Rather, it was our
view that any differences in the developmental profile of reaching
and grasping might contribute to a growing body of evidence that
the Reach and the Grasp are mediated by different sensorimo-
tor channels (for a review of other infant work directed toward
this question see Karl and Whishaw, 2014). As noted by Hebb
Frontiers in Psychology | Developmental Psychology January 2015 | Volume 5 | Article 1526 |6
Thomas et al. Development of infant self-contacts
(1949) “The problem of understanding behavior is the problem
of understanding the total nervous system and visa versa (xiv).”
Specifically, three aspects of hand-to-body contact were docu-
mented in relation to infant age: an increasing incidence of caudal
body relative to rostral body contacts, an increasing incidence
of palmar relative to dorsum hand contacts, and an increasing
incidence of contacts that resulted in Grasps of the body and
clothes. An increase in the incidence of palmar and caudal con-
tacts occurred at a somewhat earlier age than did the increase in
the incidence of Grasps. Because the Reach in adults is associated
with forelimb movement and a more open hand to make palmar
contact with a target, we suggest that the forelimb movement and
palmar contact in infants is a manifestation of an infant Reach.
Because the Grasp in adults includes digit flexion and closing to
purchase and manipulate an object, we suggest that self-grasping
in infants is an early manifestation of an infant Grasp. Thus, we
suggest that the developmental pattern of these Reach and Grasp
movements in infants supports the Dual Visuomotor Channel
Theory, which proposes that the reaching act is enabled by sep-
arate Reach and Grasp neural systems. Of course, morphological
development including increases in the length of the arms, the size
of the hands, and body strength in all likelihood are also necessary
for some part of the maturation of the movements. Nevertheless,
the hand to body self-touching movements seen in the infants
likely continue throughout life and likely continue to serve some
of the same purposes in adults that they serve in infancy.
The design of the present experiment is similar to that of a
number of our previous studies in that it is ethological, focuses
on infant spontaneity, and searches for structural organization
within this activity. It also featured a number of procedures
to ensure accurate measurement of spontaneous hand-to-body
contacts in infants (Wallace and Whishaw, 2003; Sacrey and
Whishaw, 2010; Foroud and Whishaw, 2012). First, toys and other
distractions were removed to ensure that self-directed movements
were unbiased by extraneous influences. Second, to control for
individual differences in the frequency of hand-to-body contacts,
40 consecutive contacts within each 10-min recording period
were used for analysis. Third, high inter-rater reliability scores
among 3 independent raters on the main behaviors that were
measured confirmed the validity of the scoring method. These
procedures ensured that the infants were similarly relaxed and
alert and otherwise not disturbed and so were likely to engage
in a common class of relatively spontaneous activities across the
study period.
In many respects, this work differs from the more formal stud-
ies of visually guided reaching in which both the task and the
outcome are constrained. For example, in the Wimmers studies
(Wimmers et al., 1998a,b), described in the introduction, infants
are encouraged to purchase a proffered object, resulting in seem-
ingly age-related dichotomous behavior, reaching without grasp-
ing followed by reaching with grasping. Spontaneous self-directed
movements of the hand described here also reflect a developmen-
tal profile in which the Reach matures before the Grasp, but one
behavior does not completely replace the other. The spontaneous
manual interaction with objects when documented in a etho-
logical context also suggests that reaching without grasping and
reaching with grasping co-occur (Lobo et al., 2014). Although
the present study was not directed at examining how reaching
and grasping occur, work with older infants suggests that there
is a very prolonged developmental period, likely lasting beyond 2
years of age, in which the Reach and Grasp are not yet fully mature
and not yet fully integrated (Karl and Whishaw, 2014). Further
work using high speed filming of infant self-grasping could be
used to examine the detailed architecture of the Reach and the
Grasp in self-grasping because it might be expected that online
somatosensory guidance of reaching matures before the online
visual guidance of reaching (Karl et al., 2012b).
A number of caveats in relation to the present methods must be
noted. First, infants were filmed in a variety of settings including
the home and laboratory, the time of day during which filming
occurred was variable, and the postures of the infants did vary
somewhat depending upon their age, and all infants could not be
filmed at every age. It might be considered, however, that such
variation strengthens the ethological relevance of the sampling
method. Second, infants were usually clothed and so it was not
possible to confirm that similar hand-to-body behavior would be
demonstrated in the absence of clothing. For example, the pres-
ence of clothing might serve to encourage grasping behavior. It
was noted, however, that there were no obvious differences in
the behavior of infants for whom clothes were tight fitting versus
loose fitting. Third, the sampling periods were limited to resting
behavior and did not include other activities, including breast or
bottle feeding or interpersonal play, which could provide addi-
tional information concerning the development of hand contacts
to the self and proximal objects. In addition, the infants’ sponta-
neous activity included many other activities such as movements
of the head, trunk, and legs and these activities were not docu-
mented. Nevertheless, the high number of hand-to-body contacts
that occurred in each infant and the systematic changes in the
location and way that the hand contacted the body across the
developmental period examined suggests that this data sample is
sufficiently robust to provide insights into an activity that must
occur in infants many hundreds of times each day.
There are a number of features of the present results that
we feel justify concluding that they reveal a novel insight into
the developmental progression of reaching behavior and its rela-
tion to the distinctive Reach and Grasp movements of adults as
characterized by the Dual Visuomotor Channel Theory. First,
studies that have manipulated the visual contribution to reach-
ing show that without vision the Reach consists of a movement
ofextendingthearmandhandwithopendigitsinordertomake
palmar contact with a target (Karl et al., 2012a; Karl and Whishaw,
2013). We suggest that in infants, the development of hand-to-
body contacts from rostral to caudal body locations associated
with the increasing frequency of opening the hand to make pal-
mar contacts might be a developmental precursor of the adult
manifestation of the Reach. That is, in the initial weeks of the
samples, arm movements were largely movements around the
shoulders with the digits in a mainly closed configuration (Sacrey
and Whishaw, 2010) that resulted in incidental hand to body con-
tact. Eventually, the arm movements included movements of the
trunk and all of the forelimb joints, including extension of the
digits. In doing so, they included palmar contact that began to
have an exploratory character and that increasingly included the
www.frontiersin.org January 2015 | Volume 5 | Article 1526 |7
Thomas et al. Development of infant self-contacts
caudal regions of the body. The movements also became coordi-
nated with other body movements as exemplified by reaches that
contacted the feet and toes that were themselves in motion. It is
also noteworthy in this respect that regression profiles of touches
on caudal body locations and the use of palmar contacts were very
similar. Thus, in their eventual configuration, infant reaches to
touch the body resembled the Reach made by unsighted adults in
that the arm carries an open hand to make a palmar contact with
a target.
It is interesting that Pellijeff et al. (2006) show that reaches
made by adults to their own hand, located near their own torso,
are associated with fMRI activation in the cortical area of the
anterior precuneus and medial intraparietal sulcus in the superior
parietal lobe. This is the same region that is activated for both pro-
prioceptively and visually guided reaching toward external objects
(Filimon et al., 2009). Therefore, we suggest that infant reaches
toward the torso and body are analogous to adult reaching to dis-
tal targets, adding support to our suggestion that caudal directed
reaches and touches serve as a developmental precursor/addition
to reaching to visual targets.
We were, of course, unable to determine the extent to which
reaches to various body parts were vacuous versus goal directed
but we propose that the scope and frequency of the movements
provides ample room for arm movements to mature both in
their configuration (von Hofsten, 1984) and intent (Lew and
Butterworth, 1997). We note that after palmar contacts begin
to occur they also begin to take on an exploratory character
in frequently caressing the part of the body that is contacted.
As such, the practice/development of these movements made to
body targets might well be preparatory/facilitatory for reaches
that will subsequently be directed to targets during visually guided
reaching (White et al., 1964; McDonnell, 1975; von Hofsten
and Fazel-Zandy, 1984; von Hofsten and Ronnqvist, 1988; Lobo
et al., 2004; Lobo and Galloway, 2013). In the present study, we
observed few movements directed toward the mouth, and accord-
ingly did not separately document them, but other research has
found that these movements only become frequent after about 4
months of age, an observation consistent with the present results
that it is at about this age that hand movements are becoming goal
directed (Lew and Butterworth, 1997; Sacrey et al., 2012).
According to the Dual Visuomotor Channel Theory, the Grasp
preshapes the digits relative to target size and adjusts the digits
for appropriate target purchase (Arbib, 1981). In the absence of
vision, shaping and grasping are instructed by haptic informa-
tion provided by touch (Karl et al., 2012a; Karl and Whishaw,
2013). In the infants examined in the present study, the first
grasps featured hooking one or another digit into the clothing,
they then involved clasping with the thumb or other digits, and
by the end of the observational period they featured whole hand
grasps that included manipulation. We suggest that this pattern
features a progression in “maturation and learning to grasp.” Our
observations and interpretation are consistent with an extensive
literature on infant and fetal hand use (Twitchell, 1965; Hepper,
1990; Hepper et al., 1991; Sparling and Wilhelm, 1993; Sparling
et al., 1999). Nevertheless, prior to the various grasping acts, there
was no obvious shaping of the digits prior to target contact nor
was obvious hand shaping present between successive contacts.
The absence of digit preshaping is not surprising because evidence
from studies on the development of visually guided reaching sug-
gests that hand preshaping continues to mature beyond 2 years of
age (McCarty et al., 2001; Karl and Whishaw, 2014).
Evidence that grasping movements have a partially different
developmental onset than reaching movements was supported by
our finding that the developmental profile of grasping frequency
was statistically unrelated to the Rostrocaudal profile of body con-
tact and was only somewhat weakly related to the Dorsopalmar
profile of hand contact, which were themselves tightly coupled.
That is, the onset of frequent self-grasping occurred at a some-
what later age than the onset of frequent caudal body contacts
and palmar contacts. We suggest that this difference provides
further support for the idea that the Reach and the Grasp have
different developmental onset. That is, our results suggest that
the Reach, consisting of an ability to move the hand to a body
target with the digits open to make a Palmar contact with the
target, is achieved before the hand begins to engage in substan-
tial object purchase, which characterizes the Grasp. Of course,
the movements are not completely unrelated because a Reach
with Palmar contact necessarily precedes a Grasp. Nevertheless,
it is interesting that an examination of the early development
of visually guided reaching similarly suggests that Reach matu-
ration precedes Grasp maturation (Karl and Whishaw, 2014;see
also Von Hofsten and Lindhagen, 1979; Trevarathen, 1982; von
Hofsten, 1984; von Hofsten and Fazel-Zandy, 1984; Ruff, 1989;
Savelsbergh and van der Kamp, 1994; Wimmers et al., 1998a,b;
Corbetta and Snapp-Childs, 2009).
In previous work, we have suggested that the Reach and the
Grasp have different evolutionary origins, the Reach derived from
stepping and the Grasp derived from food handling movements
(Karl and Whishaw, 2013). In light of this suggestion, the present
findings might seem surprising because the development of self-
touching Reach and Grasp movements occur both before the
onset of walking (crawling) and the onset of hand use for self-
feeding. In humans, however, self-feeding and walking are devel-
opmentally delayed. It is possible that the many leg movements
associated with self-directed reaches to the caudal body are a
developmental precursor for walking and may facilitate the devel-
opment or refinement of neural circuitry in the superior parietal
lobe that is common to both stepping and reaching (Bakola et al.,
2010, 2013; Karl and Whishaw, 2013). Although leg movements
were not analyzed in the present study, the relationship between
arm movement and leg movement could be addressed by exam-
ining their relationship in human infants as well as their early
development in other animal species, especially other primate
species (e.g., Wallace et al., 2006). Similarly, hand movements in
infants are often associated with mouth movements (Iverson and
Thelen, 1999). It is possible that the species-typical developmen-
tal profile of humans results in suppression and reordering of the
development of many movements (Schott and Rossor, 2003).
Speculatively, the present results could be related to the Dual
Visuomotor Channel Theory in other ways, including the estab-
lishment of body spatial schema and hand action schema related
to objects (Granmo et al., 2008; Yamada et al., 2013). In this
respect it is relevant that the Reach is importantly directed to
the extrinsic (e.g., location) properties of targets using egocentric
Frontiers in Psychology | Developmental Psychology January 2015 | Volume 5 | Article 1526 |8
Thomas et al. Development of infant self-contacts
coordinates provided by proprioception. Early prereach activity
associated with self-touching could contribute to the develop-
ment of egocentric coordinate systems. It is also relevant that
the Grasp is importantly guided by the intrinsic properties (size,
shape, etc.) of a target. Infant self-grasping acts could contribute
to the development of a hand schema that provides an apprecia-
tion for the intrinsic properties of objects. Because both the body
and hands are undergoing continuous morphological change
(Newell et al., 1989, 1993), the high incidence of self-touching and
grasping could contribute to updating hand and body schema.
In summary, developmental research presupposes that devel-
oping actions are the foundation for more complex adult behav-
ior (Lobo and Galloway, 2008) and that development frequently
has a proximodistal progression (Berthier et al., 1999). Although
numerous hand-to-body contact behaviors and hand manipula-
tive capabilities have been observed in development, including in
fetal development (Hepper, 1990; Hepper et al., 1991; Sparling
and Wilhelm, 1993; Sparling et al., 1999), the present results
are consistent with these general sequences and also offer two
new insights into the development of reaching. First, we suggest
that hand-to-body contact is a formative stage in the develop-
ment of the adult Reach. It is likely that the maturation of self-
contact movements into self-grasping movements is an important
preparatory stage for the development of the adult Grasp. Second,
we suggest that the early development of arm movement and
hand touching compared to the later development of the pat-
tern of self- grasping and manipulation provide evidence that the
Reach and the Grasp have at least partially separate developmen-
tal profiles. Finally, we suggest that the development of the Reach
and the Grasp and their integration is importantly related to prac-
tice provided by the high incidence and changing patterns of hand
self-contact behavior.
ACKNOWLEDGMENTS
The authors would like to thank Patricia Wallace, Lori-Ann
Sacrey, and Afra Foroud for their assistance with data gather-
ing and compilation, as well as Layne Lenhart and Jessica Kuntz
for their assistance with data scoring and analysis. This research
was supported by the Natural Sciences and Engineering Research
Council of Canada (Jenni M. Karl, Ian Q. Whishaw) and Alberta
Innovates—Health Solutions (Jenni M. Karl).
SUPPLEMENTARY MATERIAL
The Supplementary Material for this article can be found online
at: http://www.frontiersin.org/journal/10.3389/fpsyg.2014.
01526/abstract
REFERENCES
Arbib, M. A. (1981). “Perceptual structures and distributed motor control,” in
Handbook of Physiology, Section 1, Vol. 2, Part 2, ed V. B. Brooks (Bethesda,
MD: American Physiological Society), 1449–1480.
Bakola, S., Gamberini, M., Passarelli, L., Fattori, P., and Galletti, C. (2010). Cortical
connections of parietal field PEc in the macaque: linking vision and somatic
sensation for the control of limb action. Cereb. Cortex 20, 2592–2604. doi:
10.1093/cercor/bhq007
Bakola, S., Passarelli, L., Gamberini, M., Fattori, P., and Galletti, C. (2013).
Cortical connectivity suggests a role in limb coordination for macaque
area PE of the superior parietal cortex. J. Neurosci. 33, 6648–6658. doi:
10.1523/JNEUROSCI.4685-12.2013
Berthier, N. E., Clifton, R. K., McCall, D. D., and Robin, D. J. (1999). Proximodistal
structure of early reaching in human infants. Exp. Brain Res. 127, 259–269. doi:
10.1007/s002210050795
Cavina-Pratesi, C., Ietswaart, M., Humphreys, G. W., Lestou, V., and Milner, A. D.
(2010). Impaired grasping in a patient with optic ataxia: primary visuomotor
deficit or secondary consequence of misreaching? Neurop sychol ogia 48, 226–234.
doi: 10.1016/j.neuropsychologia.2009.09.008
Clifton, R. K., Muir, D. W., Ashmead, D. H., and Clarkson, M. G. (1993). Is visu-
ally guided reaching in early infancy a myth? Child Dev. 64, 1099–1110. doi:
10.2307/1131328
Corbetta, D. (2010). “Perceptual development: visually guided reaching,” in
Encyclopedia of Perception, ed B. Goldstein (Thousand Oaks, CA: SAGE
Publications), 772–775.
Corbetta, D., Thurman, S. L., Wiener, R. F., Guan, Y., and Williams, J. L. (2014).
Mapping the feel of the arm with the sight of the object: on the embodied origins
of infant reaching. Front. Psychol. 5, 1–18. doi: 10.389/fpsyg.2014.00576
Corbetta, D., and Snapp-Childs, W. (2009). Seeing and touching: the role of
sensory-motor experience on the development of infant reaching. Infant. Behav.
Dev. 32, 44–58. doi: 10.1016/j.infbeh.2008.10.004
Culham, J. C., and Valyear, K. F. (2006). Human parietal cortex in action. Cur r.
Opin. Neurobiol. 16, 205–212. doi: 10.1016/j.conb.2006.03.005
de Bruin, N., Sacrey, L. A., Brown, L. A., Doan, J., and Whishaw, I. Q. (2008). Visual
guidance for hand advance but not hand withdrawal in a Reach-to-eat task in
adult humans: reaching is a composite movement. J. Motor. Behav. 40, 337–346.
doi: 10.3200/jmbr.40.4.337-346
Dijkerman, H. C., and de Haan, E. H. (2007). Somatosensory processes
subserving perception and action. Behav. Brain Sci. 30, 189–201. doi:
10.1017/s0140525x07001392
Fiehler, K., Burke, M., Bien, S., Roder, B., and Rosler, F. (2009). The human dorsal
action control system develops in the absence of vision. Cereb. Cortex 19, 1–12.
doi: 10.1093/cercor/bhn067
Fiehler, K., and Rösler, F. (2010). Plasticity of multisensory dorsal stream functions:
evidence from congenitally blind and sighted adults. Restor. Neurol.Neurosci. 28,
193–205. doi: 10.3233/rnn-2010-0500
Filimon, F., Nelson, J. D., Huang, R. S., and Sereno, M. I. (2009). Multiple
parietal reach regions in humans: cortical representations for visual and pro-
prioceptive feedback during on-line reaching. J. Neurosci. 29, 2961–2971. doi:
10.1523/JNEUROSCI.3211-08.2009
Filimon, F. (2010). Human cortical control of hand movements: parietofrontal net-
works for reaching, grasping, and pointing. Neuroscientist 16, 388–407. doi:
10.1177/1073858410375468
Foroud, A., and Whishaw, I. Q. (2012). The consummatory origins of visu-
ally guided Reaching in human infants: a dynamic integration of whole-
body and upper-limb movements. Behav. Brain Res. 231, 343–355. doi:
10.1016/j.bbr.2012.01.045
Granmo, M., Petersson, P., and Schouenborg, J. (2008). Action-based body maps in
thespinalcordemergefromatransitoryfloatingorganization.J. Neurosci. 28,
5494–5503. doi: 10.1523/JNEUROSCI.0651-08.2008
Greenman, G. W. (1963). “Visual behavior of newborn infants,” in Modern
Perspectives in Child Dev, eds A. J. Solnit and S. A. Provence (New York, NY:
Hallmark), 75–79.
Hall, L. A., Karl, J. M., Thomas, B. L., and Whishaw, I. Q. (2014). Reach and Grasp
reconfigurations reveal that proprioception assists reaching and hapsis assists
grasping in peripheral vision. Exp. Brain Res. 232, 2807–2819. doi: 10.1007/
s00221-014-3945-6
Heathcock, J. C., Bhat, A. N., Lobo, M. A., and Galloway, J. C. (2004). The perfor-
mance of infants born preterm and full-term in the mobile paradigm: learning
and memory. Phys Ther. 84, 808–821.
Hebb, D. O. (1949). The Organization of Behaviour.NewYork,NY:JohnWiley&
Sons.
Heck, R. H., Thomas, S. L., and Tabata, L. N. (2014). “Examining individual change
with repeated measures data,” in Multilevel and Longitudinal Modeling with IBM
SPSS,2nd Edn. (New York, NY: Routledge), 167–238.
Hepper, P. G. (1990). Diagnosing handicap using the behaviour of the fetus.
Midwifery 6, 193–200. doi: 10.1016/S0266-6138(05)80114-7
Hepper, P. G., Shahidullah, S., and White, R. (1991). Handedness in the human
fetus. Neuro psychologia 29, 1107–1111. doi: 10.1016/0028-3932(91)90080-r
Iverson, J., and Thelen, E. (1999). Hand, mouth, and brain: the dynamic emergence
of speech and gesture. J. Conscious. Stud. 6, 19–40.
www.frontiersin.org January 2015 | Volume 5 | Article 1526 |9
Thomas et al. Development of infant self-contacts
Jeannerod, M. (1981). “Intersegmental coordination during Reaching at natural
visual objects,” in Attention and Performance IX, eds J. Long and A. Baddeley
(Hillsdale, NJ: Lawrence Erlbaum Associates), 153–169.
Jeannerod, M. (1999). Visuomotor channels: their integration in goal-directed
prehension. Hum. Mov. Sci. 18, 201–218. doi: 10.1016/s0167-9457(99)00008-1
Karl, J. M., Sacrey, L. R., Doan, J. B., and Whishaw, I. Q. (2012a). Hand shaping
using hapsis resembles visually guided hand shaping. Exp. Brain Res. 219, 59–74.
doi: 10.1007/s00221-012-3067-y
Karl, J. M., Sacrey, L. R., Doan, J. B., and Whishaw, I. Q. (2012b). Oral hapsis guides
accurate hand preshaping for grasping food targets in the mouth. Exp. Brain Res.
221, 223–240. doi: 10.1007/s00221-012-3164-y
Karl, J. M., and Whishaw, I. Q. (2013). Different evolutionary origins for the
Reach and the Grasp: an explanation for dual visuomotor channels in primate
parietofrontal cortex. Front. Neurol. 4:208. doi: 10.3389/fneur.2013.00208
Karl, J. M., and Whishaw, I. Q. (2014). Haptic Grasping configurations in early
infancy reveal different developmental profiles for visual guidance of the Reach
versus the Grasp. Exp. Brain Res. 232, 3301–3316. doi: 10.1007/s00221-014-
4013-y
Kremenitzer, J. P., Vaughan, H. G., Kurtzberg, D., and Dowling, K. (1979). Smooth-
pursuit eye movements in the newborn infant. Child Dev. 50, 442–448. doi:
10.2307/1129421
Lew, A. R., and Butterworth, G. (1997). The development of hand-mouth coor-
dination in 2- to 5-month-old infants: similarities with reaching and grasping.
Infant. Behav. Dev. 20, 59–69. doi: 10.1016/s0163-6383(97)90061-8
Lobo, M. A., and Galloway, J. C. (2008). Postural and object-oriented experiences
advance early reaching, object exploration and means-end behavior. Child Dev.
79, 1869–1890. doi: 10.1111/j.1467-8624.2008.01231.x
Lobo, M. A., and Galloway, J. C. (2013). The onset of reaching significantly impacts
how infants explore both objects and their bodies. Infant. Behav.D ev. 36, 14–24.
doi: 10.1016/j.infbeh.2012.09.003
Lobo, M. A., Galloway, J. C., and Savelsbergh, G. J. P. (2004). General and task-
related experiences affect early object interaction. Child Dev. 75, 1268–1281.
doi: 10.1111/j.1467-8624.2004.00738.x
Lobo, M. A., Kokkoni, E., de Campos, A. C., and Galloway, J. C. (2014).
Not just playing around: infants’ behaviors with objects reflect ability,
constraints, and object properties. Infant. Behav. Dev. 37, 334–351. doi:
10.1016/j.infbeh.2014.05.003
Lockman, J. L., Ashmead, D. H., and Rushnell, E. W. (1984). The development of
anticipatory hand orientation during infancy. J. Exp. Child Psychol. 37, 176–186.
doi: 10.1016/0022-0965(84)90065-1
McCarty, M. E., Clifton, R. K., Ashmead, D. H., Lee, P., and Goubet, N. (2001).
How infants use vision for grasping objects. Child Dev. 72, 973–987. doi:
10.1111/1467-8624.00329
McDonnell, P. M. (1975). The development of visually guided reaching. Perce pt.
Psychophys. 18, 181–185. doi: 10.3758/BF03205963
Myowa-Yamakoshi, M., and Takeshita, H. (2006). Do human fetuses anticipate self-
oriented actions? A study by four-dimensional (4D) ultrasonography. Infancy
10, 289–301. doi: 10.1207/s15327078in1003_5
Newell, K. M., McDonald, P. V., and Baillargeon, R. (1993). Body scale and infant
grip configurations. Dev. Psychol. 26, 195–205. doi: 10.1002/dev.420260403
Newell, K. M., Scully, D. M., McDonald, P. V., and Baillargeon, R. (1989). Task
constraints and infant grip configurations. Dev. Psychobiol. 22, 817–831. doi:
10.1002/dev.420220806
Pellijeff, A., Bonilha, L., Morgan, P. S., McKenzie, K., and Jackson, S. R.
(2006). Parietal updating of limb posture: an event-related fMRI study.
Neuro psychologia 44, 2685–2690. doi: 10.1016/j.neuropsychologia.2006.01.009
Rizzolatti, G., Luppino, G., and Matelli, M. (1998). The organization of the cor-
tical motor system: new concepts. Electroencephalogr. Clin Neurophysiol. 106,
283–296. doi: 10.1016/s0013-4694(98)00022-4
Ruff, H. A. (1989). The infant’s use of visual and haptic information in the
perception and recognition of objects. Can. J. Psychol. 43, 302–319. doi:
10.1037/h0084222
Sacrey, L. R., Karl, J. M., and Whishaw, I. Q. (2012). Development of rotational
movements, hand shaping, and accuracy in advance and withdrawal for the
Reach-to-eat movements in human infants aged 6-12 months. Infant. Behav.
Dev. 35, 543–560. doi: 10.1016/j.infbeh.2012.05.006
Sacrey, L. R., and Whishaw, I. Q. (2010). Development of collection precedes tar-
geted reaching: resting shapes of the hands and digits in 1-6-month-old human
infants. Behav. Brain Res. 214, 125–129. doi: 10.1016/j.bbr.2010.04.052
Sacrey, L. R., and Whishaw, I. Q. (2012). Subsystems of sensory attention for
skilled Reaching: vision for transport and pre-shaping and somatosensation
for Grasping, withdrawal and release. Behav. Brain Res. 231, 356–365. doi:
10.1016/j.bbr.2011.07.031
Savelsbergh, G. J., and van der Kamp, J. (1994). The effect of body orientation
to gravity on early infant reaching. J. Exp. Child Psychol. 58, 510–528. doi:
10.1006/jecp.1994.1047
Schott, J. M., and Rossor, M. N. (2003). The grasp and other primitive reflexes. J.
Neurol. Neurosurg. Psychiatry 74, 558–560. doi: 10.1136/jnnp.74.5.558
Soska, K. C., and Adolph, K. E., Infancy. (2014). Postural position con-
strains multimodal object exploration in infants. Infancy 19, 138–161. doi:
10.1111/infa.12039
Sparling, J. W., Van Tol, J., and Chescheir, N. C. (1999). Fetal and neonatal hand
movement. Phys Ther. 79, 24–39.
Sparling, J. W., and Wilhelm, I. J. (1993). Quantitative measurement of fetal
movement: Fetal-Post and Movement Assessment (F-PAM). Phys.Occup.Ther.
Pediatr. 12, 97–114. doi: 10.1080/J006v12n02_06
Tanné-Gariépy, J., Rouiller, E. M., and Boussaoud, D. (2002). Parietal inputs to
dorsal versus ventral premotor areas in the macaque monkey: evidence for
largely segregated visuomotor pathways. Exp. Brain Res. 145, 91–103. doi:
10.1007/s00221-002-1078-9
Thelen, E., and Spencer, J. P. (1998). Postural control during reaching in
young infants: a dynamic systems approach. Neur osci. Bio behav. Rev. 22,
507–514.
Trevarathen, C. (1982). “Basic patterns of psychogenic change in infancy,” in
Regressions in Learning, ed T. Bever (Hillsdale, NJ: Erlbum), 7–46.
Twitchell, T. E. (1965). The automatic Grasping responses of infants.
Neuro psychologia 3, 247–259. doi: 10.1016/0028-3932(65)90027-8
Verbeke, G. (2009). Linear Mixed Models for Longitudinal Data.NewYork,NY:
Springer.
von Hofsten, C. (1982). Eye-hand coordination in the newborn. Dev. Psychol. 18,
450–461. doi: 10.1037/0012-1649.18.3.450
von Hofsten, C. (1984). Developmental changes in the organization of pre-
reaching movements. Dev. Psychol. 20, 378–388. doi: 10.1037/0012-1649.
20.3.378
von Hofsten, C., and Fazel-Zandy, S. (1984). Development of visually guided hand
orientation in reaching. J. Exp. Child Psychol. 38, 208–219. doi: 10.1016/0022-
0965(84)90122-X
Von Hofsten, C., and Lindhagen, K. (1979). Observation on the development of
reaching for moving objects. J. Exp. Child Psychol. 28, 158–173.
von Hofsten, C., and Ronnqvist, L. (1988). Preparation for grasping an object: a
developmental study. J. Exp. Psychol. Human 14, 610–621.
von Hofsten, C., and Rosander, K. (1997). Development of smooth pursuit track-
ing in young infants. Vision Res. 37, 1799–1810. doi: 10.1016/s0042-6989(96)
00332-x
Wallace, P. S., and Whishaw, I. Q. (2003). Independent digit movements and
precision grip patterns in 1-5-month-old human infants: hand-babbling,
including vacuous then self-directed hand and digit movements, precedes tar-
geted reaching. Neuropsycho logia 41, 1912–1918. doi: 10.1016/s0028-3932(03)
00128-3
Wallace, P. S., Vandeleest, J., and Whishaw, I. Q. (2006). Hand Babbling in Macaca
mulatta: Evidence for a Developmental Progression of Movements of a Nonhuman
Primate. Atlanta, GA: Society for Neuroscience Abstracts
White, L. B., Castle, P., and Held, R. (1964). Observations on the development
of visually-directed Reaching. Child Dev. 35, 349–364. doi: 10.111/j.1467-
8624.1964.tb05944
Wimmers, R. H., Savelsbergh, G. J., van der Kamp, J., and Hartelman, P. (1998a).
A developmental transition in prehension modeled as a cusp catastrophe. Dev.
Psychob iol. 32, 23–35. doi: 10.1002/(SICI)1098-2302(199801)32:1<23::AID-
DEV3>3.0.CO;2-V
Wimmers, R. H., Savelsbergh, G. J., Beek, P. J., and Hopkins, B. (1998b). Evidence
for a phase transition in the early development of prehension. Dev. Psychobiol.
32, 235–248. doi: 10.1002/(SICI)1098-2302(199804)32:3<235::AID-
DEV7>3.0.CO;2-P
Yamada, Y., Fujiiz, K., and Kuniyoshi, Y. (2013). “Impacts of environment, nervous
system and movements of preterms on body map development: fetus simula-
tion with spiking neural network,” in Development and Learning and Epigenetic
Robotics (ICDL), IEEE The Third IEEE International Conference on Development
and Learning and on Epigenetic Robotics, (Osaka), 1–7.
Frontiers in Psychology | Developmental Psychology January 2015 | Volume 5 | Article 1526 |10
Thomas et al. Development of infant self-contacts
Conflict of Interest Statement: The authors declare that the research was con-
ducted in the absence of any commercial or financial relationships that could be
construed as a potential conflict of interest.
Received: 11 July 2014; accepted: 10 December 2014; published online: 08 January
2015.
Citation: Thomas BL, Karl JM and Whishaw IQ (2015) Independent development of
the Reach and the Grasp in spontaneous self-touching by human infants in the first 6
months. Front. Psychol. 5:1526. doi: 10.3389/fpsyg.2014.01526
This article was submitted to Developmental Psychology, a section of the journal
Frontiers in Psychology.
Copyright © 2015 Thomas, Karl and Whishaw. This is an open-access arti-
cle distributed under the terms of the Creative Commons Attribution License
(CC BY). The use, distribution or reproduction in other forums is permitted, pro-
vided the original author(s) or licensor are credited and that the original publi-
cation in this journal is cited, in accordance with accepted academic practice. No
use, distribution or reproduction is permitted which does not comply with these
terms.
www.frontiersin.org January 2015 | Volume 5 | Article 1526 |11
... They babble and touch their own body, attracted and actively involved in investigating the rich intermodal redundancies, temporal contingencies, and spatial congruence of self-perception." Thomas et al. [35], biweekly recording resting alert infants from birth to 6 months of age, show that infants frequently touch their bodies, with a rostro-caudal progression as they grow older: head and trunk contacts are more frequent in the beginning, followed by more caudal body locations including hips, then legs, and eventually the feet. DiMercurio et al. [36], following infants from 3 to 9 weeks after birth, found no consistent differences in the rate of touch between the head and the trunk. ...
... Are the touches on the body spontaneous or systematic? If there is a particular structure-which seems to be the case [35], [36]-what drives this developmental progression? Piaget [38] theorized that in newborns, action and perception as well as the "spaces" of individual sensory modalities are separated (cf. ...
... Behavioral studies investigating infant spontaneous behaviors with a specific focus on touch to the body [35], [36] provide data that inform our modeling. First, in the first weeks after birth, contacts with the rostral areas of the body (head and trunk) are dominant. ...
Article
Full-text available
An early integration of tactile sensing into motor coordination is the norm in animals, but still a challenge for robots. Tactile exploration through touches on the body gives rise to first body models and bootstraps further development such as reaching competence. Reaching to one’s own body requires connections of the tactile and motor space only. Still, the problems of high dimensionality and motor redundancy persist. Through an embodied computational model for the learning of self-touch on a simulated humanoid robot with artificial sensitive skin, we demonstrate that this task can be achieved (i) effectively and (ii) efficiently at scale by employing the computational frameworks for the learning of internal models for reaching: intrinsic motivation and goal babbling. We relate our results to infant studies on spontaneous body exploration as well as reaching to vibrotactile targets on the body. We analyze the reaching configurations of one infant followed weekly between 4 and 18 months of age and derive further requirements for the computational model: accounting for (iii) continuous rather than sporadic touch and (iv) consistent redundancy resolution. Results show the general success of the learning models in the touch domain, but also point out limitations in achieving fully continuous touch.
... This opens the door for children to engage in more complex behaviors with a greater variety of objects, including objects that are larger in size, have multiple components, or moving parts. Role-differentiated bimanual behaviors inform children about relations between different objects and allows planning and execution of complex action sequences-an ability later applied for mean-end problem solving, object construction, and tool-use (Babik & Michel, 2016;Kahrs & Lockman, 2014;Keen, 2011;Kimmerle, Ferre, Kotwica, & Michel, 2010;Lobo & Galloway, 2013b;Marcinowski, Nelson, Campbell, & Michel, 2019;Needham, Barrett, & Peterman, 2002;Thomas, Karl, & Whishaw, 2015). ...
... Children also learn through physical exploration of their own bodies. By touching their bodies and surfaces, children not only collect haptic information about the size, shape, temperature, and texture of their target, but also receive rich proprioceptive feedback about their hand's position in space; this information increases children's understanding of surfaces' properties and affordances, the capabilities of their bodies, and possible body-environment interactions (Bertenthal & von Hofsten, 1998;Corbetta & Snapp-Childs, 2009;Corbetta, Thurman, Wiener, Guan, & Williams, 2014;DiMercurio, Connell, Clark, & Corbetta, 2018;Gibson, 1988;Lobo et al., 2014;Thelen et al., 1993;Thelen & Spencer, 1998;Thomas et al., 2015). Furthermore, early hand-to-mouth movements advance the development of manual coordination necessary for reaching, object exploration, and self-feeding (Lew & Butterworth, 1997;Rochat, 1993). ...
Chapter
Children born with a variety of environmental or medical risk factors may exhibit delays in global development. Very often, such delays are identified at preschool or school age, when children are severely overdue for effective early interventions that can alleviate the delays. This chapter proposes a conceptual model of child development to inform the creation of interventions and rehabilitative technologies that can be provided very early in development, throughout the first year of life, to optimize children's future developmental outcomes. The model suggests that early sensorimotor skills are antecedent and foundational for future motor, cognitive, language, and social development. As an example, this chapter describes how children's early postural control and exploratory movements facilitate the development of future object exploration behaviors that provide enhanced opportunities for learning and advance children's motor, cognitive, language, and social development. An understanding of the developmental pathways in the model can enable the design of effective intervention programs and rehabilitative technologies that target sensorimotor skills in the first year of life with the goal of minimizing or ameliorating the delays that are typically identified at preschool or school age. Specific examples of early interventions and rehabilitative technologies that have effectively advanced children's motor and cognitive development by targeting early sensorimotor skills and behaviors are provided.
... Source: (Babik et al., 2017;Blake et al., 1994;Corbetta et al., 2016;Fitzpatrick et al., 1996;Hirai & Kanakogi, 2018;Karl et al., 2018;Kita, 2003;Lobo & Galloway, 2013;Roemer et al., 2018;Thomas et al., 2015;von Hofsten & Lindhagen, 1979;Wallace & Whishaw, 2003;Williams et al., 2015) Movements and actions obtained mainly from arms movements of the caregiver and/or infant. ...
... The act of reaching can be described as a movement which moves the hand to a target location while the hand is open and ready to grasp the target-object. Code under reaching also pre-reaching and pre-grasping movements: for example extending the arm and hand to establish body contact with someone else's body, extending a fisted hand to swat at a distal target without contacting the objects, and possibly extending the arm and open hand to touch distal targets (Babik et al., 2017;Corbetta et al., 2016;Thomas et al., 2015;Williams et al., 2015). ...
Preprint
Within this manual you will find a descriptive guide to the MHINT coding procedure, general rules for coding, and detailed descriptions of each ‘behaviour group’ with illustrative examples.This manual aims to capture as many relevant behaviours for the evaluation of an interaction as possible, with the underlying hypothesis that individual differences in behaviours can occur subtly and that micro-behaviours are of great importance because they provide specific targets for intervention.The coding scheme can be applied to footage obtained from video cameras installed in the home, those used by an observer, or as in our own research, through wearable headcams and a ‘spy’ photo-frame video camera (Lee et al., 2017). Combined, these methods give the observer the opportunity to code behaviours from different perspectives and, interestingly, to obtain the perspective of the participants. The advantages of this approach are explained in Lee et al. (2017).For ease of use, this manual has been divided into five different sections: perspectives, independent variables, subjects, behaviours, and modifiers. To begin, each of these terms is defined.
... It is possible that this is due to a lack of sensory feedback to guide handshaping for rodents. Humans not only use visual feedback to locate the pellet, but also to evaluate the properties of the target object (e.g., shape, size, orientation) in order to pre-shape their hands (Whishaw & Karl, 2014). With no visual feedback, rodents likely over-extend their digits to increase the probability of grasping the object, regardless of its size or orientation. ...
... Observations of infants suggest that the reach and grasp components develop separately. Early reaching movements in infants are directed towards rostral areas of the self (e.g., head or trunk) and contact is made with the hand's dorsum (Thomas et al., 2014). However, over time contact shifts to more caudal body parts (e.g., the leg or foot) with the palm of the hand. ...
Thesis
Dexterous motor skills are essential for normal, everyday functioning but are impaired in many neurological disorders (e.g., Parkinson Disease, dystonia) or other central nervous system pathologies (e.g., stroke, tumor). Therefore, understanding the neural mechanisms that underlie dexterous skills is essential for developing effective therapies for these conditions, as well as for advancing fundamental models of motor control. The rodent skilled reaching task is commonly used to study dexterous motor skill learning and performance, as rodent reach-to-grasp movements are strikingly similar to those of humans. Until recently, implementing the skilled reaching task required significant time and effort, and analyses were limited to simple outcome measures (e.g., success rate) or required time-intensive and subjective manual analysis of skilled reaching videos. These limitations prevented detailed analysis of how neural circuits regulate dexterous skill learning and performance. I used a novel automated skilled reaching task combined with machine learning methods for markerless position tracking to extract detailed forelimb and digit kinematics as rats learned skilled reaching. I found that improvements in fine digit kinematics evolved over a longer timescale than improvements in gross forelimb kinematics. However, the improvements in fine digit kinematics continued even after success rate stabilized, suggesting that aspects of motor control that do not optimize task outcome are refined in skilled reaching. I also found that even after rats had achieved stable success rates, significant variability in reach-to-grasp movements still remained. Brain dopamine is essential for normal motor function as evidenced by its role in Parkinson Disease and other movement disorders. To determine the role of dopamine in skilled reaching performance, I optogenetically stimulated or inhibited substantia nigra pars compacta dopamine neurons as rats performed reach-to-grasp movements. I found that gross forelimb kinematics and coordination between gross and fine movements gradually changed with repeated manipulations. However, once aberrant kinematics were established, rats transitioned rapidly between baseline and aberrant kinematics in a dopamine-dependent manner. Together, these results suggest history-dependent effects of precisely-timed dopamine signals on dexterous motor skill performance, distinct from simple reinforcement learning or ‘vigor’ models of dopamine. This work establishes a paradigm for dissecting the neural circuitry that underlies dexterous motor skills, and highlights the importance of robust quantifiable measurements of movement kinematics. The characterization of how fine and gross motor control evolve as skilled reaching is learned provides a foundation for interpreting studies applying neural circuit manipulations during skilled reaching. Finally, our findings of the effects of dopamine manipulations on skilled reaching kinematics generated new hypotheses regarding dopaminergic control of coordinated movements and the pathophysiology of parkinsonism.
... This visuomotor coupling produced by contingencies between self-initiated movements and environmental feedback has been proposed to constitute the emergence of reaching (Corbetta et al., 2014). Similarly, when learning the correspondences between the body and immediate environment, facilitates the development of body representations (Thomas et al., 2015;Hoffmann et al., 2017). While arm-based learning is more prominent at the beginning of life (Rochat, 1993), caudal body parts (e.g., hips, legs) are integrated into infants' body representation as infants gain more experience with leg-based learning Thomas et al., 2015). ...
... Similarly, when learning the correspondences between the body and immediate environment, facilitates the development of body representations (Thomas et al., 2015;Hoffmann et al., 2017). While arm-based learning is more prominent at the beginning of life (Rochat, 1993), caudal body parts (e.g., hips, legs) are integrated into infants' body representation as infants gain more experience with leg-based learning Thomas et al., 2015). Recently, studies focusing on the ability to learn contingencies revealed that detecting the contingency between a specific limb movement and mobile is an ability that develops with age (Watanabe and Taga, 2006;Jacquey et al., 2020b). ...
Article
Full-text available
In this review article, we describe the mobile paradigm, a method used for more than 50 years to assess how infants learn and remember sensorimotor contingencies. The literature on the mobile paradigm demonstrates that infants below 6 months of age can remember the learning environment weeks after when reminded periodically and integrate temporally distributed information across modalities. The latter ability is only possible if events occur within a temporal window of a few days, and the width of this required window changes as a function of age. A major critique of these conclusions is that the majority of this literature has neglected the embodied experience, such that motor behavior was considered an equivalent developmental substitute for verbal behavior. Over recent years, simulation and empirical work have highlighted the sensorimotor aspect and opened up a discussion for possible learning mechanisms and variability in motor preferences of young infants. In line with this recent direction, we present a new embodied account on the mobile paradigm which argues that learning sensorimotor contingencies is a core feature of development forming the basis for active exploration of the world and body. In addition to better explaining recent findings, this new framework aims to replace the dis-embodied approach to the mobile paradigm with a new understanding that focuses on variance and representations grounded in sensorimotor experience. Finally, we discuss a potential role for the dorsal stream which might be responsible for guiding action according to visual information, while infants learn sensorimotor contingencies in the mobile paradigm.
... At birth, despite a massive, abrupt change of environment, babies show body know-how that is in continuity with the know-how that can be observed in utero. Newborns also engage in spontaneous tactile exploration of the body (Thomas, Karl, & Whishaw, 2015;. They are able to differentiate the tactile sensations caused by the exploration of their own body from those caused by external stimuli. ...
... For example, Rochat and Hespos (1997) observed that newborns did not show the "rooting reflex" (a reflexive movement of the head in response to a caress on the cheek) when the tactile stimulation applied to their cheek was caused by contact with their own hand, whereas they did when tactile stimulation was applied by an experimenter. Over the first six months of life, spontaneous tactile exploration of the body evolves, from movements directed toward the top half of the body (face and trunk) with the outside of the hand, to movements directed toward the bottom half of the body (legs and feet), with the palm of the hand and then with grasping (Thomas et al., 2015;DiMercurio et al., 2018). ...
Article
This literature review examines how babies’ body know-how develops during the first year of life. It surveys studies describing this development through the exploration of the body and of the physical environment. This early development may help babies acquire a sense of agency and a sense of body ownership. The development of body know-how, as a precursor to more in-depth knowledge of the body and of the self, may play an essential role in children’s socio-cognitive and psychomotor development.
... A small number of studies have examined perception of causality in infancy (for review, see Hubbard, 2013b), and several studies suggest that sensitivity to causality in the launching effect emerges by approximately 6 months of age (e.g., Leslie & Keeble, 1987;Newman et al., 2008;Schlottmann et al., 2012), although one study suggests sensitivity to causality in a launching effect can emerge as early as 4.5 months if visual perception matches action experience (Rakison & Krogh, 2012). Interestingly, an emphasis on whether visual perception matches action experience is consistent with theories of visual perception of causality and visual perception of force that suggest such perception is based on haptic experience of motor actions upon objects (e.g., White, 2012b), and the time frame in which infants develop the ability to reach toward and grasp objects (e.g., Thomas et al., 2015) seems similar to the time frame for emergence of perception of causality. When an impetus heuristic might emerge within development is not known, but the framework presented here predicts an impetus notion would develop soon after the ability to grasp and act upon objects. ...
Article
Evidence consistent with a belief in impetus is drawn from studies of naïve physics, perception of causality, perception of force, and representational momentum, and the possibility of an impetus heuristic is discussed. An impetus heuristic suggests the motion path of an object that was previously constrained or influenced by an external source (e.g., object, force) appears to exhibit the same constraint or influence even after that constraint or influence is removed. Impetus is not a valid physical principle, but use of an impetus heuristic can in some circumstances provide approximately correct predictions regarding future object motion, and such predictions require less cognitive effort and resources than would predictions based upon objective physical principles. The relationship of an impetus heuristic to naïve impetus theory and to objective physical principles is discussed, and use of an impetus heuristic significantly challenges claims that causality or force can be visually perceived. Alternatives to an impetus heuristic are considered, and potential boundary conditions and falsification of the impetus notion are discussed. Overall, use of an impetus heuristic offers a parsimonious explanation for findings across a wide range of perceptual domains and could potentially be extended to more metaphorical types of motion.
... Nonetheless, hand-mouth coordination continues to develop after birth. Infants seem to frequently explore their body at around 2 or 3 months, and from birth to 6 months, infants display self-touch progressively throughout their body, from frequently touching rostral parts such as the head and trunk to more caudal parts of the body such as the hips, legs, and feet [174]. From the evidence brought forth by Rochat and Morgan [118,146,147], it seems that infants develop the ability to perceive multisensory spatial contingencies (e.g., visualproprioceptive or visuotactile) soon after birth (e.g., [8]; see also [17] for a review), and also form the perceptual body schema (via intermodal calibration) by 3 months old. ...
Article
Full-text available
Safe human-robot interactions require robots to be able to learn how to behave appropriately in spaces populated by people and thus to cope with the challenges posed by our dynamic and unstructured environment, rather than being provided a rigid set of rules for operations. In humans, these capabilities are thought to be related to our ability to perceive our body in space, sensing the location of our limbs during movement, being aware of other objects and agents, and controlling our body parts to interact with them intentionally. Toward the next generation of robots with bio-inspired capacities, in this paper, we first review the developmental processes of underlying mechanisms of these abilities: The sensory representations of body schema, peripersonal space, and the active self in humans. Second, we provide a survey of robotics models of these sensory representations and robotics models of the self; and we compare these models with the human counterparts. Finally, we analyze what is missing from these robotics models and propose a theoretical computational framework, which aims to allow the emergence of the sense of self in artificial agents by developing sensory representations through self-exploration.
Article
Most research with the mobile paradigm has the underlying assumption that young infants can selectively move the limb causing the contingent feedback from the mobile while avoiding irrelevant motor responses. Contrary to this long‐held belief, others have argued that such differentiation ability is not fully developed early in life. In the current study, we revisited the traditional mobile paradigm with a contemporary research approach (using high‐precision motion capture techniques, a yoked‐control design, and a large sample size) to investigate whether response differentiation ability emerges before 5 months of age. The data collected from 76 infants (aged between 115 and 159 days) revealed that infants can learn sensorimotor contingencies by increasing the movement of the connected leg relative to their baseline level. However, they did not differentially increase the movement of the leg causing an effect in the environment compared with that of other limbs. Our results illustrate that response differentiation ability emerges later than previously suggested.
Article
Full-text available
Recent neuroimaging studies allowed us to explore abnormal brain structures and interhemispheric connectivity in children with cerebral palsy (CP). Behavioral researchers have long reported that children with CP exhibit suboptimal performance in different cognitive domains (e.g., receptive and expressive language skills, reading, mental imagery, spatial processing, subitizing, math, and executive functions). However, there has been very limited cross-domain research involving these two areas of scientific inquiry. To stimulate such research, this perspective paper proposes some possible neurological mechanisms involved in the cognitive delays and impairments in children with CP. Additionally, the paper examines the ways motor and sensorimotor experience during the development of these neural substrates could enable more optimal development for children with CP. Understanding these developmental mechanisms could guide more effective interventions to promote the development of both sensorimotor and cognitive skills in children with CP.
Article
Full-text available
This study aimed to evaluate determinants of differences in leisure reading behavior and school achievement. We specifically examined reading enjoyment, mental imagery, and sex as predictors in a large, age-homogeneous sample of Dutch secondary school students (N = 1,071). Results showed that the prevalence of leisure reading was low in both the lower, pre-vocational track (19.5%) and the higher, pre-academic track (32.5%). Boys read even less than girls. Almost all leisure readers enjoyed reading and engaged in mental imagery, i.e., the propensity "to see images" of a written story in the mind's eye. Overall, boys who did not like to read for leisure had the poorest school performance. Non-leisure readers who reported that they enjoyed reading got higher school grades in the higher educational track. In the lower track, this was the case for girls. Our study findings imply that reading promotion programs should take into account individual differences in sex, achievement level, and reading enjoyment when aiming to decrease the academic achievement gap.
Article
Full-text available
Mindfulness programs for schools are popular. We systematically reviewed the evidence regarding the effects of school-based mindfulness interventions on psychological outcomes, using a comprehensive search strategy designed to locate both published and unpublished studies. Systematic searches in 12 databases were performed in August 2012. Further studies were identified via hand search and contact with experts. Two reviewers independently extracted the data, also selecting information about intervention programs (elements, structure etc.), feasibility, and acceptance. Twenty-four studies were identified, of which 13 were published. Nineteen studies used a controlled design. In total, 1348 students were instructed in mindfulness, with 876 serving as controls, ranging from grade 1 to 12. Overall effect sizes were Hedge's g = 0.40 between groups and g = 0.41 within groups (p < 0.0001). Between group effect sizes for domains were: cognitive performance g = 0.80, stress g = 0.39, resilience g = 0.36, (all p < 0.05), emotional problems g = 0.19 third person ratings g = 0.25 (both n.s.). All in all, mindfulness-based interventions in children and youths hold promise, particularly in relation to improving cognitive performance and resilience to stress. However, the diversity of study samples, variety in implementation and exercises, and wide range of instruments used require a careful and differentiated examination of data. There is great heterogeneity, many studies are underpowered, and measuring effects of Mindfulness in this setting is challenging. The field is nascent and recommendations will be provided as to how interventions and research of these interventions may proceed.
Article
Full-text available
For decades, the emergence and progression of infant reaching was assumed to be largely under the control of vision. More recently, however, the guiding role of vision in the emergence of reaching has been downplayed. Studies found that young infants can reach in the dark without seeing their hand and that corrections in infants' initial hand trajectories are not the result of visual guidance of the hand, but rather the product of poor movement speed calibration to the goal. As a result, it has been proposed that learning to reach is an embodied process requiring infants to explore proprioceptively different movement solutions, before they can accurately map their actions onto the intended goal. Such an account, however, could still assume a preponderant (or prospective) role of vision, where the movement is being monitored with the scope of approximating a future goal-location defined visually. At reach onset, it is unknown if infants map their action onto their vision, vision onto their action, or both. To examine how infants learn to map the feel of their hand with the sight of the object, we tracked the object-directed looking behavior (via eye-tracking) of three infants followed weekly over an 11-week period throughout the transition to reaching. We also examined where they contacted the object. We find that with some objects, infants do not learn to align their reach to where they look, but rather learn to align their look to where they reach. We propose that the emergence of reaching is the product of a deeply embodied process, in which infants first learn how to direct their movement in space using proprioceptive and haptic feedback from self-produced movement contingencies with the environment. As they do so, they learn to map visual attention onto these bodily centered experiences, not the reverse. We suggest that this early visuo-motor mapping is critical for the formation of visually-elicited, prospective movement control.
Article
Afin d'obtenir des informations sur l'evolution de la prehension manuelle au cours des premiers mois de la vie, l'auteur etudie les precurseurs de cette activite (mouvements des bras et de la main) chez 23 bebes de 1 a 16 semaines auxquels il presente un objet mobile
Article
This paperback edition is a reprint of the 2000 edition. This book provides a comprehensive treatment of linear mixed models for continuous longitudinal data. Next to model formulation, this edition puts major emphasis on exploratory data analysis for all aspects of the model, such as the marginal model, subject-specific profiles, and residual covariance structure. Further, model diagnostics and missing data receive extensive treatment. Sensitivity analysis for incomplete data is given a prominent place. Several variations to the conventional linear mixed model are discussed (a heterogeity model, conditional linear mixed models). This book will be of interest to applied statisticians and biomedical researchers in industry, public health organizations, contract research organizations, and academia. The book is explanatory rather than mathematically rigorous. Most analyses were done with the MIXED procedure of the SAS software package, and many of its features are clearly elucidated. However, some other commercially available packages are discussed as well. Great care has been taken in presenting the data analyses in a software-independent fashion. Geert Verbeke is Professor in Biostatistics at the Biostatistical Centre of the Katholieke Universiteit Leuven in Belgium. He is Past President of the Belgian Region of the International Biometric Society, a Board Member of the American Statistical Association, and past Joint Editor of the Journal of the Royal Statistical Society, Series A (2005--2008). He is the director of the Leuven Center for Biostatistics and statistical Bioinformatics (L-BioStat), and vice-director of the Interuniversity Institute for Biostatistics and statistical Bioinformatics (I-BioStat), a joint initiative of the Hasselt and Leuven universities in Belgium. Geert Molenberghs is Professor of Biostatistics at Universiteit Hasselt and Katholieke Universiteit Leuven in Belgium. He was Joint Editor of Applied Statistics (2001-2004) and Co-Editor of Biometrics (2007-2009). He was President of the International Biometric Society (2004-2005), and has received the Guy Medal in Bronze from the Royal Statistical Society and the Myrto Lefkopoulou award from the Harvard School of Public Health. He is founding director of the Center for Statistics and also the director of the Interuniversity Institute for Biostatistics and statistical Bioinformatics. Both authors have received the American Statistical Association's Excellence in Continuing Education Award in 2002, 2004, 2005, and 2008. Both are elected Fellows of the American Statistical Association and elected members of the International Statistical Institute.
Article
The issue examined was whether infants require sight of their hand when first beginning to reach for, contact, and grasp objects. 7 infants were repeatedly tested between 6 and 25 weeks of age. Each session consisted of 8 trials of objects presented in the light and 8 trials of glowing or sounding objects in complete darkness. Infants first contacted the object in both conditions at comparable ages (mean age for light, 12.3 weeks, and for dark, 11.9 weeks). Infants first grasped the object in the light at 16.0 weeks and in the dark at 14.7 weeks, a nonsignificant difference. Once contact was observed, infants continued to touch and grasp the objects in both light and dark throughout all sessions. Because infants could not see their hand or arm in the dark, their early success in contacting the glowing and sounding objects indicates that proprioceptive cues, not sight of the limb, guided their early reaching. Reaching in the light developed in parallel with reaching in the dark, suggesting that visual guidance of the hand is not necessary to achieve object contact either at the onset of successful reaching or in the succeeding weeks.
Article
The Dual Visuomotor Channel theory posits that reaching consists of two movements mediated by separate but interacting visuomotor pathways that project from occipital to parietofrontal cortex. The Reach transports and orients the hand to the target while the Grasp opens and closes the hand for target purchase. Adults rely on foveal vision to synchronize the Reach and the Grasp so that the hand orients, opens, and largely closes by the time it gets to the target. Young infants produce discrete preReach and preGrasp movements, but it is unclear how these movements become synchronized under visual control throughout development. High-speed 3-D video recordings and linear kinematics were used to analyze reaching components, hand orientation, hand aperture, and grasping strategy in infants aged 4-24 months compared with adults who reached with and without vision. Infants aged 4-8 months resembled adults reaching without vision; in that, they delayed both Reach orientation and Grasp closure until after target contact, suggesting that they relied primarily on haptic cues to guide reaching. Infants aged 9-24 months oriented the Reach prior to target contact, but continued to delay the majority of Grasp closure until after target contact, suggesting that they relied on vision for the Reach versus haptics for the Grasp. Changes in sensorimotor control were associated with sequential Reach and Grasp configurations in early infancy versus partially synchronized Reach and Grasp configurations in later infancy. The results argue that (1) haptic inputs likely contribute to the initial development of separate Reach and Grasp pathways in parietofrontal cortex; (2) the Reach and the Grasp are adaptively uncoupled during development, likely to capitalize on different sensory inputs at different developmental stages; and (3) the developmental transition from haptic to visual control is asymmetrical with visual guidance of the Reach preceding that of the Grasp.