You know that infants can count different quantities of blocks and that primates can count different amounts of bananas but did you know that crows can count different quantities of rainbow-colored circles?
Four animal behaviorists conducted an experiment to prove that jungle crows, Corvus macrorhynchos, were capable of discriminating between different amounts of the same sample. There was prior information about crows numerical ability. In this study they wanted to further test this knowledge by seeing if crows can discriminate between small and large quantities.
Eight birds were captured for the experiment, which was conducted in an outdoor aviary. Initial training was done with the birds to acclimate them to the experimental setting. The training used the quantity five as a control group, a group that stayed the same through the entire experiment. The first part of the training consisted of a cup with two pieces of rainbow-colored circles and a cup with five rainbow-colored circles, when the crows picked the cup with five it was given dog food as a reward. This was done until the crows made 15 out of 20 correct choices in two sets of ten trials. The purpose of this was to engrave in the crows brain that it should choose the five quantity cup. After the training process the crows were put through four rigorous tests.
These tests were done along with the training to show the results when different variables of the experiment were altered. The first test was done in the same process as the training except with new patterns that were changed with each new trial. The second test changed the rainbow-colored circles to different shapes. The next test presented the crows with different sized shapes, for example, the cup with the smaller quantity used bigger shapes and the cup with the larger quantity used smaller shapes. The final test was done to see if the crow would repetitively choose five items when presented with smaller items in one test and larger quantities in the next test.
After the long, grueling, agonizing, and slightly blood shedding experiment the following results were documented. When the crow was challenged to discriminate between the quantities of two and five, the crow learned to choose the five quantity after a few repetitions. The results the shape test showed that the altered variable did not change the crows ability to choose the five quantity cup. When the crow was tested to see if it would choose between the five quantity and a larger quantity, it always chose the larger amount of rainbow-colored circles.
So how would the crows do this? The reason how the crows chose the larger quantities was because of their visual cues. It is possible that each crow had its own reasoning for choosing the quantity that it did. When the crows were tested with the smaller quantities it was hypothesized that they could count up to four and remember that number, this was how they discriminated between quantities four and five. When, the crows were faced with larger quantities they were not capable of counting and simply just chose the larger amount of rainbow-colored circles. Now you must be wondering why crows would do this? It is believed that crows want to put all of their energy into gathering as much food as they possibly can. Now where do the animal behaviorists go from here? They would conduct the same experiment on the crows except without the initial training.
I just thought this article was an easy read but still very interesting.
Here is the link to the article http://www.sciencedirect.com/science/article/pii/S0003347211002338
Posted by Whitney Huynh (2)
Whitney- Wow, that's really interesting; I've never heard about crows having the ability to count before! But then again, I'm not too terribly surprised, since I watched a video of a species of crow in Japan that had learned to drop walnuts on cross-walks. Not only had they figured out that cars will run over the nuts & crack them open (since they can't crack them open with their beaks), but they'd learned to wait until all traffic had stopped & people were using the cross-walks to fly down & pick up their nuts, avoiding the danger of being hit by cars altogether. Despite what a lot of people say about crows, they seem to be a lot smarter than most think! You can check out that clip here:
ReplyDeletehttp://www.youtube.com/watch?v=BGPGknpq3e0
Posted by Brianna Eddy
The general public does not give crows enough credit. I agree with Brianna, they are a lot smarter than we assume! I worked at a wildlife rehabilitation center over the summer and we took in a crow that was not releasable. When I left, its fate was still up in the air, but we wanted it to become an education animal. He seemed to be very easy to socialize and would call when he heard anyone near his enclosure, and this was without us spending any time actually trying to acclimate him to human contact. It makes sense that a crow would be able to recognize larger quantities when collecting food in the wild. I wonder if it would be able to do the opposite and pick smaller quantities, too? Or in a range of quantities, could it be trained to pick one out in the middle? I don't know how these abilities would apply to surviving in the wild.
ReplyDeletePosted by Chelsea Van Thof
I don't think anyone realizes how smart crows actually are! Many people disregard them because of the negative connotation between crows and bad luck/death. Have you heard about the crow vending machine? This guy named Joshua Klein built a crow vending machine that taught crows to pay a coin to get peanuts. He did this by initially putting coins and peanuts around the machine and of course the crows came and ate the peanuts. Then he removed the peanuts and put coins near the coin slot. The crows came to look for peanuts and swept some coins in the machine, and when this happened peanuts would be dispensed. They quickly learned that putting coins in the slot produced peanuts!
ReplyDeleteHere's a video of him explaining the experiment:
http://www.ted.com/talks/joshua_klein_on_the_intelligence_of_crows.html
Posted by Caitlin Descovich O'Hare
I had absolutely no idea that crows could count before reading this article. First off, I'm curious why exactly the experimenters used rainbow colored circles. Are their colors that crows cannot see? Also this article made me wonder if other more primitive birds or other primitive species that can count. Do you think that the origins of the human ability to count was descended from crows?
ReplyDeleteLast comment posted by Nick Gast
ReplyDeleteThis comment has been removed by the author.
ReplyDelete@Brianna: I know exactly what you are talking about. I think I read about the crows in Japan in a newspaper article.
ReplyDelete@Chelsea: To answer your question, I think it is possible for crows to pick smaller quantities if you teach them. It is called operant conditioning where the individual is rewarded after they have done the task correctly. The crows had a hard time discriminating between numbers that were close together like 6 and 7 and I highly doubt that they would be able to pick something in the middle unless it is sandwiched between 2 giant amounts, making it stand out drastically.
Posted by Whitney Huynh
Whitney,
ReplyDeleteI also agree with some of the above comments that crows do not get enough credit by society. However, not everyone is willing to take the time, sit down, and read an interesting article such as this. We are the minority and hopefully our thinking will broaden the minds of those around us.
I enjoyed this article, though it was hard to follow because if the intricacy of the experiments. I want to know how scientists come up with such rigorous experiments and what they look for with their results.
Anyways...crows. They are very intelligent animals and just like every animal species out there will do what they need to survive. I wonder what other skills can be learned from crows?
Posted by: Em Arsenault
Very interesting article. When I think of crows, I picture big black annoying birds in the yard, waking me up with their caw and eating all the bird seed from the feeder. This blog has altered my view and I am very impressed that these crows can differentiate between numbers. It also makes sense that they would learn this because they are getting food out of it and when they are exposed to the larger quantity of nourishment, they learn to go for the cup with the largest amount of circles. I also find it interesting that when they reach a certain amount of circles, their learning ability diminishes. Are there any other species of birds or even mammals out there that can differentiate and learn with this ability?
ReplyDeletePosted by Ryan Dulmaine