What's Your IQ

EXAMPLE GAME · PLAY TO SEE YOURS

How close can two numbers be before they blur?

What matters isn't the difference between the two clouds but their ratio: 10 against 20 is as easy as 20 against 40. Your accuracy at each ratio gives your Weber fraction, a standard measure of number sense.

YOUR WEBER FRACTION0.20Typical adult range (about 0.11 to 0.25 in published studies). You need roughly a 20% difference to tell two amounts apart reliably.

83%overall accuracy0.94 saverage decision time

ACCURACY BY RATIO · BARS ARE YOU, RINGS ARE YOUR FITTED CURVE

50% · guessing

100%

67%

100%

3:2e.g. 15 vs 104:3e.g. 13 vs 106:5e.g. 12 vs 108:7e.g. 11 vs 10

NUMBER SENSE LAB

Ratio, not difference

The approximate number system works like other senses: the bigger the amounts, the bigger the gap you need to tell them apart. That's Weber's law, first described for weights in the 1830s.

1 · Same difference, different difficultyBoth pairs differ by 4 dots. Slide the smaller number up and watch the predicted accuracy fall for a typical adult (Weber fraction 0.15).

12 vs 897% correctratio 1.50

24 vs 2080% correctratio 1.20

Smaller cloud in the second pair20

2 · Why dot sizes keep changingIf every dot were the same size, the cloud with more dots would also have more yellow, and you could cheat by judging area. The game alternates between two tricks that break that shortcut.

16 vs 11dots130%left's yellow area vs right's

Same-sized dots: more dots means more yellow, so area gives the answer away. On these trials, judging area would work.

WHAT THIS GAME TRAINS

Sensing quantity at a glance

Dot-comparison tasks measure the approximate number system: the fast, inexact sense of 'how many' that babies, adults and many animals share. It works without counting, and its precision is summarised by the Weber fraction.

corestrongsomelight

coreNumber senseJudging which amount is bigger without counting.

strongProcessing speedTaking in a whole scene in under a second.

strongVisual attentionSpreading attention across the whole cloud, not one patch.

someInhibitionIgnoring dot size and total area when they mislead.

REAL-WORLD MOMENTS

Pick a moment to see what's going on

Tap a situation to see which part of the skill it relies on.

SKILLS THESE MOMENTS DRAW ON

Number sensecore

Processing speedstrong

Visual attentionsome

1 / 3

Choosing a checkout queueSeeing at a glance which queue has fewer people or items.

WHAT'S GOING ONJudging which amount is bigger without counting.

IN THE GAMEThe game drills number sense in short, scored rounds, the same ability this moment calls on.

Leans on: number sensecore

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, in the parietal lobe, holds the brain's number map. Its neurons respond to approximate quantities, whether shown as dots, sounds or digits.

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

From gut feel to exact numbers

Estimation is fast and rough. These games move towards precise, quick processing of numbers and symbols.

All pattern recognition games →

EXACT ARITHMETICMental MathSolve as many sums as you can in 60 seconds.Swap rough estimates for precise answers at speed.

VISUAL SPEEDSymbol SearchIs the target symbol in the group?Scan a group quickly, but for one exact item.

PERCEPTUAL SPEEDInspection TimeWhich line was longer? Shown for a split second.Another flash judgement, this time about length.

VISUAL MEMORYChange DetectionSpot which square changed colour.Take in a whole display at once, then hold it.

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