Chaotic pigeons are helping redefine what we know about learning

Pigeons, often seen strutting and fluttering through urban landscapes, have proven remarkably adaptable to their ever-changing surroundings. However, it is not just their environment that is in constant flux. Recent studies indicate that pigeons themselves shun stability in their choices, opting instead to operate “at the edge of chaos.” These birds, serving as model species for studying learning and behavior, are assisting researchers in examining a century-old principle concerning how humans and other creatures learn.

When acquiring new skills, both humans and animals are inclined to repeat actions that yield rewards. This concept, first introduced by Edward Thorndike in 1898, is firmly entrenched in psychology as the law of effect. This law suggests that while rewards increase the frequency of a behavior, they also enhance its consistency, thereby reducing variability in how the behavior is executed over time.

While the impact of rewards on the frequency of behaviors has been extensively studied, their influence on consistency remains less explored. Edward A. Wasserman, an experimental psychologist from the University of Iowa, along with his team, sought to investigate this in pigeons—a species central to learning studies at the university’s Comparative Cognition Laboratory for over 50 years. The findings, published in the Journal of Experimental Psychology: Animal Learning and Cognition, suggest that pigeons find variability to be the essence of life.

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To understand how rewarded behaviors vary, researchers presented pigeons with a series of five colorful buttons to peck. The pigeons could peck any button in any sequence, and upon pecking five times, they would receive a treat. Contrary to previous learning theories that suggested pigeons might settle into a routine, perhaps by repeating successful patterns or pecking the nearest button five times, the pigeons continued to engage in a variety of patterns.

“There would be no reason not to expect that the animals would converge on a single favorite, but it never got to that point,” Wasserman states. “You could argue the birds are just utterly resistant to locking into anything stable.”

The researchers propose that a preference for variability may offer pigeons an evolutionary advantage in dealing with new environmental challenges—and they suspect that this resistance to uniformity might not be exclusive to birds. Current tests aim to determine whether rewarded behaviors maintain variability across different animals, potentially shedding light on how the brain navigates behavioral decisions during learning.

Aaron Blaisdell, a psychology professor at the University of California, Los Angeles, who was not involved in the study, finds the results unsurprising. “But this paper leaves open many questions about the [neurological] mechanisms” for future scientists to explore, he notes.

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