The aim of this study was to use two variants of the Iowa gambling test, which have been shown to dissociate between patients with dorsolateral and orbitofrontal cortex lesions, to investigate whether decision making deficits found in normal older adults are similar to patterns associated with patients with lesions to the dorsolateral or obritofrontal cortex. This study was designed to advance previous findings that subsets of older adults are impaired on the Iowa Gambling task by determining whether this can be attributed to executive dysfunction, associated with dorsolateral prefrontal cortex, or a problem shifting response set, associated with orbitofrontal cortex. We tested 32 participants aged 18-29 and 30 participants aged 55-84. Our study found that a subgroup of older adults had difficulties shifting response set, thereby suggesting that the orbitofrontal cortex may be subject to premature ageing.