You do not like your new neighbour because he is messy and loud. You also think other negative things about him, such as "he is probably sexist" and "he is such a narcissist," even though you don't have evidence of those traits. This is an example of

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Quizplus · Accepted Answer

The horns effect is when a negative impression of someone in one area (e.g., being messy and loud) leads to negative assumptions about them in other, unrelated areas (e.g., being sexist or a narcissist) without evidence. This is the opposite of the halo effect, where a positive impression in one area leads to positive assumptions in others.

You Do Not Like Your New Neighbour Because He Is