Thorndike studied animal intelligence and its basis in forming connections through trial and error learning, using puzzle-box experiments with cats. He observed that animals learn to solve problems by attempting various actions until achieving the desired result, which is reinforced by rewards. His findings led to the 'law of effect', stating that behaviors followed by satisfying outcomes are strengthened, while those followed by negative outcomes are weakened.

1. Thorndike
• Interested in studying
animal intelligence
• He found that animal
intelligence is based on
the ability to form
connections
• Set up puzzle-box
experiments to
investigate instrumental
conditioning

2. Trial & Error learning - Thorndike
• Describes an organism’s attempts to
learn/solve a problem by trying alternative
possibilities until a correct solution or
desirable outcome is achieved
Usually involves
1. A number of attempts & a number of errors
- Before correct behaviour is learnt
2. Motivation (to achieve a goal)
3. Exploration – either random or purposeful
4. Reward – the correct response is rewarded –
• which will lead to repeat performance of
the correct response, strengthening the
association between the behaviour & its
outcome
• Once learnt behaviour will usually be
performed quickly and with fewer errors

3. Thorndike’s Puzzle-box experiment
• Thorndike put a hungry cat in a
‘puzzle box’ & placed fish, just
out of reach
1. At first the cat to escape from the
box through trial & error
(random voluntary movements)
2. Eventually the cat accidentally
pulled the string, escaped from
the box so that it could reach its
reinforcement (the fish)
• When the cat was put back in the
box, once again it went through a
series of incorrect responses
before pushing the lever
• The cat became progressively
quicker at escaping (and had
fewer incorrect behaviours)

4. Thorndike ‘Law of Effect’
• Thorndike concluded that the cat had
learned the association between its
behaviour (pulling the string) & the
consequences (reaching the food)
• Results led Thorndike to devise the
‘Law of effect’ that is a behaviour
that is followed by a satisfying
consequence is strengthened (more
likely to happen) than a behaviour
that is followed by an annoying
consequence which is weakened (less
likely to occur)
• The food was a satisfying
consequence – hence the cat would
try to escape
• Behaviour that kept the cat in the
box (annoying consequence) was less
likely to occur