The Value of Dimensional Models of Early Experience: Thinking Clearly About Concepts and Categories

Abstract

We review the three prevailing approaches—specificity, cumulative risk, and dimensional models—to conceptualizing the developmental consequences of early-life adversity and address fundamental problems with the characterization of these frameworks in a recent Perspectives on Psychological Science piece by Smith and Pollak. We respond to concerns raised by Smith and Pollak about dimensional models of early experience and highlight the value of these models for studying the developmental consequences of early-life adversity. Basic dimensions of adversity proposed in existing models include threat/harshness, deprivation, and unpredictability. These models identify core dimensions of early experience that cut across the categorical exposures that have been the focus of specificity and cumulative risk approaches (e.g., abuse, institutional rearing, chronic poverty); delineate aspects of early experience that are likely to influence brain and behavioral development; afford hypotheses about adaptive and maladaptive responses to different dimensions of adversity; and articulate specific mechanisms through which these dimensions exert their influences, conceptualizing experience-driven plasticity within an evolutionary-developmental framework. In doing so, dimensional models advance specific falsifiable hypotheses, grounded in neurodevelopmental and evolutionary principles, that are supported by accumulating evidence and provide fertile ground for empirical studies on early-life adversity.

Caregiver–child proximity as a dimension of early experience

“…Situating early caregiving environments (including proximity) within dimensional frameworks enables us to test hypotheses about whether specific features of early caregiving are related to child outcomes. The majority of research studies on early adversity consider either a single type of adverse experience (e.g., physical abuse), group experiences like abuse and neglect together in a "maltreatment" category, or count up the types of events experienced using a cumulative approach (for review and discussion of frameworks of adversity, see [McLaughlin et al, 2021]). Dimensional models, an alternative approach, jointly consider similar experiences along dimensions of severity to capture like forms of adversity (McLaughlin et al, 2021).…”

Differentiating distinct and converging neural correlates of types of systemic environmental exposures

“…The existing literature suggests different dimensions of environmental exposures could relate to both convergent and distinct neural structures across neurodevelopment (McLaughlin, Sheridan, Humphreys, Belsky, & Ellis, 2021;Vargas, Conley, & Mittal, 2020). Neural correlates, while theorized, have yet to be tested and thus remain poorly understood.…”

“…Exposure to individual or systemic environmental factors can have an independent impact through both stress exposure and alterations in neural development and as a result do not require conscious awareness of exposure having occurred to be impactful (McLaughlin et al, 2021). As a result, studying neural correlates of systemic environmental factors during critical developmental periods provides a crucial perspective.…”

Are all threats equal? Associations of childhood exposure to physical attack versus threatened violence with preadolescent brain structure

“…Foundational research exploring mental health effects of childhood adversity generally examined either qualitative differences in adverse experiences (i.e., specificity models investigating one adversity at a time) or quantitative differences in the number of adversities a child experienced (i.e., cumulative risk models). ( Smith and Pollak, 2021 ; McLaughlin et al, 2021) . Cumulative risk models have provided valuable insight over time and continue to guide practice and policy ( Lanier et al, 2018) .…”

“…Cumulative risk models have provided valuable insight over time and continue to guide practice and policy ( Lanier et al, 2018) . More recently, however, investigators have proposed “dimensional” models that consider both qualitative and quantitative features of a child’s adverse experiences to provide greater insight into neurobiological mechanisms mediating childhood adversity and mental disorders ( McLaughlin et al, 2021 , McLaughlin et al, 2019 Dec 24 ).…”