Internal working model of attachment
Internal working model of attachment is a psychological approach that attempts to describe the development of mental representations, specifically the worthiness of the self and expectations of others' reactions to the self. This model is a result of interactions with primary caregivers which become internalized, and is therefore an automatic process. John Bowlby implemented this model in his attachment theory in order to explain how infants act in accordance with these mental representations. It is an important aspect of general attachment theory.
Attachment measures
Scores on the anxiety and avoidance scales can still be used to classify people into the four adult attachment styles. 
The four styles of attachment defined in Bartholomew and Horowitz's model were based on thoughts about self and thoughts about partners. The anxiety scale in the ECR and ECR-R reflect thoughts about self. Attachment anxiety relates to beliefs about self-worth and whether or not one will be accepted or rejected by others. The avoidance scale in the ECR and ECR-R relates to thoughts about partners. Attachment avoidance relates to beliefs about taking risks in approaching or avoiding other people. Combinations of anxiety and avoidance can thus be used to define the four attachment styles. The secure style of attachment is characterized by low anxiety and low avoidance; the preoccupied style of attachment is characterized by high anxiety and low avoidance; the dismissive avoidant style of attachment is characterized by low anxiety and high avoidance; and the fearful avoidant style of attachment is characterized by high anxiety and high avoidance.