Illuminating the conceptual structure of the space of moral violations with searchlight representational similarity analysis

Abstract

Characterizing how representations of moral violations are organized, cognitively and neurally, is central to understanding how people conceive and judge them. Past work has identified brain regions that represent morally relevant features and distinguish moral domains, but has not yet advanced a broader account of where and on what basis neural representations of moral violations are organized. With searchlight representational similarity analysis, we investigate where category membership drives similarity in neural patterns during moral judgment of violations from two key moral domains: Harm and Purity. Representations converge across domains in a network of regions resembling the mentalizing network. However, Harm and Purity violation representations respectively converge in different regions: precuneus (PC) and left inferior frontal gyrus (LIFG). Examining substructure within moral domains, Harm violations converge in PC regardless of subdomain (physical harms, psychological harms), while Purity subdomains (pathogen-related violations, sex-related violations) converge in distinct sets of regions – mirroring a dissociation observed in principal-component analysis of behavioral data. Further, we find initial evidence for representation of morally relevant features within these two domain-encoding regions. The present analyses offer a case study for understanding how organization within the complex conceptual space of moral violations is reflected in the organization of neural patterns across the cortex.

The computational and neural substrates of moral strategies in social decision-making

“…Therefore, we instead employed multivariate pattern analysis, which can map multidimensional psychological states or processes to specific brain regions 19–24 . Specifically, the second moment of multi-voxel brain representations across stimuli can reflect meaningful differences in how stimuli are psychologically organized, as demonstrated in representational similarity analysis (RSA) 25–27 For example, the psychological organization of moral judgments, such as harm versus impurity judgments, can be estimated from multivariate activity patterns in the mentalizing network 28 .…”

Neural substrates for moral judgments of psychological versus physical harm

“…This study presents new analyses of previously published data ( Koster-Hale et al , 2013 ; Chakroff et al , 2016 ; Wasserman et al , 2017 ). Here, we focus on examining neural distinctions between moral judgments of physical harm and moral judgments of psychological harm using univariate analyses and multivariate pattern analyses as well as comparing these results across two different groups: a neurotypical group and an ASD group.…”

“…The remaining vignettes involved different types of purity violations (e.g. smearing feces on one’s own face [pathogen] vs. having sex with a sibling [incest]); we will not be reporting on these items as they have been reported elsewhere ( Chakroff et al , 2016 ; Wasserman et al , 2017 ).…”

A Guide To Representational Similarity Analysis for Social Neuroscience

“…RSA has been used to test hypotheses about the neural representation of social categories and dimensions (Chavez and Heatherton, 2014;Freeman et al, 2018;Pegado et al, 2018;Vida et al, 2017;Wasserman et al, 2017). In most of these studies, the stimuli that are compared can be dimensionalized along some predefined metric.…”

“…In social neuroscience, many stimuli can also be Freeman et al, 2018;Stolier and Freeman, 2016;Stolier et al, 2018b), actions can vary on kinematics, effectors, transitivity and intentions (Urgen et al, 2019;Wurm et al, 2017), social concepts can vary on affective and psycholinguistic dimensions (Thornton and Tamir, 2017) and friendships can vary in their social distance and network topology (Parkinson et al, 2014;Parkinson et al, 2017). With this new tool, researchers can even investigate complex representations such as morality (Pegado et al, 2018a;Pegado et al, 2018b;van Baar et al, 2019;Volz et al, 2017;Wasserman et al, 2017) and the development of object concepts (Long et al, 2018).…”