Copycat eating: how we subconsciously keep time with dining partners

Researchers have found female diners unconsciously copy the actions and intake of their companions. Flickr/iambents

Young women who dine together tend to mimic each other’s eating behaviour to the point where they eat about the same amount and even take bites at similar times, research has found.

A study of 70 pairs of young women who shared meals under observation from researchers found that unconscious behavioural mimicry could partially explain not just how much each woman ate, but when.

Several studies have shown that when people share meals, they tend to eat a similar amount as their companions. In this study, however, researchers paired female diners who did not know each other, and noted the timing and number of their bites. The results appear in the latest edition of the journal PLoS ONE.

Developmental psychopathologist Roel Hermans and colleagues from the Radboud University Nijmegen in the Netherlands set up a “lab restaurant”, where they served full meals to participants who were seated opposite each other - then watched them secretly from adjacent rooms.

One of the pair was allowed to eat as little or as much as she liked. The other was told beforehand to eat a small, medium or large amount of food.

By the end of the 20-minute meal, the amount of food eaten by participants in each pair, measured in grams, closely correlated.

The results also showed that the “young females generally mimicked each other’s eating behavior,” the authors wrote. That is, both women were more likely to take a bite within 5 seconds of their companion than not.

“The matched actions of both eating companions fall within the typical definition of behavioral mimicry … the process in which a person unwittingly imitates the behavior of another person.”

Both women were more than three times as likely to mimic the intake of their eating companion in the first 10 minutes compared to the last.

“It is possible that young women’s tendency to ingratiate themselves with their eating companion was especially marked at the beginning of the interaction, resulting in an increased likelihood of behavioral mimicry,” the authors wrote.

They cautioned that their study did not rule out the possibility that the young women deliberately adjusted their behaviour to match perceptions of ‘appropriate’ eating.

But Dr Lenny Vartanian, a senior lecturer at the University of New South Wales’ School of Psychology, said his own studies had suggested that people were not making decisions at “a conscious, deliberate level” when modelling their eating on the behaviour of those around them.

“Afterward, when we asked people why they ate as much as they did, almost none of them said it was because of what the other people ate, or because of what they felt was appropriate.

"Invariably, they rated hunger and taste as the main factors. I don’t think they had any idea what they were doing.”

Dr Vartanian said the research might have implications for children with parents or older siblings who were obese or had big appetites.