Mary Ainsworth used this feature in addition to "stranger wariness" and reunion behaviours, other features of attachment behaviour, to develop a research tool called the "strange situation" for developing and classifying different attachment styles.
Mary Ainsworth brugt denne funktion plus "fremmed wariness" og Reunion adfærd, andre funktioner i tilknytning adfærd, at udvikle et forsknings-værktøj kaldet "Strange Situation Procedure" for at udvikle og klassificere forskellige vedhæftede stilarter.