Manuel de Vega

Event-related Brain Potentials Elicited by Morphological, Homographic, Orthographic, and Semantic Priming

The morphological structure of words, in terms of their stem morphemes and affixes, could influence word access and representation in lexical memory. Three experiments were carried out to explore the attributes of event-related potentials evoked by different types of priming. Morphological priming, with pairs of words related by their stem (hijo/hija [son/ daughter]), produced a sustained attenuation (and even a tendency to positivity) of the N400 shown by unrelated words across the three experiments. Homographic priming (Experiment 1), using pairs of words with a superficially similar stem, but without morphological or semantic relation (foco/foca [floodlight/seal]), produced an initial attenuation similar to the morphological pairs, but which rapidly tended to form a delayed N400, due to the impossibility of integration. However, orthographic priming (rasa/rana [flat/frog]) in Experiment 2 does not produce attenuation of the N400 but an effect similar to that of unrelated pairs. Experiment 3 shows that synonyms advance more slowly than morphological pairs to meaning coherence, but finally produce a more positive peak around 600 msec.

On doing two things at once: Temporal constraints on actions in language comprehension

In two experiments, we investigated how text comprehension is influenced by the interaction between the properties of actions and the temporal relations specified by adverbs. Participants read short narratives describing a protagonist who performed two actions that involved similar sensorimotor systems (e.g., chopping wood and painting a fence) or different ones (e.g., whistling a melody and painting a fence). The actions were described as simultaneous or successive by means of the temporal adverbswhile andafter, respectively. Comprehension, both in Spanish and in English, was markedly impaired (longer reading times and lower subjective coherence) for sentences including the adverb while and actions involving the same sensorimotor system. However, when one of the same sensorimotor system actions was described as a mental plan (e.g., chopping wood and thinking of painting a fence), comprehension was equally easy with the adverbswhile andafter. These results are compatible with a revised version of the indexical hypothesis that specifies how comprehension is guided by syntax and embodied constraints within multiple noninteracting mental spaces.

To Know or Not to Know: Comprehending Protagonists' Beliefs and Their Emotional Consequences

Six experiments explored how readers take the protagonists mental perspective in stories involving conflicting beliefs about a situation. Experiments 1. 2 and 3 demonstrated that readers with privileged information build emotional inferences corresponding to the protagonists (wrong) beliefs. The time course of inferences was studied in Experiments 2, 4, 5, and 6. The results suggest that inferences related to the protagonists beliefs are backward inferences at the text integration stage. Experiment 3 showed that negation markers are not necessary for mental perspective effects. It was concluded that readers as side participants are able to dissociate the protagonists and their own beliefs about a narrative situation.

Updating spatial layouts mediated by pointing and labelling under physical and imaginary rotation

The present experiments manipulated the modality in which participants communicated object directions (by pointing or verbal labelling) in a learned layout, and the mode in which they were required to rotate (physically or imaginary). The results showed that the pointing modality was strongly influenced by the mode of rotation (Experiment 1). Pointing was faster and more accurate in the physical than in the imaginary rotation. In addition, a different pattern of dimension accessibility was observed: equi-accessibility in physical rotation (front-back = right-left) and standard in imaginary rotation (front-back < right-left). By contrast, the verbal modality was less influenced by the mode of rotation. The same standard pattern of dimension accessibility and similar speed was obtained in physical and imaginary rotation. These results are explained by proposing a first-order embodiment, typical of ordinary pointing, which involves a low-cost sensory-motor updating of object positions and a second-order embodiment, most typical of language, which involves a represented (rather than physical) self and an object-to-frame high-cost updating.

Processing of temporal information: Evidence from eye movements

Universidad de La Laguna, Tenerife, Spain In two experiments, we recorded eye movements to study how readers monitor temporal order information contained in narrative texts. Participants read short texts containing critical temporal information in the sixth sentence, which could be either consistent or inconsistent with temporal order information given in the second sentence. In Experiment 1, inconsistent sentences yielded more regressions to the second sentence and longer refixations of it. In Experiment 2, this pattern of eye movements was shown only by readers who noticed the inconsistency and were able to report it. Theoretical and methodological implications of the results for research on text comprehension are discussed.

Human brain potentials indicate morphological decomposition in visual word recognition.

Stem homographs are pairs of words with the same orthographic description of their stem but which are semantically and morphologically unrelated (e.g. in Spanish: rata/rato (rat/moment)). In priming tasks, stem homographs produce inhibition, unlike morphologically related words (loca/loco (madwoman/madman)) which produce facilitation. An event-related potentials study was conducted to compare morphological and stem homographic priming effects. The results show a similar attenuation of the N400 component at the 350-500 ms temporal window for the two conditions. In contrast, a broad negativity occurs only for stem homographs at the 500-600 ms window. This late negativity is interpreted as the consequence of an inhibitory effect for stem homographs that delays the stage of meaning integration.

The comprehension of action-related sentences may cause interference rather than facilitation on matching actions

This study used a dual-task paradigm to analyze the time course of motor resonance during the comprehension of action language. In the study, participants read sentences describing a transfer either away from (“I threw the tennis ball to my rival”) or toward themselves (“My rival threw me the tennis ball”). When the transfer verb appeared on the screen, and after a variable stimulus onset asynchrony (SOA), a visual motion cue (Experiment 1) or a static cue (Experiment 2) prompted participants to move their hand either away from or toward themselves to press a button. The results showed meaning–action interference at short SOAs and facilitation at the longest SOA for the matching conditions. These results support the hypothesis that motor processes associated with the comprehension of action-related language interfere with an overlapping motor task, whereas they facilitate a delayed motor task. These effects are discussed in terms of resonance processes in the motor cortex.

Understanding action language modulates oscillatory mu and beta rhythms in the same way as observing actions

The mu rhythms (8-13 Hz) and the beta rhythms (15 up to 30 Hz) of the EEG are observed in the central electrodes (C3, Cz and C4) in resting states, and become suppressed when participants perform a manual action or when they observe anothers action. This has led researchers to consider that these rhythms are electrophysiological markers of the motor neuron activity in humans. This study tested whether the comprehension of action language, unlike abstract language, modulates mu and low beta rhythms (15-20 Hz) in a similar way as the observation of real actions. The log-ratios were calculated for each oscillatory band between each condition and baseline resting periods. The results indicated that both action language and action videos caused mu and beta suppression (negative log-ratios), whereas abstract language did not, confirming the hypothesis that understanding action language activates motor networks in the brain. In other words, the resonance of motor areas associated with action language is compatible with the embodiment approach to linguistic meaning.

Metaphors are Embodied, and so are Their Literal Counterparts.

This study investigates whether understanding up/down metaphors as well as semantically homologous literal sentences activates embodied representations online. Participants read orientational literal sentences (e.g., she climbed up the hill), metaphors (e.g., she climbed up in the company), and abstract sentences with similar meaning to the metaphors (e.g., she succeeded in the company). In Experiments 1 and 2, participants were asked to perform a speeded upward or downward hand motion while they were reading the sentence verb. The hand motion either matched or mismatched the direction connoted by the sentence. The results showed a meaning-action effect for metaphors and literals, that is, faster hand motion responses in the matching conditions. Notably, the matching advantage was also found for homologous abstract sentences, indicating that some abstract ideas are conceptually organized in the vertical dimension, even when they are expressed by means of literal sentences. In Experiment 3, participants responded to an upward or downward visual motion associated with the sentence verb by pressing a single key. In this case, the facilitation effect for matching visual motion-sentence meaning faded, indicating that the visual motion component is less important than the action component in conceptual metaphors. Most up and down metaphors convey emotionally positive and negative information, respectively. We suggest that metaphorical meaning elicits upward/downward movements because they are grounded on the bodily expression of the corresponding emotions.

Canceling updating in the comprehension of counterfactuals embedded in narratives

Participants were given counterfactual sentences—for example, “If Mary had won the lottery she would have bought a Mercedes car” —or factual sentences—for example, “Because Mary won the lottery, she bought a Mercedes car” —embedded in short narratives. Reading times showed that readers were immediately sensitive to the special status of counterfactual information (Experiment 1). In addition, probe-recognition latencies demonstrated that old information was more accessible in counterfactual than in factual stories, and new information was equally accessible in both kinds of stories (Experiment 2). However, after reading additional clauses, new information became less accessible in counterfactual than in factual stories (Experiment 3). These results suggest that counterfactual events are momentarily represented but are later suppressed and the readers’ attention goes back to previous events in the story.