Two Studies From 1968 Explain Why Most Persuasion Attempts Fall Flat

In 1968, two unrelated studies landed within months of each other. Neither was about sales or persuasion directly, but together they explain why most attempts at influence don’t stick.

The first came from Harvard psychologist Robert Rosenthal, working with school principal Lenore Jacobson in a California public school. They randomly picked a group of students and told their teachers these particular kids were intellectual bloomers, about to surge ahead academically. Nothing about the students had actually changed, same ability as everyone else. The only thing that changed was what the teacher believed about them. By the end of the year, those students showed real, measurable IQ gains, because the teachers, believing the label, unconsciously gave them more warmth, more patience, and more attention. The students picked up on it and rose to meet it, living up to a reputation they never asked for and didn’t know existed. This is now widely cited in leadership research as the expectation effect: a manager’s belief in someone shapes how that person performs, and the same holds for the story you run about yourself.

The second study came from Robert Zajonc at the University of Michigan, published the same year. Participants were shown a series of random objects, made up words, unfamiliar symbols, Chinese characters, unfamiliar faces, with no context and no argument made for any of them. The only variable was repetition. The more often someone saw a particular symbol or face, the more favourably they rated it. No added information, no clever pitch, just repeated exposure. This has since been replicated widely in advertising, branding, and political campaigns. Familiarity lowers perceived risk, and the brain treats harmless repeated exposure as a safety signal: I’ve seen this before and nothing bad happened.

Neither study involved a clever technique or a perfectly worded pitch. What both point to is far less flashy: consistent belief and consistent presence, sustained over time, beat a one-off persuasive attempt every time. Fix your self-talk first, because belief leaks into how you show up before words do. Show up consistently rather than loudly, because repetition builds trust faster than reach ever will. And expect more from people, because they tend to rise to meet it. If you’re chasing influence, stop hunting for a better pitch. Look instead at what you believe, and how consistently you show up. That’s the actual mechanism. Everything else is decoration.