The g Factor: The Science of Mental Ability

For over two thousand years, debates about human intelligence remained trapped in philosophical speculation, with no scientific foundation for understanding why people differ in mental ability. Jensen's work tackles this fundamental problem by examining decades of rigorous psychometric research that reveals a startling discovery: all cognitive abilities share a single underlying factor called g, or general intelligence. This short systematically dismantles competing theories while demonstrating how g connects to biological processes, genetic inheritance, and real-world outcomes from education to employment. Through careful analysis of factor analysis, brain imaging studies, and population data, Jensen shows that g represents measurable differences in neural efficiency rather than cultural bias or learned skills. His work answers one of psychology's most contentious questions, challenging both blank-slate ideology and simplistic notions of multiple intelligences.