Arnold & Nozari 2017
SUPPORTING MATERIAL FOR:
Arnold,J.E. & Nozari, N. (in press). The effects of utterance planning and stimulation of left prefrontal cortex on the production of referential expressions. Cognition.
ABSTRACT
We examined the relationship between the timing of utterance initiation and the choice of referring expressions, e.g., pronouns (it), zeros (…and went down), or descriptive NPs (the pink pentagon). We examined language production in healthy adults, and used anodal transcranial direct current stimulation (tDCS) to test the involvement of the left prefrontal cortex (PFC) on the timing of utterance production and the selection of reference forms in a discourse context. Twenty-two subjects (11 anodal, 11 sham) described fast-paced actions, e.g. The gray oval flashes, then it moves right 2 blocks. We only examined trials in contexts that supported pronoun/zero use. For sham participants, pronouns/zeros increased on trials with longer latencies to initiate the target utterance, and trials where the previous trial was short. We argue that both of these conditions enabled greater message pre-planning and greater discourse connectedness: The strongest predictor of pronoun/zero usage was the presence of a connector word like and or then, which was also tended to occur on trials with longer latencies. For the anodal participants, the latency effect disappeared. PFC stimulation appeared to enable participants to produce utterances with greater discourse connectedness, even while planning incrementally.
See also the companion paper: Nozari, Arnold & ThompsonSchill (2014). The effects of anodal stimulation of the left prefrontal cortex on sentence production. Brain Stimulation. This paper is made available here through Elsevier’s Green Open Access policy, after the embargo period of 12 months.
MANUSCRIPT
This is the word document of the final published paper, including proof corrections.
Post-print word document.
DATA
The data in the main analysis in the paper are available here. This is an Excel spreadsheet. Sheet 1 contains the data; Sheet 2 contains an explanation of columns.
POWERPOINT EXAMPLE OF TASK.
Download powerpoint document, begin presentation mode, and press the space bar. Note that this example was recorded by a research assistant, and is not part of the actual data analyzed in the paper.