Abstract

The “Baldwin effect” occurs when natural selection supplements adaptive phenotypic changes acquired during an organism’s lifetime. This effect, first described in 1896, is now usually considered to be rare and insignificant, and is not part of the explanatory repertoire of most evolutionary scientists. Arguments against it are examined here and found to be inadequate, either because they misunderstand the effect, or confuse it with Lamarckism, or fail to perceive it even while describing it. The article proposes examples showing that the Baldwin effect is far more prevalent and powerful than even Baldwin’s few supporters realize. Evolved features of the human mind are described that make this effect unusually difficult to perceive. Some of these mental features are themselves Baldwin effects. Natural selection’s supporters, and its skeptics, appear to disregard the Baldwin effect for different reasons. The article proposes that acceptance of the Baldwin effect can significantly improve the study of human nature, as practiced by both sides in the nature-nurture controversy, and can even provide a bridge to end this controversy.