Is Language Production Planning Emergent From Action Planning? A Preliminary Investigation

Abstract

The nature of syntactic planning for language production may reflect language-specific processes, but an alternative is that syntactic planning is an example of more domain-general action planning processes. If so, language and non-linguistic action planning should have identifiable commonalities, consistent with an underlying shared system. Action and language research have had little contact, however, and such comparisons are therefore lacking. Here, we address this gap by taking advantage of a striking similarity between two phenomena in language and action production. One is known as syntactic priming-the tendency to re-use a recently produced sentence structure-and the second is hysteresis-the tendency to re-use a previously executed abstract action plan, such as a limb movement. We examined syntactic priming/hysteresis in parallel language and action tasks intermixed in a single experimental session. Our goals were to establish the feasibility of investigating language and action planning within the same participants and to inform debates on the language-specific vs. domain-general nature of planning systems. In both action and language tasks, target trials afforded two alternative orders of subcomponents in the participant's response: in the language task, a picture could be described with two different word orders, and in the action task, locations on a touch screen could be touched in two different orders. Prime trials preceding the target trial promoted one of two plans in the respective domain. Manipulations yielded higher rates of primed behavior in both tasks. In an exploratory cross-domain analysis, there was some evidence for stronger priming effects in some combinations of action and language priming conditions than others. These results establish a method for investigating the degree to which language planning is part of a domain-general action planning system.

Keywords: action planning; domain general processing; hysteresis; language emergence; language production; syntactic priming.

FIGURE 1

(A) Examples of action prime trials. (B) Examples of action target trials. Full set in Supplementary Material. (C) Examples of action filler trials.

FIGURE 2

(A) Example language prime sentences. Participants received either two object-first primes (left) or recipient-first primes (right). (B) Example language target stimuli. Full set in Supplementary Material. (C) Examples of language filler trials.

FIGURE 3

Trial sequence. Participants saw a series of interleaved, fully randomized action and language targets, with five trials between each target trial. A prime-target-filler sequence began with two prime trials, either two action or two language primes. A target of the same domain (action or language) followed the two prime trials. Three filler trials, which afforded no sequencing options, followed the target. Each group of three fillers contained at least one language and one action filler trial. In this figure, screen displays are grouped to illustrate the trial sequence, but each trial in the experiment proceeded immediately following the end of the previous trial.

FIGURE 4

Proportion of target trials in which participants produced prime-congruent responses. For action targets, bars reflect the proportion of screen touches that match the primed direction from the Start diamond (left-first/right-first, totaling to 1). For language targets, bars reflect the proportion of utterances (object-first/recipient-first, totaling to 1) that matched the structure of the primed object/recipient ordering. Means and standard errors are calculated over each participant’s mean score. Overall, prime order predicts rates of prime-congruent vs. prime-incongruent responses in both action and language trials, and for action trials the size of priming is greater for left-first primes.

FIGURE 5

Influence of presentation list on proportion of primed responses. Action and language prime types varied between participants resulting in four combinations of primes (presentation lists). Proportion of prime-congruent action responses (green) and language responses (white) are shown grouped by presentation list. (A) Participants with Left-first and Object-first Primes. (B) Participants with Left-first and Recipient-first Primes. (C) Participants with Right-first and Object-first Primes. (D) Participants with Right-first and Recipient-first Primes.