Friday, November 09, 2007

Making decisions while considering the cost and benefit

A study conducted by Ruud van den Bos on Wistar rats evaluated the process by which decisions are made, and was able to show that rats use similar processes as human in order to estimate the cost versus benefits of a particular option before choosing it.

Unlike humans, rats are often placed in a position where they are obligated to make most of their decisions under a great amount of stress, because many factors that have to be considered are usually not under their control. In other words, a human who is considering buying a car must take into consideration the cost of the car with their ability to be able to make payments every month. If an expensive car is wanted, one has the ability to work the number of jobs necessary to pay for it. On the other hand, "In its natural habitat, rats are facing the problem that little is under their control, so they are facing various levels and forms of uncertainty all the time. For instance, the quality and amount of food items at patches varies over time and between different patches, thus benefits are not always the same", says Ruud Van Den Bos.

To support the statements above, Van Den Bos’ study was done by constructing a T-shaped maze with different steepness barriers that had the ability to be controlled by the experimenter. The maze was connected with two arms, one possessing a pellet of sugar while the other had three or more sugar treats. At first, rats climbed the less steep barriers in order to get to the pellet of sugar that was on the other side, but after attempting to climb the steeper barrier that resulted in a reward of three or more pellets of sugar they decided that it was worth the extra energy, therefore, continued to only climb the steep barriers that resulted in a bigger reward. This behavior was discontinued after signs of pain were manifested in the limbs, thus making the rodents stick with the barrier resulting in one pellet of sugar considering that the pain yielded to little gain after no longer being hungry.

This experiment enabled researchers to support the hypothesis that rats behave by calculating what the cost and benefit of their action will yield. Going back to the car purchaser example above, if a car is purchased over one’s budget, one will have to expend more energy to pay for it since more than one job will be required. Is it worth it?
Most human would say no. This study also had the ability to examine how much energy an individual is willing to expand in order to be rewarded.

Posted by Vanessa Raphaël (7)


At 11:16 AM, Anonymous Anonymous said...

Interesting article. Did it examine any other stresses that rats might have in the wild other than food availability and quality? Did they test maybe something like predation risk or maybe competition between other rats?

Posted by Elizabeth Adams


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