Document Type

Dissertation

Date of Degree

Spring 2015

Degree Name

PhD (Doctor of Philosophy)

Degree In

Neuroscience

First Advisor

Natalie Denburg

Abstract

Natural aging leads to substantial brain changes. These biological changes can, and often do, precede changes in affect, cognition, and behavior. Even subtle changes, for example in affective experience, can create problematic outcomes in day-to-day emotion regulation and decision-making. For example, poor emotion regulation may lead an individual to fall prey to an emotionally potent scam. Similarly, an overly positive individual may not fully attend to or consider potentially negative future outcomes when faced with a decision. This work characterizes changes in affect across the lifespan, and how affect corresponds to brain function, as indexed by the blood oxygen dependent signal, during tasks taxing emotion regulation and decision-making functions. I predicted that age would correlate with greater positive relative to negative emotions and with a more global (i.e., less specific and less complex) representation of emotions. The former predicted pattern indicates increased "affective optimization" and the latter indicates reduced "affective complexity." I predicted that affective optimization and complexity would correlate with brain function during emotion regulation and decision-making. I used time-based experience sampling, self-reported affect, implicit measures of affect, and performance based measures of affect to determine the associations between age and affective optimization and complexity. Results show that age negatively correlates with affective complexity. Specifically, older age was associated with less negative affect complexity, less positive emotion regulation, less affective awareness. Also, older age corresponded to lower levels of negative affect, as indexed by their experiences and an implicit measure of affect. Next, I examined emotion regulation using a cognitive reappraisal task. I found that older age was associated with less successful reappraisal of negative and positive affect. I also found individual differences in the ventromedial prefrontal cortex among older adults during emotion regulation. Lastly, I examined decision-making patterns using an intertemporal choice task. I found that younger adults’ experienced affect aligned more closely with their decision patterns. Among older adults, affective acceptance correlated with individual differences in the striatum and insula. Taken together, these results support the idea that lower levels of affective competence, rather than higher levels, characterize older age. Also, individual differences in affect parallel individual differences in brain function in the somatic marker circuitry. This suggests possible deficits in interpreting visceral information important to emotion regulation and decision-making. The findings from this work will be important for understanding why some older adults are more susceptible to scams, fraud, and decision-making problems.

Public Abstract

Fraudsters target older more often than younger adults for scams. Fraudsters also tend to exploit the victims’ emotions to persuade decisions to spend or send money or to provide personal information. What leads individuals to fall prey to these scams? The research presented in this thesis helps determine individual differences in emotion and brain function that might cause deficits in emotion regulation and decision-making - both key abilities for reducing scam vulnerability. I measured trait-affect, including competency and experience, across a lifespan sample of adults. I then examined emotion regulation across the lifespan and brain function related to emotion regulation among older adults. Lastly, I examined decision-making across the lifespan and brain function related to decision-making among older adults. I found that older age relates to lower levels of affective competence. Older age predicted a reduced ability to use cognitive emotion regulation strategies to reduce positive and negative affect. Trait-affect was less likely to parallel decision-making patterns among older adults. Together, this work suggests that older adults are less successful at regulating emotions and that they are less skillful at using affective signals to make decisions. Moreover, older adults showed individual differences in brain function related to trait-affect. Specifically, the prefrontal cortex, striatum, and insula, brain regions critical for interpreting “gut feelings,” showed individual differences during emotion regulation and decision-making. Therefore, older adults with faster rates of decline in this brain circuitry may be more prone to emotion regulation or decision-making difficulties and, consequently, more susceptible to scams.

Keywords

publicabstract, Affect, Aging, Decision-Making, Emotion Regulation, Functional Magnetic Resonance Imaging, Intertemporal Choice

Pages

x,114

Bibliography

102-114

Copyright

Copyright 2015 Kameko Halfmann

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