Comparing visual search and eye movements in bilinguals and monolinguals

Myogenic artifacts masquerade as neuroplasticity in the auditory frequency-following response

The frequency-following response (FFR) is an evoked potential that provides a neural index of complex sound encoding in the brain. FFRs have been widely used to characterize speech and music processing, experience-dependent neuroplasticity (e.g., learning and musicianship), and biomarkers for hearing and language-based disorders that distort receptive communication abilities. It is widely assumed that FFRs stem from a mixture of phase-locked neurogenic activity from the brainstem and cortical structures along the hearing neuraxis. In this study, we challenge this prevailing view by demonstrating that upwards of ~50% of the FFR can originate from an unexpected myogenic source: contamination from the postauricular muscle (PAM) vestigial startle reflex. We measured PAM, transient auditory brainstem responses (ABRs), and sustained frequency-following response (FFR) potentials reflecting myogenic (PAM) and neurogenic (ABR/FFR) responses in young, normal-hearing listeners with varying degrees of musical training. We first establish that PAM artifact is present in all ears, varies with electrode proximity to the muscle, and can be experimentally manipulated by directing listeners' eye gaze toward the ear of sound stimulation. We then show this muscular noise easily confounds auditory FFRs, spuriously amplifying responses 3-4-fold with tandem PAM contraction and even explaining putative FFR enhancements observed in highly skilled musicians. Our findings expose a new and unrecognized myogenic source to the FFR that drives its large inter-subject variability and cast doubt on whether changes in the response typically attributed to neuroplasticity/pathology are solely of brain origin.

Myogenic artifacts masquerade as neuroplasticity in the auditory frequency-following response (FFR)

The frequency-following response (FFR) is an evoked potential that provides a "neural fingerprint" of complex sound encoding in the brain. FFRs have been widely used to characterize speech and music processing, experience-dependent neuroplasticity (e.g., learning, musicianship), and biomarkers for hearing and language-based disorders that distort receptive communication abilities. It is widely assumed FFRs stem from a mixture of phase-locked neurogenic activity from brainstem and cortical structures along the hearing neuraxis. Here, we challenge this prevailing view by demonstrating upwards of ~50% of the FFR can originate from a non-neural source: contamination from the postauricular muscle (PAM) vestigial startle reflex. We first establish PAM artifact is present in all ears, varies with electrode proximity to the muscle, and can be experimentally manipulated by directing listeners' eye gaze toward the ear of sound stimulation. We then show this muscular noise easily confounds auditory FFRs, spuriously amplifying responses by 3-4x fold with tandem PAM contraction and even explaining putative FFR enhancements observed in highly skilled musicians. Our findings expose a new and unrecognized myogenic source to the FFR that drives its large inter-subject variability and cast doubt on whether changes in the response typically attributed to neuroplasticity/pathology are solely of brain origin.

Integration of visual context in early and late bilingual language processing: evidence from eye-tracking

Previous research on the processing of language embedded in a rich visual context has revealed the strong effect that a recently viewed action event has on language comprehension. It has been shown that listeners are more likely to view the target object of a recently performed event than look at the target object of a plausible future event during sentence utterance, regardless of the tense cue. In the current visual-world eye-tracking experiments, we tested the strength of the recently observed visual context with a group of English monolingual and two groups of English-French early and late bilingual speakers. By comparing these different groups, we examined whether bilingual speakers, as a consequence of greater cognitive flexibility when integrating visual context and language information, show early anticipatory eye-movements toward the target object. We further asked whether early and late bilinguals show differences in their processing. The findings of the three eye-tracking experiments revealed an overall preference for the recently seen event. However, as a result of the early provision of tense cue, this preference was quickly diminished in all three groups. Moreover, the bilingual groups showed an earlier decrease in reliance on the recently seen event compared to monolingual speakers and the early bilinguals showed anticipatory eye-movements toward the plausible future event target. Furthermore, a post-experimental memory test revealed that the bilingual groups recalled the future events marginally better than the recent events, whereas the reverse was found in the monolingual groups.

Consideration of culture in cognition: How we can enrich methodology and theory

In this paper, we argue that adopting an inclusive approach where diverse cultures are represented in research is of prime importance for cognitive psychology. The overrepresentation of participant samples and researchers from WEIRD (Western, Educated, Industrialized, Rich, and Democratic) cultures limits the generalizability of findings and fails to capture potential sources of variability, impeding understanding of human cognition. In an analysis of articles in representative cognitive psychology journals over the five-year period of 2016-2020, we find that only approximately 7% of articles consider culture, broadly defined. Of these articles, a majority (83%) focus on language or bilingualism, with small numbers of articles considering other aspects of culture. We argue that methodology and theory developed in the last century of cognitive research not only can be leveraged, but will be enriched by greater diversity in both populations and researchers. Such advances pave the way to uncover cognitive processes that may be universal or systematically differ as a function of cultural variations, and the individual differences in relation to cultural variations. To make a case for broadening this scope, we characterize relevant cross-cultural research, sample classic cognitive research that is congruent with such an approach, and discuss compatibility between a cross-cultural perspective and the classic tenets of cognitive psychology. We make recommendations for large and small steps for the field to incorporate greater cultural representation in the study of cognition, while recognizing the challenges associated with these efforts and acknowledging that not every research question calls for a cross-cultural perspective.

Predictions about the Cognitive Consequences of Language Switching on Executive Functioning Inspired by the Adaptive Control Hypothesis Fail More Often than Not

The adaptive control hypothesis developed by Green and Abutalebi is the most influential theory of bilingual language control. The focus of this article is on the predictions that other researchers have derived based on the three different modes of interactional context described by the hypothesis. Foremost, that dual-language contexts should enhance domain-general executive functions more than single-language contexts. Several recent and ambitious behavioral tests of these predictions are reviewed. Although there was some evidence that dual-language contexts are associated with smaller switch costs, the evidence is inconsistent and there were no similar advantages for inhibitory control. The hypothesis also predicts neuroanatomical adaptations to the three types of interactional context. A careful evaluation of the relevant fMRI and ERP studies that take into account whether behavioral differences align with neuroscience differences and resolves valence ambiguities led to the conclusion that the neuroscience evidence for the hypothesis is, at best, inconsistent. The study also includes new analyses of two large-sample studies that enable the identification of relatively pure cases of single-language bilinguals, dual-language bilinguals, and dense-code switchers. Across nine different measures of executive functioning, the predicted advantage of the dual-language context never materialized. The hypotheses derived from the adaptive control hypothesis do not accurately predict behavioral performance on tests of executive functioning and do not advance our understanding as to what dimensions of bilingualism may lead to enhancements in specific components of executive functioning.

On the ambiguity regarding the relationship between sequential congruency effects, bilingual advantages in cognitive control, and the disengagement of attention

Grundy, Bialystok, and colleagues have reported that at short response-stimulus intervals bilinguals have smaller sequential congruency effects in flanker tasks compared to monolinguals. They interpret these differences to mean that bilinguals are more efficient at disengaging attentional control. Ten empirical studies are presented that show no differences between bilinguals and monolinguals under conditions that produced robust sequential congruency effects. These null results are discussed with respect to the rate at which sequential congruency effects dissipate and the fact these effects are not adaptive in the sense of improving overall performance. Arguments made by Goldsmith and Morton [1] that smaller sequential congruency effects should not be interpreted as "advantages" are extended. Evidence is also presented that neither simple congruency effects, nor sequential congruency effects, correlate across tasks. This lack of convergent validity is inconsistent with the hypothesis that either provides a measure of domain-general control that could underlie an advantage accrued through experience in switching languages. Results from other tasks purporting to show bilingual advantages in the disengagement of attention are also reviewed. We conclude that sequential congruency effects in nonverbal interference tasks and differences in the rate of disengaging attention are unlikely to contribute to our understanding of bilingual language control and that future research might productively examine differences in proactive rather than reactive control.

Bilingual Advantages in Inhibition or Selective Attention: More Challenges

A large sample (N = 141) of college students participated in both a conjunctive visual search task and an ambiguous figures task that have been used as tests of selective attention. Tests for effects of bilingualism on attentional control were conducted by both partitioning the participants into bilinguals and monolinguals and by treating bilingualism as a continuous variable, but there were no effects of bilingualism in any of the tests. Bayes factor analyses confirmed that the evidence substantially favored the null hypothesis. These new findings mesh with failures to replicate language-group differences in congruency-sequence effects, inhibition-of-return, and working memory capacity. The evidence that bilinguals are better than monolinguals at attentional control is equivocal at best.