Political violence is widespread in potential but uneven in expression. I propose a two-level integrative framework that helps explain the capacity for and expression of political violence, derived from the broadening interdisciplinary behavioral science research on violence. The first level of this framework centers on species-typical psychological mechanisms (common across humans) that regulate coalitional dynamics such as moralization, identity categorization, and collection action for violence. The second level focuses on individual-level catalysts: person-specific variable traits that predispose some individuals to cross the threshold into violent action. While each perspective is supported by extensive research across the social sciences, political science has yet to synthesize them explicitly into a single coherent model. Integrating these two levels offers a comprehensive foundation for analyzing a broad spectrum of political violence, at once both reconciling and moving beyond fruitless nature-vs-nurture type stalemates to help explain both the ubiquity and variability of an ancient vice.

This article examines the role of sociolinguistic expectations in linguistic convergence, using glide-weakened /aɪ/—a salient feature of Southern US English—as a test case. I present the results of two experiments utilizing a novel experimental paradigm for eliciting convergence—the WORD-NAMING GAME task—in which participants read aloud (baseline) or hear (exposure) clues describing particular words and then give their guesses out loud. Participants converged toward a Southern-shifted model talker by producing more glide-weakened tokens of /aɪ/, without ever hearing the model talker produce this vowel. Participants in the control (Midland talker) condition exhibited no such response. Convergence was facilitated by both living in the South and producing less-weakened baseline /aɪ/ glides, but attitudinal and domain-general individual-differences measures did not reliably predict convergence behaviors. Results are discussed in terms of implications for the cognitive mechanisms underlying convergence behaviors and the mental representations of sociolinguistic knowledge.

How and why speakers differ in the phonetic implementation of phonological contrasts, and the relationship of this ‘structured heterogeneity’ to language change, has been a key focus over fifty years of variationist sociolinguistics. In phonetics, interest has recently grown in uncovering ‘structured variability’—how speakers can differ greatly in phonetic realization in nonrandom ways—as part of the long-standing goal of understanding variability in speech. The English stop voicing contrast, which combines extensive phonetic variability with phonological stability, provides an ideal setting for an approach to understanding structured variation in the sounds of a community's language that illuminates both synchrony and diachrony. This article examines the voicing contrast in a vernacular dialect (Glasgow Scots) in spontaneous speech, focusing on individual speaker variability within and across cues, including over time. Speakers differ greatly in the use of each of three phonetic cues to the contrast, while reliably using each one to differentiate voiced and voiceless stops. Interspeaker variability is highly structured: speakers lie along a continuum of use of each cue, as well as correlated use of two cues—voice onset time and closure voicing—along a single axis. Diachronic change occurs along this axis, toward a more aspiration-based and less voicing-based phonetic realization of the contrast, suggesting an important connection between synchronic and diachronic speaker variation.

We investigate the role of two possible sets of factors, cognitive and social, in modulating an individual's linguistic context-sensitivity: the capacity of a neurocognitive system to identify information in a communicative context that satisfies the meaning requirements of a given expression in that context. We assess whether the degree of contextual facilitation of an otherwise dispreferred reading of an English have-sentence is correlated with domain-general cognitive factors—by using the AUTISM-SPECTRUM QUOTIENT (AQ) to index an individual's ‘autistic-like’ traits—and/or with social factors associated with gender expression—by using participants' gender group.

Acceptability ratings (n = 271) for a dispreferred but plausible locative reading were significantly higher only after the facilitatory context, suggesting that relevant context can modulate the acceptability of different readings of a have-sentence. Crucially, the degree of facilitation correlates with participants' AQ scores, but not gender group, directly implicating cognitive variability in linguistic context-sensitivity differences, and leaving open the question of individual-level variability arising from social factors. Our findings are consistent with a model of language variation in which individuals with certain cognitive styles implement their grammatical knowledge at a larger ‘communicative scope’ than others, thereby inducing novel usage patterns of existing variants in their speech community.

How flexible is an individual's accent during adulthood, and how does this flexibility relate to longer-term change? Previous work has found that accents are remarkably flexible in conversational interaction, but predominantly stable over years, leading to very different views of the role of individuals in community-level sound change. This article examines MEDIUM-TERM accent dynamics (days to months) by taking advantage of a ‘natural experiment’: a reality television show where contestants live in an isolated house for three months and are constantly recorded, forming a closed system where it is possible to both determine the dynamics of contestants’ speech from day to day and reason about the sources of any observed changes. We build statistical models to examine time dependence in five phonetic variables within individuals, in 14.5 hours of spontaneous speech from twelve English-speaking contestants. We find that time dependence in pronunciation is ubiquitous over the medium term: large daily fluctuations in pronunciation are the norm, while longer-term change over weeks to months occurs in a minority of cases. These patterns mirror the conflicting findings of previous work and suggest a possible bridge between the two. We argue that time dependence in phonetic variables is influenced by contrast between sounds, as well as systematic differences between speakers in how malleable their accents are over time; however, we find only limited evidence for convergence in individuals’ accents. Our results have implications for theories of the role of individuals in sound change, and suggest that medium-term pronunciation dynamics are a fruitful direction for future work.

Understanding the relation between speech production and perception is foundational to phonetic theory, and is similarly central to theories of the phonetics of sound change. For sound changes that are arguably perceptually motivated, it is particularly important to establish that an individual listener's selective attention—for example, to the redundant information afforded by coarticulation—is reflected in that individual's own productions. This study reports the results of a pair of experiments designed to test the hypothesis that individuals who produce more consistent and extensive coarticulation will attend to that information especially closely in perception. The production experiment used nasal airflow to measure the time course of participants' coarticulatory vowel nasalization; the perception experiment used an eye-tracking paradigm to measure the time course of those same participants' attention to coarticulated nasality. Results showed that a speaker's coarticulatory patterns predicted, to some degree, that individual's perception, thereby supporting the hypothesis: participants who produced earlier onset of coarticulatory nasalization were, as listeners, more efficient users of nasality as that information unfolded over time. Thus, an individual's perception of coarticulated speech is made public through their productions.

We examined the growth of English-L2 clausal density (CD) in narrative language samples from 129 school-age Syrian refugee children during their first 5 years of residency in Canada. First, we found that CD showed unique developmental trajectories from MLUw, and relatively rapid acquisition, consistent with studies with non-refugee participants. Second, faster growth in CD was associated with superior cognitive abilities and higher maternal education. An older-age advantage was found at Time 1, but a younger-age advantage emerged across Time 2–3. Factors more specific to the refugee experience (time in refugee camps and wellbeing difficulties) also predicted variance in CD and MLUw development but to a lesser extent. Finally, modeling performance on sentence repetition tasks revealed stronger contributions of lexical diversity and MLUw than CD. We conclude that complex syntax is relatively resilient in the L2 acquisition of refugee children and that CD in naturalistic production and SRT capture different abilities.

Research on multilingualism often assumes homogeneity within monolingual and multilingual groups, overlooking diversity in language environments, such as differences in language exposure and combinations. This study examines three such diversity indicators – language entropy, context entropy and linguistic distance – and their relationship to vocabulary in 4- to 5-year-old mono- and multilingual children (N = 257). Results reveal significantly greater vocabulary in monolinguals than multilinguals when comparing one language, but multilinguals outperform monolinguals on conceptual vocabulary. Vocabulary size in multilinguals showed a quadratic relationship with language and context entropy, initially increasing but declining at higher entropy levels. Additionally, children with greater linguistic distances generally had larger dominant vocabularies. However, within the group with high linguistic distance, further increased distance was linked to smaller dominant vocabularies. These findings suggest that the applied diversity indicators capture meaningful variation in language environments, offering valuable insights about diversity in environments on vocabulary outcomes in multilingual children.

This article provides an overview of key challenges in second language (L2) pronunciation learning and teaching within the context of instructed second language acquisition (SLA), with the goal of identifying promising directions for future research. It begins by examining persistent difficulties in L2 pronunciation instruction, such as the typically limited quality of input and the dominant emphasis on grammar and vocabulary in communicative language teaching (CLT). These conditions often result in learners having limited awareness of their pronunciation needs and teachers facing challenges in incorporating pronunciation instruction into CLT-based curricula. The article then reviews emerging instructional approaches that aim to integrate attention to phonetic form within CLT, highlighting the need for further empirical investigation. In addition, several pronunciation training techniques, some underexplored (HVPT, shadowing, embodied pronunciation training, captioned video, accent imitation, and pronunciation self-assessment), are briefly described, with an emphasis on their pedagogical potential both inside and outside the classroom. Finally, the article considers the role of individual differences in L2 pronunciation development and proposes directions for future research in instructed SLA.

The surge of online psychological assessments have brought the autism research community both opportunities and challenges: while they enable rapid large-scale data collection and more power to characterize individual differences, they also bring concerns about data quality, generalizability beyond online samples, and whether autistic traits can be reliably characterized with self-report measures administered online. Here we tackle these concerns by providing a systematic characterization of the autistic traits variability across individuals in a large cross-sectional dataset (N = 2826) as well as its temporal reliability within individuals in a test-retest dataset (N = 247), with both online and in-lab samples. We measured autistic traits using the Social Responsiveness Scale, 2nd version, Adult Self Report (SRS-2-ASR) – a tool that quantifies individual differences in autistic traits along a continuum for the general adult population. Across individuals, we found elevated SRS scores in online samples and were able to trace this effect to specific subsets of SRS items. SRS scores also covaried with internalizing symptoms, decreased with age, and were lower in women compared to other genders. Within individuals, we find moderate-to-good test-retest reliability of SRS scores over long intervals, with no difference between online and in-lab samples, suggesting robust temporal stability. We conclude that there are systematic differences in autistic traits between online and in-lab samples that are partly explained by systematic population-level differences in internalizing symptoms, particularly social anxiety. Future studies that sample across different populations should measure, control for, or stratify with respect to these factors.

The present study investigated if/how individual differences in heritage language (HL) experience modulate gender agreement processing among Spanish heritage speakers (HSs). We reanalyzed the data from Luque and colleagues (2023), which reported an aggregate biphasic N400–P600. The present analysis revealed that sensitivity to morphological markedness was positively modulated by HL proficiency and exposure/use. Higher proficiency led to increased P600 across markedness conditions—the typical signature of L1-dominant processing—while increased Spanish exposure/use resulted in increased N400 for Default Errors—a signature attested only in HSs in this domain. Formal instruction led to increased N400 but reduced P600 for Feature Clash Errors. We interpret these results to suggest that the N400 reflects a morphophonological pattern-matching strategy with some HSs relying (more) on this mechanism as Spanish exposure and use increases. Markedness also modulated the relative engagement of pattern-matching (N400) versus automatic grammatical processing (P600), depending on the transparency/saliency of morphophonological patterns.

People’s decisions may change when made in a foreign language (FL). Research testing this foreign language effect (FLE) has mostly used scenarios where uncertainty is expunged or reduced to a form of risk, whereas real-life decisions are usually characterized by uncertainty around outcome likelihood. In the current work, we aimed to investigate whether the FLE on decision-making extends to uncertain scenarios. Moreover, as it is still unclear what linguistic and psychological factors contribute to the FLE, we tested the effects of participants’ FL background, cognitive style and risk-taking attitude on decision processes under certain and uncertain conditions. Overall, we report null effects of language context (native versus foreign language) and problem condition (certain versus uncertain prospects) on participants’ choices. In addition, we found that both FL background and decision makers’ traits modulated participants’ choices in a FL, without emerging into the ‘classic’ FLE on decision-making. However, the direction of such effects was complex, and not always compatible with previous FLE theories. In light of these results, our study highlights the need to reconceptualize the FLE and its implications on decision-making.

Designers often rely on their self-evaluations – either independently or using design tools – to make concept selection decisions. When evaluating designs for sustainability, novice designers, given their lack of experience, could demonstrate psychological distance from sustainability-related issues, leading to faulty concept evaluations. We aim to investigate the accuracy of novice designers’ self-evaluations of the sustainability of their solutions and the moderating role of their (1) trait empathy and (2) their beliefs, attitudes and intentions toward sustainability on this accuracy. We conducted an experiment with first-year engineering students comprising a sustainable design activity. In the activity, participants evaluated the sustainability of their own designs, and these self-evaluations were compared against expert evaluations. We see that participants’ self-evaluations were consistent with the expert evaluations on the following sustainable design heuristics: (1) longevity and (2) finding wholesome alternatives. Second, trait empathy moderated the accuracy of self-evaluations, with lower levels of fantasy and perspective-taking relating to more accurate self-evaluations. Finally, beliefs, attitudes and intentions toward sustainability also moderated the accuracy of self-evaluations, and these effects vary based on the sustainable design heuristic. Taken together, these findings suggest that novice designers’ individual differences (e.g., trait empathy) could moderate the accuracy of the evaluation of their designs in the context of sustainability.

This study presents findings from a 4-year panel study examining three major questions regarding the measurement of social value orientation (SVO). First, we investigate the test–retest reliability of the Slider Measure (SLM, Murphy et al., 2014) over a period of up to 4 years in a large, demographically diverse sample. Second, we compare the stability of the SLM to related measurements of prosociality and distributional preferences along the behavior–behavioral tendency–trait continuum, including single behaviors (e.g., the Dictator Game and the Prisoner’s Dilemma), alternative behavioral tendencies (e.g., survey-based measures of altruism), and broader personality traits (e.g., Big-Five, HEXACO, Dark Factor D). Third, we explore differences in individual trajectories of SVO, focusing on how age and gender influence its stability and change over time. Our study thus complements earlier research on the stability of the SLM by extending the time period and depth of analysis, and putting the measure in the context of other related measures. The results show a considerable degree of stability, higher than all behavioral games, but often lower than fully fledged measures of personality traits. Furthermore, we find that age has a stabilizing effect on behavior in the SLM. With regard to gender, we find that women behave generally more prosocial than men but that they do not differ in their stability. We conclude that the SLM is a suitable method for assessing individual SVO over longer time periods and is best thought of as covering a sweet spot between stable personality traits and immediate behavioral expressions.