It is important to understand how humans make decisions in isolation (i.e. with no other people to be involved). In a series of studies (Journal of Neuroscience, 2008; 2010; PNAS 2009) we tried to uncover the behavioral, computational and neuronal underpinnings of risk. Among other findings, we identified a brain signal at right dorsolateral prefrontal cortex that was associated with higher risk aversion and behavioral and neuronal representations of how humans distort probabilities in a non-linear fashion.
Risk aversion paper (Journal of Neuroscience): Get paper here
Probability distortion paper (Journal of Neuroscience): here
Risk vs. utility (PNAS): here