Page "Linguistic relativity" Paragraph 34

Lenneberg's main criticism of Whorf's works was that he had never actually shown the causality between a linguistic phenomenon and a phenomenon in the realm of thought or behavior, but merely assumed it to be there.

Together with his colleague, Roger Brown, Lenneberg proposed that in order to prove such a causality one would have to be able to directly correlate linguistic phenomena with behavior.

They took up the task of proving or disproving the existence of linguistic relativity experimentally and published their findings in 1954.