Study finds heavy drinking creates a blind spot for angry expressions

A study investigating the effects of alcohol on emotion recognition and empathy found that alcohol impairs the recognition of anger, but not other specific emotions. Participants who drank alcohol also reported higher affective empathy, i.e., relating better to other study participants. The research was published in Scientific Reports.

After a person drinks alcohol, it is rapidly absorbed through the stomach and small intestine into the bloodstream. The alcohol then travels to the brain, where it affects the release of neurotransmitters, producing relaxation and reduced inhibition. As blood alcohol concentration rises, judgment, coordination, and reaction time become increasingly impaired. The liver begins metabolizing alcohol, but it can only process a limited amount per hour, causing excess alcohol to circulate in the body.

Alcohol also affects the cardiovascular system by dilating blood vessels, which can create a sensation of warmth while actually lowering core body temperature. In the short term, drinking can increase urine production, leading to dehydration and electrolyte imbalance. The gastrointestinal system may become irritated, resulting in nausea or vomiting at higher doses.

As alcohol continues to circulate, it disrupts normal sleep, reducing restorative REM sleep despite making people feel sleepy. When blood alcohol levels begin to fall, withdrawal-like symptoms such as anxiety or irritability may appear in some individuals.

Study author Lakshmi Kumar and their colleagues investigated how an intoxicating dose of alcohol (0.74 g/kg in females and 0.82 g/kg in males) affects cognitive and affective empathy. As prior studies were inconclusive, they started this investigation with no specific hypotheses about the directions of the expected effect.

Study participants were 156 individuals who reported drinking at least one day per week and binge drinking at least four times in the past month. Participants’ average age was 23 years. Thirty-one percent of participants were women.

Binge drinking was defined as 5 or more standard alcoholic drinks on the same occasion for men and 4 or more for women. A standard alcoholic drink is a drink containing about 14 grams of pure ethanol. This is roughly equivalent to a small beer (350 ml), a glass of wine (150 ml), or a shot of spirits (45 ml).

Participants were randomly assigned to groups of 3 unacquainted persons. Each of these 3-person groups was then randomly assigned to either drink an alcoholic beverage or a placebo beverage. In this way, 117 participants were assigned to drink alcohol and 39 to drink the placebo beverage. However, participants did not know which beverage they would be drinking – they all believed that they would be drinking alcohol.

The alcoholic beverage was a cranberry-vodka cocktail dosed for each participant to achieve a peak blood alcohol concentration of 0.08%. The placebo drink was flattened tonic water, and study authors showed these participants false blood alcohol level recordings to maintain their belief that they were drinking alcohol.

After drinking the assigned drink, participants completed 3 assessments of subjective intoxication experience and blood alcohol level (using a breathalyzer) in 30-minute intervals. While the blood alcohol level was increasing after drinking, participants completed assessments of empathy and emotion recognition (MET and GERT, tests based on recognizing emotions of people in photographs and in short video clips).

Results showed that participants who drank alcohol had impaired recognition of anger, but no other specific emotions. These individuals also reported higher affective empathy, i.e., that they related well to another participant, in response to direct interactions with other participants.

“Findings suggest alcohol worsens anger recognition and increases perceptions of relating to another,” the study authors concluded.

The study contributes to the scientific understanding of the psychological effects of alcohol. However, study authors note that participants interacted in groups of strangers (other study participants they were not previously acquainted with) prior to completing the emotion recognition and empathy assessments. Differences in these interaction experiences could have affected participants’ levels of engagement and subsequently reported empathy.

The paper, “Alcohol’s acute effects on emotion recognition and empathy in heavy-drinking young adults,” was authored by Lakshmi Kumar, Kasey G. Creswell, Kirk W. Brown, Greta Lyons, and Brooke C. Feeney.