Researchers at the University of Sydney have uncovered a fascinating phenomenon called “serial dependence” that reveals how our visual perceptions can unconsciously influence the way we evaluate and choose food. This study provides valuable insights for food marketers, clinicians, and anyone interested in the complex interplay between our eyes, brains, and appetites. Visual perception and cognitive biases play a bigger role in our food decisions than we might realize.
The Power of Precedence
The study, which features in the journal Current Biology, shows that perceptions of food are not made in isolation. They are just in turn biased, but a little more subtly this time via the evaluations that came before them. It’s a psychological phenomenon called “serial dependence” and shows up when people are faced with a series of consecutive decisions to make.
This means, in a food context, if a person has rated one food highly appealing they are more likely to say the next dish is also appealing — regardless of how many calories it contains or how delicious it sounds. If on the other hand, a food from before had been unattractive, the current one will be rated less pleasant hon the score. This is a huge cascade that can really change our relationship with foods and how we shift the way we live without us even knowing about it.
Dissecting the Neuromechanisms
Over 600 participants took part in the study by researchers led by Professor David Alais, who were asked to rate how much calorie content and appeal they thought there was in a variety of images of food. The results suggested a robust presence of serial dependence in the participants’ ratings, that is to say, ratings were generally positively auto-correlated with prior judgments.
The visual brain appears to reference caloric content of foods in just a few hundreds of milliseconds, potentially guiding subsequent evaluations. Professor Thomas Carlson, co-author of the study, says: “Our prior work has shown that the brain encodes the calories of foods at a glance in less than a tenth of second. AJ Wrankoff: “It would be interesting to see how these cognitive biases interact with visual processing in future work.
What this means for food marketers and clinicians
The practical implications of this study are numerous and could significantly inform various applications, from marketing and clinical interventions. Serial dependence can indicate how food marketers and restaurateurs should present and sequence menu items to make the most of their appeal, ultimately helping stimulate sales.
In a clinical context, an understanding of conditioning through these prior food ratings might lead to better cognitive-behavioral therapies for binge eating disorders, obesity or even simple compulsive eating. Therapists could use such insights to alter the ways in which patients think and make decisions about food, and thus improve their compliance with recommended diets or reduce dropout from obesity treatment.
In addition to these obviously low-level aspects of colour perception, Professor Alais and his team have found similar visual trends seen in other contexts too (be they people’s assessments of dating profiles or the beauty of paintings). Together, these data show that serial dependence may be a widespread cognitive mechanism underlying our choices and behaviors in the (real world) environment beyond food choice.
