2.6. Assessment of the nine year old children 
2.7. Assessment of the twelve year old children 
2.8. Assessment of the fifteen year old children 
3. Isolation of variables (application under "natural" conditions) 
3.1. Description of the concept 
3.2. Description of the measures: Equipment and materials 
3.3. Investigation procedures and instructions 
3.4. Scoring instructions and coding rules 
3.5. List of variables at age 12 (urban sample) 
3.6. Assessment of the twelve year old children 
3.7. Assessment of the fisteen years old children 
3.8. Assessment of the seventeen year old children 
4. References 
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140 
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