What's Your IQ

HOW A ROUND WORKS

Compare each turn with the one n steps back

Here's a sample of eight turns. Switch the level and see which turns become matches: the further back you have to look, the more positions you must keep updating in your head.

turn 1

too early

turn 2

too early

turn 3

MATCH

turn 4

turn 5

turn 6

MATCH

turn 7

turn 8

MATCH

At 2-back, 3 of these 8 turns are matches. You compare each square with the one 2 turns earlier, then drop the oldest from memory and add the newest: a constant update, not just recall.

HOW YOU'RE SCORED · EXAMPLE ROUND

Pressing every time won't help

Every turn lands in one of four boxes, depending on whether it was a match and whether you pressed. Accuracy rewards both kinds of right answer.

YOU PRESSEDYOU HELD BACK

WAS A MATCH

Hit5Right: you spotted it.

Miss2The match slipped past you.

NO MATCH

False alarm3You pressed on a non-match.

Correct rejection12Right: you held back.

ACCURACY( 5 hits + 12 rejections ) ÷ 22 turns77%

level downstaylevel up

WHY GUESSING FAILS · ABOUT 30% OF TURNS ARE MATCHES

Press every turn30%

Never press70%

Your round77%

Perfect play100%

THE SCIENCE

What the n-back does, and doesn't, do

Invented in 1958Wayne Kirchner designed the n-back to study how short-term memory changes with age. It became the standard way to load working memory in brain-imaging studies.

It lights up the prefrontal cortexImaging studies consistently show activity in frontal and parietal regions that grows as n increases.

Single vs dualThis version tracks one stream. The dual n-back adds spoken letters, roughly doubling the load. Start here, then move up.

Transfer is limitedYou will get better at the n-back. Whether that boosts general intelligence is disputed: large reviews find little transfer beyond similar tasks.

Kirchner, W. K. (1958), age differences in short-term retention of rapidly changing information; Owen et al. (2005), Human Brain Mapping meta-analysis of n-back imaging studies; Melby-Lervåg & Hulme (2013), meta-analysis of working-memory training.

WHAT THIS GAME TRAINS

Constantly updating what you remember

N-back never lets your memory settle: every new item has to be compared with one from n steps ago, then the list shifts along. It trains updating, the busiest part of working memory.

corestrongsomelight

coreWorking memory updatingDropping old items and adding new ones every few seconds.

strongSustained attentionStaying locked on the sequence for a whole block.

strongInterference controlIgnoring lures that match 1 or 3 back instead of n.

someProcessing speedResponding before the next item appears.

OUTSIDE THE GAME

Where you'll notice it in everyday life

01Following conversationsKeeping track of who said what as a discussion moves on.

02Tracking changing informationScores, prices or instructions that keep updating.

03Focus enduranceConcentrating for longer stretches without drifting.

INSIDE YOUR BRAIN

The brain areas doing the work

Step through each area, or tap one below. The matching marker grows on the brain; dashed markers sit deep inside.

Side view of the brain with the four lobes shaded in different colours

Based on Gray's Anatomy, fig. 728 (public domain)

AREA 1 OF 3

1Prefrontal cortexfront of the brain

The brain's control centre for planning, decision-making and holding goals in mind. It's the last region to mature, finishing in your mid-twenties.

ITS JOB IN THIS GAMEKeeps you on task and filters out distractionsDorsolateral prefrontal cortex is the hub of n-back; its activity rises with each step of n.

DID YOU KNOWIt makes up roughly a third of the human cortex, a larger share than in any other primate.

ALL AREAS

WHERE TO GO FROM HERE