Follow the dated publications in this collection. Read each paper for its findings and limits rather than treating publication order as proof that one view replaced another.
Legal approaches to parenting disputes also changed during this period. Many common-law jurisdictions moved away from parental presumptions, including maternal preference under the Tender Years Doctrine, towards assessing the individual child’s welfare or best interests. The timing and legal tests differed between jurisdictions.
This legal history should not be confused with attachment science. Modern attachment research recognises that children can form distinct, important relationships with multiple familiar caregivers. It does not support selecting a preferred parent because of sex, treating one safe parent as developmentally irrelevant, or deriving an exact parenting-time schedule from attachment theory.
2010 to 2024, with later papers shown
The selected papers below address different questions. The 2015 reply defended the earlier overnight study. The later attachment cohort did not test overnight schedules.
The Australian report found poorer results on some parent-reported measures for selected groups of very young children who frequently stayed overnight. McIntosh and colleagues nevertheless argued for caution, particularly for infants and in difficult family circumstances.
The study did not prove that overnights caused the reported differences.
Their framework still recommended closer attention where a parent was unfamiliar, conflict was frequent, safety was uncertain, or a demanding schedule did not suit the child.
McIntosh, Pruett, and Kelly rejected a general rule against all overnight care during the first three years. They said early security and continuing relationships with both parents could both be protected.
McIntosh, Smyth, and Kelaher replied directly to Warshak. They defended the purpose, methods, findings, and stated limits of their overnight study. They also rejected the claim that their study supported primary maternal care or discouraged shared parenting by fathers.
Their conclusion was that science had not yet resolved the infant overnight debate.
McIntosh and Booth said the evidence for babies and preschool children remained limited and that no one arrangement fits every family. They retained concern about violence, conflict, poor parenting, unsettled schedules, and repeated separation from an attachment figure.
They also stated that the long-term benefit of safe involvement by both parents was not in question and acknowledged the concern that too little overnight time may weaken the second parent-child relationship.
McIntosh and colleagues followed an Australian population cohort from infancy to preschool. Secure attachment was observed in 59 percent of the age-one sample (314 children) and 71 percent of the age-four sample (368 children). These percentages describe different-sized assessment samples. Gaining or losing secure status was associated with changes in maternal caregiving sensitivity. This was attachment research, not a study of post-separation overnight schedules.
The researchers found no difference in caregiving sensitivity scores for mothers and fathers of preschool children.
36 linked research records
Marianne S. De Wolff & Marinus H. van IJzendoorn
Judith Solomon & Carol George
van IJzendoorn, Schuengel & Bakermans-Kranenburg
Joan B. Kelly & Michael E. Lamb
Robert Bauserman
Anna Sarkadi, Robert Kristiansson, Frank Oberklaid & Sven Bremberg
Rae Kaspiew, Matthew Gray, Ruth Weston, Lawrie Moloney, Kelly Hand, Lixia Qu & the Family Law Evaluation Team
Jennifer McIntosh, Bruce Smyth, Margaret Kelaher, Yvonne Wells & Caroline Long
Christine McWayne, Jason T. Downer, Rodrigo Campos & Robby D. Harris
Sara McLanahan, Laura Tach & Daniel Schneider
Tornello, Emery, Rowen, Potter, Ocker & Xu
Jennifer E. McIntosh, Bruce M. Smyth & Margaret Kelaher
Richard A. Warshak, with endorsers listed in the article
Marsha Kline Pruett, Jennifer E. McIntosh & Joan B. Kelly
Jennifer E. McIntosh, Marsha Kline Pruett & Joan B. Kelly
Malin Bergström, Emma Fransson, Bitte Modin, Marie Berlin, Per A. Gustafsson & Anders Hjern
Amandine Baude, Jessica Pearson & Sylvie Drapeau
Linda Nielsen
William V. Fabricius & Go Woon Suh
Richard A. Warshak
Nicole E. Mahrer, Karey L. O'Hara, Irwin N. Sandler & Sharlene A. Wolchik
Linda Nielsen
Richard A. Warshak
Fabricius, Aaron, Akins, Assini & McElroy
Malin Bergström, Emma Fransson, Helena Fabian, Anders Hjern, Anna Sarkadi & Raziye Salari
Malin Bergström, Anna Sarkadi, Anders Hjern & Emma Fransson
Anja Steinbach
Katja Linde, Franziska Lehnig, Michaela Nagl & Anette Kersting
Anders Hjern, Malin Bergström, Emma Fransson & Stine Kjaer Urhoj
Lara Augustijn
Jin Zhang, Yunyan Liu & Tianqiang Hu
Erin Louise Robinson, Jennifer StGeorge & Emily Elsa Freeman
Trine B. Johansen, Hege Nøkleby, Lars J. Langøien & Tiril C. Borge
Forslund, Granqvist, van IJzendoorn, Sagi-Schwartz, Glaser, Steele, Hammarlund et al.
Dagan, Schuengel, Verhage, Madigan, Roisman et al.
Que Zheng, Liman Cai, Peishan Huang, Wei Huang & Yushan Ni