The brain continuously monitors speech output to detect potential errors between its sensory prediction and its sensory production (Daliri et al., 2020). When the brain encounters an error, it generates a corrective motor response, usually in the opposite direction, to reduce the effect of the error. Previous studies have shown that the type of auditory error received may impact a participant’s corrective response. In this study, we examined whether participants respond differently to categorical or non-categorical errors. We applied two types of perturbation in real-time by shifting the first formant (F1) and second formant (F2) at three different magnitudes. The vowel /ɛ/ was shifted toward the vowel /æ/ in the categorical perturbation condition. In the non-categorical perturbation condition, the vowel /ɛ/ was shifted to a sound outside of the vowel quadrilateral (increasing both F1 and F2). Our results showed that participants responded to the categorical perturbation while they did not respond to the non-categorical perturbation. Additionally, we found that in the categorical perturbation condition, as the magnitude of the perturbation increased, the magnitude of the response increased. Overall, our results suggest that the brain may respond differently to categorical and non-categorical errors, and the brain is highly attuned to errors in speech.

The present study examined the effects that mild traumatic brain injury (mTBI) has on an individual’s episodic memory by looking at participants’ abilities to recall stories both immediately after being verbally told and after a delay. Thirty-seven participants were sorted into a control group (N=27) and a mTBI group (N=10) and then given the Wechsler Memory Scale’s two subtests, Logical Memory I and Logical Memory II. Logical Memory I consists of two verbally given stories in which the participant immediately retells the story to the assessor with as much detail and original vocabulary as they can remember. Logical Memory II has the participants, without prior knowledge, retell the same two stories after a thirty-minute delay. Once recorded, researchers transcribed and scored the participants’ story recalls, gathering data on what errors, correct ideas, and vocabulary the participants made and remembered. The data was then analyzed through an Analysis of Variance (ANOVA), looking at the interaction of Story (of the two stories that the participants were told), Group (whether mTBI or control) , and Delay (whether it was the immediate or delayed recall). Trends in the data show that participants with a history of mTBI do more poorly than the control group proving that memory is affected by acquired brain injury and that further studies to examine how and why this is the case are needed.