Infant Exploratory Behaviors During the Strange Situation Procedure: Links With Attachment Quality and Temperament

The secure base phenomenon was ascribed to changes in exploration observed during Ainsworth’s Strange Situation Procedure (SSP), related to the quality of the attachment relationship. However, infant temperament was not taken into consideration. The current study aims to replicate Ainsworth’s findings regarding infant exploration and attachment quality during the SSP and extend the findings by examining the role of infant temperament. One hundred thirty-two mother-infant dyads participated in the SSP when infants were 12 months old. Video recordings were coded for attachment quality and for duration of locomotion, duration of engagement with toys, and quality of engagement with toys. Temperamental activity level and fear were assessed with the Infant Behavior Questionnaire. Results showed that—irrespective of infant temperament—infants with insecure-resistant attachment relationships engaged less with toys compared to infants with secure or insecure avoidant relationships, and these differences were amplified during separation from the mother. Duration of engagement with toys was thus a robust indicator of attachment-related infant exploratory behavior. Duration of locomotion increased in response to separation from the mother and decreased after reunion. This likely reflects a mix of exploratory and proximity seeking behavior, and was more affected by controlling for temperamental fear. For quality of engagement with toys, no associations with attachment and temperament were found. During the SSP, the manifestation of the secure base phenomenon depended on the combination of the type of exploratory behaviors and the quality of the attachment relationship, but also on infant temperament.