Building from priors in a silent gesture communication game: Innovating a system interactively.

This study demonstrates how interaction – specifically negotiation and repair – facilitates the emergence, evolution, and conventionalization of a silent gesture communication system. In a modified iterated learning paradigm (Kirby, Cornish, & Smith, 2008), partners communicated noun-verb meanings using only silent gesture (Goldin-Meadow et al., 2008; Schouwstra, 2012). In an experimental setting, interacting dyads communicated easily confusable, in co-speech gesture, noun-verb pairs (e.g. “A Hammer” and “Hammering”) using only silent gesture, including the use of their hands, arms, and face. Participants took alternating turns as “Director”- the gesturer - and “Matcher” - the guesser - in this communication game which required distinguishing between meanings to achieve the highest accuracy under a time pressure. One condition allowed for an immediate turn at repair following an incorrect guess. The need to disambiguate similar noun-verb pairs drove these "new" language users to develop a morphology that allowed for quicker processing, easier transmission, and improved accuracy. The specific morphological system that emerged came about through a process of negotiation within the dyad, namely by means of repair. Over generations, participants modified and systematized prior gestures to conform to emergent conventions in the silent gesture system. This process involves reusing elements of prior gestures, even if temporally distant, to communicate a meaning. This is complementary to the same phenomenon that occurs in speech produced over multiple turns (Goodwin, 2013). The face-to-face, contingent interaction of the experiment allows participants to build from one another’s prior gestures as a means of developing systematicity over generations. Once a gesture has been performed, it is available for future use and manipulation. Transformative operations on prior gestures can emerge through repair as well. Immediate modification on a gesture can involve a reference to the gesture space or a particular element of the gesture. We see examples of this in other-initiated repair sequences (Jefferson, 1974) within the communication game. More removed reference to a prior gesture was also demonstrated by some participants (as the Director) who would gesture to the Matcher’s previous gesture space, as a means to indicate they would be communicating a similar item. However, even when a gesture is far removed temporally from the current gesture sequence, there is evidence that participants recall, reuse, and build upon priors to communicate similar or the same meaning, as when transmitting gestures from one generation to the next. In sum, we see how interaction allows for meaning-making processes to build from outputs across generations in a silent gesture system that proxies the evolution of newly emerging signed languages. Through this mixed-methods approach, we can evaluate the processes in which a system becomes most expressive and learnable through co-operative, interactive negotiation