Latent learning

Latent learning is a form of learning that is not immediately expressed in an overt response; it occurs without any obvious reinforcement of the behavior or associations that are learned. Interest in latent learning arose largely because the phenomenon seemed to conflict with the widely held view that reinforcement was necessary for learning to occur.

In a classic study by Edward C. Tolman, three groups of rats were placed in mazes and their behavior observed each day for more than two weeks. The rats in Group 1 always found food at the end of the maze; the rats in Group 2 never found food; and the rats in Group 3 found no food for 10 days, but then received food on the eleventh. The Group 1 rats quickly learned to rush to the end of the maze; Group 2 rats wandered in the maze but did not preferentially go to the end. Group 3 acted the same as the Group 2 rats until food was introduced on Day 11; then they quickly learned to run to the end of the maze and did as well as the Group 1 rats by the next day. This showed that the Group 3 rats had learned about the organisation of the maze, but without the reinforcement of food. Until this study, it was largely believed that reinforcement was necessary for animals to learn such tasks. Other experiments showed that latent learning can happen in shorter durations of time, e.g. 3–7 days. Among other early studies, it was also found that animals allowed to explore the maze and then detained for one minute in the empty goal box learned the maze much more rapidly than groups not given such goal orientation.

In 1949, John Seward conducted studies in which rats were placed in a T-maze with one arm coloured white and the other black. One group of rats had 30 mins to explore this maze with no food present, and the rats were not removed as soon as they had reached the end of an arm. Seward then placed food in one of the two arms. Rats in this exploratory group learned to go down the rewarded arm much faster than another group of rats that had not previously explored the maze.

In 1952, Bendig investigated latent learning using a Morris water maze. In this type of maze, there are escape platforms hidden just below the surface of water in a large tank. The animal is forced to swim until it reaches (and memorises) where the platforms are. Bendig required rats to escape a water maze while satiated for food, with food located on one of the escape platforms. Upon being returned to the maze while food deprived, the rats learned where the food was located at a rate that increased with the number of pre-exposures given the rat in the training phase. This indicated varying levels of latent learning.

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