Is memory for food affected by its ‘biological relevance’?

Humans may be predisposed to encode and retain ‘biologically significant’ information (i.e., information relevant to survival and fitness). Thus, the extent to which a novel food is remembered may depend on subsequent detection of its energy density after a meal has terminated. The present study tested this proposition. Sixty participants were allocated to either a ‘high’ (414 kcal) or ‘low’ (275 kcal) energy-dense breakfast condition. Breakfasts were matched for their sensory characteristics, liking, and expected satiation (the extent to which they are regarded to be filling). In each condition, participants were given an information sheet about a fictitious food manufacturer and viewed its associated logo on a computer screen. They then tasted a mouthful of the novel breakfast and rated it on a number of sensory attributes. Finally, participants consumed the breakfast and completed hunger and fullness ratings every hour throughout the morning. Without warning, participants were asked to remember the information about the fictitious food manufacturer and identify the colour of the logo one week later. They were also asked to complete the sensory evaluation ratings based on their memory of the food. The correspondence between actual and recalled sensory ratings was significantly closer in the high energy-dense condition. These data suggest that we have better memory for the sensory characteristics of a novel high energy-dense food. This is consistent with our general hypothesis that memory is selectively enhanced by the ‘biological significance’ of post-ingestive events.