Friends Aren’t Food: Pinyon Jays (Gymnorhinus cyanocephalus) Show Context-Dependent Quantity Preference

Abstract

Animals must often choose between different quantities of objects in their environment, from food items to conspecifics. Yet we know little about how quantitative cognitive abilities compare across different types of objects. Previous research shows individuals use both the numerical difference (large − small) and numerical ratio (small/large) between two quantities to choose between them. This study investigated whether numerical difference and ratio predict preferences for quantities of food items and conspecifics in pinyon jays (Gymnorhinus cyanocephalus) using quantity preference tasks. In two replications of the food experiment (N = 12), pinyon jays chose larger quantities of mealworms more when numerical differences were large and numerical ratios were small. However, numerical difference did not influence food choice independently of ratio. In two replications of the social experiment (N = 20), when choosing between groups of conspecifics, pinyon jays did not prefer the larger over smaller group sizes and did not show numerical difference or ratio effects. Therefore, pinyon jays may use quantity information differently when deciding between quantities of food items and conspecifics. Whereas quantity was important for selecting food items, additional factors such as individual identity may be more important for selecting social groups to join. Thus, the type of objects offered can influence how animals use quantity information to choose among quantities.

Keywords

• context dependence
• corvid
• quantity
• quantitative cognition
• preference