 McDougall’s effort to reform the scientific concept of instinct was perhaps too little too late, as his work primarily served as fodder for a group of anti-hereditarian psychologists who emerged in the early 1920s. Three of the most outspoken critics of instinct were Knight Dunlap, Luther Lee Bernard, and Zing-Yang Kuo (Guō Rènyuǎn). Their arguments are worth considering, especially since many of the same objections would be revived two decades later in opposition to the ethological concept of innateness.