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Changes for page Studies: IQ

Last modified by Ryan C on 2025/06/25 20:56

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204 +{{expandable summary="Study: Brain Size, IQ, and Racial-Group Differences"}}
205 +**Source:** *Intelligence (Elsevier)*
206 +**Date of Publication:** *2003*
207 +**Author(s):** *J. Philippe Rushton, Elizabeth W. Rushton*
208 +**Title:** *"Brain size, IQ, and racial-group differences: Evidence from musculoskeletal traits"*
209 +**DOI:** [10.1016/S0160-2896(02)00137-X](https://doi.org/10.1016/S0160-2896(02)00137-X)
210 +**Subject Matter:** *Neuroanatomy, Intelligence, Evolutionary Anthropology, Racial Differences*
211 +
212 +{{expandable summary="📊 Key Statistics"}}
213 +1. **Average Brain Volumes (cc):**
214 + - Blacks: ~1267 cm³
215 + - Whites: ~1347 cm³
216 + - East Asians: ~1364 cm³
217 +
218 +2. **IQ Averages:**
219 + - Blacks: ~85
220 + - Whites: 100
221 + - East Asians: ~106
222 +
223 +3. **Correlation Between Brain Size & Morphological Traits:**
224 + - Across 37 skeletal variables, mean correlation with brain size: **r = 0.94**
225 +
226 +4. **Sample Basis:**
227 + - Study synthesizes cranial and postcranial anatomical data from global populations.
228 +{{/expandable}}
229 +
230 +{{expandable summary="🔬 Findings"}}
231 +1. **Primary Conclusion:**
232 + - Brain size differences among races are robust, **biologically grounded**, and closely track IQ differences.
233 +
234 +2. **Skeletal Evidence:**
235 + - Morphological traits (jaw shape, tooth structure, thigh curvature, pelvis width) correlate with brain volume across groups.
236 +
237 +3. **Interpretation:**
238 + - These consistent anatomical differences support the theory that **evolved brain size variation underlies racial IQ gaps**.
239 +{{/expandable}}
240 +
241 +{{expandable summary="📝 Critique & Observations"}}
242 +1. **Strengths of the Study:**
243 + - High ecological correlations (r = 0.94) across diverse skeletal metrics.
244 + - Integrates anthropometry with cognitive data for holistic biological analysis.
245 +
246 +2. **Limitations:**
247 + - Relies on preexisting datasets rather than new measurements.
248 + - Assumes uniformity within broad racial categories without finer intra-group distinctions.
249 +
250 +3. **Suggestions for Improvement:**
251 + - Add neuroimaging evidence (MRI/CT) to confirm volume estimates.
252 + - Include modern genomic ancestry estimates for greater precision.
253 +{{/expandable}}
254 +
255 +{{expandable summary="📌 Relevance to Subproject"}}
256 +- Provides **hard anatomical evidence** reinforcing racial differences in cognitive ability.
257 +- Links IQ differences to **physiological, not social** factors—countering CRT narratives.
258 +- Strong empirical foundation for hereditarian interpretations of race and intelligence.
259 +{{/expandable}}
260 +
261 +{{expandable summary="🔍 Suggestions for Further Exploration"}}
262 +1. Cross-validate musculoskeletal trait correlations using modern 3D skeletal databases.
263 +2. Explore how sexual dimorphism interacts with racial brain size differences.
264 +3. Investigate similar correlations in other species to support evolutionary reasoning.
265 +{{/expandable}}
266 +
267 +{{expandable summary="📄 Download Full Study"}}
268 +[[Download Full Study>>attach:rushton2003.pdf]]
269 +{{/expandable}}
270 +{{/expandable}}
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