"everyone knows plutonians are sneaky little wretches who will steal you blind if you aren't careful. polly is a plutonian. therefore, polly is a thief." this line of reasoning is typical of

The answer is "stereotyping".

Stereotyping is characterized as a "distorted, typically disparaging, mentality individuals hold toward those outside one's own experience who are extraordinary. They are an aftereffect of deficient or distorted data acknowledged as truth without question". A stereotype is basically a broadly held conviction that an individual is an individual from a specific gathering in view of characteristics. Because of the procedure of over generalization inside social discernment, stereotyping prompts a lot of error in social recognition.