The lack of three-year-old memories is due to the还未发展出自我意识的大脑,科学家通过镜子实验验证了这一观点。婴儿在18个月前无自我认知,这也解释了他们为何记不住早年经历。早期动物如未具备语言和时间观念,影响了其认知环境和记忆形成。