When was the first experimental evidence for the two-factor theory of emotion published?

The landmark paper appeared in 1962, based on experiments showing that emotion can depend on both physiological arousal and how a person labels that arousal. Stanley Schachter and Jerome Singer published the work in the journal Psychological Review-era literature, and it became one of the most cited ideas in emotion psychology. Their research helped shift thinking away from a purely bodily or purely cognitive explanation of emotions. The theory is still widely discussed, even though later studies have refined and criticized parts of it.