What's Your IQ

EXAMPLE ROUND · PLAY TO SEE YOURS

How many squares you really held

Accuracy alone flatters easy trials. Researchers use Cowan's K, which corrects for guessing: K = set size × (hit rate − false-alarm rate). If your K stops rising as the arrays get bigger, you've found your limit.

YOUR CAPACITY · K6.0Above the typical adult range. You're holding a full set of slots.

ACCURACY AND K BY NUMBER OF SQUARES

K 3.0100%

3 squares

K 3.088%

4 squares

K 6.0100%

6 squares

96%overall accuracy

92%changes spotted

0%false alarms

THE MAGICAL NUMBER FOUR

Why more squares don't mean more remembered

In 1997 Steven Luck and Edward Vogel found that people hold about four objects in visual working memory, and that past that point extra items simply aren't stored. Set your capacity and the array size to see what the slot model predicts.

Your capacity (K)4Squares shown6

4 / 6squares stored

83%predicted accuracy

Only 4 of 6 squares get a slot. If the tested square is one of the others, you're guessing: that's why accuracy falls towards 50% as arrays grow.

TYPICAL CAPACITY

Young adults3.5

Older adults (70+)2.6

Children (age 7)2.1

Rhesus monkeys1.5

WHAT THIS GAME TRAINS

Visual working memory, isolated

Change detection strips memory down to its core: hold a picture in mind for under a second, then compare. It's one of the cleanest measures of working-memory capacity there is.

corestrongsomelight

coreVisual working memoryHolding several colours and places in mind at once.

strongVisual attentionSpreading attention across the whole array during a brief flash.

someComparison and decisionMatching what you see against what you stored.

lightProcessing speedTaking in the display before it disappears.

THE SAME SKILL, ELSEWHERE

Three places this skill turns up

Each one leans on a different part of what the game trains.

Spot the price changeNoticing when one figure on a bill or menu is different from last time.Uses visual working memory

Spotting differencesProofreading, comparing versions, noticing what's moved on a desk or screen.Uses visual attention

Reasoning headroomMore memory slots leave more room for juggling steps in a problem.Uses comparison and decision

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

1Parietal lobetop and back

Combines what you see, hear and touch into a map of where things are. It also handles numbers and directing your attention through space.

ITS JOB IN THIS GAMETracks where things are and how many there areThe intraparietal sulcus fills up as you store more items and plateaus at your capacity limit. Its activity tracks your K almost exactly.

DID YOU KNOWDamage on the right side can make people ignore everything on their left, a condition called hemispatial neglect.

ALL AREAS

WHERE TO GO FROM HERE