Bumblebees Learn a Relational Rule but Switch to a Win-Stay/Lose-Switch Heuristic After Extensive Training

Abstract

Mapping animal performance in a behavioral task to underlying cognitive mechanisms and strategies is rarely straightforward, since a task may be solvable in more than one manner. Here, we show that bumblebees perform well on a concept-based visual discrimination task but spontaneously switch from a concept-based solution to a simpler heuristic with extended training, all while continually increasing performance. Bumblebees were trained in an arena to find rewards on displays with shapes of different sizes where they could not use low-level visual cues. One group of bees was rewarded at displays with larger shapes and another group at displays with smaller shapes. Analysis of total choices shows bees increased their performance over 30 bouts to above chance. However, analyses of first and sequential choices suggest that after approximately 20 bouts, bumblebees changed to a win-stay/lose-switch strategy. Comparing bees' behavior to a probabilistic model based on a win-stay/lose-switch strategy further supports the idea that bees changed strategies with extensive training. Analyses of unrewarded tests indicate that bumblebees learned and retained the concept of relative size even after they had already switched to a win-stay, lost-shift strategy. We propose that the reason for this strategy switching may be due to cognitive flexibility and efficiency.

Non-numerical strategies used by bees to solve numerical cognition tasks

“…Videos of animals solving numerical cognition tasks can help determine how animals are solving those tasks (cf. [ 1 , 2 ]). Automated approaches combining machine vision and learning with computational behavioural analyses have the ability to discover behavioural features that humans cannot (cf.…”

“…The difficulty is that animals may not be solving the task the way we think they are. One example of this is in our own recent work where we had bees discriminate different shapes based on relative size [ 1 ]. Bees' performance increased over training to well above chance, and in the unrewarded test they seemed to have learned to discriminate shapes based on relative size.…”

Different effects of reward value and saliency during bumblebee visual search for multiple rewarding targets

“…Choices were recorded when the bee probed the flowers for reward and bees could revisit flowers in all experiments. Between training bouts, we cleaned the flowers with 99% ethanol to remove scent markings (Pearce et al 2017 ; MaBouDi et al 2020 ), and subsequently with water to remove any traces of ethanol.…”

Do that again! Memory for self-performed actions in dogs (Canis familiaris).

“…Alternatively, subjects may switch strategies when faced with novel constraints and increasing errors. For instance, recent experiments with bumblebees revealed that they switched from solving a visual discrimination task based on an abstract rule about target size to choosing responses based on recent experiences (deploying a win-stay, lose-shift rule), when the task became more effortful (MaBouDi et al, 2020). Bees continued to respond based on target size in unrewarded transfer tests, suggesting that they retained the capacity to use this strategy.…”