Psychologists investigate the broccoli paradox

broccoli PR

5 May 2017

  • If we believe our friends love vegetables - we eat them less
  • But we are poor judges of how much others’ like different foods and drinks

If we think our friends really enjoy eating broccoli, we are less likely to consume it ourselves.

That is one of the conclusions of research being presented today, Friday 5 May 2017, by Dr Jason Michael Thomas from Aston University to the annual conference of the British Psychological Society in Brighton.

In their research, psychologist Dr Thomas and his colleagues asked 227 participants (145 women, 80 men and 2 other) aged between 17 and 63 (average age 32) about the foods and drinks they liked and about both which foods and drinks their friends liked and how much of them they consumed. The foods discussed were vegetables, fruit and junk food, and the drinks were sugar-sweetened beverages and alcohol.

The results showed that how much of a particular food or drink someone consumes is linked to how much of it they think their friends consume (the more our friends consume, the more we consume). This reinforces what psychologists have learnt about social norms being a key influence on our eating and drinking behaviour.

But they also found a paradoxical effect: if we think our friends like vegetables we are less likely to eat them ourselves.

Jason said: “It is possible that the perception of particularly low or high enjoyment of vegetables by our peers produces such counterintuitive effects. For instance, if we think our friends like vegetables greatly, it might drive down our consumption if this differs from our own experience.”

The researchers also found that we are bad at judging how much our friends like different foods and drinks.

He added: “We tend to think that we like healthy foods more and unhealthy food and drinks less than our peers. Maybe it’s a bit like driving: we all think we are better than average at it.”


Notes to the editor

  • The British Psychological Society (BPS)is the representative body for psychology and psychologists in the UK, responsible for the development, promotion and application of psychology for the public good.For more information visit
  • BPS’s annual conference takes place from 3 - 5 May at the Hilton Brighton Metropole. For details of the programme visit
  • Poster title: ‘Do we eat and drink like others or drink and eat what others like? Misperceptions of social norms.’’ The study was sponsored by Direct Line Insurance Group and Charlton House & Company.
  • Founded in 1895 and a University since 1966, Aston University has been always been a force for change. For 50 years the University has been transforming lives through pioneering research, innovative teaching and graduate employability success. Aston is renowned for its opportunity enabler through broad access and inspiring academics, providing education that is applied and has real impact on all areas of society, business and industry.

For further information:  

DURING THE CONFERENCE (until 5 May) call the conference press office on: 07793 800 366 / 07773 173 510 or email

AFTER THE CONFERENCE contact the British Psychological Society Press Centre: 0116 252 9500 / 07773 173 510or email

For more information about Dr Jason Thomas contact Aston University’s media team Susi Turner/Ben Kennedy on 0121 204 4978/ 4592 or email /

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