SLEEP DEPRIVATION and DECISION-MAKING:
IT seems that most people I talk to seem to subject themselves to some pretty nasty sleeping habits sometimes. From university students to housewives, it seems everybody is sleeping less, working more and then partying harder on the weekend to compensate. I decided to find out what the facts were about staying awake.
Well, if you deprive yourself of sleep, experts say, and you are handicapping your brain. In this contemporary world where time is worth money and money is worth everything, spending those extra few hours awake each day may cause you more problems than its worth. Extended periods of wakefulness or a decrease in sleep over an extended period of time is now accepted as being damaging to your immune system. More recently, however, neuropsychologists have
demonstrated that particular areas in the frontal lobe of the brain are particularly sensitive to sleep deprivation. This weakens the brain’s capacity for higher-order cognitive processes, such as learning, memory, problem solving and in particular, one’s capacity to make valid decisions.
Our ability to make good decisions is not just governed by our genes or how we are raised as children, scientists say. A study undertaken by William Killgore, Thomas Balkin and Nancy Wesensten at the WRAIR (Walter Reed Army Institute of Research) measured the extent to which sleep can have an effect on our judgment and decision-making abilities. The team, who also conduct sleep research for the Federal Aviation Administration (FAA), used a psychological test known as the Iowa Gambling Task (IGT), which mimics real-world decision-making in uncertain conditions. This test requires participants to choose decks of playing cards, and be adaptive with their choices as they learn to avoid high-risk decks and instead choose the more predictable, low-risk decks. Sleep deprived participants tended to choose more frequently from risky decks as the game progressed.
The Iowa Gambling Task was originally developed in 1994 by Antoine Bechara, Hanna Damasio, Daniel Tranel and Antonio R. Damasio, a research team at the University of Iowa Department of Neurology. It was created in order to study cognitive patterns in brain-damaged patients. Over the course of a decade, they identified a relationship between higher-order cognitive processes (such as decision making), and damage to a particular region of the frontal lobe. As their research progressed, the function of this portion of the brain became clear. This area, the ventromedial prefrontal cortex, is an area in the front part of the brain that controls many executive functions. These are our abilities to determine good from bad, predict consequences of actions, work toward a defined goal, and social "c
ontrol" (the ability to suppress urges that, if not suppressed, could lead to socially unacceptable or frankly illegal outcomes). The patterns the research team at University of Iowa had found in cognitive abilities in cases of brain damage to the prefrontal cortex were similar to the results from the team at WRAIR: sleep deprivation caused the same effects (but to a lesser extent) in the Iowa Gambling Task, as damage to the prefrontal cortex.
So it would seem that cognitive functions known to be centered on the ventromedial prefrontal cortex, especially decision making in conditions of uncertainty, may be particularly vulnerable to sleep loss. The frontal lobe’s vulnerability to sleep loss was also detected by a team at Harvard University who were studying the effects of the frontal lobe on sleep regulation. Furthermore, they noted that susceptibility to impaired function from sleep loss may become more pronounced with increased age: the older you are, the more sensitive you are to not getting a good night’s sleep.
Sleep deprivation has such a marked effect as it reduces the cerebral metabolism (the brain activity) within the prefrontal cortex. This reduction in brain activity effectively throws in the towel for your chances to make a correct decision when placed in a situation of uncertain outcomes – something to remember the next time you’re driving tired, or writing an article late at night!
‘The older you are, the more sensitive you are to not getting a good night’s sleep’
Researchers at the Loughborough Sleep Research Centre have been able to observe sleep deprivation’s specific effects on decision making by using an adapted computer game called Masterplanner. Not unlike the Iowa Gambling Task, the test’s results indicated the same underlying principles as the WRAIR research team; sleep deprivation may affect the whole brain, but areas of the frontal lobe are hypersensitive to lack of sleep. A person may be able to respond to a complex scenario when it is suddenly presented, however, the participant will most likely pick an unoriginal solution. If presented with a similar situation multiple times with slight variations in the information presented the participant chooses the same solution, even though it might not be as applicable to the new scenario. So it was shown that a sleep-deprived brain tends to use solutions that have worked for previous problems, even when the solution isn’t really suitable for the current problem.
In a contemporary context, sleep deprivation and research into its effects has never been more relevant. In a world where individuals regularly extent their waking hours in order to achieve more in their limited waking hours, there is a distinct need to understand the underlying effects. Research has shown us, thus far, that a lack of sleep impairs many brain functions such as memory and processing of the senses, but particularly sensitive to sleep loss, is decision making. The sleep-deprived brain is not just ‘sluggish’, but actively unoriginal in the way it makes decisions and solves problems, resorting to solutions it found for previous situations. Intrinsically linked into our modern-day society and perhaps Western culture in general, sleep deprivation exists on a massive scale. In order to understand its effects on the population, it is critical that more studies are undertaken to fully understand the psychological and physiological effects of not getting enough sleep.
-Edward Joel Mendelson
Bechara, A., Damasio, H., Damasio, A., & Lee, G. (1999). Different contributions of the human amygdala and ventromedial prefrontal cortex to decision-making. The Journal of Neuroscience, 19 (13), 5473-5481.
Bechara, A., Tranel, D. & Damasio, H. (2000). Characterization of the decision-making deficit of patients with ventromedial prefrontal cortex lesions. Brain, 123(11), 2189–2202.
Jones, K. & Harrison, Y. (2001). Frontal lobe function, sleep loss and fragmented sleep. Sleep Med. Rev., 5, 463–475.
Killgore, W., Balkin, T., & Wesensten, N. (2006). Impaired decision making following 49 hours of sleep deprivation. Journal of Sleep Research, 15(1), 7.
Muzur, A., Pace-Schott, E., & Hobson, J. (2002). The prefrontal cortex in sleep. Trends in Cognitive Sciences, 6(11), 475-481.
