1950s–1980sJohn Bowlby
Attachment theory, separation, loss, and the secure base
Bowlby's early work established the importance of familiar, continuing care. Later researchers kept that insight but moved away from the popular idea that one attachment figure must always be psychologically primary. Modern research gives greater recognition to several important relationships and the child's actual family context.
Where this researcher agrees with the wider fieldContinuity of familiar care and the developmental importance of attachment relationships.
Where views still differModern researchers are more explicit that children can have several important attachment relationships and that attachment theory cannot prescribe one custody outcome.
Mary Ainsworth
Caregiver sensitivity, secure-base behaviour, and observational assessment
Ainsworth transformed attachment theory into an observational research programme. Later meta-analyses supported a meaningful sensitivity–security association but showed that sensitivity is important rather than sufficient on its own.
Where this researcher agrees with the wider fieldResponsive caregiving and relationship-specific observation remain foundational.
Where views still differLater work gives greater weight to context, fathers, multiple caregivers, measurement diversity, and nonshared influences.
Michael Rutter
Deprivation, resilience, developmental psychopathology, and context
Rutter distinguished deprivation from separation itself and emphasized variation in children’s responses. That contextual and probabilistic stance aligns closely with later cautions against simple one-factor accounts.
Where this researcher agrees with the wider fieldRisk is conditional; context, duration, relationships, and protective factors matter.
Where views still differHis work challenged broad readings of maternal-deprivation claims that treated separation as uniformly harmful.
Michael E. Lamb
Father involvement, parent–child relationships, and developmental applications
Lamb’s work helped move fathers from a peripheral role in developmental research toward relationship-specific study. In family-law writing with Kelly, he supported maintaining both relationships through developmentally responsive arrangements.
Where this researcher agrees with the wider fieldChildren can have significant relationships with multiple caregivers; quality and established involvement matter.
Where views still differHe has challenged frameworks that treat one parent category as inherently secondary.
Joan B. Kelly
How children cope with divorce and how research should guide parenting plans
Kelly's writing moved away from treating divorce as producing one predictable outcome. She emphasised that children respond differently depending on conflict, relationships, safety, care, and family circumstances. Her work with Lamb, Pruett, and McIntosh promoted plans made for the individual child rather than one rule for everyone.
Where this researcher agrees with the wider fieldConflict, relationship quality, safety, and the child's age and development should shape plans.
Where views still differShe has resisted both universal restrictions and universal schedules.
Jennifer E. McIntosh
Young children, shared care, conflict, safety, and attachment
McIntosh's 2008 to 2013 publications gave greatest emphasis to caution about conflict and frequent overnights for some very young children. Her 2014 work with Pruett and Kelly rejected a general rule against all overnights while retaining conditional caution. In 2015 she defended the purpose and limits of the original Australian study. Her later publications widened the focus toward children's experience of shared time, parenting quality, relationship security, violence, safety risks, changes in attachment, and caregiving sensitivity. Her 2021 guidance still retained caution for some infant arrangements while stating that the long-term benefit of safe involvement by both parents was not in question.
Where this researcher agrees with the wider fieldContext, safety, conflict, established relationships, caregiving quality, developmental stage, and the future health of both parent-child relationships matter.
Where views still differShe did not retract the original infant findings. Disagreement persists over their methods, interpretation, and policy weight, and over how much caution is justified when direct schedule evidence remains limited.
Marsha Kline Pruett
Coparenting, father involvement, young children, and family courts
Pruett’s work emphasizes relational systems rather than a contest between parents. The 2014 integration paper framed a triadic secure base as a way to reconcile attachment security with continuing involvement.
Where this researcher agrees with the wider fieldBoth attachment security and early parental involvement can be supported together.
Where views still differThe appropriate pace and frequency of overnights remains conditional rather than reducible to one rule.
Richard A. Warshak
Parenting plans, shared care, and family-law policy
Warshak’s 2014 consensus report argued against blanket restrictions on infant and toddler overnights and gave greater policy weight to maintaining both relationships. It became a central counterpoint to more cautious interpretations.
Where this researcher agrees with the wider fieldNo universal plan; safety and caregiving circumstances matter; both relationships can be important.
Where views still differHe places less weight on using early overnight studies to justify broad caution than some other authors.
William V. Fabricius
Parenting time, father–child relationships, and long-term outcomes
Fabricius has studied how childhood parenting time relates to later parent–child relationships. His work with Suh reported benefits associated with overnights and argued that earlier caution overstated what prior data could support.
Where this researcher agrees with the wider fieldEstablished care and sustained relationships with both parents are developmentally relevant.
Where views still differThe retrospective design and the policy implications drawn from association remain debated.
Linda Nielsen
Shared care and father-child relationships
Nielsen's reviews bring together shared-care studies from several countries and emphasise how often children had equal or better outcomes. Other reviewers agree that the overall pattern is positive but place more emphasis on pre-existing differences between families, differences between studies, and whether results apply in every setting.
Where this researcher agrees with the wider fieldThe research does not support assuming that shared care is inherently harmful.
Where views still differResearchers differ over review methods and how confidently better average outcomes can be attributed to the arrangement.
Marinus H. van IJzendoorn
Attachment meta-analysis, sensitivity, disorganization, and research synthesis
Van IJzendoorn’s syntheses helped quantify central attachment associations and risks. Later work has strongly cautioned against turning group-level attachment findings into individual diagnostic or custody determinations.
Where this researcher agrees with the wider fieldAttachment research is valuable when its probabilistic and measurement limits are retained.
Where views still differHe and collaborators have opposed high-stakes courtroom uses that exceed the tools’ individual predictive validity.
Robbie Duschinsky and the 2022 consensus group
What attachment research can and cannot tell courts
Recent collaborative work clearly states where attachment researchers agree and where they do not. It recognises that children can have several important attachment relationships and benefit from continuing adequate care, while openly recording disagreements instead of pretending the entire field holds one view.
Where this researcher agrees with the wider fieldChildren need familiar caregivers who are safe, continuity of adequate care, and the opportunity to maintain several important relationships.
Where views still differThe group explicitly disagrees about some uses of attachment assessments in court.