How much can a person influence another's person's actions?
Following what is known as the Pygmalion effect in psychology, more than you can even imagine!
Let me explain to you the experiment that took place in 1966. Rosenthal and Jacobson went to a school and gave the students intelligence tests. But here's the catch, those were not real tests at all, but everyone thought they were, students and teachers.
Sometime after, they came back with the "results," that weren't real and simply invented randomly, and told some teachers that their students scored high punctuations in the test, and therefore, were what it was known as "gifted".
The student's who had been classified as "gifted" bettered their school performance. But there's one more thing, none of the students received any feedback from the intelligence test they did.
It was the attitude of the teachers that changed, and it was that what changed how the student performed. How? Easy. If you treat someone like an intelligent person, they'll end up falling there and performing better. It is possible that teachers started to have hope in the students and changed their ways of teaching, helped the students more because they thought they were treating really intelligent people. And that eventually led to the students performing better, because they were being taught better.
BECAUSE THE TEACHER'S EXPECTATION'S OF THE STUDENT'S CHANGED.
The teacher's expected a lot more of these students, as they were supposedly more intelligent, and long story short, people's expectations can, will, and do change how we act!