Neurolinguistic relativity

To eschew possible recruitment of linguistic codes during nonverbal tasks, one should turn to information of neural activity reflecting unconscious mental processing of nonverbal stimuli. Thierry and colleagues (2009) recorded event-related brain potentials in English and Greek native speakers when the participants were presented with a stream of shapes one by one and were asked to discriminate, by button pressing, infrequent squares (target, probability 20%) from regular circles (probability 80%), in which most of the circles are light blue (standard, probability 70%) and the rest are dark blue (deviant, probability 10%), as illustrated in Figure 2 (or the other way around; i.e., more dark blue circles and fewer light blue ones). This design was to divert participants’ attention from color deviancy. Greek differentiates light and dark

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shades of blue in its basic color terms (ghalazio and ble), but English does not. This terminological distinction led to a visual mismatch negativity (vMMN) effect greater in the Greek participants than in the English participants, but the greater deviancy effect was not observed for green (the control condition) because both Greek and English have only one basic color term for green.

Figure 2.Sample of Thierry et al.’s (2009) experimental stimuli

Usually expected in an oddball paradigm, the MMN is an automatic and unconscious brain response elicited by perceptual deviant stimuli, even the stimuli outside of the focus of attention (Czigler 2014; Näätänen, Kujala & Winkler 2011). In Thierry et al. (2009), this pre-attentive processing started before 200 milliseconds, earlier than the online access to specific lexical information reported in the literature (Costa et al. 2009; Strijkers, Costa & Thierry 2010;

Strijkers, Holcomb & Costa 2011). In other words, it could be forcefully argued that there was minimal chance of verbal contamination of the participants’ responses to the critical stimuli.

The findings suggested that repeated exposure to language-specific categorization (i.e., lexical distinction in color) affects perceptual distinction (i.e., color hue discrimination). Put simply, speakers of different languages perceive the world differently.

standard target deviant time

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In a follow-up study (Athanasopoulos et al. 2010), the Greek participants were regrouped according to different lengths of stay in the UK. A markedly reduced vMMN effect was observed in the long-stay Greek participants, indicating that the long-stay Greek participants perceived light and dark blues as more similar than the short-stay Greek participants. Different lengths of exposure to English, where there is no blue contrast, shaped the Greek speakers’

perception to different extents. The results of the follow-up study not only consistently supported linguistic relativity but also suggested that the shaping effect of language on thought is eminently plastic in nature.

Following the investigations in the domain of color, Boutonnet and colleagues (2013) tested Whorfian hypothesis in the domain of object categorization. In English, cups and mugs are two objects terminologically differentiated while they are both called taza in Spanish. With an experimental design similar to that in Thierry et al.’s (2009) color study, the participants were asked to detect target pictures of bowls in a sequence of standard and infrequent deviant pictures of cups and mugs. As expected, the deviants elicited a deviant-related negativity (DRN) of greater magnitude in the English speakers than in the Spanish speakers. The DRN is the earliest modulation of the negative component closely comparable to vMMN (Csibra, Czigler

& Ambrò 1994; Czigler, Balázs & Pató 2004; Czigler, Balazs & Winkler 2002; István Winkler et al. 2005; Turatto et al. 2002). Peaking around 160 milliseconds and substantially earlier than N2 components elicited by overt cognitive control (Folstein & Van Petten 2007), the identified

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DRN effect served as an index of automatic, pre-attentive, and pre-lexical cognitive mechanism (Costa et al. 2009; Strijkers, Costa & Thierry 2010; Strijkers, Holcomb & Costa 2011). The findings established an effect of language on high-level perceptual processing, the effect that should not be nullified by potential verbal interference or top-down strategies. Interestingly, the P1 peak of ERPs around 100-150 milliseconds, elicited by the contrast of cups and mugs, was of similar amplitude in two language groups. The P1 component was associated with early discrimination of object categories (Dering et al. 2011; Thierry et al. 2007). The insignificant P1 difference, coupled with the DRN results presented above, revealed that the participants of both language groups did perceive a cup and a mug as different objects (similar P1 amplitude), but those who use two terms to specify the two objects seemed to enjoy the privilege of distinguishing the two objects in a more spontaneous and effortless fashion than those who use only one term (greater DRN in the English speakers). The obtained ERP results not only captured the fact that speakers of different languages would not be blinded by language-specific terminologies, but meanwhile demonstrated linguistic relativity effects.

Like terminology, grammar can modulate one’s unconscious cognition as well. In the study by Boutonnet, Athanasopoulos, and Thierry (2012), the participants (native English speakers and Spanish-English bilinguals) were presented with triplets of pictures, and asked to judge whether the semantic category of the third picture of a triplet is the same as that of the first two pictures by pressing buttons. What the participants were not informed of was that the

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grammatical gender of the third picture name in Spanish was incongruent with that of the first two in half of the trials. Through the recorded ERPs along the tasks, the authors found a semantic priming effect (N400) in both groups and a negative modulation (left anterior negativity; LAN) by gender inconsistency exclusively in the Spanish–English bilinguals. The LAN, an index of morphosyntactic processing (i.e., grammatical gender in question) (Friederici

& Jacobsen 1999; Friederici, Pfeifer & Hahne 1993; Hahne & Friederici 1999; Thierry, Cardebat & Démonet 2003), was elicited in an all-in-English semantic categorization task where gender information was not required and signaled; moreover, awareness of gender manipulation was never reported by the participants. Hence, the retrieval of task-irrelevant gender information was argued to be unconscious and implicit (Thierry & Wu 2007; Strijkers, Holcomb & Costa 2011; Wu & Thierry 2010). The results suggested that conceptual object categorization could be affected by grammatically encoded information on an unconscious level, which corroborated linguistic relativity.

To sum up, the effective and convincing neurolinguistic results restore confidence in the research on linguistic relativity. The ERP components (e.g., vMMN, DRN, and LAN), unlikely to be contaminated by online language processing as in behavioral experiments, are solid neurophysiological evidence to show that language influences thought. That being the case, speakers of different languages might have differently structured minds. Language does not determine principal categories of thought, but the universality of human conceptual system