For one experiment, Topolinski used a set of number sequences that correspond to positive words, like 54323 (“liebe” — love) and 373863 (“freund” — friend), and a set for negative words, like 7245346 (“schleim” — slime) and 26478 (“angst” — fear). Volunteers were handed a cell phone with stickers over the buttons so they could only see the numbers, not the corresponding letters, and were told to type the number sequences. After typing each one, they rated how pleasant it had been to dial the number on the phone. Volunteers believed they were participating in a study on ergonomics — in the debriefing afterward, none had any idea that the numbers might relate to words.

On average, volunteers preferred dialing numbers that related to positive words over those related to negative words. Merely dialing the numbers that corresponded to those letters — not even pushing them multiple times, as you’d usually do to text words on a 10-digit keypad — was enough to activate the concepts in their minds.