Granting a strong role to nature for psychological gender differences, even suggesting that they are ‘hard-wired’, implies that differences which undermine women’s value are natural and permanent. The old ‘nature versus nurture’ controversies in child development are giving way to more complex understandings that incorporate both aspects. Systemic perspectives on development, such as U. Bronfenbrenner’s, originated from biologist Ludwig von Bertalanffy’s General Systems Theory. An influential twentieth- century developmental theorist who did emphasise the importance of culture was Lev Vygotsky. He observed that how a child’s mind develops depends on the culture and the tools that it provides, while minds in turn modify the culture. Consider, for example, the supposedly innate female inferiority on visual-spatial skills; if adolescent girls are given practice of such skills through the Tetris computer game, measurable changes in the thickness of the cortex and neural activity occur.