Pigeons keep options open despite rewards, Iowa study finds
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- University of Iowa researchers found that pigeons rewarded for pecking five buttons in any order never fully committed to a single sequence, a pattern described as 'responding at the edge of chaos' by the study's authors.
- Ed Wasserman, a professor in the Department of Psychological and Brain Sciences and a pigeon cognition researcher for more than five decades, served as the study's corresponding author alongside co-authors Odysseus Orr and Sophia Li.
- Six pigeons pecked five buttons yielding 120 possible sequences, and despite every completed sequence producing a food reward, the birds performed all 120 combinations over the course of the study.
- The pigeons' preferred sequences rose and fell throughout 8 months and roughly 30,000 trials, with researchers calling the pattern 'dramatic behavioral instability' that contradicts the century-old Law of Effect.
- The Law of Effect predicts that animals narrow their options when a behavior produces a reward, but the Iowa study showed pigeons reduced variability without ever eliminating it.
- The study, titled 'Variability, Stability, and the Law of Effect,' was published April 6, 2026, in the Journal of Experimental Psychology: Animal Learning and Cognition, extending the 'edge of chaos' concept from evolutionary biology into behavioral psychology.
Why it matters: The findings directly challenge the century-old Law of Effect in behavioral psychology, which predicts animals lock in rewarded behaviors. For comparative cognition researchers, the eight-month, 30,000-trial dataset suggests persistent exploratory behavior is a deeply embedded strategy — a result that, as co-author Orr notes, could reshape how scientists frame flexibility in more complex behaviors including human creativity.
