Locating calories: Does the high-calorie bias in human spatial memory influence how we navigate the modern food environment?

Exploring the spatial mental associations of distinct food types

Previous research explored the spatial representations of healthy low-calorie and unhealthy high-calorie food items, revealing an association of healthy low-calorie food with left and top sides, and unhealthy/high-calorie food with right and top sides. This association, namely side bias, was limited to these specific categories leaving the representations of healthy high-calorie and unhealthy low-calorie food categories yet to be explored. Present study was designed to examine the spatial representation of four food categories (unhealthy low-calorie, unhealthy high-calorie, healthy low-calorie, healthy high-calorie) using a computerized food placement task. In Experiment 1, participants placed four food items from different categories into eight locations. In Experiment 2, identical task was used with the addition of centrally presented anchor food item to investigate the mental representation of food items in relation to each other. The frequency of placing food items in specific spatial locations were measured. The results of Experiment 1 provided partial support for side bias. However, the use of anchor items in Experiment 2 provided compelling evidence for vertical side bias, demonstrating consistent pattern of placing healthy foods on the upper sides and unhealthy foods on the lower sides. In both experiments, real-life food choices were examined to investigate whether the high-calorie bias would be observed in actual food choice behavior. The results from both experiments indicated strong preference to select high-calorie foods, supporting high-calorie bias. Overall, this study extends the evidence on the spatial representations of distinct food categories.

Energy deficiency promotes rhythmic foraging behavior by activating neurons in paraventricular hypothalamic nucleus

Background

Dysregulation of feeding behavior leads to a variety of pathological manifestations ranging from obesity to anorexia. The foraging behavior of animals affected by food deficiency is not fully understood.

Methods

Home-Cage system was used to monitor the behaviors. Immunohistochemical staining was used to monitor the trend of neuronal activity. Chemogenetic approach was used to modify neuronal activity.

Results

We described here a unique mouse model of foraging behavior and unveiled that food deprivation significantly increases the general activities of mice with a daily rhythmic pattern, particularly foraging behavior. The increased foraging behavior is potentiated by food cues (mouthfeel, odor, size, and shape) and energy deficit, rather than macronutrient protein, carbohydrate, and fat. Notably, energy deficiency increases nocturnal neuronal activity in paraventricular hypothalamic nucleus (PVH), accompanying a similar change in rhythmic foraging behavior. Activating neuronal activity in PVH enhances the amplitude of foraging behavior in mice. Conversely, inactivating neuronal activity in PVH decreases the amplitude of foraging behavior and impairs the rhythm of foraging behavior.

Discussion

These results illustrate that energy status and food cues regulate the rhythmic foraging behavior via PVH neuronal activity. Understanding foraging behavior provides insights into the underlying mechanism of eating-related disorders.

Human spatial memory is biased towards high-calorie foods: a cross-cultural online experiment

Background

Human memory appears to prioritise locations of high-calorie foods, likely as an adaptation for foraging within fluctuating ancestral food environments. Importantly, this “high-calorie bias” in human spatial memory seems to yield consequences for individual eating behaviour in modern food-abundant settings. However, as studies have mainly been conducted in European (Dutch) populations to date, we investigated whether the existence of the cognitive bias can be reasonably generalised across countries that vary on culturally-relevant domains, such as that of the USA and Japan. Furthermore, we investigated whether sociodemographic factors moderate the expression of the high-calorie spatial memory bias in different populations.

Methods

In a cross-cultural online experiment, we measured the food location memory of diverse participants from the USA (N = 72; 44.4% Male; 54 ± 15.99 years) and Japan (N = 74; 56.8% Male; 50.85 ± 17.32 years), using a validated computer-based spatial memory task with standardised images of high-calorie and low-calorie foods. To directly compare the magnitude of the high-calorie spatial memory bias in a broader cultural scope, we also included data from a previous online experiment that identically tested the food spatial memory of a Dutch sample (N = 405; 56.7% Male; 47.57 ± 17.48 years).

Results

In the US sample, individuals more accurately recalled (i.e. had lower pointing errors for) locations of high-calorie foods versus that of low-calorie alternatives (Mean difference = -99.23 pixels, 95% CI = [-197.19, -1.28]) – regardless of one’s hedonic preferences, familiarity with foods, and encoding times. Likewise, individuals in the Japanese sample displayed an enhanced memory for locations of high-calorie (savoury-tasting) foods (Mean difference = -40.41 pixels, 95% CI = [-76.14, -4.68]), while controlling for the same set of potential confounders. The magnitude of the high-calorie bias in spatial memory was similar across populations (i.e. the USA, Japan, and the Netherlands), as well as across diverse sociodemographic groups within a population.

Conclusions

Our results demonstrate that the high-calorie bias in spatial memory transcends sociocultural boundaries. Since the cognitive bias may negatively impact on our dietary decisions, it would be wise to invest in strategies that intervene on our seemingly universal ability to efficiently locate calorie-rich foods.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01252-w.