MRI studies of the brains of humans (and monkeys!) indicate that we have an inbuilt ‘number sense’, but we are particularly attuned to the numbers one, two and three, and, beyond that, to detecting large (not small) differences in comparing numbers of an object. We often fall back on these evolutionary number skills. But much of life involves calculations that are more complex than comparing the relative size of small numbers. A century ago the great science fiction writer H. G. Wells said: … endless social and political problems are only accessible and only thinkable to those who have had a sound training in mathematical analysis, and the time may not be very remote when… for complete initiation as an efficient citizen of one of the new great complex world-wide States that are now developing, it is as necessary to be able to compute, to think in averages and maxima and minima, as it is now to be able to read and write. Wells’s reference to how important mathematical understanding is to ‘endless social and political problems’ seems made for our times, but we’ve got a long way to go before we’ll completely satisfy his vision. Countless experiments show that around 10 per cent of the public don’t understand simple percentages.
For example, if you spin a coin twice, what’s the probability of getting two heads? The answer is 25 per cent, because there are four equal-probability outcomes: two heads, two tails, heads then tails and tails then heads. Worryingly, only one in four people in a nationally representative survey got this right
B. Duffy, The perils of perception (2018), loc. 325 & 340
For example, if you spin a coin twice, what’s the probability of getting two heads? The answer is 25 per cent, because there are four equal-probability outcomes: two heads, two tails, heads then tails and tails then heads. Worryingly, only one in four people in a nationally representative survey got this right
B. Duffy, The perils of perception (2018), loc. 325 & 340
