Speaking of chickens, intelligence, and the ineffectiveness of directly comparing results, there's one very cool study I read about recently, which suggests that chickens possess the kind of self-awareness usually tested for with the famous "mirror test". So far, very few animals pass the mirror test, meaning that they understand the mirror is showing their own reflection, and not a separate animal. Chickens are not among the select few. In the test, a dot of color is sneakily placed on the animal's face. When the animal looks in the mirror, the idea is that if they try to remove the dot from their own face, then they must understand that what they saw in the mirror represents their own face. Human children don't pass the mirror test until somewhere between a year and two years of age (my daughter passed it at about 14 months).
This test, however, has some serious limitations. It assumes that the animal cares about having something on their face, and would want to clean it up. But what if they don't care?
So a team of scientists decided to design a test using a more relevant behavior in chickens. Roosters have an instinct to protect the flock and to alarm others of danger. So when they see a predator, they will sound an alarm if other chickens are present. But if they are alone, they will stay quiet, so as not to attract attention to themselves. So the scientists conducted a two-part experiment. In part 1, they closed a rooster in a test space with a divider through which he could see another chicken. They projected the image of a bird of prey flying overhead. In the control group, the rooster was all by himself. They conducted the experiment on a large number of roosters, to get statistically significant results. The vast majority of alarm calls were made by the rooster who could see another chicken, and the lone rooster largely stayed quiet. Part 2 of the experiment replaced the second chicken with a mirror. And there were barely any calls at all from either group!
So what this demonstrates is that the roosters understood that the mirror represented their own reflection, and not a second chicken. Therefore, technically, the roosters passed the mirror test. But they needed a second experiment designed with their particular brains in mind. And that's why it's so hard to apply one-size-fits-all measures to different animals, or grade them on the same point scale. It just doesn't translate.
Here's a description of the study:
https://neurosciencenews.com/rooster-self-awareness-25119/
This test, however, has some serious limitations. It assumes that the animal cares about having something on their face, and would want to clean it up. But what if they don't care?
So a team of scientists decided to design a test using a more relevant behavior in chickens. Roosters have an instinct to protect the flock and to alarm others of danger. So when they see a predator, they will sound an alarm if other chickens are present. But if they are alone, they will stay quiet, so as not to attract attention to themselves. So the scientists conducted a two-part experiment. In part 1, they closed a rooster in a test space with a divider through which he could see another chicken. They projected the image of a bird of prey flying overhead. In the control group, the rooster was all by himself. They conducted the experiment on a large number of roosters, to get statistically significant results. The vast majority of alarm calls were made by the rooster who could see another chicken, and the lone rooster largely stayed quiet. Part 2 of the experiment replaced the second chicken with a mirror. And there were barely any calls at all from either group!
So what this demonstrates is that the roosters understood that the mirror represented their own reflection, and not a second chicken. Therefore, technically, the roosters passed the mirror test. But they needed a second experiment designed with their particular brains in mind. And that's why it's so hard to apply one-size-fits-all measures to different animals, or grade them on the same point scale. It just doesn't translate.
Here's a description of the study:
https://neurosciencenews.com/rooster-self-awareness-25119/