Aging and decision making
Miller Sophie dissertation 2010.doc (1.354Mb)
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The study sought to clarify the effects of aging in regard to decision making abilities. Decision making is dependent upon the Frontal Cortex structures; the Orbitofrontal Cortex and the Dorsolateral Prefrontal Cortex. These structures are thought to decline with age, and so functioning of these areas important for decision making is also thought to deteriorate. Structural deterioration of the Frontal Cortex is often regarded as disproportionate. An objective of the current study was to compare the functioning involved in decision making of an older group of participants to that of Orbitofrontal Cortex lesion patients and Dosolateral Prefrontal Cortex lesion patients, and therefore ascertain which lesion patients the older participants of the current study performed most similarly to. To do this three decision making tasks were implemented which included the Original Iowa Gambling Task, the Variant Iowa Gambling Task and the Reversal Learning Task. All tasks tested the decision making abilities of participants attributed to the functioning of the Orbitofrontal Cortex and the Dorsolateral Prefrontal Cortex. A two way analysis of variance was carried out on both Iowa Gambling Tasks, whilst a repeated measures analysis of variance was also completed for both tasks. Independent t-tests were implemented in the Reversal Learning Task. The study showed an impairment of the older group on both Iowa Gambling Tasks when compared to the younger control group. Impairment on the Original Iowa Gambling Task suggested a possible impairment of the Orbitofrontal Cortex but this was not reflected in the Reversal Learning Task. Impairment on both the Iowa Gambling Tasks indicated that older participants performed most similarly to Dorsolateral Prefrontal Cortex lesion patients. Consequently, the functioning of the Dorsolateral Prefrontal Cortex in older participants looks to have declined more rapidly than the functioning of the Orbitofrontal Cortex.