The Fascinating Psychology of Numbers: Why Even Numbers Are ‘Good’ and Odd Numbers Are ‘Bad’

Numbers themselves are objective, but people always unconsciously project non-mathematical meanings onto them. Malinowski, a cognitive psychologist at the University of Amsterdam, has studied how people evaluate numbers under 100 (good/bad, exciting/calming). The statistical results clearly show that even numbers are considered “good” and odd numbers are “bad”.

In a similar joint study conducted by Professor Wang of the National University of Singapore Business School and Janiszewski of the University of Florida, researchers asked participants to express their preference for random numbers within 100 (like/dislike/neutral), and the results showed that even numbers and odd numbers ending in 5 were more popular than other numbers.

It seems that people from different geographical and cultural backgrounds have a fairly consistent perception of numbers. In Western culture, 13 is an ominous number, while in Eastern cultures, the preference for 6 and 8 is constantly reflected in the price tag. Does WD-39 sound weird? Because odd numbers always seem a bit surreptitious and mysterious, and disturbing. And Douglas Adams’ novel “The Hitchhiker’s Guide to the Galaxy” – “42” – is neither mysterious nor triggering associations, and humans and animals are harmless and boring.

The impact of odd-even preferences is both direct and subtle – another study by Prof. Wang also showed that the same cleaning product’s brand name was more attractive to consumers when it contained even rather than odd numbers. He believes the reason may be that the brain processes even numbers more easily than odd ones, so even-numbered brand names make the brain accept them more smoothly and comfortably, so it automatically likes them.

In fact, research by Hines, a professor of neurobiology at Pace University in New York, has shown that our brains take longer to respond to odd numbers than even numbers. In a test he devised, random numbers flashed on the screen in pairs, and subjects had to press a button when both numbers were odd or even. The results showed that it took an average of 20 percent longer to recognize odd pairs than even pairs.

For the brain, even numbers are natural, while odd numbers are unnatural and strange. Perhaps this also explains why many odd numbers give people a sense of mystery: for even numbers, the brain can let it go with ease and comfort; for odd numbers, it is used to being more careful and cross-examining. Odd numbers are also more challenging mathematically, especially prime numbers. They are less common, harder to calculate, harder to divide, and even more likely to be the wrong answer to a math problem, causing us to feel negative. The only exception is 5, probably because humans have five fingers on each hand, and 5 × 2 = 10 is also the base number used most often in the base system.

None of this, however, explains quite a few people’s preference for the number 7. As the most non-mainstream number that can be counted on two hands, it’s a bit of mystery, a bit of personality, and a bit of uncertainty, but it’s still in control, which may be the source of its charm.