Memory may influence food choice more than preference

The team of Basel University psychologists asked participants to rate 48 snacks, each of which was associated with a specific location. Participants then had to repeatedly choose between two snacks for which only the location was shown.

The researchers found that people were more likely to choose snacks for which they could remember the location, even if this was a less preferred food choice. Only extremely unattractive snack options were rejected even though the location was remembered.

The psychologists, led by Sebastian Gluth, took MRI brain scans whilst the subjects conducted the memory recall tests. This allowed them to analyse the neural mechanisms linking the hippocampus – a classic memory region – and the ventromedial prefrontal cortex in the frontal lobe, a decision-making region.

Gluth said: "Our study builds a bridge between two central research fields of psychology, that is, memory and decision-making research."​

Minimising risk through memory​

According to the scientists, the possibility of forgetting information limits decision accuracy and introduces a bias towards remembered options – a sort of unconscious risk mitigation.

“Why are people driven towards choice options which they remember better? One explanation is that people pay more attention to these options while making decisions. As soon as a past experience from a restaurant visit is recalled, for instance, one’s attention is automatically drawn to that restaurant as a potential candidate," ​wrote the researchers in Neuron Journal​.

“It has recently been established that options which receive more attention are more likely to be chosen.” ​

“A second but not mutually exclusive explanation is that (better) remembered options can be seen as safer options (‘at least I know what I get’) and taking a forgotten alternative can be regarded as a risky ​decision.”​

The study​

A total of 84 male and female individuals aged 18-37 years took part in the study. Participants were asked not to eat for three hours prior to the experiment and, upon arrival, were shown 48 snacks - all well-known products readily available in German supermarkets classified into six categories such as chips, bars, chocolate and salty snacks.

After learning the name and location of the snacks, individual preferences for each were rated by participant’s willingness to pay. Subjects then performed the memory recall test whereby they chose between two snacks for which they were shown only the location.

A control group performed the same task but with the snacks visible during the decision-making phase.  

The researchers wrote: “The behavioural results... indicate that people are limited by memory constraints and biased toward options which they remember better.” ​

“(…) Our newly developed paradigm could be further employed to investigate the specific role of memory in applied research areas such as dietary choice.”​

Source: Neuron Journal​

First published online:  20 May 2015, vol. 86, pp. 1078-90      doi: 10.1016/j.neuron.2015.04.023.

“Effective connectivity between hippocampus and ventromedial prefrontal cortex controls preferential choices from memory”​

Authors:S. Gluth, T. Sommer et al.