a crow, when first faced with a bit of meat dangling from a bit of string, figures out a solution pretty much instantly. This has led researchers to posit that crows build mental models that generate solutions, instead of relying on trial and error. Now, a bunch of Kiwis have published research in PLoS One that suggests crows don’t actually build models.
What is the difference between model-based solutions and feedback-based solutions? When we rely on feedback, we first perform an action—pull on the string and trap it underfoot—if we perceive that we are closer to our goal (the meat is now closer), we repeat the action. A model-based solution, on the other hand, involves understanding that the meat is connected to a bit of string, and that to get the meat, we must pull the string up. In the second case, feedback after each step is not required, because we understand the problem and know that we will be rewarded in the end. [...]
I must admit to having a little problem with that conclusion. First, one crow did solve the problem; second, the crows all varied widely in their performance on all of the tests, suggesting that problem-solving abilities vary wildly between individuals—no surprise there. Finally, I think the distinction between model-building and feedback-based problem solving skills are artificial points in a mental toolkit that spans a continuum.