Will A Turkey Inspire You to Trust People?

Do you really trust those people you share meals with during the holiday season? Do you know just how much turkey we eat during those meals? And what does one have to do with the other anyway? Between Thanksgiving and Christmas Americans consume about 67 million turkeys. In fact, according to the University of Illinois, 29% of all turkeys gobbled down in the U.S. are consumed during the holidays. 'Tis the season for giblets, wattles, and snoods - oh my!

And where turkey is being eaten there is inevitably talk of tryptophan - a naturally occurring chemical found in turkey and other foods that makes you sleepy soon after the meal. But actually it doesn't. Tryptophan alone cannot explain the popular turkey-makes-you-sleepy phenomenon. It turns out there are far more important factors. Scientists have concluded, for example, that two-thirds of all post-turkey comas are brought on by my Uncle Carl's story about parking at the airport. So there is that, plus the very real fact that lots of booze combined with a load of carbohydrates followed by lots of booze can lead to feelings of sleepiness. OK that explains that. But does tryptophan do anything?

Although the effects of L-tryptophan (TRP) on drowsiness are minimal, researchers in the Netherlands have discovered that doses of it can promote interpersonal trust. I'm talking about that feeling you get when you look somebody in the eye, shake their hand and think, "I can cooperate with this person and they would reciprocate."

In a study published in the October 2013 edition of the journal Psychological Science, volunteers were given an oral dose of TRP or a placebo. Each pair then sat in separate cubicles and played a game where one person (the truster) was given $7 and had to decide how much to transfer to the other person. The transferred money was then multiplied by 3 and the trustee could give back part of the tripled money. The more money you are willing to give away in the first place the greater your return in the end, but only if you trust the other to cooperate. A very simple and profitable game if played right.

The researchers found that the TRP group gave $4.81 on average and the placebo group offered only $3.38. This is a 42% increase in transferred money between the placebo group and the tryptophan group!

Does this mean that if I eat too much turkey I'll actually respond to the emails I get from Nigeria requesting an urgent business relationship? Or from the guy in the Democratic Republic of Congo who is "in need of my immediate assistance?" Not likely. There is no evidence that TRP makes you fall for internet scams. Some people just seem to be especially vulnerable to phone and internet cons - but that's a story for another day. Here is the brain science behind how the tryptophan-trust connection works.

TRP is an essential amino acid found in many foods including eggs, soybeans, chocolate, cheeses, fish, nuts, and, of course, turkey. The brain region associated with interpersonal trust, called the medial prefrontal cortex, is powered by serotonin. This very important neurotransmitter is controlled in part by the release of TRP. This means that as you increase levels of TRP you are releasing serotonin in the brain region specially designed to process trust. Think of a flashing neon sign that reads trust this person, trust this person.

Keep in mind, however, that our decisions to trust or not to trust do not rely solely on ingesting TRP. In the real world we take into account personality factors, how well we know someone, previous cooperation with that person, tone of voice, eye contact, body language, etc. These all have a hand in shaping the conscious and unconscious rules that govern our pro-social behavior and trust preferences.

So this holiday season eat your turkey (or salmon, cashews, cottage cheese, and chocolate) and enjoy the company of loved ones. It may or may not be the tryptophan working on your mind, but either way you'll enjoy it. Just trust me.

   By Kevin L Bennett