Compression Stereotypes

One of the most mindblowing things I learnt while I was doing my undergrad in Computer Science and Engineering was Lempel-Ziv-Welch (LZW) compression. It’s one of the standard compression algorithms used everywhere nowadays.

The reason I remember this is twofold – firstly, I remember implementing this as part of an assignment (our CSE program at IITM was full of those), and feeling happy to be coding in C rather than in the dreaded Java (which we had to use for most other assignments).

The other is that this is one of those algorithms that I “internalised” while doing something totally different – in this case I was having coffee/ tea with a classmate in our hostel mess.

I won’t go into the algorithm here. However, the basic concept is that as and when we see a new pattern, we give it a code, and every subsequent occurrence of that pattern is replaced by its corresponding code. And the beauty of it is that you don’t need to ship a separate dictionary -the compressed code itself encapsulates it.

Anyway, in practical terms, the more the same kind of patterns are repeated in the original file, the more the file can be compressed. In some sense, the more the repetition of patterns, the less the overall “information” that the original file can carry – but that discussion is for another day.

I’ve been thinking of compression in general and LZW compression in particular when I think of stereotyping. The whole idea of stereotyping is that we are fundamentally lazy, and want to “classify” or categorise or pigeon-hole people using the fewest number of bits necessary.

And so, we use lazy heuristics – gender, caste, race, degrees, employers, height, even names, etc. to make our assumptions of what people are going to be like. This is fundamentally lazy, but also effective – in a sense, we have evolved to stereotype people (and objects and animals) because that allows our brain to be efficient; to internalise more data by using fewer bits. And for this precise reason, to some extent, stereotyping is rational.

However, the problem with stereotypes is that they can frequently be wrong. We might see a name and assume something about a person, and they might turn out to be completely different. The rational response to this is not to beat oneself for stereotyping in the first place – it is to update one’s priors with the new information that one has learnt about this person.

So, you might have used a combination of pre-known features of a person to categorise him/her. The moment you realise that this categorisation is wrong, you ought to invest additional bits in your brain to classify this person so that the stereotype doesn’t remain any more.

The more idiosyncratic and interesting you are, the more the number of bits that will be required to describe you. You are very very different from any of the stereotypes that can possibly be used to describe you, and this means people will need to make that effort to try and understand you.

One of the downsides of being idiosyncratic, though, is that most people are lazy and won’t make the effort to use the additional bits required to know you, and so will grossly mischaracterise you using one of the standard stereotypes.

On yet another tangential note, getting to know someone is a Bayesian process. You make your first impressions of them based on whatever you find out about them, and go on building a picture of them incrementally based on the information you find out about them. It is like loading a picture on a website using a bad internet connection – first the picture appears grainy, and then the more idiosyncratic features can be seen.

The problem with refusing to use stereotypes, or demonising stereotypes, is that you fail to use the grainy pictures when that is the best available, and instead infinitely wait to get better pictures. On the other hand, failing to see beyond stereotypes means that you end up using grainy pictures when more clear ones are available.

And both of these approaches is suboptimal.

PS: I’ve sometimes wondered why I find it so hard to remember certain people’s faces. And I realise that it’s usually because they are highly idiosyncratic and not easy to stereotype / compress (both are the same thing). And so it takes more effort to remember them, and if I don’t really need to remember them so much, I just don’t bother.

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