LIFE SCIENCES – Randomness
Even pretending to construct random sequences is a young person’s game, ANDREW MASTERSON reports.
Code-breaking, at its heart, involves looking at lots of numbers and trying to spot tell-tale patterns that may provide a key to decryption.
Spies long ago realised that the best way to create truly random encryption is to ask a computer to do it. This is because humans are rather poor at creating lists of random numbers, even when they are consciously trying to do so.
“Some early cryptographers assumed they could generate huge amounts of random keys by haphazardly tapping away at a typewriter,” wrote physicist Simon Singh in his history of espionage, The Code Book (Fourth Estate, 1999).
“This might be a quick way of generating a [cipher] key, but the resulting sequence has structure and is no longer random.”
Looking for an insight into why randomness – or apparent randomness – is so challenging, a team of researchers from the Laboratoire de Recherche Scientifique in Paris, France, recently devised a series of tests and applied them to a pool of 3,400 people, aged between four and 91.
Each of the participants was asked to complete a series of tasks, all of which required the construction of lists that would appear random when viewed by an observer.
The tasks included making up a set of 12 coin-toss results, and inventing the numbers shown by 10 hypothetical die throws. The results, published in the journal PLOS Computational Biology, reveal that age 25 is the peak for achieving truly random-looking lists.
“This experiment is a kind of reverse Turing test for random behaviour, a test of strength between algorithms and humans,” says co-author Hector Zenil.
The findings add weight to previous studies that suggest – perhaps counterintuitively – that constructing properly random lists requires very high-level cognitive processes. Randomness may be connected to other cognitive activity, particularly creativity.
So if you need to jot something truly random, what should you do? Singh’s advice: “The best random keys are created by harnessing natural physical processes, such as radioactivity, which is known to exhibit truly random behavior.”