A glass of wine is enough to compromise a person’s sense of agency

Sense of agency, the feeling of being in control of our actions, can be compromised by one pint of beer or a large glass of wine, according to a new paper

The study focused on low doses of alcohol, typically consumed during social drinking, that are not  considered to produce a large impairment of behavior, unlike the well-established loss of inhibitory control produced by obvious drunkenness, perhaps manifested by impulsivity, aggression, and risky behavior.

Dr. Silvana De Pirro, lead author of the research paper and neutoscientist at the University of Sussex, said, “Measuring a person’s sense of agency is tricky. When people are explicitly asked to tell how in control they feel, their answers are affected by several cognitive biases, such as poor introspection, the desire to conform to researchers’ expectations, or even the inability to understand the question correctly.”

The researchers used an indirect measure called ‘intentional binding’, which has been developed to investigate the unconscious mechanisms of ‘volition’. When physical stimuli (such as sounds or lights) follow voluntary actions (such as moving a finger or a hand), people judge actions as occurring later and stimuli as occurring earlier than in reality, hence ‘binding’ the two. The neural mechanisms responsible for this phenomenon are thought to participate in creating the sense of agency.

In the experiments, subjects drank a cocktail containing doses of alcohol proportional to their BMI to produce blood alcohol concentrations within the legal limits for driving in England and Wales. These doses of alcohol, corresponding to one or two pints of beer, produced tighter binding between voluntary actions and sensory stimuli. This suggests that small amounts of alcohol might exaggerate the sense of agency, leading to overconfidence in one’s driving ability and to inappropriate, potentially dangerous behavior.

If even one pint of beer is enough to significantly compromise a person’s sense of agency, are the legal limit for driving in England, Wales (currently 80 mg/100 ml) and Scotland (50 mg/100 ml) low enough?