This five-minute intelligence test for kids is surprisingly effective:
Imagine seven cards laid out on a table in front of you, each card two inches square, with vertical lines of different lengths in the middle of each card.Your task is to move the cards around and put them in order so that the longest line is on the left, and the shortest is on the right. If you do this fairly well, getting a majority in the right order, I’ll ask you to repeat the task with another set of seven cards, this time with lines even more similar in length.
Now I hand you three discs, each the exact same size but somewhat different in weight — more or less the weight of a tennis ball. You need to arrange them in order, heaviest to lightest. Again, if you sort them correctly, I’ll hand you three weights with less discernible differences.
In less than five minutes, we’re done.
So, how effective is this Swiss test?
On 5 and 6 year-old kids, this simple test is virtually synonymous with a 90-minute intelligence test of their full cognitive capacities; the two tests have a 99% correlation. It turns out that kindergartners who are really good at sorting line length and relative weight are the exact same kids who score high on tests of conceptual reasoning, memory, and attention. Whatever the neurobiological advantage is, it’s driving performance on both tests — at least at that age.
Why does it work so well?
They don’t yet completely understand why the simple test works so incredibly well. But to do the tasks correctly, your brain is fundamentally making a series of comparisons, incorporating visual and haptic sensory information. The key here is that the white space of the cards prevents you from putting the two lines exactly next to each other. Your eyes flip back and forth between lines, and the lines are just far enough apart that your brain has to make a figural representation of one line, store that in short term working memory, bring that mental image over to a real line, and then compare the line in memory against the line on the card, discriminating the difference.What does that have to do with reasoning? Well, reasoning too is fundamentally a matter of noticing pattern differences, holding things temporarily in your mind, and making comparisons — just that the complexity becomes multi-dimensional.