Sociologists and psychologists have independently identified the same general period in individual development for the formation of many memories. Yet the cross-disciplinary similarity is rarely recognized, because most psychologists study autobiographical memories of personal events, while sociologists focus on collective memories of national and world events. We examine autobiographical and collective memories together within a large national cross-section survey of Americans. Both types of memory are located primarily in the same broad period, identified here as ages 5–30 years. However, within that period, autobiographical personal memories as measured by cue-word associations typically refer to earlier ages, while collective memories assessed with a standard open-ended question typically refer to somewhat later ages. Other types of questions yield still other memory content and ages. Reconceptualizing the reminiscence bump or critical period reconciles these diverse results.