Which of the following factors does NOT affect perception?

Perception is significantly influenced by various psychological and environmental factors, including past experiences, threats, time, opportunity, and self-concept. However, among these, past experiences are intrinsic elements that shape how individuals interpret and respond to new information and situations.

When individuals encounter new stimuli, their previous experiences inform their understanding and reactions. This process is deeply rooted in cognitive psychology, where past events construct frameworks that guide one's perception of current scenarios. For example, someone who has previously been in a stressful flying experience may perceive all future flights with increased anxiety or apprehension due to that prior context.

In contrast, the other factors—element of threat, time and opportunity, and self-concept—serve as more immediate influencers on perception or how an individual perceives a situation at a given moment, rather than being foundational in shaping that perception over time. Therefore, past experiences uniquely serve as a critical pillar in developing a person's perceptual framework, explaining why it is the factor that does not belong in the context of the question.