Please identify the most current, cutting edge, theories in
psychology, philosophy, or science in general which attempt to explain
how and why an individual's perceptions of the world change and what
specific factors motivate these changes in perception. Specifically,
are changes in perception motivated by conscious decisions or
thoughts, or are they the result of wranglings of the deeper
unconscious workings of the mind (including pure emotion, natural
instinct, intuition, etc.). If it is the latter, what theories most
specifically explain the details of the process (not in terms of
biology but more in terms of a step by step logical, practical
explanation)?

By perception, I would hope to stay specific to real and measurable
degrees of how we perceive various concepts or characteristics. As for
example when you perceive an object to be larger or smaller than it
really is, or an area as seeming bright or dark at different times, or
the experience of the passage of time as being a fast or slow process.

In short, theories that would explain how and why an individual's
perception of his world changes and are these changes more a result of
conscious thinking or a mix of unconscious activity.