In the City of Sin, sleep might be your last priority, yet could sacrificing slumber cost you even more than the unfavorable odds of gambling already predict? According to researchers at Duke University, sleep deprivation results in a strategy alteration toward gain seeking behavior as opposed to protecting against loss during risky decision making. Numerous studies have established that insufficient sleep results in impaired attention, working memory, and learning. In this study, Vinod Venkatraman and his colleagues demonstrated that inadequate sleep also produces a bias in decision-making that is distinct from the general effect of diminished cognition due to the poor vigilance associated with sustained wakefulness.
Twenty-nine adult males, with an average age of 22.34 years, participated in this study. The subjects were presented with a number of complex mixed five-outcome gambles, with each outcome consisting of two positive monetary outcomes, a neutral reference outcome, and two negative financial loss outcomes. The outcomes fell under two categories: Gain-focus trials, and Loss-focus trials. For outcomes offered in the gain focus trials, participants could either choose to maximize their gain by increasing the value of the highest offered outcome (Gmax) or choose to improve their overall probability of winning money compared to losing money (Pmax). In the loss-focus trials, participants were able to either choose the Pmax option or choose to minimize their loss by decreasing the amount of their most negative outcome (Lmin). Following the presentation of all the trials, a few of the gambles were arbitrarily chosen and calculated to an actual monetary loss or gain, which were then shown to the subject. Each participant completed the task after a full night of sleep and again after being forced to remain awake for 24 hours, both times while being imaged by using fMRI technology. The participants were also required to complete the Psychomotor Vigilance task every hour throughout the night when they were forced to remain awake, in order to gather a measure of continual attention.
The results of the study revealed that in the sleep deprived state, participants demonstrated a greater inclination toward seeking gain, witnessed by the larger ratio of Gmax Vs. Pmax choices in the gain-focus trials and a decreased proportion of Lmin Vs. Pmax decisions in the loss-focus trials. Sleep deprivation did bring about decreased psychomotor vigilance in the subjects, yet the extent of the bias shown in risky decision-making did not correlate with the level of reduction in attention. Compared to judgments made following a normal night of sleep, sustained wakefulness resulted in increased activity in the ventromedial prefrontal cortex and decreased activation of the right anterior insula. The ventromedial prefrontal cortex has been correlated with gain-seeking behavior, and the anterior insula has been associated with loss- averse behavior. Combined, the imaging results suggest that sleep deprivation causes individuals to be less troubled by losses and more interested in behaving with the intent of capitalizing gain.
In sum, inadequate sleep causes a prejudice in valuation by augmenting the importance afforded to profit gain as compared to preventing losses. In light of the finding that such judgmental impairment exists independent of measured vigilance, consideration must be given to the possibility that conventional treatments to maintain performance during prolonged wakefulness (i.e. stimulants) may be ineffective. Such treatments might succeed in enhancing attention, yet may not influence separate features of cognition. Thus, for financial sake, perhaps the appointment of a designated decision-maker is as important as the designated driver, when setting out on multiple sleepless nights in Vegas.
Original article can be found at: http://www.jneurosci.org/content/31/10/3712.full