People have reported seeing a face on Mars, or Elvis in the form of a tree, or even seeing the Virgin Mary in a toasted cheese sandwich.
This sort of expectancy effect is really common throughout cognition, and psychology, more generally.
Example
A manager tells subordinate that they are good at analysis but bad at interpersonal influence. The person’s analysis results improve but their relationships with others deteriorates.
So What?
To get someone to behave in a certain way, first believe that they are capable of doing this and then communicate your expectation to the other person.
Defending
When people expect you to fail, reject this and set your own expectations.
http://changingminds.org/explanations/theories/interpersonal_expectancy.htm
