Data from: Prior associations affect bumblebees' generalization performance in a tool-selection task

A small brain and short life allegedly limit cognitive abilities. Our view of invertebrate cognition may also be biased by the choice of experimental stimuli. Here, the stimuli (color) pairs in Match-To-Sample (MTS) tasks affected the performance of buff-tailed bumblebees (Bombus terrestris). We trained the bees to roll a tool, ball, to a goal that matched its color. Color-matching performance was slower with yellow-and-orange/red than with blue-and-yellow stimuli. When assessing the bees' concept learning in a transfer test with a novel color, the bees trained with blue-and-yellow (novel color: orange/red) were highly successful, the bees trained with blue-and-orange/red (novel color: yellow) did not differ from random, and those trained with yellow-and-orange/red (novel color: blue) failed the test. These results highlight that stimulus salience can affect the conclusions on test subjects' cognitive ability. Therefore, we encourage paying attention to stimulus salience (among other factors) when assessing invertebrate cognition.