Leaps in Logic
Head scratchers to boost your brain
By Andrea Bartz published March 15, 2011 - last reviewed on June 9, 2016
Behold the power of puzzles! Working on brainteasers, such as these ones from designer Scott Kim, Ph.D., can increase concentration, improve spatial reasoning, and boost your ability to draw logical conclusions. Bonus: “You generally don’t get brain fatigue because you’re enjoying yourself,” says neuroscientist Richard Restak, M.D., who, with Kim, coauthored The Playful Brain. Grab a pencil and follow along for hints, help, and a little added info on just how you’re stimulating that gray matter. —Andrea Bartz
Word Up ↑
“There are really two problems here,” Kim says. “First you have a deduction puzzle: You’re given information and you’ve got to draw conclusions from it.” The second step is a word jumble: Once you’ve figured out what letters you’re working with, you must rearrange them to make a word.
Take inventory: The answer word shares four letters with the word TWEAK, so we can deduce that exactly one letter of TWEAK is not in the secret word. The answer word shares two letters with the word MOUTH. One of these letters must be the same as one of the shared letters from TWEAK, since there are only five letters in the answer word.
“You’re engaging your working memory to remember the letters, envision them in your mind, and rearrange them,” Restak says. “You must be vigilant and remain focused, which are frontal lobe functions. These puzzles are very useful for building up frontal lobe endurance for patience and observation.” As you try out words, you draw on your brain’s language centers, especially Wernicke’s and Broca’s areas.
Feel that little burst of pleasure when the answer falls into place? Thank your anterior temporal lobe (the one in your left hemisphere, since you’re dealing with words). “It sits near the amygdala, a sensory area, and links into the pleasure circuit,” Restak explains. “That’s why the eureka moment feels great.”
Can You Digit? ↓
Step one: Don’t freak out. “Logic puzzles tend to be intimidating because they look like stuff you did in school,” Restak says. This one looks scary until you know where to start. Start with the brown box—what number times 3 equals a number that ends with the digit 7?
Notice how readily multiplication comes back to you. “You’re stimulating the part of your brain responsible for math skills, fighting disuse atrophy,” Restak says. And those times tables? “That’s overlearned material from years of rote memorization.” Thank your fourth-grade teacher.
Now, figure out which digits go in the tan boxes. That 1 in the hundreds place of the top number means there’s no carry to the thousands place, and yet you need a numeral on top that’ll require filling in two tan squares on the bottom.
Be systematic—plug digits in one by one. The last squares will fall into place when you have only a few leftover numbers.
“There are two trains of logic going on,” Kim notes, “and you flip back and forth between them as you try numbers.” You plug in a number and try the math, and then—holding it in your working memory—you flip your mind-set to see if it fits the no-numbers-are-repeated rule.
“This flip-flopping highlights a fascinating limit of the brain,” Restak adds. “Imagine a line drawing of a cube—you can perceive it sticking out one way or the other, and you can flip rapidly, but you can’t see them both at the same time.” Our brains, amazing as they are, can’t totally sync up the processing of specialized regions.