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Wiki source code of Studies: IQ

Version 14.1 by Ryan C on 2025/06/21 06:33
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1 = IQ =
2
3 {{expandable summary="
4
5 Study: Is there a Dysgenic Secular Trend Towards Slowing Simple Reaction Time?"}}
6 **Source:** *Intelligence (Elsevier)*
7 **Date of Publication:** *2014*
8 **Author(s):** *Michael A. Woodley, Jan te Nijenhuis, Raegan Murphy*
9 **Title:** *"Is there a Dysgenic Secular Trend Towards Slowing Simple Reaction Time?"*
10 **DOI:** [10.1016/j.intell.2014.05.012](https://doi.org/10.1016/j.intell.2014.05.012)
11 **Subject Matter:** *Cognitive Decline, Intelligence, Dysgenics*
12
13 {{expandable summary="📊 Key Statistics"}}
14 1. **General Observations:**
15 - The study examines reaction time data from **13 age-matched studies** spanning **1884–2004**.
16 - Results suggest an estimated **decline of 13.35 IQ points** over this period.
17
18 2. **Subgroup Analysis:**
19 - The study found **slower reaction times in modern populations** compared to Victorian-era individuals.
20 - Data from **Western countries (US, UK, Canada, Australia, Finland)** were analyzed.
21
22 3. **Other Significant Data Points:**
23 - The estimated **dysgenic rate is 1.21 IQ points lost per decade**.
24 - Meta-regression analysis confirmed a **steady secular trend in slowing reaction time**.
25 {{/expandable}}
26
27 {{expandable summary="🔬 Findings"}}
28 1. **Primary Observations:**
29 - Supports the hypothesis of **intelligence decline due to genetic and environmental factors**.
30 - Reaction time, a **biomarker for cognitive ability**, has slowed significantly over time.
31
32 2. **Subgroup Trends:**
33 - A stronger **correlation between slower reaction time and lower general intelligence (g)**.
34 - Flynn effect (IQ gains) does not contradict this finding, as reaction time is a **biological, not environmental, measure**.
35
36 3. **Specific Case Analysis:**
37 - Cross-national comparisons indicate a **global trend in slower reaction times**.
38 - Factors like **modern neurotoxin exposure** and **reduced selective pressure for intelligence** may contribute.
39 {{/expandable}}
40
41 {{expandable summary="📝 Critique & Observations"}}
42 1. **Strengths of the Study:**
43 - **Comprehensive meta-analysis** covering over a century of reaction time data.
44 - **Robust statistical corrections** for measurement variance between historical and modern studies.
45
46 2. **Limitations of the Study:**
47 - Some historical data sources **lack methodological consistency**.
48 - **Reaction time measurements vary by study**, requiring adjustments for equipment differences.
49
50 3. **Suggestions for Improvement:**
51 - Future studies should **replicate results with more modern datasets**.
52 - Investigate **alternative cognitive biomarkers** for intelligence over time.
53 {{/expandable}}
54
55 {{expandable summary="📌 Relevance to Subproject"}}
56 - Provides evidence for **long-term intelligence trends**, contributing to research on **cognitive evolution**.
57 - Aligns with broader discussions on **dysgenics, neurophysiology, and cognitive load**.
58 - Supports the argument that **modern societies may be experiencing intelligence decline**.
59 {{/expandable}}
60
61 {{expandable summary="🔍 Suggestions for Further Exploration"}}
62 1. Investigate **genetic markers associated with reaction time** and intelligence decline.
63 2. Examine **regional variations in reaction time trends**.
64 3. Explore **cognitive resilience factors that counteract the decline**.
65 {{/expandable}}
66
67 {{expandable summary="📄 Download Full Study"}}
68 [[Download Full Study>>attach:10.1016_j.intell.2014.05.012.pdf]]
69 {{/expandable}}
70 {{/expandable}}
71
72 {{expandable summary="Study: Survey of Expert Opinion on Intelligence: Intelligence Research, Experts' Background, Controversial Issues, and the Media"}}
73 **Source:** *Intelligence (Elsevier)*
74 **Date of Publication:** *2019*
75 **Author(s):** *Heiner Rindermann, David Becker, Thomas R. Coyle*
76 **Title:** *"Survey of Expert Opinion on Intelligence: Intelligence Research, Experts' Background, Controversial Issues, and the Media"*
77 **DOI:** [10.1016/j.intell.2019.101406](https://doi.org/10.1016/j.intell.2019.101406)
78 **Subject Matter:** *Psychology, Intelligence Research, Expert Analysis*
79
80 {{expandable summary="📊 Key Statistics"}}
81 1. **General Observations:**
82 - Survey of **102 experts** on intelligence research and public discourse.
83 - Evaluated experts' backgrounds, political affiliations, and views on controversial topics in intelligence research.
84
85 2. **Subgroup Analysis:**
86 - **90% of experts were from Western countries**, and **83% were male**.
87 - Political spectrum ranged from **54% left-liberal, 24% conservative**, with significant ideological influences on views.
88
89 3. **Other Significant Data Points:**
90 - Experts rated media coverage of intelligence research as **poor (avg. 3.1 on a 9-point scale)**.
91 - **50% of experts attributed US Black-White IQ differences to genetic factors, 50% to environmental factors**.
92 {{/expandable}}
93
94 {{expandable summary="🔬 Findings"}}
95 1. **Primary Observations:**
96 - Experts overwhelmingly support **the g-factor theory of intelligence**.
97 - **Heritability of intelligence** was widely accepted, though views differed on race and group differences.
98
99 2. **Subgroup Trends:**
100 - **Left-leaning experts were more likely to reject genetic explanations for group IQ differences**.
101 - **Right-leaning experts tended to favor a stronger role for genetic factors** in intelligence disparities.
102
103 3. **Specific Case Analysis:**
104 - The study compared **media coverage of intelligence research** with expert opinions.
105 - Found a **disconnect between journalists and intelligence researchers**, especially regarding politically sensitive issues.
106 {{/expandable}}
107
108 {{expandable summary="📝 Critique & Observations"}}
109 1. **Strengths of the Study:**
110 - **Largest expert survey on intelligence research** to date.
111 - Provides insight into **how political orientation influences scientific perspectives**.
112
113 2. **Limitations of the Study:**
114 - **Sample primarily from Western countries**, limiting global perspectives.
115 - Self-selection bias may skew responses toward **those more willing to engage with controversial topics**.
116
117 3. **Suggestions for Improvement:**
118 - Future studies should include **a broader range of global experts**.
119 - Additional research needed on **media biases and misrepresentation of intelligence research**.
120 {{/expandable}}
121
122 {{expandable summary="📌 Relevance to Subproject"}}
123 - Provides insight into **expert consensus and division on intelligence research**.
124 - Highlights the **role of media bias** in shaping public perception of intelligence science.
125 - Useful for understanding **the intersection of science, politics, and public discourse** on intelligence research.
126 {{/expandable}}
127
128 {{expandable summary="🔍 Suggestions for Further Exploration"}}
129 1. Examine **cross-national differences** in expert opinions on intelligence.
130 2. Investigate how **media bias impacts public understanding of intelligence research**.
131 3. Conduct follow-up studies with **a more diverse expert pool** to test findings.
132 {{/expandable}}
133
134 {{expandable summary="📄 Download Full Study"}}
135 [[Download Full Study>>attach:Rindermann et al. - 2020 - Survey of expert opinion on intelligence Intelligence research, experts' background, controversial.pdf]]
136 {{/expandable}}
137 {{/expandable}}
138
139 {{expandable summary="Study: A Review of Intelligence GWAS Hits: Their Relationship to Country IQ and the Issue of Spatial Autocorrelation"}}
140 **Source:** *Intelligence (Elsevier)*
141 **Date of Publication:** *2015*
142 **Author(s):** *Davide Piffer*
143 **Title:** *"A Review of Intelligence GWAS Hits: Their Relationship to Country IQ and the Issue of Spatial Autocorrelation"*
144 **DOI:** [10.1016/j.intell.2015.08.008](https://doi.org/10.1016/j.intell.2015.08.008)
145 **Subject Matter:** *Genetics, Intelligence, GWAS, Population Differences*
146
147 {{expandable summary="📊 Key Statistics"}}
148 1. **General Observations:**
149 - Study analyzed **genome-wide association studies (GWAS) hits** linked to intelligence.
150 - Found a **strong correlation (r = .91) between polygenic intelligence scores and national IQ levels**.
151
152 2. **Subgroup Analysis:**
153 - Factor analysis of **9 intelligence-associated alleles** revealed a metagene correlated with **country IQ (r = .86)**.
154 - **Allele frequencies varied significantly by continent**, aligning with observed population differences in cognitive ability.
155
156 3. **Other Significant Data Points:**
157 - GWAS intelligence SNPs predicted **IQ levels more strongly than random genetic markers**.
158 - Genetic differentiation (Fst values) showed that **selection pressure, rather than drift, influenced intelligence-related allele distributions**.
159 {{/expandable}}
160
161 {{expandable summary="🔬 Findings"}}
162 1. **Primary Observations:**
163 - Intelligence-associated SNP frequencies correlate **highly with national IQ levels**.
164 - Genetic selection for intelligence appears **stronger than selection for height-related genes**.
165
166 2. **Subgroup Trends:**
167 - **East Asian populations** exhibited the **highest frequencies of intelligence-associated alleles**.
168 - **African populations** showed lower frequencies compared to European and East Asian populations.
169
170 3. **Specific Case Analysis:**
171 - Polygenic scores using **intelligence-related alleles significantly outperformed random SNPs** in predicting IQ.
172 - Selection pressures **may explain differences in global intelligence distribution** beyond genetic drift effects.
173 {{/expandable}}
174
175 {{expandable summary="📝 Critique & Observations"}}
176 1. **Strengths of the Study:**
177 - **Comprehensive genetic analysis** of intelligence-linked SNPs.
178 - Uses **multiple statistical methods (factor analysis, Fst analysis) to confirm results**.
179
180 2. **Limitations of the Study:**
181 - **Correlation does not imply causation**; factors beyond genetics influence intelligence.
182 - **Limited number of GWAS-identified intelligence alleles**—future studies may identify more.
183
184 3. **Suggestions for Improvement:**
185 - Larger **cross-population GWAS studies** needed to validate findings.
186 - Investigate **non-genetic contributors to IQ variance** in addition to genetic factors.
187 {{/expandable}}
188
189 {{expandable summary="📌 Relevance to Subproject"}}
190 - Supports research on **genetic influences on intelligence at a population level**.
191 - Aligns with broader discussions on **cognitive genetics and natural selection effects**.
192 - Provides a **quantitative framework for analyzing polygenic selection in intelligence studies**.
193 {{/expandable}}
194
195 {{expandable summary="🔍 Suggestions for Further Exploration"}}
196 1. Conduct **expanded GWAS studies** including diverse populations.
197 2. Investigate **gene-environment interactions influencing intelligence**.
198 3. Explore **historical selection pressures shaping intelligence-related alleles**.
199 {{/expandable}}
200
201 {{expandable summary="📄 Download Full Study"}}
202 [[Download Full Study>>attach:Piffer - 2015 - A review of intelligence GWAS hits Their relationship to country IQ and the issue of spatial autoco.pdf]]
203 {{/expandable}}
204 {{/expandable}}
205
206 {{expandable summary="Study: Thirty Years of Research on Race Differences in Cognitive Ability"}}
207 **Source:** *Psychology, Public Policy, and Law*
208 **Date of Publication:** *2005*
209 **Author(s):** *J. Philippe Rushton & Arthur R. Jensen*
210 **Title:** *"Thirty Years of Research on Race Differences in Cognitive Ability"*
211 **DOI:** [10.1037/1076-8971.11.2.235](https://doi.org/10.1037/1076-8971.11.2.235)
212 **Subject Matter:** *Psychometrics, Racial Differences, Intelligence, Heritability*
213
214 {{expandable summary="📊 Key Statistics"}}
215 1. **General Observations:**
216 - Mean IQ gap between Blacks and Whites in the U.S.: **15 points**.
217 - Heritability estimates for IQ: **0.5 to 0.8** (moderate to high).
218 - Brain volume differences align with IQ differences: **50 cm³ difference** on average.
219
220 2. **Subgroup Analysis:**
221 - **Black Americans** consistently score about 1 SD below **White Americans** across age groups.
222 - **East Asians** tend to score slightly higher than Whites on non-verbal IQ tests.
223
224 3. **Other Significant Data Points:**
225 - Between-group differences are found on **culture-free, g-loaded** tests.
226 - Adoption studies: **Black children raised in White households** still show IQ closer to Black population mean.
227 {{/expandable}}
228
229 {{expandable summary="🔬 Findings"}}
230 1. **Primary Observations:**
231 - The Black–White IQ gap is **persistent, replicable**, and appears early in life.
232 - **g factor (general intelligence)** underlies the racial IQ gap across diverse cognitive tasks.
233
234 2. **Subgroup Trends:**
235 - Differences are larger on more **g-loaded tests**, suggesting the gap is not a test artifact.
236 - Socioeconomic status **does not eliminate** the gap, though it can influence expression.
237
238 3. **Specific Case Analysis:**
239 - Minnesota Transracial Adoption Study: **Black children adopted into affluent White homes** scored lower than White adoptees.
240 - U.S. military data (e.g. AFQT scores) showed **consistent racial stratification** in cognitive performance.
241 {{/expandable}}
242
243 {{expandable summary="📝 Critique & Observations"}}
244 1. **Strengths of the Study:**
245 - Synthesizes **hundreds of studies** spanning psychometrics, neuroscience, and genetics.
246 - Applies rigorous **meta-analytic and test-construction logic**.
247 - Challenges purely environmental or cultural explanations with empirical evidence.
248
249 2. **Limitations of the Study:**
250 - The review is **intensely controversial**, particularly due to assumptions about race as a valid biological category.
251 - Heritability within groups **does not automatically justify** between-group heritability claims — critics argue this is misused.
252 - Critics allege selective reporting or bias in study inclusion (e.g. underrepresenting null results).
253
254 3. **Suggestions for Improvement:**
255 - Further work could benefit from **modern genomic tools** (e.g. polygenic risk scoring) to isolate population-level traits.
256 - Greater inclusion of **cross-cultural replications** would help test universality vs. U.S.-specific effects.
257 {{/expandable}}
258
259 {{expandable summary="📌 Relevance to Subproject"}}
260 - This is one of the most comprehensive defenses of **biological origins of racial cognitive differences**.
261 - Supports the view that racial gaps in academic or occupational outcomes are **not purely environmental**.
262 - Challenges dominant narratives in education policy, DEI programming, and social justice frameworks.
263 {{/expandable}}
264
265 {{expandable summary="🔍 Suggestions for Further Exploration"}}
266 1. How have genetic studies (e.g. GWAS) since 2005 confirmed or contradicted Rushton & Jensen’s findings?
267 2. What are the **policy implications** of acknowledging cognitive group differences — in education, immigration, or welfare?
268 3. To what extent do **cultural suppression and academic censorship** affect open discussion of these results?
269 {{/expandable}}
270
271 {{expandable summary="📄 Download Full Study"}}
272 [[Download Full Study>>attach:rushton2005 OCR.pdf]]
273 {{/expandable}}
274 {{/expandable}}
275
276 {{expandable summary="
277
278
279 Study: Brain Size, IQ, and Racial-Group Differences"}}
280 **Source:** *Intelligence (Elsevier)*
281 **Date of Publication:** *2003*
282 **Author(s):** *J. Philippe Rushton, Elizabeth W. Rushton*
283 **Title:** *"Brain size, IQ, and racial-group differences: Evidence from musculoskeletal traits"*
284 **DOI:** [10.1016/S0160-2896(02)00137-X](https://doi.org/10.1016/S0160-2896(02)00137-X)
285 **Subject Matter:** *Neuroanatomy, Intelligence, Evolutionary Anthropology, Racial Differences*
286
287 {{expandable summary="📊 Key Statistics"}}
288 1. **Average Brain Volumes (cc):**
289 - Blacks: 1267 cm³
290 - Whites: 1347 cm³
291 - East Asians: 1364 cm³ 
292
293 2. **IQ Averages:**
294 - Blacks: 85
295 - Whites: 100
296 - East Asians: 106 
297
298 3. **Correlation Between Brain Size & Morphological Traits:**
299 - Across 37 skeletal variables, mean correlation with brain size: **r = 0.94**
300
301 4. **Sample Basis:**
302 - Study synthesizes cranial and postcranial anatomical data from global populations.
303 {{/expandable}}
304
305 {{expandable summary="🔬 Findings"}}
306 1. **Primary Conclusion:**
307 - Brain size differences among races are robust, **biologically grounded**, and closely track IQ differences.
308
309 2. **Skeletal Evidence:**
310 - Morphological traits (jaw shape, tooth structure, thigh curvature, pelvis width) correlate with brain volume across groups.
311
312 3. **Interpretation:**
313 - These consistent anatomical differences support the theory that **evolved brain size variation underlies racial IQ gaps**.
314 {{/expandable}}
315
316 {{expandable summary="📝 Critique & Observations"}}
317 1. **Strengths of the Study:**
318 - High ecological correlations (r = 0.94) across diverse skeletal metrics.
319 - Integrates anthropometry with cognitive data for holistic biological analysis.
320
321 2. **Limitations:**
322 - Relies on preexisting datasets rather than new measurements.
323 - Assumes uniformity within broad racial categories without finer intra-group distinctions.
324
325 3. **Suggestions for Improvement:**
326 - Add neuroimaging evidence (MRI/CT) to confirm volume estimates.
327 - Include modern genomic ancestry estimates for greater precision.
328 {{/expandable}}
329
330 {{expandable summary="📌 Relevance to Subproject"}}
331 - Provides **hard anatomical evidence** reinforcing racial differences in cognitive ability.
332 - Links IQ differences to **physiological, not social** factors—countering CRT narratives.
333 - Strong empirical foundation for hereditarian interpretations of race and intelligence.
334 {{/expandable}}
335
336 {{expandable summary="🔍 Suggestions for Further Exploration"}}
337 1. Cross-validate musculoskeletal trait correlations using modern 3D skeletal databases.
338 2. Explore how sexual dimorphism interacts with racial brain size differences.
339 3. Investigate similar correlations in other species to support evolutionary reasoning.
340 {{/expandable}}
341
342 {{expandable summary="📄 Download Full Study"}}
343 [[Download Full Study>>attach:rushton2003.pdf]]
344 {{/expandable}}
345 {{/expandable}}

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