Relative reward memories retain multidimensional information in bumblebees

Bumblebees trained with rewards varying in sucrose concentration and NaCl content prefer options that were locally better on both dimensions, not just those with higher ordinal rank.

• Why it matters: Prior work showed relative reward memory in bumblebees preserves only ordinal rank when rewards vary along one dimension, leaving unknown whether multidimensional natural rewards retain more detail.
• What they did: Bees were trained in separate contexts with two intrinsic reward dimensions, then tested with options never seen together; preference was assessed when only sucrose varied versus when both sucrose and NaCl varied, including a 48 h probe.
• The result: When both dimensions varied, the “local-better” equivalence broke: bees chose the option locally better on both sucrose and NaCl, and a two-dimensional advantage yielded a stronger preference than a one-dimensional advantage 48 h after training.

AI summary of the abstract · may contain errors · not medical advice · read the paper.