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.