What’s so bad about bias?

The dictionary definition usually goes like this:

biasn. inclination or prejudice for or against someone or something (a person or group, or an opinion, or a theory, ……). v. incline, or cause to be inclined, in favour of someone or something

Unbiased brain image johnnycullen.net

A preference for anything is a bias. A preference for a particular food, or person, or pet, or idea is a bias.  Animals too exhibit behaviour which humans would interpret as bias. A bias is clearly a cognitive state based on the knowledge, memories and values stored in that brain at that time. It is also clearly a dynamic state and changes as the state of the brain changes. Consider a brain fully capable of thinking but empty of all memory, all values, and all knowledge. A brain with no preferences for anything! Such a brain would begin as truly unbiased when required to form an opinion. An impossible state, of course, but useful as a thought experiment for defining a zero bias condition.

A preference for anything is, in fact, the result of a cognitive judgement made by a brain based on the knowledge and memories it has and on the internal value scales it uses. Our empty, thinking brain could not form an opinion about anything without first having some knowledge and some value scale to apply. Forming an opinion, is itself, the creation of a preference and a bias. Expressing an opinion is an expression of bias. All knowledge is bias. The greater the knowledge held by a brain, the greater the bias it has. The clearer the set of values held by a brain, the greater its bias. An unbiased mind is an empty mind.

Bias, itself, is not a value. It is, I think, a description of a cognitive state. A knowledgeable person, a person with opinions, is a biased person.

A learned judge is a biased judge. An unbiased music critic with no prior opinions is a useless critic. A food critic without taste preferences would be unbiased but would also be worthless as a critic. Unbiased parents would show no preference for their own children. Without bias, “good” and “bad” start with equal value. I am incurably biased against what I consider “bad” and against people I don’t like. Bias is merely the current state of a functioning brain.

Yet, bias is considered “bad” and to be unbiased is considered “good”. I suspect it is because we conflate the state of bias with the value scale of fairness.

But bias and fairness are entirely different things.



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