One strength of the behaviourist approach is that it is based on well controlled research:
Observable behaviour
Highly controlled lab environment
Behaviour broken down into basic stimulus-response units
Cause-and-effect relationships were established
Oversimplification of the learning process
One limitation of the behaviourists' approach is that they may have oversimplified the learning process:
Reductionist
Internal processes (e.g. thought) ignored
Other theories, SLT and cognitive approach, do identify internal processes
Therefore, learning is more complex than observable behaviour alone
Real-world application
A strength of the behaviourist approach is that the principles of conditioning have been applied to real-world behaviours and problems. For example, operant conditioning is the basis of token economy systems:
Used in schools, homes, prisons/psychiatric settings
Rewarding appropriate behaviour with tokens that can be exchanged for privileges
Environmental determinism
One limitation of the behaviourist approach is that it sees all behaviour as conditioned by past conditioning experiences:
Skinner suggested that everything we do is the sum total of our reinforcement history
Skinner claims that there is no "free will" and that it is an illusion
Ignores the influence of conscious decision-making
Extra limitations
Low phylogenetic similarity: we can't generalise findings from Skinner's animals as they are very different from humans and they are less sentient beings.