Children ages 30 to 34 months, assessed at 18 months for security of attachment and categorized as anxious/avoidant, anxious/resistant, or securely attached, were observed exploring with their mothers in a large-scale laboratory space. (Quality of attachment was assessed by means of Ainsworth's standard strange-situation procedure.) After learning a specific route through the laboratory space to a goal, the children were required to invent new routes to the goal. Quantity of exploration was measured by number of movements, and mode of exploration was measured by the extent of active versus passive movements. Among the results, children who had been classified as securely attached explored more independently and had less restricted patterns of exploration than did anxiously attached children. Securely attached children also scored higher on tasks of spatial ability. Findings suggest that individual differences in security of attachment, mode of exploration, and cognitive mapping abilities exert mutual effects upon each other throughout children's early development. (Author/DB)