College of Education

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Subject: search.filters.subject.Psychology, Physiological

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    The response-monitoring mechanism: Influence of feedback and temperament
    (2008-05-06) Martin McDermott, Jennifer; Fox, Nathan A; Human Development; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The purpose of the current study was to examine behavioral and physiological processes underlying response-monitoring and to document the manner in which these processes are expressed during early childhood. As well, this study examined two factors important in understanding individual differences in monitoring: performance feedback and temperament. A total of seventy-four children (mean age 7.5 years) were tested using a modified flanker paradigm administered in both no-feedback and feedback conditions. Accuracy and reaction time measures of behavioral performance were assessed as well as event-related potentials linked to response execution and feedback presentation. Data were also examined in relation to the temperamental dimensions of shyness and inhibitory control. The results indicate a strong impact of trial-by-trial feedback on both behavioral and physiological measures. Overall, feedback served to increase children's task engagement as evidenced by fewer errors of omission and faster reaction times. Similarly, the physiological measures also varied as a function of feedback such that the error-related Positivity (Pe) and the feedback-related negativity (FRN) were more pronounced on incorrect as compared to correct trials in the feedback condition. Larger FRN responses were also associated with fewer errors of commission. These findings were further moderated by individual differences in temperament. Specifically, feedback was particularly influential in increasing task involvement for children low in inhibitory control and enhancing performance accuracy for children low in shyness Overall these results confirm a strong impact of feedback on task engagement as assessed by children's behavioral performance and physiological reactivity. Findings are presented in the framework of individual differences in cognitive control and variations in children's physiological measures of response-monitoring are discussed. Several avenues for future research are provided which emphasize the need for investigations of response-monitoring in young children and also highlight the importance of exploring the applicability of these assessments across various cognitive and social contexts.
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    The Social Engagement System: Functional Differences in Individuals with Autism
    (2004-05-03) Denver, John William; Porges, Stephen W; Human Development
    The Polyvagal Theory links the evolution of the autonomic nervous system to affective experience, emotional expression, facial gestures, vocalization and social engagement behavior. Therefore, the theory provides a plausible explanation for the bio-behavioral indices of several psychiatric disorders. The vagus as a "system" provides a rich organizing principle to investigate several of the behavioral, psychological, and physiological features associated with compromised social behavior in several psychiatric disorders. The Polyvagal Theory describes this integrated system as the Social Engagement System. Observations of the behaviors and physiological responses of autistic individuals suggest that they have great difficulties in recruiting the neural circuit that regulates the social engagement system. This model predicts that a deficit in the system would produce atypical social behaviors such as social withdrawal; improper communication (i.e., poor intonation and prosody); difficulty listening (inability to extract human voice from background noise); poor eye contact; inappropriate facial expressivity (i.e., flat affect); and atypical visceral functioning (i.e., low cardiac vagal tone). These indices are directly related to the atypical behaviors associated with autism, and several other psychiatric disorders. In the current study, measures related to the functioning of these components were obtained to test the hypothesis that autistic individuals have a compromised social engagement system. Forty subjects participated in the study (20 autistic, 31 males, ages 9-24). Data were collected to assess autonomic functioning (i.e., cardiac vagal tone), the ability to extract human voice from a compromised environment, an estimate of right ear advantage, and looking behavior (i.e., eye contact). Analyses showed that autistic individuals scored poorer on all measures assessing social engagement system functioning. Compared to controls, the autistic group had lower mean cardiac vagal tone and shorter heart periods, performed poorer on extracting human voice from a compromised environment, on a dichotic listening task, and on a measure of right ear advantage. They also spent significantly less time fixating on the eyes and more time fixating off of the face when viewing a movie of a person telling them a story. Results support the hypothesized relation between a compromised social engagement system and the atypical features associated with autism.