Superfluous information. Your conscious mind has what it came for and discards the rest. Think if it as data compression.
Your typical mp3 song sounds indistinguishable from lossless wave yet it’s a tenth of the size because all those high sounds you can’t hear anyways gets discarded.
Mostly these shortcuts are very useful to us but it can be a vulnerability to be exploited.
Source: A whole lotta thinking about it.
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