Integrating stereotypes and factual evidence in interpersonal communication

Over the past century, social psychology has shown that stereotypes—generalized beliefs organized along dimensions like warmth and competence—shape initial impressions and predictions about others. Even merely believing one is interacting with a younger, less competent partner can induce more emphatic communication. However, overreliance on stereotypes without updating them in light of contrary evidence can fuel prejudice and systemic biases. Constructivist developmental psychology emphasizes that humans routinely coordinate perspectives through interaction, and children’s developing appreciation of others’ minds (e.g., false-belief understanding) is influenced by access to social interactions. Despite this, how stereotype-based expectations combine with interaction-derived evidence during live interpersonal communication remains unclear, as these domains are often studied separately and outside interactive contexts. This study asks: Which neuroanatomical and developmental factors modulate the real-time integration of stereotype beliefs with interaction-based evidence during live social exchanges? Focusing on the general expectation that younger individuals may require more explanatory guidance, the authors used a nonverbal communication game that separates stereotype-driven adjustments from interaction-driven convergence, while holding partner behavior constant via a role-blind confederate. The design creates a conflict between pre-existing stereotype beliefs (child presumed less competent) and matched partner competence observed during interaction, enabling precise quantification of the dynamics of communicative adjustments.

• Social psychology demonstrates pervasive effects of stereotypes on impressions and communication, with risks of prejudice and systemic bias when evidence is ignored.
• Constructivist and interactionist views in developmental psychology propose that social understanding develops through participation in joint activities and perspective coordination; early access to social interactions relates to false-belief understanding.
• Neuropsychological evidence implicates medial prefrontal regions (notably right hemisphere) in stereotype-influenced judgments and communicative tailoring; patients with medial prefrontal lesions fail to differentiate communication based on partner stereotypes in the same task.
• Developmental findings indicate early daycare exposure predicts flexible communicative adjustment at age 5 beyond familial influences, suggesting a sensitive period for social interaction.
• These literatures motivate predictions that right medial prefrontal structures, particularly ACCg, support leveraging stereotypes, and that early-life social exposure (e.g., daycare) shapes interaction-driven adjustments across development.

Design and task: A two-player nonverbal communication game on a 3×3 digital grid was used across 40 consecutive trials. Only the participant knew the hidden object (acorn) location among 13 possible positions; the partner (a role-blind confederate) could collect it based on the participant’s movements of a bird avatar. The avatar could only occupy the center of each grid square, preventing direct overlay on multi-location squares and enforcing communicative disambiguation. Difficulty (one, two, or three candidate locations within a square) was pseudo-randomly intermixed and increased over time. Participants alternated blocks with presumed adult vs child partners (8 blocks of 5 trials), but behavior and understanding of both presumed partners were matched via the same confederate. Photographs indicated the presumed partner before and during each block.

Participants: Drawn from the Nijmegen Longitudinal Study (community-based cohort; followed since infancy). Ninety-six adolescents (47 females; 17.2 ± 0.2 years) participated; 95 completed the game successfully. Exclusions: one participant for task adherence. MRI: 72 consented; one excluded for MRI quality, yielding 70 for structural analyses. All were screened for psychiatric/neurological history and had normal or corrected vision. Ethics approval and informed consent were obtained; participants received compensation.

Early social and familial measures: Early exposure to non-familial social interactions indexed by average days/week in daycare at 15 and 28 months (regular daycare and childminders; excludes kin babysitting; mean 1.4 ± 1.2 days/week). Familial environment indexed by parents’ socio-economic status via average parental education at 15 months (7-point scale; 5.2 ± 1.6) and presence of siblings (dichotomous; most had 0–1 siblings, 0.8 ± 0.6). Parental education was residualized against maternal working hours to reduce multicollinearity with daycare. Later social experiences: number of friends at age 7 (6.01 ± 1.6), extracurricular activities at age 12 (sum score up to 25; mean 9.42 ± 2.47), and time with friends at age 14 (10.86 ± 7.5 h/week). Participant’s own education at age 16 (9-point scale; mean 5.4 ± 1.5) was included as a covariate in controls.

Behavioral measures and analyses:

• Stereotype-based adjustment: Defined as the time (ms) spent with the bird in the object-containing square, compared between presumed child vs adult partners. To control for generic movement speed changes (task difficulty, learning), time in the target square was residualized against number of candidate locations, planning time, and time spent in other visited locations using a linear mixed-effects model (R lme4). Paired t-tests assessed average differences by presumed partner. Temporal dynamics were estimated as differences between consecutive blocks (7 partner transitions), signed by expected direction (adult→child as +1; child→adult as −1), and tested via cluster-based statistics with TFCE at p < 0.05 over 10,000 permutations.
• Interaction-based adjustment: Quantified as convergence over transitions in the same time metric, focusing on decline of stereotype-driven differences. Spearman correlations related daycare exposure to adjustment at each transition; cluster-based correction across transitions was applied. A per-participant linear slope of adjustment from transition 2 to 5 indexed rate of convergence; partial Spearman correlation tested daycare effects on slope controlling for intercept. Follow-up partial correlations controlled for familial environment and later social experiences, and then for ACCg structural measures.

Neuroimaging: Structural MRI acquired on 3T Siemens Trio/Prisma (32-channel head coil; MP-RAGE TR/TE 2.30 s/3.03 ms; 1 mm isotropic; FOV 256 mm); comparable image quality verified with CAT12. Two structural measures were derived:

• Voxel-based morphometry (VBM): Gray matter density maps segmented and DARTEL-registered to MNI, smoothed with 8 mm FWHM. A voxelwise gray matter asymmetry index (right relative to homotopic left) was computed to enhance sensitivity to lateralized effects.
• Surface-based morphometry (SBM): Cortical thickness from reconstructed surfaces, smoothed 15 mm FWHM. Multiple linear regressions related these structural indices to stereotype-driven adjustment, controlling for gender, scanner type, and salivary testosterone (proxy for pubertal status). ROI assessments included right ACCg volume/thickness (masking PFWE < 0.05 and Desikan–Killiany caudal ACC parcel). Generalizability was tested in two additional datasets (same cohort at age 14; independent sample on same task), and age-14 ACCg volume was included as a covariate in temporal specificity analyses.

Salivary testosterone: Two samples per participant collected 2 hours apart after 10:00 AM; CLIA assay (sensitivity 0.0025 ng/ml). First sample values were log-transformed and sex-standardized for use as covariates in structural analyses.

• Task performance: Dyads succeeded well above chance (89.8 ± 11.7% vs chance 7.7%).
• Stereotype-driven communicative adjustment: Participants spent more time in the object-containing square when believing the partner was a child (mean difference 32 ms; t(94)=2.31; p=0.023; Cohen’s d=0.24). Effects were specific to communicatively relevant behavior and not attributable to differences in confederate performance.
• Temporal dynamics: Cluster-based analysis revealed a positive adjustment cluster spanning transitions 2–3, indicating stereotype effects are prominent early and decline with accumulating interaction evidence.
• Neuroanatomy (VBM): Stereotype-based adjustment correlated with right-lateralized gray matter asymmetry in the anterior cingulate gyrus (ACCg; MNI [3, 33, 24]; PFWE < 0.014, whole-brain corrected). Right ACCg volume positively correlated with adjustment (P(65)=0.516; p<0.001); left ACCg showed no association (P(65)=−0.130; p=0.29). The right ACCg effect replicated in the same sample at age 14 and in an independent sample; the age-17 association remained significant after adjusting for right ACCg volume at age 14.
• Neuroanatomy (SBM): Cortical thickness in right ACCg positively associated with adjustment (P(65)=0.286; p=0.019), with additional effects in a distributed right-hemispheric network overlapping theory-of-mind regions (superior frontal gyrus, superior temporal sulcus, temporoparietal junction, precuneus; PFWE < 0.05 or < 0.01 thresholds as reported). VBM/SBM effects remained significant after controlling for early social experience variance (ACCg volume P(64)=0.484; p<0.001; thickness P(64)=0.362; p=0.003).
• Early social experiences (daycare): Cluster-based analysis identified negative correlations between daycare attendance and stereotype-driven adjustment across transitions 3–5. Averaged over transitions 3–5, daycare time correlated inversely with adjustment (P(91)=−0.384; p=0.001). Greater daycare exposure predicted a faster decline (more rapid convergence) in stereotype-driven differences over transitions (slope correlation P(88)=−0.228; p=0.031). These relations held when controlling for familial environment (parental SES, siblings), later social experiences (friends at 7, extracurriculars at 12, time with friends at 14), education at 16, and were largely robust when controlling for ACCg volume/thickness (P(67)=−0.196; p_one-tailed=0.054; P(67)=−0.226; p_one-tailed=0.031).
• Overall: Stereotype usage is linked to structural variation in right ACCg and a right-lateralized social-cognitive network, whereas the capacity to recalibrate behavior based on interaction evidence relates to early-life social exposure (daycare), independent of familial and later-life social factors.

The study demonstrates that stereotype-based and interaction-based processes jointly shape interpersonal communication but are dissociable in their neuroanatomical and developmental bases. Stereotypes set initial expectations, producing small, targeted adjustments in communicatively relevant behavior that are strongest early in interaction and diminish as partners accumulate mutual evidence of equal competence. These adjustments likely reflect abstraction from prior social knowledge rather than retrieval of surface features or generic priming. Structurally, individual differences in applying stereotypes correlate with gray matter density asymmetry and cortical thickness in right ACCg and a broader right-hemispheric theory-of-mind–related network, supporting a role for medial prefrontal circuitry in schema-based, adaptive use of social knowledge. Developmentally, greater early-life exposure to interactions with unrelated conspecifics (daycare) predicts faster interaction-driven convergence, indicating a lasting influence of early social environments on the ability to update and moderate stereotype priors during communication. Control analyses show that neuroanatomical variance in right ACCg does not account for daycare-related interaction effects, and vice versa, reinforcing the complementary nature of these contributions. Together, the findings clarify how stereotypes and evidence from live interaction are integrated, reconciling social-psychological and developmental accounts within a single framework of communicative adjustment dynamics.

Humans can overcome initial stereotype tendencies through ongoing social interaction. Stereotype-driven communicative adjustments are supported by structural features of right anterior cingulate gyrus and a right-lateralized social-cognitive network, while early-life social experiences—indexed by daycare exposure—have long-lasting effects on the capacity to recalibrate behavior based on interaction-derived evidence. These results unify perspectives from social and developmental psychology and identify targets for future research on the mechanisms of prejudice reduction and the societal impact of early social environments. Future studies could examine causal interventions (e.g., training, longitudinal manipulations of social exposure), broader stereotype domains, and developmental neuroplasticity trajectories linking early experiences to adolescent brain structure and communicative behavior.