The heavy systemizer (hi). Extreme ‘male brain’ (cognitively masculine). Summary of traits and profile:

COGNITIVE TRAITS:

• Rule-based, "if p, then q" reasoning. The defining cognitive signature. High systemizers direct their attention toward detecting 'if p, then q' rules (or input-operation-output reasoning). Building law-like models that predict how a system will behave.

• Hyper-attention to detail. Excellent attention to fine-grained features, because each tiny detail in a system might have a functional role leading to new information of the form 'if p, then q'.

• Local processing prioritization. Strong tendency to focus on local detail. They see parts before wholes, which produces superior performance on tasks like the Embedded Figures Test and visual search.

• Sensory hypersensitivity. Heightened low-level perception across modalities (vision, hearing, smell, touch). The theory traces the chain this way: the origins of the association between autism and talent begin at the sensory level, include excellent attention to detail and end with hyper-systemizing.

• Truth-orientation. Truth defined as lawful patterns in data. People with ASC are strongly driven to discover the "truth".

NEUROLOGICAL PROFILE:

• "Extreme male brain" morphology. Associated with larger brain with more white matter, leading to increased connectivity in each hemisphere. I.e., more within-hemisphere wiring, less cross-hemisphere integration.

• Testosterone. A candidate biological driver. Fetal testosterone levels are positively correlated with scores on the Systemising Quotient and are negatively correlated with scores on the Empathy Quotient. Prenatal androgen exposure biases brain development toward pattern-analysis over social-emotional processing.

• Skewed functional connectivity: local over long-range. The most cited neural signature. At the neurological level, ASC involves an abundance of local short-range connectivity, which the theory argues explains the cognitive style of linking specific details via narrow rules.

• Lateral frontoparietal recruitment for rule learning. Complex cognitive processes are thought to be implemented via large-scale neural circuits in lateral frontal and parietal areas, the same frontoparietal control network implicated in reasoning and rule extraction.

• Regional grey-matter differences. Increased grey matter volume of the right superior temporal gyrus.