FYI - IIRC Watson, Sr., took “THINK” from NCR where he worked prior to establishing IBM. [Still have my “THINK” sign (in English) on my desk next to my piece of TRINTITE.]
THINK is to working as trinitite is to killin' (today being the sixth of August) — less input, more output. It's all about productivity, you know.
Apparently, the motto dates all the way back to December 1911 — 102 years ago real soon now.