Peter Molenaar, Ph.D. - Director

Professor of Human Development

415 BBH Bldg.
The Pennsylvania State University
University Park PA 16802

814-863-8373 (fax-814-863-7963)

Bio Statement

"Psychology is the science of human individuals. Most theories surrounding aspects of life related to psychology, for example personality, substance abuse, development, cognitive information processing, social functioning, and health, contend that significant variation occurs both between individuals at any given time and within an individual across their lifetime. Relationships among psychological constructs and outcomes may be specific to an individual and thus should be studied at the individual level to match current psychological paradigms. As a short example, the relationship between sleep disturbances and severe depression may be quite strong for one person and nonexistent for another. Knowing this relationship for the individual could help with the prediction of a severe depressive episode, prevention, and treatment plan specific to that person. Approaches for studying humans which appreciate the individual experience thus have the potential to revolutionize programs aimed towards increasing the mental and physical health of society.

Accordingly, a central theme of my work involves the development, testing and application of innovative methodological and statistical tools required for the scientific study of psychological processes at the level of individual human subjects. This work includes psycho-physiological research (fMRI, EEG, heart rate, skin conductance), as well as intensive measurements of developmental and health processes. By modeling psychological processes at the level of individual subjects, dynamic systems models are obtained which have excellent explanatory power and consequently provide us with the option to steer these processes into desired directions (treatment or prevention). Several of my ongoing research projects apply this new methodology, for instance to brain imaging, optimal treatment of diabetes type I and asthma, individual psycho-therapeutic process analysis, personality development, treatment of autistic children, and analysis of close mother-infant interaction. These projects are funded by NSF, The Pennsylvania State University, are co-funded by NIH and several other funding agencies, and are carried out in collaboration with diverse research centers throughout the USA (e.g., University of Virginia, University of Rhode Island, MIT) and Europe (e.g., University of Amsterdam, Max Planck Institute for Life Span Development, Berlin)."

Current graduate students working in these projects are: Katie Gates, Tamara Goode, Siwei Liu and Lawrence Lo.

Research interests

  • Development, Testing and Application of Innovative Methodological and Statistical Tools
  • Psycho-Physiological Research
  • Psychological Process Modeling

Select Publications

Molenaar, P. C. M. (2003). State Space Techniques in Structural Equation Modeling: Transformation of latent variables in and out of latent variable models.
State Space Techniques

Molenaar, P.C.M., & Newell, K.M. (Eds.) (2010). Individual pathways of change: Statistical models for analyzing learning and development. Washington, DC: American Psychological Association.

Gates, K.M., Molenaar, P.C.M., Hillary, F.G., Ram, N., & Rovine, M.J. (2010). Automatic search for fMRI connectivity mapping: An alternative to Granger causality testing using formal equivalences among SEM path modeling, VAR and unified SEM. NeuroImage, 50, 1118-1125.

Molenaar, P.C.M. (2010). Note on optimization of psychotherapeutic processes. Journal of Mathematical Psychology, 54, 208-213.

Molenaar, P.C.M., & Campbell, C.G. (2009). The new person-specific paradigm in psychology. Current Directions in Psychology, 18(2), 112-117.

Molenaar, P.C.M., Sinclair, K.O., Rovine, M.J., Ram, N., & Corneal, S.E. (2009). Analyzing developmental processes on an individual level using non-stationary time series modeling. Developmental Psychology, 45(1), 260-271.

Molenaar, P.C.M. (2007). On the implications of the classical ergodic theorems: Analysis of developmental processes has to focus on intra-individual variation. Developmental Psychobiology, 50, 60-69.

Molenaar, P.C.M. (2006). Psychophysical dualism from the point of view of a working psychologist. Erkenntnis, 65, 47-69.

Molenaar, P.C.M. (2004). A manifesto on Psychology as idiographic science: Bringing the person back into scientific psychology, this time forever. Measurement, 2 (4), 201-218.

Molenaar, P.C.M., Boomsma, D.I., & Dolan, C.V. (1993). A third source of developmental differences. Behavior Genetics, 23, 519-524.

Van der Maas, H.L.J., & Molenaar, P.C.M. (1992). Stagewise cognitive development: An application of catastrophe theory. Psychological Review, 99, 395-417.

Professional Experience

2005-Present: Professor of Human Development, Department of Human Development and Family Studies, The Pennsylvania State University

2001- 2005: Professor of Psychological Methodology, Mathematical Psychology and Psychometrics, University of Amsterdam, Head Methodology Department

1999-2001: Professor of Mathematical and Developmental Psychology University of Amsterdam, Head of Methodology Department and Head of Department of Cognitive Developmental Psychology

1996-1998: Professor of Developmental Psychology, University of Amsterdam, Head of Department of Cognitive Developmental Psychology

1993-1996: Professor of Developmental Psychology, University of Amsterdam and The Pennsylvania State University

1985-1993: Associate Professor of Psychology, University of Amsterdam

1976-1985: Assistant Professor of Psychology, Department of Psychology, University of Amsterdam

1970-1976: Research Assistant, Department of Psychology, University of Utrecht


Ph.D., 1981, Social Sciences, University of Utrecht, Germany
M.A., 1976, Mathematical Psychology, cum laude, University of Utrecht, Germany
B.A., 1976, Philosophical Logic, University of Utrecht, Germany
M.A., 1976, Psychophysiology, cum laude, University of Utrecht, Germany
B.A., 1972, Psychology, cum laude, University of Utrecht, Germany