The
Role of Gesture in Language, Thought, and Communication
David
McNeill, University of Chicago
The
growth point (GP) is an analytic
unit combining imagery and linguistic categorial content. GPs are inferred from the totality of
communicative events with special focus on speech-gesture synchrony and
semantic co-expressivity. Following
Vygotsky (1987), a GP is intended
to be a minimal psychological unit; that is, the smallest unit (in his
analysis) that retains the essential properties of a whole. In our case, the whole is an image and a
linguistically-codified meaning category, such as we see in the speech-gesture
window. The GP is meant to be the
starting point of the utterance generation process. GPs are, to use another of Vygotsky's concepts, psychological
predicates (not necessarily grammatical predicates). Regarding the GP as a psychological predicate suggests a mechanism of GP formation in which differentiation
of a novel focus from a background plays an essential part. Differentiation, packaged into a GP, is the
launching point of thinking for speaking and utterances.
A
case study of a GP is a non-grammatical combination, "it down", plus
a gesture in which the hands appear to thrust down a large bowling ball. This
comprised the GP of a full sentence,
"and drops it down the drainpipe," in a cartoon story narration. This inference is based on speech-gesture
synchrony and co-expressiveness.
"It down" plus the downward gesture is the core cognition of
the utterance as a whole in this analysis, a psychological predicate in a
particular context. Functionally, the
image provided a holistic version of the concept at the moment of speaking
while the linguistic categorial content ("it", "down")
located this image within the socially-constituted linguistic system. Both the holistic and analytic components
are essential to a complete cognition.
From this GP, the rest of the utterance is ‘unpacked’ via further
meaning generation and contextual contrasts.
A
related concept is that of a catchment -- a gestural trace of thematic
cohesiveness. Catchments are manifested in groups of 2 or more gestures (not
necessarily consecutive) with partially recurring gesture features of movement,
space, orientation, dynamics, etc. across discourse segments, forming a
thematic unit. Languages may differ in
their preferred catchment structures as well as in their growth points. Indeed, these should be coordinated. In the "it down" case, the
catchment consisted of four non-consecutive gestures (of which one was the
two-handed gesture with "it down") and was based on a conflict of
paths: the bowling ball DOWN vs. Sylvester UP, with the further significance of
the directions as opposed forces (evil vs. good). Catchments complement the GP analysis by giving a snapshot of
the contexts against which the GPs are differentiated.
Different
languages induce different GPs. In
motion event descriptions, English speakers choose to treat path as a series of
short, straight segments and path junctures as landmarks past which the moving
figure goes, but not as destinations.
The bowling ball's path was segmented
into 4 segments by the speaker of the "it down" example. Spanish speakers, in contrast, treat even
complex curvilinear paths as unbroken trajectories, but treat junctures as momentary termini. These
differences across languages reveal
impacts of language form on GPs – English hyper-segmentation of GPs reflecting satellite-framed packaging where
path information is divided into any number of satellite segments, Spanish
curvilinearity reflecting verb-framed packaging where path is completely encased in a single verb.