1. The SON-R non-verbal intelligence tests:
fair assessment of children
Dr. Peter Tellegen
University of Groningen
The Netherlands
p.j.tellegen@rug.nl
2. The SON-tests
Originally developed in 1943 for use with deaf children
Now two tests for general application with different age norms:
the SON-R 2,5-7 (published in 1998)
the SON-R 5,5-17 (published in 1988)
Dr. Peter Tellegen (university of Groningen, The Netherlands)
Dr. Jaap Laros (university of Brasilia, Brazil)
Publisher: Hogrefe Verlag, Germany
3. History of the SON-tests
SON (1943)
4-14 years
SON-’58 (1958)
4-16 years
SON 2½-7 (1975) SSON (1975)
3-7 years 7-17 years
SON-R 2½-7 (1998) SON-R 5½-17 (1988)
2,5-8 years 5,5-17 years
SON-I 6-40 (2008)
6-40 years
4. A non-verbal test
• The SON-tests are tests of general intelligence which do not require
the use of spoken or written language
• The focus is on fluid intelligence
• The tests are especially suitable for children with problems in the
area of language and communication
• For cross-cultural intelligence assessment, the SON-tests can be
very useful, because the test materials don’t need translation
5. Some characteristics
SON-R 2,5-7 SON-R 5,5-17
Age range 2;6 – 6;11 yrs 5;6 – 6;11 yrs
Number of subtests 6 7
Administration individually individually
Duration 50 min. 90 min.
Sample N=1.124 N=1.350
Reliability .90 .93
Generalisability .78 .85
6. Evaluation by the Dutch test
commission (COTAN)
SON-R 2,5-7 SON-R 5,5-17
Construction good good
Materials good good
Manual good good
Norms good good
Reliability good good
Construct validity good good
Criterion validity good good
7. Dimensions in the SON-tests
Concrete reasoning
Abstract reasoning
Spatial abilities
Perceptual abilities
8. SON-R and language development
Correlations of SON-R 2,5-7 and teacher evaluation
(general education, N=616)
Criterion correlation
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Intelligence .46
Language development .44
Correlations of SON-R 2,5-7 and evaluation by staff
(special groups, N=241)
Criterion correlation
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Intelligence .61
Language development .31
9. SON-R and language development
Correlations of IQ SON-R 2,5-7 with other tests
Criterion test General education Special groups
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General intelligence
Bailey .59 (50)
K-ABC .65 (115)
RAKIT .60 (165) .55 (70)
LDT .58 (80)
WPPSI .60 (53)
Language development
Reynell .45 (558) .44 (179)
TvK .59 (108) .53 (49)
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10. Subtests of the SON-R 2,5-7
Mosaics (spatial)
Categories (reasoning)
Puzzles (spatial)
Analogies (reasoning)
Situations (reasoning)
Patterns (spatial)
17. Standardisations of the SON-R 2,5-7
The Netherlands (1998) published
Germany (2005) to be published 2006
Great Britain (2005) most data collected
Czech/Slowak Republic (2006) most data collected
Brazil (2007) in preparation
Iran (2007) in preparation
Thailand (2007) in preparation
26. PRINCIPLES of ASSESSMENT
The needs of the subject
are the focus of interest
Improve Highlight the
accuracy of limitations of
measurement interpretation
27. Characteristics of administration
both verbal and non-verbal instruction
extensive examples
feedback
adaptive procedure
no time-pressure
administration stops after few errors
active involvement of the child
28. Individualized adaptive testing
3 series (a, b, c) with same levels of difficulty
Each child starts with same item a1.
Stop in each series after two errors.
Skip easy items at the beginning
(they are counted as correct)
29. Norms based on age intervals
The WISC-tests use norms based on 4-month intervals
Two children with exactly the same raw scores:
Age of John is 6;3:30
Age of Mary is 6;4:0
The age difference is only 1 day
But the difference in IQ is 8 points
John: IQ = 74
Mary: IQ = 66
30. Continuous norms
It is possible to compute standardized scores (z)
for any raw score X and for any age Y
with a formula such as:
Z = a + b.X + c.X2 + d.X3 +
e.Y + f.Y2 + g.Y3 +
h.X.Y + i.X2.Y + j.X3.Y + k.X.Y2
a ... k parameters of the model
X2, X3 second and third order of raw score
Y2, Y3 second and third order of age
31. Fair assessment
When tested with a verbal intelligence test, children who grow up with a
different language will be at a disadvantage.
Their intelligence will be underestimated and this may result in lower
educational and vocational opportunities.
32. Immigrant children in The Netherlands
Verbal intelligence should be assessed in the native language
(Carroll).
Also with the SON-tests, immigrant children score lower
compared to native Dutch children.
With verbal intelligence tests, however, the difference is twice as
large.
33. Mean IQ’s of immigrant children
groups SON-R RAKIT
Moroccan 88.7 80.5
Turkish 91.0 80.0
SON-R non-verbal intelligence test
RAKIT general intelligence test, like the WISC
34. Educational level of the father in
The Netherlands and mean IQ’s
Educational level pct. mean SON IQ
Only primary school 7% 92.9
University 7% 111.6
35. Improving the nonverbal content
Pictorial contents can also be culturally biased.
Cross-cultural research – between countries and also
between different cultures within a country –
can make the test less culture dependent.
For the new edition of the SON-R 5,5-17 such research
is carried out with the subtest Categories.
39. Cross-cultural research SON-R 5,5-17
Improvement of the subtest Categories
Group-wise administration in different countries
Comparison of results
Improving item content
Estimation of difficulty order
Evaluation of item bias
First round: Brazil, Indonesia, Kenya, Morocco, The
Netherlands
Second round: Brazil, Thailand, Iran, Slovakia, Surinam,
The Netherlands
40. The SON outside Europe
Research with the tests in:
Kenya, Morocco, Burkina Fasso, Congo Brazzaville
Brasilia, Surinam, Peru
Thailand, Iran, China, Indonesia
Australia, United States
48. Performance of the Thai children on the
SON-R 2,5-7 [a]
Udon Thani other parts
(poor rural area) Thailand
N=49 N=240
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subtest mean (sd) mean (sd)
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• Mosaics (spatial) 7.1 (2.8) 9.0 (2.9)
• Patterns (spatial) 8.3 (2.8) 11.3 (3.0)
• Categories (reasoning) 7.2 (3.2) 9.7 (3.2)
• Situations (reasoning) 7.1 (3.3) 10.0 (3.4)
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Total IQ 82.8 (14.2) 100.2 (15.7)
49. Performance of Kenyan children on the
SON-R 2,5-7
Group N mean IQ
Urban (Nakuru) 18 85.4
Rural school 12 69.3
50. Performance of Peruvian children on the
SON-R 5,5-17
Group N mean IQ
Urban (Lima) 160 94.0
Rural (Urubamba) 32 73.0
(street children / poor areas)
51. Conclusion:
how to interpret the test scores
Test performance reflects level of intelligence.
But it is also true that
Test performance reflects the situation in which children grow up.
Unless situations are fairly comparable, scores do not represent
“real” intelligence but are better described as representing
differences in cognitive development.
52. www.testresearch.nl
Pages in Dutch / German / English
General information on the SON and other intelligence tests
Of special interest on the website:
Fair Assessment of Children from Cultural Minorities: A Description of
the SON-R Nonverbal Intelligence Tests
P.J. Tellegen & J.A. Laros
In: Quality Education for Children from Socially Disadvantaged Settings
Edited by Dagmar Kopcanova (2005)
