To understand behavioral pathologies in humans, the scientific world often turns to animals. One area where this is extremely beneficial is in the examination of behaviors relating to alcohol or drugs. Understanding how humans make decisions about alcohol is important in preventing alcohol abuse.

A recent study looked at the behaviors of drosophila flies when offered food laced with ethanol. Devineni and Heberstein completed a study in 2009 that looked at the drinking behavior of the flies to see if it mirrors human behaviors and whether genetic mutations impact the results.

The study offered the drosophila flies the choice between ethanol-containing food and nonethanol-containing food. Their behaviors were examined and were identified using a preference index, which was measured as (ethanol consumption – nonethanol consumption / total consumption).

The preference index, or PI, ranged from -1 to 1. Positive numbers indicated a preference for the presence of ethanol.

The researchers measured several factors in the behaviors of the flies. They examined the basic preference of the flies and the pattern of preference change across time and concentration shifts. They also looked at the preference change after a period of starvation or complete ethanol deprivation and finally, the ethanol preference of different mutations.

The results of the study show that the flies preferred food containing ethanol, even when the caloric content was consistent across the choices. The preference for ethanol-containing food increased for a few days, but then leveled off after 4 or 5 days.

The researchers found that the level of preference for ethanol increased as the dose of ethanol increased. Also, starved flies consumed ethanol sufficiently to produce behavioral intoxication.

When the flies were denied ethanol for several days, they quickly resumed ethanol consumption when they were offered it.

One finding of the study involved a particular mutant, called krasavietz (“handsome” in Russian) that showed a lower initial preference for ethanol than the other flies. The “handsome” flies showed no preference for alcohol during the first two days.

The study offers some limitations, specifically related to differences in animal and human alcohol dependence. Animals do not have the same social and cultural factors involved in decision making that humans experience.

The study has several implications helpful for understanding alcohol-related behaviors in humans. The flies mirrored humans in their patterns of initial attraction to alcohol, with a leveling-off after several days. They also resembled human patterns with relapse after deprivation, despite the adverse taste and intoxicating effects.

The difference in the “handsome” flies may also lend important information to understanding human drinking choices. There may be genetic mutations that need to be explored to understand why some people are more attracted initially to drinking alcohol than others.