After hearing that Bryce had served a prison sentence, Janet began to perceive his friendly behavior as insincere and manipulative even he acted the same as before. This best illustrates the impact of:

perceptual sets.                                                                                                                        

Explanation:

Perceptual set: In psychology, the term "perceptual set" is described as a specified predisposition through which an individual tends to perceive different things in a few specific ways. Henceforth, it suggests that an individual generally notices only a few aspects of a particular thing, situation, or object therefore avoids the other general details of the given event, object, etc.

In the question above, the given statement best illustrates the impact of perceptual set.

i am confused, what is the question? i can you out if you put it into more depth.

because the early people found out about it.