Everything in Coherence

by Tom Walton

Learning, consciousness and evolution.

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He wishes for the cloths of heaven

This is my favourite poem. It was written by W. B. Yeats and conveys a sentiment that is ostensibly romantic, but speaks to me more generally of how vulnerable we are whenever we embark on a project that really matters to us.

Had I the heavens’ embroidered cloths,
Enwrought with golden and silver light,
The blue and the dim and the dark cloths
Of night and light and the half light,
I would spread the cloths under your feet:
But I, being poor, have only my dreams;
I have spread my dreams under your feet;
Tread softly because you tread on my dreams.

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Working for nothing: the power of variable-ratio reinforcement

The ability to manipulate behaviour simply by changing schedules of reinforcement, has always amazed me. Reinforcement is the presentation of a rewarding stimulus (e.g. food, money, praise etc) or removal of a negative stimulus (e.g. pain, anticipation etc) in response to a given behaviour. Generally speaking, the more we reinforce, the greater the frequency of response and the less likely it is that the response will disappear from the behavioural repertoire (‘extinction’). This reflects much of the behaviour we see in animals and other people.

However, the relationship isn’t a linear one and by trying different schedules of reinforcement, we can demonstrate that the predictability of reinforcement has a huge bearing on the rate of response. It turns out that by presenting reinforcement at variable intervals (e.g. on average every 10 seconds) or variable ratios (e.g. on average every

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Thinking machines

I’ve always been interested in what people have to say on the subject of thinking machines and thought I’d share a couple of my favourite quotations. The first is from the late Dutch computer scientist, Edsger Dijkstra:

The European mind (…) considers the question whether machines can think as relevant as the question whether submarines can swim. (1986, p.10)

Based on the context of the talk from which it is taken (source in the references below), it seems he was trying to say that Europeans perceive a greater difference between humans and machines than do Americans. Curiously enough, I’ve only ever heard the quotation used to emphasise the point that questions about thinking, especially where machines are concerned, are semantic inventions to be avoided if at all possible. Whilst the latter interpretation is not an opinion I share, it is, I believe, a much more interesting use of

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Cup to which I have a sentimental attachment

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As the handful of people who know me will testify, I have a very delicate emotional constitution. However, in spite of this, I’ve never been inclined to keep objects for their sentimental value. Except one. I do have one sentimental item. It is a cup that my dad bought for me when he was on a business trip in the Netherlands. But it doesn’t matter where it is from—he could have picked it up from the local petrol station and I wouldn’t care—what matters is that it vividly reminds me of my home and my family life between the ages of 10 and 18. There’s no story behind the cup, no economic value and no special properties, it’s just a cup that elicits feelings of familiarity that I would sooner not lose.

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What’s so special about a Skinner box?

An operant chamber (or ‘Skinner box’) is an apparatus used by psychologists to investigate animal learning, with a particular emphasis on schedules of reinforcement. Until a couple of days ago, I thought the benefits of the Skinner box paradigm were all fairly obvious: it reduces exposure to irrelevant stimuli, keeps the animal near the operandum (response lever or key), allows some behavioural freedom (the animal isn’t restrained) and enables the researcher to automatically control all important parameters within the experiment. However, good though these reasons are, it turns out that there is a more sophisticated theoretical rationale. Skinner (1969) explains this by contrasting operant chamber paradigms with the learning experiments conducted by Thorndike (1911). In one such experiment, a cat learns over successive trials to escape from a box by pressing a foot pedal linked to a door

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Dollar auctions and giving-up time

The economist Martin Shubnik (1971) is responsible for a fiendish yet rather entertaining game called the dollar auction. I recommend trying the game next time you’re out with friends, so here are some brief instructions and a couple of things to look out for:

  • Put a pound up for auction and invite some friends to bid for it (two works best)
  • They may bid any amount and could technically buy the pound for just one penny but, unlike in traditional auctions, the agreement is that both winner and loser must pay
  • Because the eventual loser must pay money in return for nothing, there is a large incentive for all parties to keep bidding once they have made their first bid
  • The moment someone bids fifty pence you are guaranteed to earn your pound back on the next bid; any further bids represent pure profit
  • If there is a bid of one pound, any further bid will commit the bidders to pay more than

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Beavers are amazing

Believe it or not beavers are native to the UK and we are currently in the first stages of their reintroduction to selected parts of Scotland and England. They are the ultimate equilibrium device for water distribution and flow and have enormous positive effects on biodiversity and water quality, all of which has earned them the grand biological labels: ecosystem engineers and keystone species. Here’s a list of just some of the many benefits they bring:

  • Reduced the risk of drought by increasing the height of the water table due to water retention and by slowing the rate of flow
  • Improved water quality by slowing the flow of rivers and streams, allowing sediment to be deposited
  • Reduced risk of flooding by widening channels and creating side branches and ponds
  • Increased biodiversity due to the larger range of water habitats and coppicing of local trees

If you’re interested in the

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