It wasn’t just Superman who was experimenting with life-like robots, it appears that Luthor was also doing so in Action Comics #166 (January 1952). Luthor kidnaps Perry White and switches in his robot duplicate to send Lois to dangerous assignments to keep Superman busy. Robots seem to be popping up in every comic book by the end of 1951 and beginning of 1952.
Isaac Asimov’s novel I, Robot was published at the end of 1950, so timing-wise this is probably right in the midst of a robot fixation in science fiction.