My long-suffering, long-time readers know how I feel about the necessity of having (good) snacks at ANY function where you expect the faculty to function. The way I see it,  food at things like teacher trainings (didn’t they used to be called in-services?) and faculty meetings and management team meetings and basically any sort of teacher-type meeting serves three important purposes:

1. It gets people talking. So-called PLCs-professional learning communities–are all the rage these days. All it really means is giving teachers enough time and incentive to sit around and talk about teaching and lesson ideas and the kids they have in common and what to do to help them. I had a principal about 10 years ago who had been a home ec teacher. She was also the best principal I’ve had, and not just because she fed us well. But feed us she did. During the holidays, it wasn’t unusual for her to show up for a faculty meeting with a roast and pie! Mmmmm, pie. Anyway, every one of those meetings was a buzz of talking… and not just about the food. It was about kids and lessons and everything else about teaching and our school. Eating gets people talking.

2. Yes, it’s a bribe. I suspect I am not the only one who is more amenable to listening to someone who has just fed me some tasty hors d’oeuvres, than I am if I am staring at Folgers and bottled water for the next couple hours.

3. It provides calories to the brain. Thinking takes a lot of calories. Just sitting around doing no thinking, the brain takes 20% of our calories. When we actually use it to listen and understand and think, that percentage goes way up. I’m reading a great book called Thinking, Fast and Slow, by Daniel Kahneman, and he talks about this idea.

The most surprising discovery made by Baumeister’s group shows, as he puts it, that the idea of mental energy is more than a mere metaphor. The nervous system consumes more glucose than most other parts of the body, and effortful mental activity appears to be especially expensive in the currency of glucose. When you are actively involved in difficult cognitive reasoning or engaged in a task that requires self-control, your blood glucose level drops. The effect is analogous to a runner who draws down glucose stored in her muscles during a sprint. The bold implication of this idea is that the effects of ego depletion could be undone by ingesting glucose, and Baumeister and his colleagues have confirmed this hypothesis in several experiments.

Volunteers in one of their studies watched a short silent film of a woman being interviewed and were asked to interpret her body language. While they were performing the task, a series of words crossed the screen in slow succession. The participants were specifically instructed to ignore the words, and if they found their attention drawn away they had to refocus their concentration on the woman’s behavior. This act of self-control was known to cause ego depletion. All the volunteers drank some lemonade before participating in a second task. The lemonade was sweetened with glucose for half of them and with Splenda for the others. Then all participants were given a task in which they needed to overcome an intuitive response to get the correct answer. Intuitive errors are normally much more frequent among ego-depleted people, and the drinkers of Splenda showed the expected depletion effect. On the other hand, the glucose drinkers were not depleted. Restoring the level of available sugar in the brain had prevented the deterioration of performance. It will take some time and much further research to establish whether the tasks that cause glucose-depletion also cause the momentary arousal that is reflected in increases of pupil size and heart rate.

A disturbing demonstration of depletion effects in judgment was recently reported in the Proceedings of the National Academy of Sciences. The unwitting participants in the study were eight parole judges in Israel. They spend entire days reviewing applications for parole. The cases are presented in random order, and the judges spend little time on each one, an average of 6 minutes. (The default decision is denial of parole; only 35% of requests are approved. The exact time of each decision is recorded, and the times of the judges’ three food breaks—morning break, lunch, and afternoon break—during the day are recorded as well.) The authors of the study plotted the proportion of approved requests against the time since the last food break. The proportion spikes after each meal, when about 65% of requests are granted. During the two hours or so until the judges’ next feeding, the approval rate drops steadily, to about zero just before the meal. As you might expect, this is an unwelcome result and the authors carefully checked many alternative explanations. The best possible account of the data provides bad news: tired and hungry judges tend to fall back on the easier default position of denying requests for parole. Both fatigue and hunger probably play a role.

No way? Really?