Muscle activation in semantic processing: An electromyography approach

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

Recent studies have revealed the instability of the action-sentence compatibility effect (ACE). The current study was designed to demonstrate the hypothesis that the instability of the ACE may be attributed to the instability of focused information in a sentence. A pilot study indicated that the focused information of sentences was relatively stable in the sentence-picture verification task but exhibited significant interindividual variability in the action-sentence compatibility paradigm in previous studies. Experiments 1 and 2 examined the effect of sentence focus on the shape match effect and the ACE by manipulating the focused information of sentences using the focus marker word "" (is). Experiment 1 found that the shape match effect occurred in the original sentence, while it disappeared when the word "" (is) was used to make an object noun no longer the focus of a sentence. Experiment 2 failed to observe the ACE regardless of whether the sentence focus was on the action information. Experiment 3 modified the focus manipulation to observe its impact on the ACE using different fonts and underlines to highlight the focused information. The results indicated that the ACE only occurred when the action information was the sentence focus. These findings suggest that sentence focus influences mental simulation, and the instability of the ACE is likely to be associated with the instability of sentence focus in previous studies. This outcome highlights the crucial role of identifying specific information as the critical element expressed in the current linguistic context for successful simulation.

The influence of sentence focus on motor system activity in language comprehension and its temporal dynamics: Preliminary evidence from sEMG

Previous research has shown that individual experiences and experimental tasks can influence the occurrence of mental simulation during sentence comprehension. However, little research has focused on the effect of sentence focus on mental simulation and its temporal dynamics. Sentence focus refers to the hierarchical structure of information within a sentence, where focused information represents the most prominent and essential information. In contrast, nonfocused information provides a background for the focused information. The present study investigated whether sentence focus would affect the activity of the motor system in language comprehension and at which stage the effect of sentence focus occurred. We measured spontaneous arm muscle electrical activity by surface electromyography (sEMG) while participants read action-focused, nonaction-focused, and control sentences. We observed greater spontaneous muscle electrical activity in the flexor common muscle of the fingers when participants read action-focused sentences compared to nonaction-focused and control sentences. Additionally, there was an interactive trend between sentence type and time, spontaneous muscle electrical activity while reading action-focused sentences was observed in both early (1 ms to 300 ms after the presentation of the action phrase) and late time windows (901 ms to 1500 ms after the action phrase). The findings suggest that the motor system exhibits flexible engagement during language comprehension and the impact of sentence focus on motor system activity may be throughout both the lexical-semantic retrieval and sentence-meaning integration stages.

Motor features of abstract verbs determine their representations in the motor system

Embodied cognition theory posits that concept representations inherently rely on sensorimotor experiences that accompany their acquisitions. This is well established through concrete concepts. However, it is debatable whether representations of abstract concepts are based on sensorimotor representations. This study investigated the causal role of associated motor experiences that accompany concept acquisition in the involvement of the motor system in the abstract verb processing. Through two experiments, we examined the action–sentence compatibility effect, in the test phase after an increase in motor features during the learning phase for abstract verbs with low motor features (Experiment 1) or novel words with no conceptual features at all (Experiment 2). After associated motor experiences were added in the word learning phase, action–sentence compatibility effect was found in the semantic processing tasks during the test phase for abstract verbs (Experiment 1a) and novel words (Experiment 2). This was lacking in the word font color judgment task requiring no semantic processing (Experiment 1b). Coupled with our previous study, these findings suggest that motor features formed during word learning could causally affect embodiment in the motor system for abstract verbs, and reactivation of motor experiences in abstract verb processing depends on a given task’s demands. Our study supports the view that conceptual representations, even abstract concepts, can be grounded in sensorimotor experiences.