From his first attempts to explain attachment phenomena in the 1940s through his "Attachment and Loss" trilogy (Bowlby, 1969/1982, 1973, 1980), John Bowlby reformulated the theoretical underpinnings of attachment theory several times. He initially attempted to explain attachment phenomena in psychoanalytic terms. Then he invoked…

This introductory summary provides an overview of the content of the special issue entitled "Identity Development Process and Content: Toward an Integrated and Contextualized Science of Identity." The 16 theoretical and empirical articles that comprise this special issue were selected to highlight innovative methodologies, theoretical…

For research on emotional development, defining emotions as psychological systems of appraisals, expressions, body reactions, and subjective feelings in all phases of ontogenesis raises tricky methodological issues. How can we measure single emotions when appraisals and feelings cannot be assessed from outside, when expressions do not seem to be…

This article presents an overview of quantitative methodologies for the study of stage-sequential development based on extensions of Markov chain modeling. Four methods are presented that exemplify the flexibility of this approach: the manifest Markov model, the latent Markov model, latent transition analysis, and the mixture latent Markov model.…