Perception cannot be proportional to stimulus across its full range.

Evidence

Under these circumstances, it is unthinkable that our response would be proportional to the stimulus. If we assign one unit of brightness to the lowest detectable light level, we can easily see the difference between one and two units of brightness. However, we do not expect to be able to tell the difference between brightness levels 1,000,000 and 1,000,001, which differ by the same amount. We meet the same problem making graphs of quantities that vary by factors of hundreds, thousands, or greater. If something has a value between 1 and 10 part of the time, and then between 1 million and 2 million later, putting all the data on the same graph means compressing all the behavior in the range between 1 and 10 to a hairline so thin that it cannot be seen. — Eric J. Heller, Why You Hear What You Hear- An…, 1996

Categorization

• XREF: The graphing/compression analogy echoes how decibel scales compress audio data in signal processing. — connects to: So-called sensory relativity is really objective contradiction resolved by free choice.