It's hard to rate because it's not a very integrated paragraph. It seems to be taken from the middle of an essay. It's impossible to tell if it's been set up and resolved properly. You need to concentrate more on articles, a/the.
Wikipedia states: "Deindividualisation means treating other people according to preconceived qualities such as race, gender or creed"
Is it possible that you actually mean "Deindividuation"?
Deindividuation - Wikipedia, the free encyclopedia
Group polarization is the tendency of people to make decisions that are more extreme when they are in a group, as opposed to a decision made alone or independently
Group polarization - Wikipedia, the free encyclopedia
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