KQED comes to campus to film the behaviors of frustrated squirrels – inspired by Mikel Delgado’s new paper on this behavior – and finds it a frustrating experience! No, not really – but it wasn’t easy to get the right shots, to illustrate the research. We even recruited Gilly – her presence evoked the squirrels to display a wide range of tail signals, exactly as described in the paper!  KQED plans to air this short segment in late summer 2016.

Delgado, M. M., & Jacobs, L. F. (2016). Inaccessibility of reinforcement increases persistence and signaling behavior in the fox squirrel (Sciurus niger). Journal of Comparative Psychology, 130(2), 128–137.

Under natural conditions, wild animals encounter situations where previously rewarded actions do not lead to reinforcement. In the laboratory, a surprising omission of reinforcement induces behavioral and emotional responses described as frustration. Frustration can lead to aggressive behaviors and to the persistence of noneffective responses, but it may also lead to new behavioral responses to a problem, a potential adaptation. We assessed the responses to inaccessible reinforcement in free-ranging fox squirrels (Sciurus niger). We trained squirrels to open a box to obtain food reinforcement, a piece of walnut. After 9 training trials, squirrels were tested in 1 of 4 conditions: a control condition with the expected reward, an alternative reinforcement (a piece of dried corn), an empty box, or a locked box. We measured the presence of signals suggesting arousal (e.g., tail flags and tail twitches) and found that squirrels performed fewer of these behaviors in the control condition and increased certain behaviors (tail flags, biting box) in the locked box condition, compared to other experimental conditions. When faced with nonreinforcement, that is, frustration, squirrels increased the number of interactions with the apparatus and spent more time interacting with the apparatus. This study of frustration responses in a free-ranging animal extends the conclusions of captive studies to the field and demonstrates that fox squirrels show short-term negatively valenced responses to the inaccessibility, omission, and change of reinforcement.

pdf: J Comp Psychol 2016 Delgado