Biases of memory and cognition as contributors to, and consequences of, people's inferences about healthiness

  • Christopher Paul Delivett

Student thesis: Doctoral ThesisDoctor of Philosophy


Because ‘healthiness’ cannot be directly experienced, people primarily understand their own healthiness—and that of the foods they consume—by making inferences. But such inferences are rarely based on the totality of information available. For example, regardless of accuracy, information that feels intuitively familiar or is retrieved from memory more easily is typically appraised more positively. Through six pre-registered experiments, this thesis examines how people’s inferences about healthiness inform what they (mis)remember about food products, as well as what people infer about their own healthiness from their recollections of eating.

Experiments 1 and 2 demonstrate that health-related package images increased participants’ tendency to falsely remember reading health claims about those products, even when the products were labelled as an ‘unhealthy’ food. In Experiment 3, the inclusion of a health-related image on a dietary supplement’s packaging increased its perceived health benefits, and decreased the perceived risks, but only when the image was related to the product’s supposed function. The data fit with the interpretation that package images afforded people a quick and easy sense of comprehension, which led to more positive product evaluations.

Experiments 4-6 found—counter to initial predictions—participants formed more favourable impressions of their own diets having recalled many instances of eating healthily, rather than few instances (and vice-versa for eating unhealthily), which in turn effected the healthiness of their future eating preferences and motivations. Exploratory mediation analyses nevertheless suggested the subjective difficulty of recall may have functioned as a suppressor variable, insomuch as it appeared to partially counteract this numerosity effect.

Collectively, these findings demonstrate that people’s health-related inferences can be influenced by the ease with which information is processed and/or retrieved from memory. These data have important implications for the way in which health imagery is used in food marketing, in addition to how memory retrieval could be used to encourage healthier food choices.
Date of AwardNov 2021
Original languageEnglish
SupervisorRobert A. Nash (Supervisor), Jason Michael Thomas (Supervisor) & Claire Farrow (Supervisor)


  • processing fluency
  • food
  • imagery
  • front-of-pack labelling
  • memory

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