cognitive operation vs mental process

cognitive operation and mental process both are nouns.

Word	Noun	Adjective	Verb	Adverb
cognitive operation	Yes	No	No	No
mental process	Yes	No	No	No

As nouns, cognitive operation and mental process are synonyms defined as:

cognitive operation and mental process: (psychology) the performance of some composite cognitive activity; an operation that affects mental contents

Other synonyms of cognitive operation include cognitive process, operation, process.

cognitive operation (noun)	mental process (noun)
(psychology) the performance of some composite cognitive activity; an operation that affects mental contents	(psychology) the performance of some composite cognitive activity; an operation that affects mental contents