Why are cognitive biases so ubiquitous? In a word, Bandwidth.

This beautiful graphic illustrates the bewildering array of psychological biases that have been documented in the literature.  I must admit that I was surprised to see how numerous they are.

But most fascinating to me is the broader categorization of biases according to the “problem” that they solve.  It’s intriguing to think that despite the apparent heterogeneity in the errors we commit, there may be some common explanations that may help us to understand their causes and, perhaps, ways to diminish their adverse effects.  Two of these “problems” are familiar to me, since I teach about them in my cognitive psychology course.   What are called, “too much information” and “not enough meaning” in the graphic, I call “too much input to include in perception” and “not enough input to explain perception” in my lectures.


But both of these are related to a single, simple idea that has been observed repeatedly by neuroscientists over decades (including Vernon Mountcastle, Marcus Raichle, Charles Anderson & David Van Essen to name just a few).   Raichle has pointed out that the brain compresses the unlimited amount of information present in the perceivable world into a much, much smaller amount of information – e.g., roughly just one-millionth of the available input is conveyed to the primary visual cortex, and even less is available to attention and conscious awareness!   Such severe data compression is probably related to the remarkable energetic efficiency of the brain, an organ that consumes roughly 15 watts of power a day – less than it takes to power a light bulb.  And yet, those 15 watts represent 20% of the body’s total energy budget, despite the brain comprising only 2% of the body’s total weight.   Thus, the brain is constantly active, probably working to overcome its inherent bandwidth limitations in clever, but flawed ways.