A study on parole judges in Israel…
Experienced parole judges with several decades of experience in the legal system typically come to a prison and spend entire days reviewing applications for parole. With a big backlog of complicated cases to wade through, they start very early in the morning, wherein cases are presented in a random order. The judges spend little time on each case- an average of 6 minutes.
Only 35% of requests are approved with a default decision being denial of parole. In this study, the exact time of each decision and the times of the judges’ three food breaks – morning break, lunch, and afternoon break were recorded as well.
When they analyzed the proportion of approved requests against the time since the last food break, the investigators were in for a surprise!
They noticed that after each meal, the proportion of successful parole being granted spiked to about 65% of requests. However, during the two hours or so until the judges’ next meal, the approval rate drops steadily, to about zero just before the meal.
What is going on here? Decisions by very experienced judges being influenced by their meals!
This and many other experiments later resulted in Daniel Kahnemann, a behavioral psychologist, to became the first non-economist to win a Nobel Prize in Economics in 2002. Kahnemann’s field is the psychology of decision-making. This irrational decision-making and thinking, even on the part of highly trained and experienced judges goes to the very heart of how we human make decisions.
Kahnemann posits that our brains think in two completely different modes, one is the fast thinking mode and the other the slow thinking mode.
Fast thinking as the name indicates is quick to the draw, automatic, and completely unconscious as it reaches a decision point or conclusion. For instance, if someone throws a ball towards one’s head, we do not laboriously analyze the ball’s trajectory, its speed, or its approaching angle. Our brains take the few pieces of data available to it and make a quick decision- to duck or get out of the balls trajectory. Similarly, expert intuition is a way of fast thinking when one comes up with solutions that have worked in the past.
Slow thinking, on the other hand, is deliberate, deals with orderly computation, rules, and reasoning. As it takes in more data points it is slow to action or to reach a conclusion. This slow thinking mode also monitors our thoughts and monitors the actions or what one says taken. However, slow thinking mode, though may be more accurate requires fuel to sustain it.
Parole judges are utilizing slow deliberate thinking when going over the parole applications. These judges, when tired, hungry and depleted, fall back on the easier default position of denying requests for parole. This discrepancy occurred inspite of their training and years of experience in evaluating justly such cases.
So yes, people are strongly influenced by the level of glucose in the brain. Our brains are energy efficient machines which, when low on glucose, limit our expenditure by avoiding effortful mental computations. Cognitive tasks and logical decision-making suffers when our brains are energy depleted.
Physiologically, the blood-glucose level on which the brain depends for fuel substrate, begins to drop several hours after a meal. In response, to maintain blood glucose levels our body increases the secretion of the hormone glucagon that stimulates the breakdown of stored glycogen in the liver to replenish blood glucose levels. If fasting continues and the glycogen stores are depleted within few hours, the body as a smart machine, starts to convert proteins and fats from fat stores to produce fuel for the body. If starvation continues for several days, the body tries to curtail protein losses from muscles, by forming large amounts of ketones from mobilized fat in the liver. The ketones thus formed are released into the blood. At this time, the brain deprived of glucose begins to consume appreciable amounts of ketones in lieu of glucose. After about 3 days of starvation, about a third of the energy needs of the brain are met by ketone bodies. Now, only 40 grams of glucose is then needed per day for the brain, compared with about 120 g in the first day of starvation. Ketones utilization allows sparing of muscle proteins breakdown as only 20 grams of muscle is used daily to produce glucose compared with 75 grams early in starvation. This is most important for survival for animals (including humans in the hunter-gatherer era) which depend on being able to move rapidly and requires a large muscle mass. Use of ketone, thus minimizes muscle loss.
The implications of such a study are tremendous for decision-making processes. It is important for people to be more careful when they are hungry. It turns out that when we describe ourselves as mentally ‘drained’, we are actually being very accurate. Once our stores are depleted, we exercise less self-control, becoming irritable, easily distracted, unmindful of what we say and more likely to succumb to temptation. Willpower – interestingly – is closely tied to glucose.
For those who followed Adelle Davis’s- the famous nutritionists advice from the mid-20th century ‘Eat breakfast like a king, lunch like a prince and dinner like a beggar’ Are we correct?
For those going to do mental heavy-lifting and major decision making in the morning going in without food to fuel one’s brain is asking for trouble. Are you going to ask the cardiac surgeon who is going to operate on your heart that morning ‘have you had breakfast this morning? After all, I am talking about my life in your hands.” “If not, you should for my sake.”