Anxious attachment is an attachment style that researchers Mario Mikulincer and Phillip R. Shaver characterize by "hyperactivating strategies," seen in heightened desires for closeness and security in close relationships and preoccupation with a partner's unavailability.
Psychologist R. Chris Fraley's overview of adult attachment research at the University of Illinois credits 📝attachment theory to British psychoanalyst John Bowlby and recounts how his colleague Mary Ainsworth and her students developed the "strange situation," a laboratory procedure in which 12-month-old infants are separated from and reunited with their parents. About 20% or fewer of children became extremely distressed on separation and, when reunited, had a difficult time being soothed, showing conflicting behaviors; the overview notes these children are often called anxious-resistant.
The same overview credits Hazan and Shaver (1987) as two of the first researchers to explore Bowlby's ideas in romantic relationships. It describes anxious-resistant adults as worrying that others may not love them completely and as easily frustrated or angered when their attachment needs go unmet. A page on self-report measures by Phillip R. Shaver and Fraley names the three Hazan and Shaver styles as 📝Secure, 📝Avoidant and Anxious/Ambivalent.
Fraley's overview reports that Brennan, Clark and Shaver (1998) found two fundamental dimensions in adult attachment, attachment-related anxiety and attachment-related avoidance. People who score high on anxiety tend to worry whether their partner is available, responsive and attentive, while a prototypical secure adult is low on both dimensions. Most researchers, it states, now treat attachment styles as varying in degree rather than kind.