Now, what about social interaction? First let me mention what people say about it.
Preverbal infants manfiest a surprising range of social abilities.
These include imitation, which can occur just days and even minutes after birth
(Meltzoff & Moore 1977; Field et al. 1982; Meltzoff & Moore 1983), imitative learning
(Carpenter et al. 1998), gaze following (Csibra & Volein 2008), goal ascription
(Gergely et al. 1995; Woodward & Sommerville 2000), social referencing (Baldwin 2000)
and pointing (Liszkowski et al. 2006).
Taken together, the evidence reveals that preverbal infants have surprisingly rich
social abilities.
Perhaps the best evidence how sophisticated infant social interaction can be comes
from studies of language creation.
(This will be a key topic when we come to study knowledge of language, but let me
give you a tiny preview.)
Children with no experience of others' languages can create their own languages.
We know this from studies of profoundly deaf children brought up in purely oral
environments and therefore without experience of language
\citep{Kegl:1999es,Senghas:2001zm,Goldin-Meadow:2003pj}.
Individually or in groups these children invent their own signed languages.
These languages are not as rich as those of children with experience of other
people's languages but they have all of the essential features of language
including lexicons and syntax (*refs: Goldin-Meadow 2002, 2003).
The children invent gesture forms for words which they use with the same meanings
in different contexts, they adopt standard orderings for combining words into
sentences, and they use sentences in constructing narratives about past, present,
future and hypothetical events (*ref: Goldin-Meadow 2003: 170).
But it is not just children in extreme circumstances that create words.
Children in ordinary environments will create their own words before they learn to
use those of the adults; when children start speaking, it is often the adults who
are learning new words.
(‘Some children are so impatient that they coin their own demonstrative pronoun. For
instance, at the age of about 12 months, Max would point to different objects and
say “doh?,” sometimes with the intent that we do something with the objects, such as
bring them to him, and sometimes just wanting us to appreciate their existence’
(\citealp[p.\ 122]{Bloom:2000qz}; see further \citealp{Clark:1981bi,Clark:1982hj}).)
And even where children have mastered a lexical convention, they will readily violate
it in their own utterances in order to get a point across.
(‘From the time they first use words until they are about two or two-and-a-half,
children noticeably and systematically overextend words. For example, one child used
the word “apple” to refer to balls of soap, a rubber-ball, a ball-lamp, a tomato,
cherries, peaches, strawberries, an orange, a pear, an onion, and round biscuits’
\citep[p.\ 35]{Clark:1993bv}.)
