Aims Novelty preference or sensation seeking is an important trait related to initiating and maintaining risky behaviours, including substance abuse. Here we introduce a novel or familiar prime (image) preceding a risk choice and focus on behavioural and imaging correlates to the prime that might predict risk seeking in healthy volunteers. We aim to investigate whether novel or familiar primes affect judgments of risk. We hypothesize that subjects would be more risk seeking following a novel relative to familiar stimulus and that subjects who are more novelty seeking will have increased striatal and hippocampal activity to the novel stimulus.

Methods We adapted a risk-taking task involving acceptance or rejection of a 50:50 choice of gain or loss which was preceded by a familiar (pre-test familiarization) or novel face prime. Neutral expression faces of males and females from The Karolinska Directed Emotional Faces database were used as primes. Subjects were tested behaviourally and scanned using functional MRI as they were performing a different version of the same task.

Results Twenty-four healthy volunteers were recruited for the behavioral study and eighteen for the fMRI study. We show enhanced risk taking following novel relative to familiar images and particularly for the low gain condition. Subjects had faster reaction times to the prime when accepting rather than rejecting the risky choice. We further show that right putamen activity to novel versus familiar primes were positively correlated with risk taking choices.

Conclusions Novelty appears to have a contextually enhancing effect on augmenting risky choices possibly mediated via putaminal activity. These findings highlight the role of context in risk taking and have important implications for a wide range of behaviours including substance abuse.