Today you think you're just sitting down with loved ones to enjoy some turkey and pie and reflect on the blessings in your life. And it's true, you're definitely going to do all that (and maybe catch some football too). But according to science, there's a deeper level to feasts like Thanksgiving.

While feasts are a simple pleasure for participants, on the societal level, gathering together to stuff ourselves with food and drink and share (and display) our wealth was actually one of the primary drivers of complex modern society. Without feasts we might all still be living as hunter-gatherers, Canadian archeologist Brian Hayden argues in a fascinating and timely Aeon post (hat tip to Science of Us for the pointer).

After offering colorful descriptions of some truly lavish feasts from his field work that put even the biggest Thanksgiving gathering to shame, Hayden gets down to the business of explaining how these sort of mass celebrations cemented alliances and drove us to produce more food and more wealth. In the traditional feasts he studies, Hayden explains,

those who are invited, and who often receive gifts, are considered obligated to reciprocate the invitation and gifts within a reasonable amount of time. By accepting invitations to feasts, individuals enter into relationships of alliance with the host. Each of them supports the other in political or social conflicts as well as in economic matters. Such support is critical because social and political conflicts are rife in tribal villages, with many accusations of infidelity, theft, sorcery, inheritance irregularities, unpaid bills, ritual transgressions and crop damage from other people's domestic animals. In order to defend oneself from such accusations and threats of punishment, individuals need strong allies within the community. Feasts are a way to get them.

And while the content of our conflicts (less sorcery these days, more unreasonable landlords and downsizing employers) and the menu (less water buffalo, more yummy stuffing), this dynamic still holds for modern Thanksgiving. Despite crankily complaining about having to discuss politics with insane uncles, many of really do still use the holiday to reconnect with the family and friends we count on most for mutual aid in tough times.

Hayden goes on to explain how these simple bonds of loyalty eventually led a few super successful feast hosts to accumulate great political power and began to create the complex, hierarchical world we live in today. Feasts, he further notes, helped drive us to produce more food and wealth than we needed just for our own survival, and even to domesticate animals.

Feasts tend to be competitive because the underlying motive for feasting is to secure advantageous relationships via debts (for marriage, defense or economic endeavors). This competitiveness pressures organizers to produce or acquire enormous amounts of foods, especially meat, starches and alcohol [some things never change]. In fact, given the competition based on gifts (that is, debts) of food and prestige items, there could never be enough food since someone was always trying to produce more in order to out-compete his rivals. It is these competitive feasting pressures that, I argue, resulted in the domestication of plants and animals.

These days Thanksgiving might not spur us economically much beyond working to afford that insanely priced plane ticket home, but it's interesting to know when you sit down at the table today that you're participating in a tradition that reaches back to the dawn of civilization and which helped shape the world as we know it today.

Enjoy your turkey!