Abstract
Does lead reduce IQ at the level of g, test specificities, or both? A bare-bones psychometric meta-analysis utilizing the Method of Correlated Vectors was performed on a sample of 16 studies for which subtest-level data could be obtained satisfying stringent inclusion rules. The aggregate correlation across samples between subtest-level estimates of both g loading (g) and the deleterious impact of lead exposure (d) was 0.10 (K = 16, total N = 1935, 80% CI after correction for sampling error = 0.10 to 0.10). So, lead exposure is associated with a slightly positive vector correlation, which is consistent with the results of other studies examining the effects of other neurotoxins on IQ using MCV; this outcome is consistent with two scenarios. The first is that lead exposure may have effects on both g and test specificities owing to systemic effects on many different brain regions. The second is that two antagonistic factors are at work. It might be that the ‘control’ and exposure groups used in these kinds of studies are confounded with pre-existing differences in g – lower g being a risk factor for poorer life outcomes (including lower socioeconomic status and concomitantly heightened risk of lead exposure), whereas lead has it's primary effect on the test specificities, with both effects opposing one another, as reflected in the small magnitude vector correlation value. Strategies for distinguishing between these scenarios are discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 184-191 |
| Number of pages | 8 |
| Journal | Personality and Individual Differences |
| Volume | 137 |
| Early online date | 10 Sep 2018 |
| DOIs | |
| Publication status | Published - 15 Jan 2019 |
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Keywords
- g factor
- Intelligence
- Lead exposure
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Are the effects of lead exposure linked to the g factor? A meta-analysis. / Woodley of Menie, Michael A.; te Nijenhuis, Jan; Shibaev, Vladimir; Li, Miao; Smit, Jan.
In: Personality and Individual Differences, Vol. 137, 15.01.2019, p. 184-191.Research output: Contribution to Journal › Article › Academic › peer-review
TY - JOUR
T1 - Are the effects of lead exposure linked to the g factor? A meta-analysis
AU - Woodley of Menie, Michael A.
AU - te Nijenhuis, Jan
AU - Shibaev, Vladimir
AU - Li, Miao
AU - Smit, Jan
PY - 2019/1/15
Y1 - 2019/1/15
N2 - Does lead reduce IQ at the level of g, test specificities, or both? A bare-bones psychometric meta-analysis utilizing the Method of Correlated Vectors was performed on a sample of 16 studies for which subtest-level data could be obtained satisfying stringent inclusion rules. The aggregate correlation across samples between subtest-level estimates of both g loading (g) and the deleterious impact of lead exposure (d) was 0.10 (K = 16, total N = 1935, 80% CI after correction for sampling error = 0.10 to 0.10). So, lead exposure is associated with a slightly positive vector correlation, which is consistent with the results of other studies examining the effects of other neurotoxins on IQ using MCV; this outcome is consistent with two scenarios. The first is that lead exposure may have effects on both g and test specificities owing to systemic effects on many different brain regions. The second is that two antagonistic factors are at work. It might be that the ‘control’ and exposure groups used in these kinds of studies are confounded with pre-existing differences in g – lower g being a risk factor for poorer life outcomes (including lower socioeconomic status and concomitantly heightened risk of lead exposure), whereas lead has it's primary effect on the test specificities, with both effects opposing one another, as reflected in the small magnitude vector correlation value. Strategies for distinguishing between these scenarios are discussed.
AB - Does lead reduce IQ at the level of g, test specificities, or both? A bare-bones psychometric meta-analysis utilizing the Method of Correlated Vectors was performed on a sample of 16 studies for which subtest-level data could be obtained satisfying stringent inclusion rules. The aggregate correlation across samples between subtest-level estimates of both g loading (g) and the deleterious impact of lead exposure (d) was 0.10 (K = 16, total N = 1935, 80% CI after correction for sampling error = 0.10 to 0.10). So, lead exposure is associated with a slightly positive vector correlation, which is consistent with the results of other studies examining the effects of other neurotoxins on IQ using MCV; this outcome is consistent with two scenarios. The first is that lead exposure may have effects on both g and test specificities owing to systemic effects on many different brain regions. The second is that two antagonistic factors are at work. It might be that the ‘control’ and exposure groups used in these kinds of studies are confounded with pre-existing differences in g – lower g being a risk factor for poorer life outcomes (including lower socioeconomic status and concomitantly heightened risk of lead exposure), whereas lead has it's primary effect on the test specificities, with both effects opposing one another, as reflected in the small magnitude vector correlation value. Strategies for distinguishing between these scenarios are discussed.
KW - g factor
KW - Intelligence
KW - Lead exposure
UR - http://www.scopus.com/inward/record.url?scp=85053036341&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85053036341&partnerID=8YFLogxK
U2 - 10.1016/j.paid.2018.09.005
DO - 10.1016/j.paid.2018.09.005
M3 - Article
VL - 137
SP - 184
EP - 191
JO - Personality and Individual Differences
JF - Personality and Individual Differences
SN - 0191-8869
ER -