Why we stereotype?
According to Psychology, stereotype is a generalised belief about a particular group of people. It is a technique used by our brain to reduce the amount of thinking that is required when we meet a new person.
Psychology of Stereotyping
As a child, we start learning by characterising things into different schema. A child begins by making a schema for every object he/she sees and then categorise them. That is how they start recognising things. So, if a child will see a couple of different type of cats, they will have a schema in their brain which responds to that. When they see a lion, then the schema will be different from that of a cat.
Similarly, according to me, stereotypes are also built upon the mental schemas we make about a group of people to simplify our thinking process. We have a schema for everything, from “Mothers”, “Postman”, “Rock Star” to “Teachers”. So, when I say the word “Mother”, then you will imagine a caring woman.
These schemas are then extended into stereotypes, where we add some qualities and beliefs with the whole group. So, “Punjabis are jovial”, “Biharis are hard working”, “South Indians eat rice”. This stereotyping helps us to respond to a situation rapidly. When we meet a Punjabi, then we are automatically comfortable with them, or we meet a Bihari employee then we know he/she will complete the assigned work.
The stereotypes can be positive or negative. For example, “Biharis cannot speak good English” is a negative stereotype that people have. It is not necessary that these generalisations that we make are true.
Disadvantage of Stereotyping
The disadvantage of stereotype is that when we generalise we just ignore all the individual differences that that the group can have. In most of the cases, even when we see a person who is contradicting our generalised belief, we do not tend to alter our stereotype. We will just put that person in a special category of exceptions.
And, then there are times when we also start believing and behaving according to the stereotypes that exists for the group we belong to. People can suffer from low self esteem when they meet a new person if they know that there is a negative stereotype for them. Thus, stereotypes can be harmful.
Food for thought!
Now, my question is when we start getting all hyped up with a person about making stereotypes, then is putting that person alone at fault is also correct? Stereotyping is basically related to how our brain is wired as a human being. Thus, it is a meta cognitive thing, we need to think, how we really think. So, start thinking. 
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