Looking professional the first day, he believes, will carry over through the rest of the semester, when he reverts to the work clothes he will don until he meets a new batch of students.
His thought is that students will remember their first encounter positively and more readily give him the benefit of the doubt as the semester proceeds because they have been primed to respect him through that favorable first impression.
The sequence that we encounter matters in how we judge subsequent information. The exaggerated impact of first impressions is related to the halo effect, that phenomenon whereby the perception of positive qualities in one thing or part gives rise to the perception of similar qualities in related things or in the whole.
Here is an example: you meet a friendly person at a party and later are asked to solicit sponsors for a worthy cause. You contact that person because you think she will make a contribution. In reality, there is no inherent connection between being pleasant and being generous. Yet the halo effect leads you to make that unwarranted assumption that the two are related. Most conclude that if she was good in one category (sociable), she will also be positive in another (generous).
The halo effect is powerful, but it questionable whether it matters much in long-term relationships, such as that between teacher and student. While dressing up may predispose students to think the teacher must know his subject matter because he creates a professional first impression, the effect wears thin if the person turns out to be a poor teacher after all.
First impressions matter but substance has the final word. If you had never seen or heard of Einstein, the first time you saw him your impression would most likely be negative. Now his face is associated with genius, not madness because he is the person who has come to define what genius is.
The problem is that few of us are Einsteins and we often don’t get the chance to rectify a negative first impression.
If what others think of you matters, then pay attention to how others see you the first time you meet. As important, pay attention as to how your first impression may prejudice you against someone else.
First impressions matter, for good and bad. They are fine when you like someone on first meeting; they are not so fine when the first meeting is negative. Positive first impressions lead to social cohesion; negative first impressions lead to biases and social prejudice.
The halo effect distorts reality. It creates false impressions and can, for example, lead researchers to dismiss disconfirming information; businesses to become complacent; teachers to over- or underrate a student’s real performance; the police to wrongly identify suspects; banks to make careless loans.
The term ‘halo effect’ is misnamed since the phenomenon is as much about the devil in us as it is about our angelic side.