Presentation

Evan Usler¹, Vishruta Yawatkar², Janina Boecher³, Sayan Nanda⁴, Ho Ming Chow⁵; ¹University of Delaware

Verbal communication is likely highly influenced by what motivates individuals to approach socially-rewarding stimuli and withdraw from socially-punishing stimuli.1 Individual differences in the motivation to approach and/or withdraw from a speaking situation are likely to impact one’s communicative competence and have been theorized to play a casual role in disorders of impaired speech fluency, such as developmental stuttering.2 However, the potential association between motivation and quantitative measures of speech-language production has not been largely studied. The Behavioral Activation System (BAS) and the Behavioral Inhibition System (BIS) are motivational systems governing approach and withdrawal motivations, respectively.3,4 BAS/BIS constructs predict resting prefrontal asymmetry in electroencephalography (EEG), with asymmetry in left and right hemispheres respectively associated with greater BAS and BIS scores.5 The overall hypothesis of this project is that neural correlates of approach and avoidance motivation, as well as BAS/BIS scores, will be elicited in anticipation of speaking tasks of expository discourse. Our experimental paradigm involves expository discourse under three conditions (i.e., reward, neutral, punishment). We expect that the neural and behavioral correlates of approach motivation will be recorded in the reward condition, while correlates for withdrawal motivation will be recorded in the punishment condition. Lastly, we expect neural and behavioral correlates of approach motivation to be positively related to greater measures of speech-language productivity. A contrary relationship is expected between withdrawal motivation and reduced speech-language productivity. Participants include neurotypical adult speakers of English who provide informed consent before participating in this study (N = 30, 15 males / 15 females). Participants have no history of neurological injury or psychiatric disorders. All participants are right-handed and will be given five minutes to read about a particular topic and prepare to spontaneously produce a three-minute expository discourse about the topic they have read. The three discourses differ by condition (i.e., reward, neutral, punishment). In the reward condition, participants are told that their speech performance will be rewarded cumulatively (i.e., points rewarded) based on the information provided by the speaker. In the neutral condition, no rewards or punishments are provided. In the punishment condition, only = points are reduced when a lack of information is provided by the speaker. Between reading about the topic and each discourse will be a five-minute rest interval during which time EEG will be recorded with a 32-channel active electrode system (BrainVision LiveAmp). Participants keep their eyes shut while alpha (8–15Hz) and beta (15-25Hz) power is recorded from frontal and central electrodes. Metrics of speech-language productivity to be analyzed include speech rate, Total Number of Narrative Words (TNW) and Total Number of well-formed Sentences (TNS). Syntactic complexity is also measured using Mean Length of Utterance (MLUw). Data collection and analysis is currently ongoing. We expect that our findings will have significant clinical implications for individuals with speech-language disorders. We hope to provide empirical evidence of the link between motivation and speech-language production that can spur future neuromodulation to stimulate approach motivation and decrease withdrawal motivation during speech in clinical populations.

Topic Areas: Disorders: Developmental, Control, Selection, and Executive Processes