Attachment and Health
John Bowlby and Mary Ainsworth developed attachment theory in the 1960s while investigating the effects of maternal separation on infant development. The development of the Strange Situation task in 1965 by Ainsworth and Wittig allowed researchers to systematically investigate the attachment system operating between children and their parents. The Strange Situation involves separating infant-parent dyads and observing infant behaviours upon reunion. Infant behaviour tended to follow patterns, leading to the development of three attachment categories: Secure, Anxious-Avoidant, and Anxious-Resistant. In 1990, Ainsworth added a new category, championed by Mary Main, called Disorganized/Disoriented attachment, characterized by its less reliable pattern of behaviour.
Elaboration likelihood model
The study of attitudes and persuasion began as the central focus of social psychology, featured in the work of psychologists Gordon Allport (1935) and Edward Alsworth Ross (1908). Allport described attitudes as "the most distinctive and indispensable concept in contemporary social psychology". Considerable research was devoted to the study of attitudes and persuasion from the 1930s through the late 1970s. These studies embarked on various relevant issues regarding attitudes and persuasion, such as the consistency between attitudes and behaviors and the processes underlying attitude/behavior correspondence. However, Petty and Cacioppo noticed a major problem facing attitude and persuasion researchers to the effect that there was minimal agreement regarding "if, when, and how the traditional source, message, recipient, and channel variables affected attitude change". Noticing this problem, Petty and Cacioppo developed the elaboration likelihood model as their attempt to account for the differential persistence of communication-induced attitude change. Petty and Cacioppo suggested that different empirical findings and theories on attitude persistence could be viewed as stressing one of two routes to persuasion which they presented in their elaboration likelihood model.