88 ChapTer 3 Development Over the Life Span
know). They clap in response to pictures of things
they like. Children whose parents encourage
them to use gestures acquire larger vocabularies,
have better comprehension, are better listeners,
and are less frustrated in their efforts to commu-
nicate than children who are not encouraged to
use gestures (Goodwyn & Acredolo, 1998; Rowe
& Goldin-Meadow, 2009). When babies begin to
speak, they continue to gesture along with their
words, just as adults often gesture when talking.
These gestures are not a substitute for language
but are deeply related to its development, as well
as to the development of thinking and prob-
lem solving (Goldin-Meadow, Cook, & Mitchell,
2009). Parents, in turn, use gesture (pointing,
touching, tapping) to capture their babies’ at-
tention and teach them the meanings of words
(Clark & Estigarribia, 2011).
One surprising discovery is that babies who
are given infant “brain stimulation” videos to
look at do not learn more words than babies in a
control group, and often they are actually slower
at acquiring words. For every hour a day that
8- to 16-month-old babies watch one of these
videos, they acquire six to eight fewer words
than other children (DeLoache et al., 2010;
Zimmermann, Christakis, & Meltzoff, 2007). But
the more that parents read and talk to their ba-
bies and infants, the larger the child’s vocabulary
at age 3 and the faster the child processes familiar
words (Marchman & Fernald, 2008).In what has to have been one of the most
adorable research projects ever, three investigators
compared the way mothers spoke to their babies
and to pets, which also tend to evoke baby talk.
The mothers exaggerated vowel sounds for their
babies but not for Puffy the poodle or Merlin the
cat, suggesting that parentese is, indeed, a way
of helping infants acquire language (Burnham,
Kitamura, & Vollmer-Conna, 2002).
By 4 to 6 months of age, babies can often
recognize their own names and other words that
are regularly spoken with emotion, such as mommy
and daddy. They also know many of the key con-
sonant and vowel sounds of their native language
and can distinguish such sounds from those of
other languages (Kuhl et al., 1992). Then, over
time, exposure to the baby’s native language re-
duces the child’s ability to perceive speech sounds
that do not exist in their own. Thus, Japanese in-
fants can hear the difference between the English
sounds la and ra, but older Japanese children can-
not. Because this contrast does not exist in their
language, they become insensitive to it.
Between 6 months and 1 year, infants become
increasingly familiar with the sound structure of
their native language. They are able to distin-
guish words from the flow of speech. They will
listen longer to words that violate their expecta-
tions of what words should sound like and even
to sentences that violate their expectations of how
sentences should be structured (Jusczyk, 2002).
They start to babble, making many ba-ba and
goo-goo sounds, endlessly repeating sounds and
syllables. At 7 months, they begin to remember
words they have heard, but because they are also
attending to the speaker’s intonation, speaking
rate, and volume, they can’t always recognize
the same word when different people speak it
(Houston & Jusczyk, 2003). Then, by 10 months,
they can suddenly do it—a remarkable leap for-
ward in only three months. And at about 1 year
of age, though the timing varies considerably,
children take another giant step: They start to
name things. They already have some concepts in
their minds for familiar people and objects, and
their first words represent these concepts (mama,
doggie, truck).
Watch the Video Language Development
at MyPsychLabAlso at the end of the first year, babies de-
velop a repertoire of symbolic gestures. They ges-
ture to refer to objects (for example, sniffing to
indicate flower), to request something (smacking
the lips for food), to describe objects (raising the
arms for big), and to reply to questions (opening
the palms or shrugging the shoulders for I don’tSymbolic gestures emerge early!