Cattell Culture Fair Intelligence Test

Scales 2 and 3 use four kinds of item, each timed tightly, so speed matters as well as accuracy.

• Series. Choose the figure that continues a sequence of shapes.
• Classifications. Choose the two figures that go together and differ from the rest.
• Matrices. Complete a grid pattern by choosing the missing piece, like the practice items below.
• Conditions. Work out the rule for where a dot sits relative to shapes, then place a dot in a new figure so that it meets the same conditions.

Modern IQ scales set the average at 100 and use a standard deviation of 15. Cattell chose 24. What that means is that Cattell scores spread out further from 100 than Wechsler scores do, so the numbers look bigger even when the ability is the same.

To convert a Cattell score to the standard scale, subtract 100, multiply by 15/24 (which is 0.625), and add 100 back. A Cattell 148 becomes 100 + 48 × 0.625 = 130. The standard deviation guide shows worked conversions for all three common scales.

American Mensa accepts a Cattell IQ of 148 from a psychologist-administered test, which is the Cattell version of a Wechsler 130. The Triple Nine Society, which admits the top 0.1%, lists a Cattell Scale IIIB score of 173 as its equivalent.

Those two numbers look far apart, and both are consistent: 148 and 173 sit two and about three standard deviations above average on the Cattell scale. Triple Nine also notes that an older Cattell combined raw-score route stopped being accepted in 2015.

The test avoids words and numbers, which removes the most obvious language and schooling effects. It does not remove all cultural influence. People from cultures where diagrams and timed tests are more familiar do better, and reported correlations between the CFIT and other intelligence tests are moderate, roughly .5 to .7.

"Culture fair" is therefore a design aim, not a guarantee. The same caution applies to every non-verbal test, including Raven's matrices.

The published CFIT is a controlled test with restricted materials, and its scoring depends on timing and standardised administration. Online versions use items in its style, and some borrow its name. They cannot give a Cattell IQ, and you should not quote one as if it were a Cattell score.

The matrices subtest is the one that translates best to a web page. Here are three original matrix items of increasing difficulty.