Monday, 27 February 2017

The gender pay gap on Euristica: an imaginary island

I recently gave a talk at TEDxCoventGardenWomen about an economic agent-based modelling system I have built (readers of Thomas Schelling may see some influence). In the talk I use this system to analyse ideas around privilege, prejudice and systemic inequality - and to test some policies that might help to solve the persistent gender and racial pay gaps that we still see in most societies.

The video is below - your thoughts would be very welcome.

Thursday, 9 February 2017

Discussion 3 of 3: Lassie died one night

The much-delayed final episode in a short series of posts - part 1 and part 2 here.

Lassie died one night.

As Thomas Schelling* pointed out in a thought-provoking 1982 essay, millions of people watched it happen on television one Sunday evening, and cried. Yet they all knew Lassie was not real – and that the dog who played her was probably in perfect health. Why did they experience the same emotions, the same sense of loss that they would expect to feel if their own dog had died, or even their own grandfather? Why should fictional outcomes and situations provide us with (positive or negative) utility? (And if they do, why can we not simply conjure up unlimited happiness by indulging in films or books that we enjoy and hiding from the world?)

The two hypotheses laid out in the previous posts can provide an explanation not only for this, but for a number of other psychological phenomena:


  • H1: That potential decision outcomes are automatically evaluated by an associative network representing events that might possibly happen
  • H2: That the process of imagining future reward generates real reward in the brain


Start with H2. If imagining future reward – or, by extension, future pain – generates real reward or pain, then it is not a big leap to think that imagining a sad outcome (Lassie’s death) would cause real sadness. Our brains have evolved to allow us to imagine possible outcomes for ourselves, because we need to choose between them. If I was actually involved in the situation and had to choose between a course of action that leads to Lassie’s death and another which does not, it would be important that my mind be able to envisage the consequences of each action, imagine what the results might be and see which one I enjoy more.

H1 claims that this reward-imagining mechanism operates automatically, without our conscious intervention. If this is the case, perhaps that mechanism cannot distinguish whether the outcomes it is evaluating are fictional or not. The mechanism must be disconnected from sensory input – after all, its job is to imagine outcomes that are not presently being sensed. In a way, all of its inputs are fictional: an imagined future for the decision maker, or an imagined present for Lassie.

Let me then propose a third hypothesis: that watching a film, or reading a book, can expand the network of possible events in your head, by adding its own (fictional) concepts into that network. Even though you know it is not real, you construct a mental model that represents the people, objects, events and outcomes in the fictional world. You do this because it is usually pleasurable to imagine and evaluate these possible outcomes; this is the source of the enjoyment we gain from engaging in an imaginary world.

So in summary, the brain contains a model of possible events, which is continuously and unconsciously evaluated to see which outcomes are better. The process of evaluating the events generates reward, in proportion to how rewarding the events would be if they really happened. Reading or watching fiction can add events to this model – as our senses interpret the information, they dump it into our mental model of the world. And therefore, the brain will engage in evaluating events, fictional or otherwise, and be rewarded for doing so.

The sadness you felt when Lassie died – that’s an inevitable side-effect. You watched Lassie for the pleasure, and it tricked you into feeling the pain too.

The consequences of this model go beyond just why we watch TV. Your empathy for another person can be motivated by exactly the same mechanism: you imagine their life outcomes and evaluate them for pain and pleasure, just as you imagine your own. You experience that pain or pleasure while imagining it.

It can explain why a person experiences pleasure or pain from completely symbolic events – the success of a football team, or their government’s implementation of a policy that will never directly affect them. And it suggests why people might adopt specific beliefs in the absence of objective evidence for them.

Although these ideas may not individually seem revolutionary, together they offer a different way to think about the psychology of decision making.

  • Instead of assuming that utility is discounted exponentially in time, consider that it may be discounted by its causal distance from the current situation.
  • Instead of assuming that outcomes can be evaluated in isolation, think of them as only the endpoint of a chain of causes and effects.
  • Instead of assuming that material consumption is evaluated for the utility it provides, think about the desire to control one’s own mental state as the primary object of human behaviour.

This model could allow a much simpler theory of choice than we have been used to. It no longer requires all the axioms that underlie subjective utility theory. Stable, exogenous preferences over goods; the existence of time discounting; transitivity; all become parameters of the model instead of requirements. Some phenomena that are treated as biases in the standard model may emerge as natural consequences of this decision process: loss aversion, confirmation bias, non-independence of irrelevant options.

This is still a somewhat speculative proposal, but there is decent evidence from neuroscience and philosophy that is consistent with it. My current research involves developing the mathematics behind this model, and some experiments by which it can be tested.


* Schelling himself died just a couple of months ago, which makes me sad even though I never knew him.