2. Trial and Error Learning

1. 2. Trial and Error Learning = This type of learning occurs when an organism attempts to learn by undertaking a number of alternative behaviours (trials) and makes a number of incorrect choices (errors) before the desired behaviour is learned.

2. Trial and error learning • Involves a desire to reach some sort of goal (motivation) by the learner. • Also involves trying a number of different behaviours (exploration). And when the correct response is finally achieved, it is rewarding for the organism (reinforcement).

3. Trial and error learning • Receiving a reward of some kind leads to repeated performance of the correct response, strengthening the association between the behaviour and its outcome. • Once learned, the behaviour will usually be performed quickly and with fewer errors. • Trial and error learning is also referred to as instrumental learning and more recently operant learning.

4. Edward Thorndike was studying animal intelligence in the 1900’s. Thorndike constructed this apparatus, known as a puzzle box, from a wooden shipping crate. It was used in experiments that led him to describe the law of effect, a learning principle central in instrumental learning. Thorndike’s puzzle box experiments

5. Thorndike’s puzzle box experiments – trial and error. • Thorndike put a hungry cat in the ‘puzzle box’ and put fish on the outside. • When the cat was placed in the box, it made numerous attempts to escape. • The box had wooden slats so it could see and smell the food but it was beyond its reach. • To escape the cat needed to push a wooden lever down which was attached to a pulley device. • Thorndike measured the time it took the cat to escape from the box on each trial. • The cats had to be hungry (their motivation) and they had to be rewarded for acquiring the correct behaviour – food when it escaped from the puzzle box.

6. Thorndike’s puzzle box experiments – trial and error. • The first time the cat escaped, the lever was pushed down after a number of different behaviours. • It is unlikely at this stage that the cat made any connection between the lever and its escape until it had done it a couple of times. • Once the connection was formed, the cat would press the lever deliberately as soon as it was placed in the box.

7. Law of effect • The results of experiments like these led Thorndike to describe his law of effect. • The law of effectstates: • If a behaviour is followed by satisfying consequences it is strengthened (likely to occur again), whereas behaviours followed by unpleasant consequences are weakened (less likely to occur).