Behaviorism

Behaviourism was an emergency brake. Psychology around 1900 worked with trained introspection, and when two laboratories reached different results there was no procedure to decide between them. John B. Watson’s way out in 1913 was radical: psychology should study only what two observers can see independently.

The gain was a discipline of method that still carries the field, and a set of findings among the most robust anywhere — classical and operant conditioning are reproduced across species, laboratories and decades, and they carry the most effective procedures behaviour therapy has.

The price was a prohibition. For four decades memory, attention and imagery counted as unscientific topics. Something else stands out about this folder: all three files carry a legend the sources do not support — the bell, the deconditioning, the child in the box.