The interplay between unexpected events and behavior in the development of explicit knowledge in implicit sequence learning

Some studies in implicit learning investigate the mechanisms by which implicitly acquired knowledge (e.g., learning a sequence of responses) becomes consciously aware. It has been suggested that unexpected changes in the own behavior can trigger search processes, of which the outcome then becomes aware. A consistent empirical finding is that participants who develop explicit knowledge show a sudden decrease in reaction times, when responding to sequential events. This so called RT-drop might indicate the point of time when explicit knowledge occurs. We investigated whether an RT-drop is a precursor for the development of explicit knowledge or the consequence of explicit knowledge. To answer this question, we manipulated in a serial reaction time task the timing of long and short stimulus-onset asynchronies (SOA). For some participants, the different SOAs were presented in blocks of either long or short SOAs, while for others, the SOAs changed randomly. We expected the participants who were given a blocked presentation to express an RT-drop because of the predictable timing. In contrast, randomly changing SOAs should hamper the expression of an RT-drop. We found that more participants in the blocked-SOA condition than in the random-SOA condition showed an RT-drop. Furthermore, the amount of explicit knowledge did not differ between the two conditions. The findings suggest that the RT-drop does not seem to be a presupposition to develop explicit knowledge. Rather, it seems that the RT-drop indicates a behavioral strategy shift as a consequence of explicit knowledge.

Enhancing Detection of SSMVEP Induced by Action Observation Stimuli Based on Task-Related Component Analysis

Action observation (AO)-based brain-computer interface (BCI) is an important technology in stroke rehabilitation training. It has the advantage of simultaneously inducing steady-state motion visual evoked potential (SSMVEP) and activating sensorimotor rhythm. Moreover, SSMVEP could be utilized to perform classification. However, SSMVEP is composed of complex modulation frequencies. Traditional canonical correlation analysis (CCA) suffers from poor recognition performance in identifying those modulation frequencies at short stimulus duration. To address this issue, task-related component analysis (TRCA) was utilized to deal with SSMVEP for the first time. An interesting phenomenon was found: different modulated frequencies in SSMVEP distributed in different task-related components. On this basis, a multi-component TRCA method was proposed. All the significant task-related components were utilized to construct multiple spatial filters to enhance the detection of SSMVEP. Further, a combination of TRCA and CCA was proposed to utilize both advantages. Results showed that the accuracies using the proposed methods were significant higher than that using CCA at all window lengths and significantly higher than that using ensemble-TRCA at short window lengths (≤2 s). Therefore, the proposed methods further validate the induced modulation frequencies and will speed up the application of the AO-based BCI in rehabilitation.

Case Report: Women, Be Aware that Your Vocal Charisma can Dwindle in Remote Meetings

Remote meetings via Zoom, Skype, or Teams limit the range and richness of nonverbal communication signals. Not just because of the typically sub-optimal light, posture, and gaze conditions, but also because of the reduced speaker visibility. Consequently, the speaker’s voice becomes immensely important, especially when it comes to being persuasive and conveying charismatic attributes. However, to offer a reliable service and limit the transmission bandwidth, remote meeting tools heavily rely on signal compression. It has never been analyzed how this compression affects a speaker’s persuasive and overall charismatic impact. Our study addresses this gap for the audio signal. A perception experiment was carried out in which listeners rated short stimulus utterances with systematically varied compression rates and techniques. The scalar ratings concerned a set of charismatic speaker attributes. Results show that the applied audio compression significantly influences the assessment of a speaker’s charismatic impact and that, particularly female speakers seem to be systematically disadvantaged by audio compression rates and techniques. Their charismatic impact decreases over a larger range of different codecs; and this decrease is additionally also more strongly pronounced than for male speakers. We discuss these findings with respect to two possible explanations. The first explanation is signal-based: audio compression codecs could be generally optimized for male speech and, thus, degrade female speech more (particularly in terms of charisma-associated features). Alternatively, the explanation is in the ears of the listeners who are less forgiving of signal degradation when rating female speakers’ charisma.

Does Self-Associating a Geometric Shape Immediately Cause Attentional Prioritization?

In many cognitive tasks, stimuli associated with one’s self elicit faster responses than stimuli associated with others. This is true for familiar self-representations (e.g., one’s own name), for new self-associated stimuli, and for combinations of both. The current research disentangles the potential of self- versus stranger-representations for familiar, new, and paired (familiar + new) stimuli to guide attention. In Study 1 ( N = 34), responses to familiar and new self- versus other representations were tested in a dot-probe task with a short stimulus-onset asynchrony (SOA; 100 ms). Study 2 ( N = 31) and Study 3 ( N = 35) use a long SOA (1,000 ms) to test whether the findings are mirrored in inhibition of return (IOR). We observe significant performance differences for targets following self- versus stranger-associated stimuli (i.e., a cuing effect or IOR depending on the SOA length), yet only when familiar representations are present. This indicates that, under conditions of attentional competition between self- and stranger-representations, familiar self-representations impact the distribution of attention while new self-representations alone do not.

Spelling Errors and Shouting Capitalization Lead to Additive Penalties to Trustworthiness of Online Health Information: Randomized Experiment With Laypersons

Background The written format and literacy competence of screen-based texts can interfere with the perceived trustworthiness of health information in online forums, independent of the semantic content. Unlike in professional content, the format in unmoderated forums can regularly hint at incivility, perceived as deliberate rudeness or casual disregard toward the reader, for example, through spelling errors and unnecessary emphatic capitalization of whole words (online shouting). Objective This study aimed to quantify the comparative effects of spelling errors and inappropriate capitalization on ratings of trustworthiness independently of lay insight and to determine whether these changes act synergistically or additively on the ratings. Methods In web-based experiments, 301 UK-recruited participants rated 36 randomized short stimulus excerpts (in the format of information from an unmoderated health forum about multiple sclerosis) for trustworthiness using a semantic differential slider. A total of 9 control excerpts were compared with matching error-containing excerpts. Each matching error-containing excerpt included 5 instances of misspelling, or 5 instances of inappropriate capitalization (shouting), or a combination of 5 misspelling plus 5 inappropriate capitalization errors. Data were analyzed in a linear mixed effects model. Results The mean trustworthiness ratings of the control excerpts ranged from 32.59 to 62.31 (rating scale 0-100). Compared with the control excerpts, excerpts containing only misspellings were rated as being 8.86 points less trustworthy, those containing inappropriate capitalization were rated as 6.41 points less trustworthy, and those containing the combination of misspelling and capitalization were rated as 14.33 points less trustworthy (P<.001 for all). Misspelling and inappropriate capitalization show an additive effect. Conclusions Distinct indicators of incivility independently and additively penalize the perceived trustworthiness of online text independently of lay insight, eliciting a medium effect size.

Altered synaptic adaptation and gain in sensory circuits of the casein kinase 1 delta (CK1dT44A) mouse model of migraine

Migraine is a very common and disabling neurological disorder that remains poorly understood at the cellular and circuit level. Transgenic mice harboring a mutation in casein kinase 1 delta (CK1dT44A) represent the first animal model of non-hemiplegic migraine. These mice have decreased sensory thresholds to mechanical and thermal pain after treatment with the migraine trigger nitroglycerin; and an increased susceptibility to cortical spreading depression (CSD), which models the migraine aura. In this study, we investigated cellular and synaptic mechanisms within sensory cortical circuits that might underlie the migraine relevant phenotypes of CK1dT44A mice, using in vitro and in vivo whole cell electrophysiology. Surprisingly we found that at resting state, CK1dT44A neurons exhibited hyperpolarized membrane potentials, due to increased tonic inhibition. Despite this reduction in baseline excitability, CK1dT44A neurons fired action potentials more frequently in response to current injection. And despite similar synaptic and dendritic characteristics to wild type neurons, excitatory but not inhibitory CK1dT44A synapses failed to adapt to high frequency short-stimulus trains, resulting in elevated steady state excitatory currents. The increased steady state currents were attributable to an increased replenishment rate of the readily releasable pool, providing a presynaptic mechanism for the CK1dT44A phenotype. Finally, during in vivo experiments, CK1dT44A animals showed increased duration and membrane potential variance at ‘cortical up states’, showing that the intrinsic and synaptic changes we observed have excitatory consequences at the local network level. In conclusion excitatory sensory cortical neurons and networks in CK1dT44A animals appear to exhibit decreased adaptation and increased gain that may inform the migraine phenotype.

Spelling Errors and Shouting Capitalization Lead to Additive Penalties to Trustworthiness of Online Health Information: Randomized Experiment With Laypersons (Preprint)

BACKGROUND The written format and literacy competence of screen-based texts can interfere with the perceived trustworthiness of health information in online forums, independent of the semantic content. Unlike in professional content, the format in unmoderated forums can regularly hint at incivility, perceived as deliberate rudeness or casual disregard toward the reader, for example, through spelling errors and unnecessary emphatic capitalization of whole words (online <i>shouting</i>). OBJECTIVE This study aimed to quantify the comparative effects of spelling errors and inappropriate capitalization on ratings of trustworthiness independently of lay insight and to determine whether these changes act synergistically or additively on the ratings. METHODS In web-based experiments, 301 UK-recruited participants rated 36 randomized short stimulus excerpts (in the format of information from an unmoderated health forum about multiple sclerosis) for trustworthiness using a semantic differential slider. A total of 9 control excerpts were compared with matching error-containing excerpts. Each matching error-containing excerpt included 5 instances of misspelling, or 5 instances of inappropriate capitalization (<i>shouting</i>), or a combination of 5 misspelling plus 5 inappropriate capitalization errors. Data were analyzed in a linear mixed effects model. RESULTS The mean trustworthiness ratings of the control excerpts ranged from 32.59 to 62.31 (rating scale 0-100). Compared with the control excerpts, excerpts containing only misspellings were rated as being 8.86 points less trustworthy, those containing inappropriate capitalization were rated as 6.41 points less trustworthy, and those containing the combination of misspelling and capitalization were rated as 14.33 points less trustworthy (<i>P</i>&lt;.001 for all). Misspelling and inappropriate capitalization show an additive effect. CONCLUSIONS Distinct indicators of incivility independently and additively penalize the perceived trustworthiness of online text independently of lay insight, eliciting a medium effect size.

Mental Chronometry in the Pocket? Timing Accuracy of Web Applications on Touchscreen and Keyboard Devices

Web applications can implement procedures for studying the speed of mental processes (mental chronometry). As web applications, these procedures can be administered via web-browsers on most commodity desktops, laptops, smartphones, and tablets. This approach to conducting mental chronometry offers various opportunities, such as increased scale, ease of data collection, and access to specific samples. However, validity and reliability may be threatened due to web applications on commodity devices having less accurate timing than specialized software and hardware. We have examined how accurately web applications time stimuli and register response times on commodity touchscreen and keyboard devices running a range of popular web-browsers. Additionally, we have explored the accuracy of a range of technical innovations for timing stimuli, presenting stimuli, and estimating stimulus duration. Results offer some guidelines as to what kind of methods may be most accurate, and what kind of mental chronometry paradigms may suitably be administered via web applications. In controlled circumstances, as can be realized in a lab setting, very accurate stimulus timing and moderately accurate Reaction Time (RT) measurements could be achieved on both touchscreen and keyboard devices. In uncontrolled circumstances, as may be encountered online, short stimulus durations (of up to 100 ms) may be inaccurate, and RT measurement may be affected by the occurrence of bi-modally distributed RT overestimations.

Lactate in capillary blood after a vertical jump

This study seeks to determine if variations of carbohydrate intake, before the execution of a short stimulus, may have an impact on lactate concentrations in the athlete's body. Conducting a test with a short stimulus (Abalakov’s jump), 12 athletes were evaluated (elite category), in 4 days of interleaved testing: on the first day they were provided with a special diet (low in carbohydrates), the second day they were asked to perform the test, on the third day they changed the diet (high in carbohydrates), and on the fourth day the test was again performed to compare both moments. For the tests, capillary blood should be extracted from the ear lobe, being the athlete at rest, the subject performs a vertical jump without impulse and followed by this, samples are taken after 1, 3, 5 and 7 minutes. The procedure is the same for both tests, as a result it is observed that in both moments, the type of diet low or high in carbohydrates does not influence the concentration of lactate in the blood capillary of the athletes.