The humble prairie vole was briefly famous because of research into love and voles. Researchers such as Larry Young found that the prairie vole is one of the few socially monogamous mammals that pair bonds for extended periods of time (even for life). Interestingly, this bonding does not occur naturally in other varieties of voles—they behave like typical mammals, such as many politicians.

Larry Young found that the brains of the voles are such that the pleasure reward of sexual activity becomes linked to a specific partner. This mechanism involves oxytocin and vasopressin, and the voles become, in effect, addicted to each other. This is like how a smoker becomes addicted to cigarettes and associates pleasure with the trappings of smoking.  To confirm this, Young genetically modified meadow voles to be like prairie voles. The results showed that the bonding is probably due to the chemistry: the normally non-bonding meadow voles engaged in bonding behavior.

Humans, unlike most other mammals, also engage in pair bonding (sometimes). While humans are different from voles, the mechanism is presumably similar. That is, we are addicted to love.

Young also found that prairie voles suffer from heart ache: when a prairie voles loses its partner, it becomes depressed. Young tested this by dropping voles into beakers of water to determine the degree of struggle offered by the voles. He found that prairie voles who had just lost a partner struggled to a lesser degree than those who were not so bereft. The depressed voles, not surprisingly, showed a chemical difference from the non-depressed voles. When a depressed vole was treated for this depression, the vole struggled as strongly as the non-bereft vole.

This seems to hold for humans as well. While humans typically become saddened by the loss of a partner (by death or breakup), this research suggests that human depression of this sort has a chemical basis and could be cured. This is what is often attempted with therapy and medication.

While the mechanical model of love (and the mind) might seem new, the idea of philosophical materialism (that everything is physical in nature) dates to Thales. Descartes saw the human body as a purely mechanical system, albeit one controlled by a non-material mind. Thomas Hobbes accepted Descartes view that the body is a machine but rejected Descartes’ dualism. Influenced by the physics of his day, Hobbes held that a human being is a deterministic machine, just like all other machines and living creatures.

Perhaps the most explicit early development of the idea of humans as machines was in Julien de La Mettrie’s Man a Machine.  While La Mettrie is not as famous as Hobbes or Descartes, many of his views are duplicated today by modern scientists. La Mettrie held that humans and animals are essentially the same, although humans are more complex than other  animals. He also held that human beings are material, deterministic, mechanist systems. That is, humans are essentially biological machines. Given these views, the idea that human love and vole love are essentially the same would probably be accepted by La Mettrie and would, in fact, be exactly what his theory would predict.

Contemporary science is continuing the project started by philosophers like Thales, Hobbes and La Mettrie. The main difference is that contemporary scientists have much better equipment to work with and can, unlike La Mettrie and Hobbes, examine the chemical and genes that are supposed to determine human behavior. Probably without realizing it, scientists are proving the theories of long dead philosophers.  The chemical theory of love does have some rather interesting philosophical implications and some of these will be considered in upcoming essays.