Does the involvement of motor cortex in embodied language comprehension stand on solid ground? A p-curve analysis and test for excess significance of the TMS and tDCS evidence

No support for a causal role of primary motor cortex in construing meaning from language: An rTMS study

“…In this line, there are studies that have indeed shown effects in action language comprehension after stimulating the PMC (e.g., Gijssels et al, 2018;Willems et al, 2011) and the SMA (Courson et al, 2017). The present study did fail to provide evidence for a causal role of M1, despite being the most targeted and supported region in this field (e.g., Lo Gerfo et al, 2008;Repetto et al, 2013;Vukovic et al, 2017; for review, see Solana and Santiago, 2022), but it cannot discard that stimulating secondary motor areas might change meaning construction. Future studies are needed to clarify the causal implication of motor areas outside primary motor system.…”

“…This left us with the preregistered sample size of thirty participants (Mage = 23.1, SDage = 4.14; 5 men). It is worth noting that this sample size is greater than most of the samples used in previous rTMS studies of embodied language comprehension, which usually range between 15 and 20 participants (see Solana and Santiago, 2022). Following our preregistered plan, we did not reach N = 40 since the BF indicated strong evidence towards the absence of effect with N = 30 (see section 2.3).…”

“…As a final example, we recently meta-analyzed 43 TMS and tDCS studies of motor cortex 6 stimulation during action language comprehension by means of p-curve analyses and tests for excess significance (Solana and Santiago, 2022), as well as z-curve analyses (Solana and Santiago, 2023). Our results suggested that (1) we cannot conclude that these studies explore real effects, (2) their estimated underlying power is quite low (i.e., the majority of them may not replicate if repeated identically), and (3) they contain clear signs of a large publication bias.…”

“…Indeed, several previous rTMS studies supporting embodiment have employed this protocol (e.g., Lo Gerfo et al, 2008;Repetto et al, 2013;Tremblay et al, 2012). Left M1 was selected as target since it is the region most studied and supported by previous rTMS studies of embodied language processing (e.g., Lo Gerfo et al, 2008;Repetto et al, 2013;Vukovic et al, 2017; for review, see Solana and Santiago, 2022).…”

The influence of sentence focus on mental simulation: A possible cause of ACE instability

“…If the interaction effect was significant, simple effects analysis was conducted using the lsmeans package (Lenth, 2016). This analysis method was chosen because LMM can simultaneously consider the variation of participants and items, resulting in more accurate and stable results than ANOVA (Solana & Santiago, 2022).…”