Pair foraging degrades socially transmitted food preferences in rats.

Abstract

Following presentation of a novel food odor on the breath of a conspecific, naïve rats will exhibit a preference for that food, a form of learning called social transmission of food preference (STFP). When tested in isolation, STFPs are robust, persisting for up to a month and overcoming prior aversions. This testing protocol, however, does not account for rats' ecology. Rats and other rodents forage in small groups, rather than alone. We allowed rats to forage in pairs and found that, following social foraging, they no longer displayed a food preference, i.e., that STFPs degrade during social foraging. Non-foraging rats exposed to the same foods for the same amount of time in isolation maintained their preferences. We also examined whether individual differences between rats affect STFP. Neither boldness nor sociability predicted initial STFP strength, but bolder rats' preferences degraded more following social foraging. Shyer rats were more likely to eat at the same time as their partner. By tracking rats' interactions during social foraging, we show that they use complex rules to combine their own preferences with socially acquired information about foods in their environment. These results situate STFP within the behavioral ecology of foraging and suggest that individual traits and the interactions between them modulate how social learning is maintained, modified, or lost.