Attribute means to consider one thing as belonging to or stemming from something else.

• Some scientists attribute intelligence to ants; others say that the complex organizational life of ants should be attributed to instinct.

Ascribe means to assign or attribute a cause, quality, source, etc., to something as a property or as being characteristic of it: to ascribe good (or bad) motives to someone; to ascribe an unsigned painting to Picasso; to ascribe an artifact to the Paleolithic era.

Credit , as here considered, means to attribute or ascribe in a favourable sense: to credit a scientist with a major discovery; to credit a seemingly trivial skirmish with being the turning point of a war.

Impute means to attribute a fault, crime, etc., to a person: to impute nepotism to the manager because of his decision to give a highly paid executive position to his brother-in-law. Impute , however, is not invariably associated with derogatory contexts. It may also be used to mean simply to consider as the source or cause of: to impute one’s happiness to modest ambitions.