Concrete versus abstract forms of social concept: an fMRI comparison of knowledge about people versus social terms

Abstract

The anterior temporal lobes (ATLs) play a key role in conceptual knowledge representation. The hub-and-spoke theory suggests that the contribution of the ATLs to semantic representation is (a) transmodal, i.e. integrating information from multiple sensorimotor and verbal modalities, and (b) pan-categorical, representing concepts from all categories. Another literature, however, suggests that this region's responses are modality- and category-selective; prominent examples include category selectivity for socially relevant concepts and face recognition. The predictions of each approach have never been directly compared. We used data from three studies to compare category-selective responses within the ATLs. Study 1 compared ATL responses to famous people versus another conceptual category (landmarks) from visual versus auditory inputs. Study 2 compared ATL responses to famous people from pictorial and written word inputs. Study 3 compared ATL responses to a different kind of socially relevant stimuli, namely abstract non-person-related words, in order to ascertain whether ATL subregions are engaged for social concepts more generally or only for person-related knowledge. Across all three studies a dominant bilateral ventral ATL cluster responded to all categories in all modalities. Anterior to this ‘pan-category’ transmodal region, a second cluster responded more weakly overall yet selectively for people, but did so equally for spoken names and faces (Study 1). A third region in the anterior superior temporal gyrus responded selectively to abstract socially relevant words (Study 3), but did not respond to concrete socially relevant words (i.e. written names; Study 2). These findings can be accommodated by the graded hub-and-spoke model of concept representation. On this view, the ventral ATL is the centre point of a bilateral ATL hub, which contributes to conceptual representation through transmodal distillation of information arising from multiple modality-specific association cortices. Partial specialization occurs across the graded ATL hub as a consequence of gradedly differential connectivity across the region.This article is part of the theme issue ‘Varieties of abstract concepts: development, use and representation in the brain’.

Varieties of abstract concepts: development, use and representation in the brain

“…The first part of this section presents two studies proposing new insights and methodological tools that reveal fine-grained differences between kinds of concepts [14,15]; the second part of the section includes papers that focus each on a specific kind of abstract concept (numbers [17], emotions [18,19], moral and aesthetic concepts [20], social concepts [16]). …”

“…Rice, Hoffman, Binney and Lambon Ralph [16] use data of three neuroimaging studies comparing category-selective responses within the anterior temporal lobes (ATLs) to test the hub-and-spoke theory, which suggests that the ATL contribution to semantic representation is transmodal and concerns all categories. Rice et al compare the hub-andspoke theory with an alternative theory stating that this region's responses are modality-and category-selective, and respond specifically to socially relevant concepts including faces.…”

Individual Differences in the Connectivity of Left and Right Anterior Temporal Lobes Relate to Modality and Category Effects in Semantic Categorisation

“…We used a left ventral ATL site identified by Rice et al (2018b) as showing peak activation for semantic > non-semantic contrasts across eight studies using distortion-corrected fMRI (MNI coordinates -41, -15, -31). Since there is good evidence of bilateral engagement of ATL in semantic cognition, and Rice et al (2018b) identified a right ATL functional peak (MNI 44, -11, -36), we also included this seed in our investigation.…”

“…difficulty when the task involves both social stimuli and picture inputs) or a wider problem with social concepts (Gainotti, 2013;Gorno-Tempini et al, 1998). A recent fMRI study (Rice et al, 2018b) directly compared the neural response in ATL during semantic decisions about specific entities that were social (people) and non-social (landmarks). The social and non-social stimuli were presented as both words (i.e., people's names) and as pictures (i.e., of faces).…”

“…Although Gonzalez failed to observe any behavioural correlates of hemispheric differences in ATL connectivity, the tasks used in this previous study were not designed to maximise the involvement of this region, as they did not use specific-level concepts, or compare social and non-social concepts. To address this issue, the current study acquired resting-state fMRI from 74 participants, who completed semantic decisions about specific social and non-social concepts, presented as written words and pictures (using the stimuli from Rice et al, 2018b) in a separate testing session following the scan. We then assessed relationships between connectivity and behavioural performancewith particular focus on whether right vs. left ATL connectivity would predict performance on social vs. non-social tasks and trials presented as pictures vs. words.…”