Reddit mentions of Elementary Signal Detection Theory

I'm not entirely sure in the case of /r/askscience but I studied signal detection theory in college, from a cognitive science perspective. The idea is that the theory provides a general framework to describe and study decisions that are made in uncertain or ambiguous situations. So, the 'signal' is what you want to measure, the 'noise' is the background that you want to filter out.

For a primer, check out:

http://www.amazon.com/Elementary-Signal-Detection-Theory-Wickens/dp/0195092503

The book's not easy, but there it is. The most commonly-used application of the theory is determining if something is present, for example a doctor trying to make a diagnosis. I'm guessing that in the case of /r/askscience, the signal is the good information (upvotes), while the downvotes are meant to clear the white background noise / trash.