Finding Dory, Hidden Markov Models and Simplifying Life

Vinodh Kumar Ravindranath, CTO @ Belong

15 February 2019 • 4 mins

The other day talking to a colleague of mine, I just realised that I was perhaps memoryless. Or at least ‘more’ memory-‘less’ than her? Well before you start associating my memoryless-ness to the one that poor Dory in Disney’s Finding Nemo/Dory series is portrayed to have (somewhat unfairly and inaccurately for a fish that actually turns out to have a decent memory in reality!),let me clarify that I thought I was being memoryless albeit like a few probability distributions. Worry not if you are probability-challenged; it’s because probabilities are not on your side (pun intended!) and I will get there in a bit - but basically she was telling me how she would not forget a thing that others told or things that happened!? That triggered a bunch of discussion around life and lifehacks and more reflections and a train of thought late; I just realised something that had come to my rescue often enough, to stay afloat amidst my myriad follies and failings, as the proceedings of life get overwhelming, was the “memoryless” nature of my brain (or thinking process rather!). Memoryless like the Markovian models!

So what are these Markovian models? Markovian models are simple systems (despite their name!) that keep undergoing changes in its state regularly. Just that it goes to a new state every time just based on the present, and never by looking at the past. And when it changes state, it says (outputs) some information to the world. So where it goes and what it says is purely based on the present, making it memoryless. As it turns out some of these Markovian systems tend to be secretive about their states - while it says things when it changes states, it never reveals its states. These rather mystical memoryless systems are called Hidden Markov Models (HMM). A simple example of the same is shown in the illustration below.

Above is a simple example of Hidden Markov Models to predict weather from clothing patterns

Interestingly, these seemingly simple forgetful HMMs are rather at the heart of some of the mind-boggling technologies that we see around us - when you call out “Alexa” to your Amazon Echo device or ask Google to translate sentences into a new language. For a long time, these speech recognition or translation systems were powered by HMMs (And for the record, there are a myriad possible applications that can be built on top of it which I have done too as a data scientist, but we wont get there in the goal of simplifying things!).

If Artificial Intelligence (AI) systems could do well without the baggage of too much past (by the way the state in itself could have a lot of information about the past encoded in it!), is there something for us humans to learn from it? I know it sounds weird, for AI systems are typically trained on human knowledge and in fact AI systems are now trying to get itself “Long Term and Short Term Memory” much like humans to do its job even better, I am talking of humans wanting to learn from memoryless AI systems.

Well, I think there is no doubt that the world is getting complex and I am beginning to believe that the redemption for humans, as we navigate the complexities of the world pounded by nuggets of information every passing moment, lies in simplification. Simplifying our approach to the world around us. As the popular quote goes, one cannot control the the external world, but you can control how to react or act in response.

Yuval in Homo Deus talks of the three big pursuits of humans in the 21st century ; divinity, immortality and happiness. And Yuval also adds rather eerily that the pursuit of happiness might be through biochemical means! While I think there seems to be an touch of grim inevitability in many of those prognosis, for the moment, I daresay simplification of our thinking system is the key to survival and hopefully a pathway to happiness.

So turn memoryless, forget the past and do the best in your current state in your life’s pursuit. In fact, for us to act kind, be little more forgiving and non-retaliatory in nature or exhibit perseverance and patience, there is an element of memoryless-ness needed. Let me end on a philosophical note,when we say Time Heals, it just means our memories fade with time and the pains go away. So the faster you can develop memoryless-ness, the quicker you can move forward :) And when you take decisions without factoring in a lot of the baggage of the past, it does simplify life!

Be Markovian!

PS: I have decided to write again after 14 years, almost a self-imposed exile period, since the days I used to write short stories and blog in Tamil. Now is that a cause for worry and rueing of the missed opportunity of logging a myriad observations, inferences and details of the journey of life in this intervening period? Well, I am Markovian. I am memoryless ;)

Originally posted by me on Towards Data Science .