Marinus H. "Rien" van IJzendoorn (May 14, 1952) is professor of human development and one of the co-leaders of Generation R at the Erasmus University Rotterdam.

Two years later he obtained his PhD magna cum laude at the Free University of Berlin/Max Planck Institute for Human Development and Education.

[6] In 2011 he received the Aristotle Prize of the European Federation of Psychologists' Associations,[7] and the Bowlby-Ainsworth Founder Award of the Center for Mental Health Promotion and The New York Attachment Consortium.

Attachment has been briefly defined as children's "strong disposition to seek proximity to and contact with a specific figure and to do so in certain situations, notably when they are frightened, tired or ill".

[16] Inspired by Darwinian evolutionary theory and Harlow's experimental work with rhesus monkeys, John Bowlby was the first to propose that human genetic selection had favoured attachment behaviours since they increased infant-parent proximity, which in turn enhanced the chances for infant survival.

Together with Femmie Juffer and Marian Bakermans-Kranenburg, Van IJzendoorn developed and tested In the Video Intervention to promote Positive Parenting (VIPP) program[18] Video feedback provides the opportunity to focus on the infant's videotaped signals and expressions, thereby stimulating the parent's observational skills and empathy for his/her child.

In the Video Intervention to promote Positive Parenting-Sensitive Discipline] (VIPP-SD) thematic discussions about limit setting issues are included, based on Patterson's ideas about coercive cycles[19] (see: Morality throughout the Life Span), in order to support parents of ‘terrible two's and three's' to deal with discipline in a consistent and warm manner.

Three broad constructs have been proposed and tested as markers of susceptibility: (a) reactive temperament, (b) biological sensitivity to stress, and (c) genetic make-up.

[29] In humans, oxytocin has been shown to be associated with delivery, mood regulation, sexual functioning and parenting behaviours.

Van IJzendoorn and colleagues conducted several correlational studies documenting the role of OXTR in parenting, and carried out various randomized control trials showing that oxytocin enhances male and female sensitivity to child signals, in natural play settings as well as with a cry test, using behavioural assessments, EEG/ERP, and fMRI.

It was shown that Holocaust survivors (now grandmothers) had more signs of traumatic stress and, more often, lack of resolution of trauma than comparison subjects, but they were not impaired in their general adaptation.