You might expect that your earliest recollection would be dramatic—yet for most of us, it is fairly mundane. Only about a quarter of people report a first memory that involves a trauma, according to a 2005 study. Scientific American Mind's online survey of readers' first memories uncovered the same pattern [see chart].

Young children are more likely to recall an event if they are prompted to talk about it and probed for details. Perhaps that is why the age at which a memory first sticks varies across cultures. Among the Maori of New Zealand, for example, most children's memories start a year earlier than they do in North America—a function of a culture in which memories are honored and much discussed, according to researcher Carole Peterson of Memorial University in Newfoundland.

Memory Milestones
Infant (0–2 years): Research hints that infants form brief memories.

Toddler (2–3 years): Toddlers begin to form memories of facts and events. Yet they are ephemeral because the hippocampus—key for long-term memories—is still maturing.

Young child (4–7 years): Short-term memory improves. Prospective memory—the ability to plan and remember to execute the plan—starts to emerge.

Child (8–10 years): Children have now forgotten about two thirds of their memories before age three. Recall of facts and spatial relationships improves greatly.

Early adolescent (10–12 years): As hippocampal growth cools down, connections in that region start to get pruned, and long-term memory improves. The ability to consciously suppress memories appears to increase as well.

Young adult (13–21 years): The superior temporal cortex, which helps to integrate information, and the dorsolateral prefrontal cortex, involved in short-term memory, continue to mature into our early 20s. This pattern might explain why memory becomes richer and more complex throughout the young adult years. —V.S.