Graduation Year

2019

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Psychology

Major Professor

Edelyn Verona, Ph.D.

Committee Member

Mark Goldman, Ph.D.

Committee Member

Geoffrey Potts, Ph.D.

Committee Member

Robert Schlauch, Ph.D.

Committee Member

Brent Small., Ph.D.

Keywords

ERP, Experimental, Violence, Cognition

Abstract

Although shorter sleep duration is theorized to increase the risk of engaging in aggressive behavior, experimental studies examining this relationship yield conflicting findings. Since sleep serves in part to regulate the functioning of prefrontal brain regions, insufficient sleep may deleteriously impact the individual’s ability to inhibit rash action and alter emotional processing, which could in turn increase aggressive tendencies. However, no studies have examined the extent to which naturally occurring insufficient sleep is linked to aggression or potential mechanisms of this relationship, limiting understanding of and the generalizability of extant findings. Thus, the present study examined whether cognitive (deficits in response inhibition) and emotional processes (increased negative emotional processing) help explain relationships between sleep duration and aggression. Approximately 143 participants between the ages of 18 and 40 were recruited from a larger, grant-funded aggression study. Participants wore Fitbit Flex sleep-tracking devices and kept a sleep diary to monitor sleep duration over a three-day period prior to the laboratory session. At the laboratory session, electrophysiological indices of emotional processing and response inhibition (P3 and N2) were measured via an Emotional Go/No-Go task, and aggression under provocation was measured using a laboratory aggression paradigm. Mixed-model repeated measure ANOVAs tested the relationships between sleep duration, emotional processing, response inhibition, and aggression, controlling for potential confounds (e.g., substance abuse, gender). Path analyses examined whether emotional processing and response inhibition mediated the sleep-aggression relationship. As expected, less sleep duration was associated with greater intensity of aggression observed in the laboratory. Interestingly, despite showing increased inhibition processing towards emotional stimuli, lower sleepers performed similarly across emotional conditions, indicating that the emotional processing biases apparent at lower levels of sleep did not translate to better performance. Moreover, although inhibitory and emotional processing related to sleep and aggression, albeit in somewhat different patterns, these mechanisms did not explain the sleep-aggression link. These results provide the first evidence that shorter sleep duration predicts laboratory aggressive behavior, and preliminarily suggests that shorter sleepers work harder in emotional contexts to inhibit behavior comparably to neutral contexts. Implications of these findings for understanding aggression will be discussed.

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