The author

Computers & Evolution

Steven Pemberton, CWI, Amsterdam


Lightning in slow motion



This is very like a certain style of computer problem-solving program.

Imagine trying to find a route through a forest: at each fork in the path, you try one direction, and if that doesn't lead to where you want, you backtrack and try another.

There are several possible variants:


This method can solve an amazing range of problems.

HOW TO RETURN (route, state) aim:
   IF state = aim:
      RETURN ("success", route with state)
   IF state in route OR deadend state:
      RETURN ("failure", {})
   PUT route with state IN new.route
   FOR option IN options state:
      PUT (new.route, state altered.for option) aim IN result, route
      IF result = "success":
         RETURN ("success", route)
   RETURN ("failure", {})

In an article I wrote, I used this to solve the Farmer and the Produce problem, the Two Jugs problem, and even the Towers of Hanoi (just for two disks, it found 12 solutions!), but it will also solve the Eight Queens problem, Sudoku, and many others.


Backtracking is comparable to how evolution works


EvolutionSee the original interactive version here: evogeneao

Cheese and the theory of evolution (Bas Haring)

Book cover

The 3 requirements for evolution:


In early evolution, the only source of variation was mutation, and mutation is only rarely successful, more likely leading to deleterious effects. (Compare with changing one ingredient at random in a recipe.)

Once sex evolved, there was more source of variation (and they were combinations of things that were already successful).

Which explains the success of sex.


If everything survived, then there would be no selection of advantageous genes.

However, there is a guarantee of competition, because in the long run there aren't enough resources to support an ever increasing population.

Death is evolution's backtracking, that is: death without offspring.

(Later we will see how the definition of offspring has changed).


Striped HyenaThe environment changes (and therefore redefines success).

This is how species happen.

It is interesting to consider that since cats and dogs have a common ancestor, that common ancestor had two children, one of which was the first cat, and one that was the first dog.

(If you wonder what a cat-dog would look like, you might like to know that the hyena is actually a cat, not a dog)

It is also interesting to contemplate that humans may already have speciated without us knowing it (yet).

Genetic Memory

You can see the accretion of successful genes as a form of learning, or a form of memory.

It is similar to the 'route' in the backtracking program earlier.

Examples of genetic learning/memory in humans

Hayley Mills and Roy Boulting

People like sugar and fat: in the past calories were in short supply. Our bodies rewarded us for eating them.

Sex being fun: creatures that enjoyed sex were more likely to reproduce...

Age differences in couples: you are more likely to find couples where the man is older than where the woman is older.


After Sex, true memory was a major development, and allowed learning behaviours: you no longer needed genetic memory to survive, you could use recent outcomes to decide how to act.

An example of a creature with no memory can be seen in the Sphex Wasp behaviour.


Hypnosis experiments show that you may not always be aware of the reasons you do things. You may rationalise them differently to the 'true' reason.

Example from Surely You're Joking, Mr. Feynman! "All the time you're saying to yourself, "I could do that, but I won't" – which is just another way of saying that you can't."

Some think that there may not even be conscious free will at all, but that we always rationalise after the action.

What people like and don't like

It is fun to watch out for things that people apparently love (because they cluster round it, for instance) and try to postulate the evolutionary advantage that it represents.


People at a lake


Sacre Coeur, Paris


People at Sacre Coeur, Paris



What else do people stare at for hours, apart from a campfire?


My hypothesis is that we like fire not because it is warm, or that it frightens wild animals off, but because it flickers.

The genetic advantage we got was that it was warm and frightened off predators, but that wasn't the reason we liked it in the first place.

This may have consequences for the success of e-ink, and that people will prefer the flickering LED screens without knowing why.


The visable manifestations of genes (as affected by environment):

Extended phenotype: created by genes, but not a part of your body. E.g.:


A major development for humans was language.

It allows evolution with planning: survival techniques that you can pass on, memories that last longer than a lifetime.

It creates the concept of Memes, in analogy to genes, carriers of information that may (or may not) help survival.

Examples: Clothes. Houses, washing your hands, ...

An example of a bad meme that has died: blood letting as a cure.

McLuhan (The Medium is the Massage):

"The wheel is an extension of the foot, the book is an extension of the eye; clothing, an extension of the skin, electric circuitry, an extension of the central nervous system"

Having ideas is now just as important as having babies.


Writing was another major development, because it allowed ideas and memories to survive your death in a permanent form.

Printing extended this by making it easier to spread the ideas.

The Extended Human Phenotype

Using memes, not genes, to extend our abilities.

Protection: Helmets, clothes, raincoats, houses.

Memory: writing, photography, video.

Repair: Glasses, medicine, hospitals, deafness.

Abilities: Cars, planes, boats.

Communication: Telephone, radio, newspapers, books.

Sensing: Telescopes, weather radar, satnav - we were the last generation of people who could get lost.

The Computer as Extended Phenotype

The computer is being used in so many ways to extend our abilities, I can see no other possibility than to regard it as part of our extended phenotype, an external extension of our brain.

The Singularity

Paradigm shifts over the agesRay Kurzweil has observed that 'paradigm shifts' have been happening over human history faster and faster.

Compare society now with that of my grandparents: they had no hot water in house, no toilets, no electricity. There were no films, radio, television, cars. The only 'modern' technologies they had were trains and photography.

We are now seeing new shifts: mobile telephones, cheap computers that can understand and talk back, self-driving cars, ...

The accelerating rate of change is pointing to a time in the near future where paradigm shifts will occur daily. This is referred to as the singularity.

Closing the loop

DNA is a sort of memory → Evolution of true memory → Language, passes memories → Writing records memories that outlive you.

Now researchers have found a way to use DNA as a (very slow) storage medium.

DNA storage breakthrough: 700TB of data in one gram (That would require 140,000 DVDs, or 150kg of hard disks).


The reason that humans have succeeded so well in comparison with many other life forms is the development of language, and therefore of memes that make us much more flexible in our ability to survive.

Particularly successful memes have caused paradigm shifts in human society, fueling the next generation of memes. Evidence shows that the rate of change of change has been increasing exponentially over hundreds of thousands of years.

Possibly within our lifetimes, we will be confronted with a very interesting time, when we may have to contend with six new paradigms before breakfast every day.

(The slides are online)