The ability to use probability as a reasoning tool has long been considered a trait unique to humans.
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Ravens and crows are part of the corvid family.
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We knew that crows were able to use tools, had abstract thinking and mathematical skills, and thought before making decisions.
Work by biologist Melissa Johnston and her colleagues at the University of Tübingen, Germany, now shows that these birds are capable of statistical inference, a mental ability also observed in great apes, macaques, giraffes and some parrots.
Statistical inference is the ability to use limited information to draw conclusions about the probability of an event. It is essential for decision-making in the event of uncertainty, note the researchers in their work published in the journal Current Biology ( New window) (in English).
We show that crows are capable of associating reward probabilities memorized to deduce reward-maximizing decisions. […] Our study provides compelling evidence for decision making based on the relative frequency of rewards.
A quote from Melissa Johnston, University of Tübingen
Statistical inference is based on the influence of previous experience #x27;a choice about the probability of making that choice again.
This cognitive ability involves the use of limited information about a situation to draw conclusions and make decisions.
For example, in humans, it could result in the choice of one restaurant rather than another depending on the x27;probable crowds in the two businesses.
The two crows were first trained to peck images on a touch screen to obtain treats.
Then, the experiment was complicated to include the concept of probability. Thus, each peck in the images did not necessarily lead to a reward. The crows thus learned to associate specific images with different chances of obtaining a reward.
Then, finally, the crows were trained to associate nine different images with treat reward probabilities ranging from 10% to 90%. After 10 days of training and more than 5,000 trials, biologists found that when presented with multiple images, crows chose the one associated with the highest probability of reward more than 75 percent of the time. cases.
According to the researchers, these results show the ability of these birds to use statistical inference.
This supports the idea that crows can learn and flexibly apply probabilistic information learned through previous experiences when making statistical inferences, note the authors of the work.
The German team resumed the experiment after a month's break, without however allowing the birds to continue their training. The crows remembered the reward probabilities and chose the highest number every time.