An improved understanding of risky decision-making in sleep-deprived persons could have important real-world consequences. Traditional expectation-based models assume that individuals integrate information across outcomes and probabilities. Neuroeconomic studies that seek to understand the neural mechanisms underlying economic decision-making often target a particular decision variable, incorporate that variable into a model function, manipulate the level of that variable across a range of stimuli, and then identify aspects of brain function that track changes in that variable. Separating decision and outcome phases in the imaging analysis could also be important as sleep deprivation (SD) might interact with task context and feedback to influence neural responses and behavior. The shifts in economic preferences in the multiple outcome gambling experiment as well as relative valuation for social and monetary stimuli were independent of the effects of SD on psychomotor vigilance, consistent with the suggestion that effects of SD vary according to cognitive domain.

This chapter considers three distinct but related classes of evidence: behavioral studies, neuroimaging, and brain-damaged patient case studies. It discusses recent advances in the study of implicit perception, considering the ways in which they do and do not improve on earlier approaches. The chapter highlights claims for implicit perceptual or semantic processing of discrete stimuli, largely overlooking implicit skill learning, artificial grammar learning, or other forms of procedural knowledge that might well be acquired without awareness. It also considers recent arguments about how best to study implicit perception. Claims for and against implicit perception received extensive empirical attention starting in the late 1950s, with sentiment in the field vacillating between acceptance and skepticism. Finally, the chapter discusses how qualitative differences in the nature of perceptual processing may be of theoretical significance even without a clear demonstration that processing occurs entirely outside of awareness.