July 26, 2012

Birds And Children Show Similarities Solving “Aesop’s Fable” Riddle

Brett Smith for - Your Universe Online

A recent experiment modeled after Aesop´s Fable could be a window into how children´s minds learn cause-and-effect relationship.

In the fable, a thirsty crow approaches a half-filled jug of water. Unable to reach through the jug´s narrow neck and down to the water, the crow drops stones into the container until the level of the water raises enough for it to drink.

Previous studies have shown that some crows are able to learn how to perform this task by using stones to raise a water level in order to reach a reward. In addition to the rocks, the birds were also offered floating objects to see if they could to figure out which items would allow them to reach their treat.

The latest study, by three University of Cambridge researchers, determined to see at what age children were likely to accomplish this feat and also if they recognized the mechanism behind it.

In the children´s experiment, the researchers tested children between the ages of four to ten to see if they could retrieve a floating token that could be exchanged for a sticker in three different setups.

The first task involved two tubes: one contained a prize in sawdust while the other had a prize floating just out of reach in water. The subject was given objects and allowed to choose which tube to drop the objects into, either the sawdust tube or the water tube. While dropping objects into the sawdust tube did not raise the level of the prize, objects dropped into the tube containing water raised the prize within the reach of the subject.

The second task involved only one tube of water, but the subject was given two different sets of objects to use: objects that float or others that sink and displace more water.

The third task involved an apparatus that consisted of one u-shaped tube with a wide arm and one narrow arm, and one single straight tube. The bottoms of the two tubes were masked by an opaque base so that the joining nature of the U-tube was hidden, creating the appearance of two identical wide tubes with a narrow tube between them, all filled equally with water. The prize was located inside the narrow arm of the u-tube, which was too small for the given objects to be inserted.

This setup created a choice for the subject. If they picked the wider arm of the u-tube, then the height of the reward would rise, but if they chose the single tube, it would not. Because the join of the u-tube was hidden, it appeared that dropping an item in one tube caused the level of water in a different tube to rise: which is impossible.

Five and seven-year-olds performed on about the same level as the birds, with both groups learning how to complete the task after about 5 trials. Children eight years and older finished in all tasks on their first try.

Lucy Cheke, a PhD student at the university, said while younger children performed as well as the crows, the birds were probably reward-driven and did not understand the cause-and-effect relationships occurring between dropping the stones and the raising of the water level.

"(The result) makes sense because it is children's job to learn about new cause and effect relationships without being limited by ideas of what is or is not possible,” she said.

“The children were able to learn what to do to get the reward even if the chain-of-events was apparently impossible. Essentially, they were able to ignore the fact that it shouldn't be happening to concentrate on the fact that it was happening. The birds however, found it much harder to learn what was happening because they were put off by the fact that it shouldn't be happening."

"The Aesops fable paradigm provides an incredibly useful means by which to compare cause-effect learning with understanding of underlying mechanisms, i.e. folk physics,” Cheke concluded.

“We are planning on extending this paradigm to really try to understand what's going on in the heads of adults, children and animals when they deal with problems in the physical world."