Disambiguating the ambiguity disadvantage effect: Behavioral and electrophysiological evidence for semantic competition

Semantic ambiguity has been shown to slow comprehension, although it is unclear whether this ambiguity disadvantage is attributable to competition in semantic activation or difficulties in response selection. We tested the two accounts by examining semantic relatedness decisions to homonyms, or words with multiple unrelated meanings (e.g., football/electric fan). Our behavioral results showed that the ambiguity disadvantage arises only when the different meanings of words are of comparable frequency, and are thus activated in parallel. Critically, this effect was observed regardless of response-selection difficulties, both when the different meanings triggered inconsistent responses on related trials (e.g., fan–breeze) and consistent responses on unrelated trials (e.g., fan–snake). Our electrophysiological results confirmed that this effect arises during semantic activation of the ambiguous word, indexed by the N400, not during response selection. Overall, the findings show that ambiguity resolution involves semantic competition and delineate why and when this competition arises

Right hemisphere involvement for pun processing – Effects of idiom decomposition

The present study investigated hemispheric processing of puns involving decomposable idioms (e.g. Old skiers never die, they just go downhill) and non-decomposable ones (e.g., Old cleaners never die, they just bite the dust) using a divided visual field paradigm. In two cross-modal priming experiments, participants listened to puns and made lexical decisions for targets presented either in the left or right visual fields. To investigate hemispheric asymmetries at different processing stages (early vs. late), the prime-target inter-stimulus interval was 0 ms in Experiment 1 and was increased to 750 ms in Experiment 2. The results from both experiments demonstrated a left hemisphere advantage for processing puns triggered by non-decomposable idioms; puns motivated by decomposable idioms were processed equally fast in both hemispheres, suggesting that this type of pun induced right hemisphere involvement and led to bilateral processing. We discuss the results in light of predictions derived from the ‘graded salience’ hypothesis and the ‘fine-coarse coding’ hypothesis and argue that the data are more consistent with the graded salience hypothesis

Transcranial alternating current stimulation at 10 Hz modulates response bias in the Somatic Signal Detection Task

Ongoing, pre-stimulus oscillatory activity in the 8-13 Hz alpha range has been shown to correlate with both true and false reports of peri-threshold somatosensory stimuli. However, to directly test the role of such oscillatory activity in behaviour, it is necessary to manipulate it. Transcranial alternating current stimulation (tACS) offers a method of directly manipulating oscillatory brain activity using a sinusoidal current passed to the scalp. We tested whether alpha tACS would change somatosensory sensitivity or response bias in a signal detection task in order to test whether alpha oscillations have a causal role in behaviour. Active 10 Hz tACS or sham stimulation was applied using electrodes placed bilaterally at positions CP3 and CP4 of the 10-20 electrode placement system. Participants performed the Somatic Signal Detection Task (SSDT), in which they must detect brief somatosensory targets delivered at their detection threshold. These targets are sometimes accompanied by a light flash, which could also occur alone. Active tACS did not modulate sensitivity to targets but did modulate response criterion. Specifically, we found that active stimulation generally increased touch reporting rates, but particularly increased responding on light trials. Stimulation did not interact with the presence of touch, and thus increased both hits and false alarms. ACS stimulation increased reports of touch in a manner consistent with our observational reports, changing response bias, and consistent with a role for alpha activity in somatosensory detection

Inappropriate stereotypical inferences? An adversarial collaboration in experimental ordinary language philosophy

This paper trials new experimental methods for the analysis of natural language reasoning and the (re)development of critical ordinary language philosophy in the wake of J.L. Austin. Philosophical arguments and thought experiments are strongly shaped by default pragmatic inferences, including stereotypical inferences. Austin suggested that contextually inappropriate stereotypical inferences are at the root of some philosophical paradoxes and problems, and that these can be resolved by exposing those verbal fallacies. This paper builds on recent efforts to empirically document inappropriate stereotypical inferences that may drive philosophical arguments. We demonstrate that previously employed questionnaire-based output measures do not suffice to exclude relevant confounds. We then report an experiment that combines reading time measurements with plausibility ratings. The study seeks to provide evidence of inappropriate stereotypical inferences from appearance verbs that have been suggested to lie at the root of the influential ‘argument from illusion’. Our findings support a diagnostic reconstruction of this argument. They provide the missing component for proof of concept for an experimental implementation of critical ordinary language philosophy that is in line with the ambitions of current ‘evidential’ experimental philosophy

Speaker-specific cues influence semantic disambiguation.

Addressees use information from specific speakers’ previous discourse to make predictions about incoming linguistic material and to restrict the choice of potential interpretations. In this way, speaker specificity has been shown to be an influential factor in language processing across several domains e.g., spoken word recognition, sentence processing, and pragmatics. However, its influence on semantic disambiguation has received little attention to date. Using an exposure-test design and visual world eye tracking, we examined the effect of speaker-specific literal vs. nonliteral style on the disambiguation of metaphorical polysemes such as ‘fork’, ‘head’, and ‘mouse’. Eye movement data revealed that when interpreting polysemous words with a literal and a nonliteral meaning, addressees showed a late-stage preference for the literal meaning in response to a nonliteral speaker. We interpret this as reflecting an indeterminacy in the intended meaning in this condition, as well as the influence of meaning dominance cues at later stages of processing. Response data revealed that addressees then ultimately resolved to the literal target in 90% of trials. These results suggest that addressees consider a range of senses in the earlier stages of processing, and that speaker style is a contextual determinant in semantic processing

Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions

Fluctuations of pre-stimulus oscillatory activity in the somatosensory alpha band (8-14Hz) observed using human EEG and MEG have been shown to influence the detection of supra- and peri-threshold somatosensory stimuli. However, some reports of touch occur even without a stimulus. We investigated the possibility that pre-stimulus alpha oscillations might also influence these false reports of touch - known as tactile misperceptions. We recorded EEG while participants performed the Somatic Signal Detection Task (SSDT), in which participants must detect brief, peri-threshold somatosensory targets. We found that pre-stimulus oscillatory power in the somatosensory alpha range exhibited a negative linear relationship with reporting of touch at electrode clusters over both contralateral and ipsilateral somatosensory regions. As pre-stimulus alpha power increased, the probability of reporting a touch declined; as it decreased, the probability of reporting a touch increased. This relationship was stronger on trials without a somatosensory stimulus than on trials with a somatosensory stimulus, although was present for both trial types. Spatio-temporal cluster-based permutation analysis also found that pre-stimulus alpha was lower on trials when touch was reported - irrespective of whether it was present - over contralateral and ipsilateral somatosensory cortices, as well as left frontocentral areas. We argue that alpha power may reflect changes in response criterion rather than sensitivity alone. Low alpha power relates to a low barrier to reporting a touch even when one is not present, while high alpha power is linked to less frequent reporting of touch overall