The following article was written by Chance Johnson 
Manfred Diehl, a professor in the Department of Human Development and Family Studies at Colorado State University, edited two recently released scholarly books that he hopes will assist fellow researchers in the field of human development and aging: the Handbook of Intraindividual Variability Across the Life Span and Volume 35 of the Annual Review of Gerontology and Geriatrics – Subjective Aging: New Developments and Future Directions.
The Handbook of Intraindividual Variability Across the Life Span, published by Routledge/Taylor & Francis, edited by Diehl and colleagues Karen Hooker and Martin J. Sliwinski, features research across the entire life span. Recent findings in human development are summarized with a focus on how, when, and why individuals change over time. Intraindividual Variability (IIV) is the overarching concept of the publication that reflects momentary, within-person change in behavior. Diehl analyzes IIV, looking at its historical and theoretical background while also observing the role it plays throughout the different developmental stages of life. The book makes the case that the IIV approach is relevant to multiple disciplines within the College of Health and Human Sciences such as occupational therapy, health and exercise science, human development and family studies, food science and human nutrition, social work, and education.
Volume 35 of the Annual Review of Gerontology and Geriatrics, published by Springer Publishing Company, was edited by Diehl and his research collaborator Hans-Werner Wahl. The title of the volume, Subjective Aging: New Developments and Future Directions, asks the questions, “How do individuals perceive their own aging?” and “Can this perception predict developmental outcomes such as functional health or mortality?” The publication reflects on a new stage of development in the discipline of subjective aging and creates a foundation for future theoretical and empirical work. The volume represents the work of leading national and international scholars in the field of subjective aging, drawing on presentations from a series of workshops and an international conference.
Research interests
Diehl is a life-span developmental psychologist who studies processes of adult development and aging, with a particular focus on successful and healthy aging. His research interests are in three major areas: (1) How certain personality characteristics contribute to positive adult development, including the development of resilience; (2) how certain self-regulatory behaviors, such as coping behavior and emotion regulation, develop across the adult life span; and (3) how adults develop an awareness of their own age-related changes and how this awareness is linked to developmental outcomes. Diehl was recently recognized with the Humboldt Research Award from the Alexander von Humboldt Foundation, Germany.
