To investigate the relationship of differences in 2-year-old children's reactions to strangers to differences in their temperaments and their security of attachment with their mothers, a correlational study was conducted with 47 infants and their parents. In the first component of the study, both parents completed a child temperament rating questionnaire at home. The second component consisted of two separate 5-minute encounters between the infant and a female stranger who approached the child in a friendly way. From videotapes of these sessions independent raters coded each child's facial expression, vocalization, and visual and gross-motor behaviors. In the third component, mother and child participated in an assessment of the child's behavior in solving four tool-using tasks of graduated difficulty that required retrieving lures from within three types of containers using an implement such as a stick. The final two tasks were too difficult for 2-year-olds to solve alone and required the assistance of their mothers, who were instructed to help or not as they felt necessary. From videotapes of these sessions raters counted frequencies of children's compliance, help seeking, whining, frustration, and other behaviors, and also coded mothers' abilities to give emotional support and to effectively communicate strategies for solving the problems. Results are discussed. (Author/RH)