Developmental Ability to Use Vocalizations Intentionally Accompanying Pointing

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Feb 23, 2014 (3 years and 7 months ago)

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Developmental Ability to Use Vocalizations
I
ntentionally Accompanying Pointing

Zhen Wu & Julie Gros
-
Louis

Department of Psychology, Delta Center, the University of Iowa, USA

INTRODUCTION

Question



Do infants’ use vocalizations intentionally?

Background



T
hree diagnostic criteria for intentional behavior
(Bates,
et al., 1975; Leavens & Hopkins, 1999
):


in accordance with
attentional

states of the
audience


gaze alternation


goal directed


Infants
understand the communicative goal
of
pointing
(
Tomasello

et al., 2007)


Gaze alternation is not reliable; instead, infants may rely
on auditory information (
Liszkowski
,
2006)


Infants seem to produce
vocalizations
intentionally when
pointing
(Haynes et al., 2004;
Liszkowski

et al., 2008)


Captive chimpanzees alter vocalizations depending on the
context and communicative demands of the situation
(Hopkins et al., 2007;
Hostetter

et al., 2001
)

Purpose



T
o explore infants’ development of intentional
vocalizations and combined pointing in
naturalistic
interaction

METHODS

Participants





Procedure



Natural
freeplay

interactions with mothers for 15
mins








Coding and Reliability



Pointing
: Extension of arm (either fully or slightly bent)
and index finger or open hand, in the direction of an object


Vocalizations
: any sound, with the exclusion of vegetative
sounds and sustained crying. Coded within 2 s before
pointing (
before
), during pointing (
during
), and within 2 s
after pointing (
after
)


Mother’s
attentional

states
: attend to infant (
AI
), attend to
object that infant points to (
AO
), attend to both (
AIO
),
attend to other objects that are not attended by infant (
RO
)

-
before, during,

and
after

infants’ pointing



Mother’s responses
:
Sensitive

(comments
or actions
on
object
that
infant was pointing
to);
Redirective

(
comments
or actions on

an
object that the infant was
not attending to);
AQ

(asked questions for clarification);
None

(did nothing
to interact with the infant but just watched)

-
before
, during,

and
after

infants

pointing




Interrater

reliability was 0.87, 0.94, 0.70 and 0.8,
respectively

RESULTS

DISCUSSION


Infants’ ability to integrate vocalizations and pointing
together as communicative acts increases with age


Vocal production by infants older than 12 months varies
as a
function of

audience’s
attentional

states and responses (see also
Liszkowski

et al., 2008),
suggesting that

infants
have some
voluntary control of their
vocalization



Vocalizations to get other’s attention
, which
is also
seen in captive chimpanzees (Hopkins et al., 2007;
Hostetter

et al., 2001)




Supports the importance of
prelinguistic

vocalization in
infants’ development of
intentional communication


Contact: zhen
-
wu@uiowa.edu

REFERENCES

Bates, E.,
Camaioni
, L., &
Volterra
, V.
Merrill
Palmer Quarterly

21
, 205 (1975).

Haynes
,
W. O.,
Zylla
-
Jones
,
E., Smith
,
J., et al,
Infant
Behavior &
Development
27
, 230
(2004
).

Hopkins, W. D.,
Taglialatela
, J. P. & Leavens, D. A,
Animal
Behaviour

73
, 281 (2007
).

Hostetter
, A. B.,
Cantero
, M., Hopkins, W. D,
Journal of
Comparative Psychology

115
, 337 (2001
).

Leavens, D., & Hopkins, W.
D,
J
Comp
Psychol

113
, 417(1999)

Liszkowski
, U., Albrecht, K., Carpenter, M. et al
, Infant Behavior
&
Development

31
, 157 (2008
).

Liszkowski
,
U, In
N. Enfield & S.
Levinson (Eds
.),
The roots of
human sociality: Culture, cognition, and interaction
(pp. 153

178). Oxford:
Berg (2006).

Tomasello
, M., Carpenter, M. &
Liszkowski
,
U,
Child
Development
78
, 705 (2007).



Age (
Mos.)

Total

Pointers

Valid%

10

20

8

40

12

34

18

53

13

24

16

67

0%
20%
40%
60%
80%
100%
10
12
13
Percent
of total
vocalization

Age (months)

RO
AO
AIO
AI

Ten
-
month
-
olds did not vocalize differently when mom’s
attentional

states differed (
p

= 0.69). Older infants vocalized more when mom was
not attending to the target (RO and AI) than when mom was already
attending to the target (AO and AIO) [
F
(1, 32) = 12.77,
p
< 0.001].

0%
20%
40%
60%
80%
100%
10
12
13
Percent
of total
vocalization

Age (
months
)

Sensitive
Redirective
NONE
AQ

Younger infants vocalized more when mom asked questions; older
children vocalized more when mom had
redirective

responses (
p’s

<
0.05).