Factors determining awareness
- functional receptor? (damage)
- receptor mechanisms (esp. thresholds)
- selective attention (sensation vs. perception)
- emotions, experience, etc.
The fundamental concept is: what the cortex "perceives" as reality is not identical to the original stimulus, and therefore the perception of the environment will vary from individual to individual and from species to species.
Optical illusions show that perception is not always an accurate representation of the world.