Decision making...in the rat

Well it seems that rats can make some pretty complex decisions:

"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," says study leader Dr Ruud van den Bos of the Faculty of Veterinary Medicine at Utrecht University in The Netherlands.

"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."

"The amount of energy spent to obtain these different items varies during the different foraging sessions, as sometimes it's cold, sometimes it's hot, sometimes it rains, sometimes sudden obstacles are present after heavy storms, etc."

It looks like they adapted a T maze for the task:

At the end of each arm was a chamber filled with treats. One side had a low reward - one sugar pellet - while the other side had three to five sugar pellets.

Rats that wanted the higher rewards had to climb steep barriers. It would be like placing a person's favourite dessert behind a high wall that would have to be scaled before the individual could nosh.

The researchers varied the size of the barrier and the amount of reward on that side to see how the rodents would react.

At first the rats went for the easy pickings, but when they determined more sweets were available on the other side of the maze, they exerted additional effort, but only after a certain point.

When the pain yielded too little gain, they stuck with the tiny treat.