Psychology article summary - Essay Example

Most experiments dealing with aversive conditioning in vertebrates use electric shock as pain reinforcement. However, electric shocks have not had much effectiveness on studying learning in vertebrates. The majority of these experiments fail to produce significant results, and one of them even resulted in the death of the creatures during or after the experiment. But another type of experiments was proved to be very effective- one which uses chemical stimuli, for example in the flavor aversion procedure.

These experiments used the toads ability to respond to the level of salt found in water. This is an important source of physiological stress for them because of the risk for dehydration. So the two experiments here rely on the toads sensitivity for detecting the composition of fluids around him and the stress it feels when conditions arent suitable for it- which leads to changes in both his heart rate and in its attempts to avoid these conditions and run away. Researchers therefore used an amount of sodium chloride which neither caused the toads to gain weight or loss weight, to create a "neutral" situation and then test their responses.

Experiment 1: Autonomic ConditioningA pilot experiment showed an increase in the heart rate of toads, which is important to set off their attempts to flee the environment. It used two solutions, one was good for the toads and the other wasnt. This technique was also good to evaluate the functional significance of conditioning (like in Pavlovs experiment with the dogs) in the context of water balance.The toads used were sexually mature, healthy ones caught around Buenos Aires in their habitats.

Their weight was changed in time to fit what the researchers wanted.During the experiment, researchers put the toads in Plexiglas cages, added water, changed the chemical composition of the water and lastly drained the tank. Toads were either put with another toad in the tank or placed there alone. There were mostly insignificant differences between the groups, but one significant find was that the toads placed with another toad in a tank learned to expect the reinforcement better. The toads showed learning abilities, as they anticipated the changes in water composition after it was done to them several times.

Their anticipation could be witnessed by their increased heart rate. They managed to avoid losing weight almost as well as the toads never exposed to the different solution in the water.Experiment 2: One-Way Avoidance ConditioningThis experiment added another feature- an added compartment in the Plexiglas tank in which there was no altered solution. The toads could escape there to avoid being in contact with the solution. The results showed that all toads showed a consistent weight loss and did learn to avoid being in contact with the changed solutions.

The experiments demonstrate that toads easilt acquire aversive conditioning when the stimulus is exposure to a solution that can cause dehydration. Experiment 1 showed Pavlov-like conditioning, as toads expected the change of solution and increased their heart rate. Experiment 2 showed that the toads acquired an avoidance response to avoid the solution when there was instrumental contingency. This shows their ability to learn, something which hasnt been proven well enough in previous studies. The results show that this format can be once again used to test both appetitive and aversive conditioning.

It shows that toads coped with the harmful difference in water solution in two ways: one was using a behavioral strategy to prevent coming in contact with the water; the other was developing compensatory responses to avoid weight loss when there was no way to avoid being in contact with the solution. Unlike previous research, the present results suggest that aversive learning can be rapid and efficient in amphibians when saline solutions of different molarities are used as signals and reinforcements.