The dynamics of perception ordinarily delineate patterns in a field of perceived foreground and an apperceived background. However, to understand how patterns emerge, what they are, and how to change them requires the proper tools and the diligence of a Moshe Feldenkrais or a Robert Irwin. An approximate psychological law relating the degree of response or sensation of a sense organ and the intensity of the stimulus. The law asserts that equal increments of sensation are associated with equal increments of the logarithm of the stimulus, or that the just noticeable difference in any sensation results from a change in the stimulus which bears a constant ratio to the value of the stimulus. By way of example, lighting a candle in broad daylight at noon produces no consciously noticeable difference in brightness.
Differences become apparent at midnight.
I can't understate how important this is when it comes to consider the consequences for understanding how an ATM effects its changes. To say one color is darker, or one pressure heavier, is not to indicate another intensity but is to make a judgement that relates the two. Such judgements are inextricably entangled with the workings of our body. Differences are not sensations but fundamental judgements yoked to the contiguous perturbations that created them. Perturbations arising external or internal to our selves are not sensations in the traditional sense.