Variable, sometimes absent, but never negative: Applying multilevel models of variability to the backward crosstalk effect to find theoretical constraints.

When performing two tasks at the same time, the congruency of the second task's features influences performance in the first task. This is called the backward crosstalk effect (BCE), a phenomenon that influences both theories of binding and of dual-task capacity limitations. The question of whether the BCE is found in all participants at all times is relevant for understanding the basis of the effect. For example, if the BCE is based on strategic choices, it can be variable, but if it is automatic and involuntary, it should never vary in whether it is present or not. Variability in observed BCE sizes was already documented and discussed when the group average effect was first reported (Hommel, 1998). Yet the theories discussed at the time did not motivate a more direct analysis of this variability, nor did the readily available statistical tools permit it. Some statistical approaches recently applied in cognitive psychology allow such a variability-focused analysis and some more recent theoretical debates would benefit from this as well. We assessed the variability of the BCE as well as a BCE-like free-choice congruency effect by applying a Bayesian multilevel modeling approach to the data from a dual-tasking experiment. Trials consisted of a two- and a four-response task. We manipulated which task was presented first and whether the response to the four-choice task was free or forced choice. RT data were best predicted by a model in which the BCE is zero in part of the population and drawn from a normal distribution truncated at zero (and thus always positive) in the rest of the population. Choice congruency bias data were best predicted by a model assuming this effect to be drawn from a normal distribution truncated at zero (but, in contrast to the RT data, without the subset of the population where it is zero). The BCE is not an inflexible and universal phenomenon that is directly linked to an inherent structural trait of human cognition. We discuss theoretical constraints implied by these results with a focus on what we can infer about the traits of the factors that influence BCE size. We suggest that future research might add further major constraints by using multi-session experiments to distinguish between-person and within-person variability. Our results show that the BCE is variable. The next step is understanding along which axes it is variable and why it varies.

Perceptions of critically ill individuals with acute and chronic spinal cord injury requiring a tracheostomy tube.

STUDY DESIGN: Observational study. OBJECTIVES: To evaluate the perceptions of patients requiring a tracheostomy tube and to identify possible different perceptions in critically ill patients with tracheostomy tubes who have acute (ASCI) or chronic spinal cord injuries (CSCI). SETTING: Medical and surgical intensive care units (ICU) and intermediate care unit of the BG University Hospital Bergmannsheil Bochum, Germany. METHODS: Patients who met the inclusion criteria completed a 25-item questionnaire on two consecutive days regarding their experiences and perceptions in breathing, coughing, pain, speaking, swallowing, and comfort of the tracheostomy tube. RESULTS: A total of 51 persons with ASCI (n = 31) and CSCI (n = 20) were included with a mean age of 53 years. Individuals with ASCI reported significantly more frequent pain and swallowing problems as compared to individuals with CSCI (p ≤ 0.014) at initial assessment. There were no differences between ASCI and CSCI reported with respect to speaking and overall comfort. CONCLUSIONS: It is necessary to regularly assess the perceptions of critically ill patients with tracheostomy tubes with ASCI or CSCI in the daily ICU care routine. We were able to assess these perceptions in different categories. For the future, evaluating the perception of individuals with SCI and a tracheostomy should be implemented to their daily routine care. TRIAL REGISTRATION: DRKS00022073.

Behavioral pain scale may not be reliable in awake non-verbal intensive care patients: a case control study.

BACKGROUND: The evaluation of pain in patients, unable of oral communication, often relies on behavioral assessment. However, some critically ill patients, while non-verbal, are awake and have some potential for self-reporting. The objective was to compare the results of a behavioral pain assessment with self-reporting in awake, non-verbal, critically ill patients unable to use low-tech augmentative and alternative communication tools. METHODS: Prospective cohort study of intubated or tracheotomized adult, ventilated patients with a RASS (Richmond Agitation Sedation Scale) of -1 to + 1 and inadequate non-verbal communication skills in a surgical intensive care unit of a tertiary care university hospital. For pain assessment, the Behavioral Pain Scale (BPS) was used. Self-reporting of pain was achieved by using an eye tracking device to evaluate the Numeric Rating Scale (NRS) and the pain/discomfort item of the EuroQol EQ-5D-5 L (EQ-Pain). All measurements were taken at rest. RESULTS: Data was collected from 75 patients. Neither the NRS nor the EQ-Pain (r < .15) correlated with the BPS. However, NRS and EQ-Pain were significantly correlated (r = .78, p = < 0.001), indicating the reliability of the self-reporting by these patients. Neither the duration of intubation/tracheostomy, nor cause for ICU treatment, nor BPS subcategories had an influence on these results. CONCLUSIONS: Behavioral pain assessment tools in non-verbal patients who are awake and not in delirium appear unreliable in estimating pain during rest. Before a behavioral assessment tool such as the BPS is used, the application of high-tech AACs should be strongly considered. TRIAL REGISTRATION: German Clinical Trials Register, Registration number: DRKS00021233. Registered 23 April 2020 - Retrospectively registered, https://drks.de/search/en/trial/DRKS00021233 .

Can frequent long stimulus onset ansynchronies (SOAs) foster the representation of two separated task-sets in dual-tasking?

Recent findings suggest that in dual-tasking the elements of the two tasks are associated across tasks and are stored in a conjoint memory episode, meaning that the tasks are not represented as isolated task-sets. In the current study, we tested whether frequent long stimulus onset ansynchronies (SOAs) can foster the representation of two separated task-sets thereby reducing or even hindering participants to generate conjoint memory episodes-compared to an integrated task-set representation induced by frequent short SOAs. Alternatively, it is conceivable that conjoint memory episodes are an inevitable consequence of presenting two tasks within a single trial. In two dual-task experiments, we tested between consecutive trials whether repeating the stimulus-response bindings of both tasks would lead to faster responses than repeating only one of the two tasks' stimulus-response bindings. The dual-task consisted of a visual-manual search task (VST) and an auditory-manual discrimination task (ADT). Overall, the results suggest that, after processing two tasks within a single trial, generating a conjoint memory episode seems to be a default process, regardless of SOA frequency. However, the respective SOA frequency affected the participants' strategy to group the processing of the two tasks or not, thereby modulating the impact of the reactivated memory episode on task performance.

Across-task binding: The development of a representation in learning a continuous movement sequence.

Across-task binding is defined as the stimulus/response of one task being linked to the response of another task. The purpose of the present experiment was to determine across-task binding in a continuous movement sequence task with an auditory task of high and low pitch tones and the development of a movement sequence representation. According to the two systems theory of sequence learning, we expected that the developed representation in the across-task binding context relies on the multi-dimensional system rather than on the unidimensional system which is restricted to a set of modules where each module processed information along one task/dimension. An inter-manual transfer design was used to disentangle the sequence representations. The mirror transfer test required the same pattern of muscle activation and joint angles (motor coordinates) in the contralateral limb as experienced during the acquisition phase, while in the non-mirror transfer test, the visual-spatial locations (spatial coordinates) of the target waveform were reinstated. The main finding was that consistently combining visual-spatial positions in a sequence and auditory dimensions such as the tone pitch does not rely on a multidimensional system as predicted by the two-systems theory.

The Power Is in the Word-Do Laypeople Interpret Descriptors of Dog Emotional States Correctly?

A basic understanding of dog behaviour and emotion is relevant not only for professionals, such as veterinary personnel or dog trainers, but also for dog owners and for people with little contact with dogs. Information about dog behaviour and emotions is mostly conveyed verbally. This study explores whether definitions of dog behaviour and emotion are understood in such a way that they can be allocated to a descriptor (i.e., a label such as "fearful"), even by people with low background knowledge. If people can match descriptors to definitions, this suggests that the definitions are distinct enough and elicit mental representations of behaviour that can fit the label. Good agreement on the definitions is a prerequisite for the validity of the descriptors used; however, no study to date has tested this. A sample of 236 adults was asked to match descriptors of Qualitative Behaviour Assessment (QBA) for veterinary and shelter situations to their correct definitions, e.g., the descriptor "fearful" to its definition "dog may try to flee, hide or freeze; ears back". Matching was substantially above chance; nonetheless, the mean proportion of correct responses was only 50% (SD ± 16.6%) for the veterinary QBA set and 33% (SD ± 14.3%) for the shelter QBA set. Performance in the matching task was positively correlated with measures of experience with dogs. Taken together, the results suggest that descriptor-definition pairs used to describe dog behaviour need to be clearly defined to avoid misinterpretations when teaching laypeople how to interpret canine behaviour.

Element-level features in conjoint episodes in dual-tasking.

The usual way of thinking about dual-tasking is that the participants represent the two tasks separately. However, several findings suggest that the participants rather seem to integrate the elements of both tasks into a conjoint episode. In three experiments, we aimed at further testing this task integration account in dual-tasking. To this end, we investigated how the processing of the previous Trial n-1 shapes the processing of the current Trial n. We observed performance benefits when the stimulus-response mappings of both tasks repeat in consecutive trials (full repetition: FR) as compared to when only one such mapping repeats (partial repetition: PR). In particular, our experiments focused on the question which elements of the two tasks in dual-tasking might be bound together. For this purpose, in Experiments 1 and 2, all participants performed a dual-task consisting of a visual-manual search task (VST) and an auditory-manual discrimination task (ADT). In the VST the stimulus-response mappings were variable, so that none of the stimuli of this task systematically predicted a certain response. In Experiment 1, the stimuli and responses of the VST were either both repeated or both changed in consecutive trials. In Experiment 2, we removed the stimulus repetitions in the VST and only the responses repeated across trials. In Experiment 3, we changed the ADT into a visual-auditory matching task (VAMT) with variable stimulus-response mappings, so that in both tasks only the responses repeated across trials. In Experiments 1 and 2, we observed better performance for FR than for PR, while this difference disappeared in Experiment 3. Together, the results suggest that the stimulus of one task is sufficient to retrieve the entire episode from the previous trial.

Lollipops Help Align Visual and Statistical Fit Estimates in Scatterplots With Nonlinear Models.

Scatterplots overlayed with a nonlinear model enable visual estimation of model-data fit. Although statistical fit is calculated using vertical distances, viewers' subjective fit is often based on shortest distances. Our results suggest that adding vertical lines ("lollipops") supports more accurate fit estimation in the steep area of model curves (https://osf.io/fybx5/).

First experiences of communication with mechanically ventilated patients in the intensive care unit using eye-tracking technology.

INTRODUCTION: Eye-tracking (ET) may be a novel tool for communication with intubated and mechanically ventilated critically ill patients. We hypothesized that ET could be learned fast and be used successfully by intensive care unit (ICU) and intermediate care (IMC) patients with artificial airways for communication. METHODS: Including all patients with mechanical ventilation via oral intubation or tracheostomy, who were at least 18 years of age with a score of -1 to +1 points on the Richmond agitation-sedation scale and a history of ventilation for more than 48 h. A commercially available ET was used. The investigations were performed by a physician with the support of a psychologist following a standardized study protocol. RESULTS: During a 4-week period a total of 11 patients completed all of the five steps of our study protocol. The time to complete our study protocol was 64 ± 23.8 min (range 43-125 min) with a mean of 1.5 ± 0.9 sessions (range 1-4 sessions). Seven patients (63.6 %) could run through all of the five steps within their first session. All patients (100%) preferred the gaze fixation technique to control the ET to the wink control. CONCLUSION: Mechanically ventilated ICU and IMC patients are able to use ET in a very short time for communication to indicate their basic needs, answer rating scales and pain scores as well as questionnaires about quality of life and self-esteem.Implications for rehabilitationCOMFORT - The novel communication device improves the patients' ability to communicate with the attending physicians, physiotherapists and nurses in order to provide a tailored rehabilitation approach.COMPLIANCE - The use of the eye-tracking technology enables the patients to communicate special needs and fears during the course of the rehabilitation.COMPLICATIONS - The eye-tracking technology enables the attending rehabilitation team to earlier detect complications (e.g. pain, depression) during the course of the rehabilitation.

Development of the Tracheostomy Well-Being Score in critically ill patients.

PURPOSE: Little attention has been given to understanding the experiences and perceptions of tracheostomized patients. This study aimed to measure the impact of tracheostomy on well-being in critically ill patients with the development of the Tracheostomy Well-Being Score (TWBS). METHODS: This is a prospective, monocentric, observational study including critically ill patients with a tracheostomy without delirium. A 25-item questionnaire with items from six categories (respiration, coughing, pain, speaking, swallowing, and comfort) was used to select the 12 best items (two per category) to form the TWBS score after testing on two consecutive days. Item selection secured (1) that there were no skewed response distributions, (2) high stability from day 1 to day 2, and (3) high prototypicality for the category in terms of item-total correlation. RESULTS: A total of 63 patients with a mean age of 56 years were included. The 12 items of the TWBS were characterized by a high retest reliability (τ = 0.67-0.93) and acceptable internal consistency. The overlap with the clinician rating was low, suggesting that acquiring self-report data is strongly warranted. CONCLUSION: With the TWBS, an instrument is available for the assessment of the subjective effects a tracheostomy has on in critically ill patients. The score potentially offers a chance to increase well-being of these patients. Additionally, this score could also increase their quality of life by improving tracheostomy and weaning management. CLINICAL TRIAL REGISTRATION: German Clinical Trials Register Identifier DRKS00022073 (2020/06/02).

Color-Encoded Links Improve Homophily Perception in Node-Link Diagrams.

Node-link diagrams enable visual assessment of homophily when viewers can identify and evaluate the relative number of intra-cluster and inter-cluster links. Our online experiment shows that a new design with link type encoded edge color leads to more accurate perception of homophily than a design with same-color edges.

Sedation, sleep-promotion, and non-verbal and verbal communication techniques in critically ill intubated or tracheostomized patients: results of a survey.

BACKGROUND: The aim of this survey was to describe, on a patient basis, the current practice of sedation, pharmacologic and non-pharmacologic measures to promote sleep and facilitation of communication in critically ill patients oro-tracheally intubated or tracheostomized. METHODS: Cross-sectional online-survey evaluating sedation, sleep management and communication in oro-tracheally intubated (IP) or tracheostomized (TP) patients in intensive care units on a single point. RESULTS: Eighty-one intensive care units including 447 patients (IP: n = 320, TP: n = 127) participated. A score of ≤ -2 on the Richmond Agitation Sedation Scale (RASS) was prevalent in 58.2% (IP 70.7% vs. TP 26.8%). RASS -1/0 was present in 32.2% (IP 25.9% vs. TP 55.1%) of subjects. Propofol and alpha-2-agonist were the predominant sedatives used while benzodiazepines were applied in only 12.1% of patients. For sleep management, ear plugs and sleeping masks were rarely used (< 7%). In half of the participating intensive care units a technique for phonation was used in the tracheostomized patients. CONCLUSIONS: The overall rate of moderate and deep sedation appears high, particularly in oro-tracheally intubated patients. There is no uniform sleep management and ear plugs and sleeping masks are only rarely applied. The application of phonation techniques in tracheostomized patients during assisted breathing is low. More efforts should be directed towards improved guideline implementation. The enhancement of sleep promotion and communication techniques in non-verbal critically ill patients may be a focus of future guideline development.

Using position rather than color at the traffic light - Covariation learning-based deviation from instructions in attention deficit/hyperactivity disorder.

Based on instructions people can form task representations that shield relevant from seemingly irrelevant information. It has been documented that instructions can tie people to a particular way of performing a task despite that in principle a more efficient way could be learned and used. Since task shielding can lead to persistence of inefficient variants of task performance, it is relevant to test whether individuals with attention deficit/hyperactivity disorder (ADHD) - characterized by less task shielding - are more likely and quicker to escape a suboptimal instructed variant of performing a task. The paradigm used in this online study builds on the observation that in many environments different covarying features could be used to determine the appropriate response. For instance, as they approach a traffic light, drivers and pedestrians monitor the color (instructed stimulus feature) and/or the position of the signal (covarying stimulus feature, more efficient in case of reduced color sight). Similarly, we instructed participants to respond to the color of a stimulus without mentioning that color covaried with the position of the stimulus. In order to assess whether with practice participants would use the non-instructed feature position to an increasing extent, we compared reaction times and error rates for standard trials to trials in which color was either ambiguous or did not match the usual covariation. Results showed that the covariation learning task can be administered online to adult participants with and without ADHD. Performance differences suggested that with practice ADHD participants (n = 43 out of a total N = 245) might increase attention to non-instructed stimulus features. Yet, they used the non-instructed covarying stimulus feature to a similar extent as other participants. Together the results suggest that participants with ADHD do not lag behind in abandoning instructed task processing in favor of a learned alternative strategy.

Given the option, people avoid incongruent responses in a dual-tasking situation.

While past work on how people can optimize dual-tasking has focused on strategic timing (i.e., when to select responses), little is known about the extent to which people can optimize dual-tasking by taking care of which responses they select. Here we test whether spatial (in)congruency influences response selection in free-choice trials. In two experiments, we combined two visual-manual tasks with spatial stimulus- and response characteristics: Participants responded to the stimulus words "left" and "right" in a forced choice task and responded "up", "down", "left" or "right" with an arrow-key to either a free choice prompt or an X located at the respective position. In Experiment 1, participants reduced the proportion of incongruent pairs of responses (i.e., left in one and right in the other task). In Experiment 2, we found that such flexibility in response selection also holds in more constrained environments: Within runs of four trials the free-choice options were continuously reduced based on the responses already given. The combined results of Experiments 1 and 2 suggest that response selection in free choice trials is driven by performance optimization beyond response conflict.

Spontaneous discovery of novel task solutions in children.

Children often perform worse than adults on tasks that require focused attention. While this is commonly regarded as a sign of incomplete cognitive development, a broader attentional focus could also endow children with the ability to find novel solutions to a given task. To test this idea, we investigated children's ability to discover and use novel aspects of the environment that allowed them to improve their decision-making strategy. Participants were given a simple choice task in which the possibility of strategy improvement was neither mentioned by instructions nor encouraged by explicit error feedback. Among 47 children (8-10 years of age) who were instructed to perform the choice task across two experiments, 27.5% showed a full strategy change. This closely matched the proportion of adults who had the same insight (28.2% of n = 39). The amount of erroneous choices, working memory capacity and inhibitory control, in contrast, indicated substantial disadvantages of children in task execution and cognitive control. A task difficulty manipulation did not affect the results. The stark contrast between age-differences in different aspects of cognitive performance might offer a unique opportunity for educators in fostering learning in children.

Muscle activity in explicit and implicit sequence learning: Exploring additional measures of learning and certainty via tensor decomposition.

Sequence learning in serial reaction time tasks (SRTTs) is usually inferred through the reaction time measured by a keyboard. However, this chronometric parameter offers no information beyond the time point of the button-press. We therefore examined whether sequence learning can be measured by muscle activations via electromyography (EMG) in a dual-task paradigm. The primary task was a SRTT, in which the stimuli followed a fixed sequence in some blocks, whereas the sequence was random in the control condition. The secondary task stimulus was always random. One group was informed about the fixed sequence, and the other not. We assessed three dependent variables. The chronometric parameter premotor time represents the duration between stimulus onset and the onset of EMG activity, which indicates the start of the response. The other variables describe the response itself considering the EMG activity after response start. The EMG integral was analyzed, and additionally, tensor decomposition was implemented to assess sequence dependent changes in the contribution of the obtained subcomponents. The results show explicit sequence learning in this dual-task setting. Specifically, the informed group show shorter premotor times in fixed than random sequences as well as larger EMG integral and tensor contributions. Further, increased activity seems to represent response certainty, since a decrease is found for both groups in trials following erroneous responses. Interestingly, the sensitivity to sequence and post-error effects varies between the subcomponents. The results indicate that muscle activity can be a useful indicator of response behavior in addition to chronometric parameters.

Learning of across- and within-task contingencies modulates partial-repetition costs in dual-tasking.

Dual-task costs might result from confusions on the task-set level as both tasks are not represented as distinct task-sets, but rather being integrated into a single task-set. This suggests that events in the two tasks are stored and retrieved together as an integrated memory episode. In a series of three experiments, we tested for such integrated task processing and whether it can be modulated by regularities between the stimuli of the two tasks (across-task contingencies) or by sequential regularities within one of the tasks (within-task contingencies). Building on the experimental approach of feature binding in action control, we tested whether the participants in a dual-tasking experiment will show partial-repetition costs: they should be slower when only the stimulus in one of the two tasks is repeated from Trial n - 1 to Trial n than when the stimuli in both tasks repeat. In all three experiments, the participants processed a visual-manual and an auditory-vocal tone-discrimination task which were always presented concurrently. In Experiment 1, we show that retrieval of Trial n - 1 episodes is stable across practice if the stimulus material is drawn randomly. Across-task contingencies (Experiment 2) and sequential regularities within a task (Experiment 3) can compete with n - 1-based retrieval leading to a reduction of partial-repetition costs with practice. Overall the results suggest that participants do not separate the processing of the two tasks, yet, within-task contingencies might reduce integrated task processing.

Investigating time-based expectancy beyond binary timing scenarios: evidence from a paradigm employing three predictive pre-target intervals.

When the duration of a pre-target interval probabilistically predicts the identity of the target, participants typically form time-based expectancies: they respond faster to frequent interval-target combinations than to infrequent ones. Yet, previous research investigating the cognitive time-processing mechanisms underlying time-based expectancy assessed time-based expectancy always in situations with a binary set of intervals (i.e. short vs. long). Here we aim to test whether time-based expectancy transfers to more complex settings with three different predictive time intervals (short, medium, long) in which each predicts one of three different target stimuli with 80% probability. In three experiments we varied how the medium interval was computed (arithmetic mean, geometric mean, or in between both). Our results showed that participants were able to learn the time-event contingencies for the short and the long as well as for the medium interval, and were, thus able to flexibly redirect their target expectancy two times during the course of a trial. The evidence concerning the impact of the manipulation of the medium intervals' absolute duration on time-based expectancy was, however, mixed, as time-based expectancy for the medium interval could only be observed in one of three reported experiments. In sum, the findings of the present study suggest a previously unknown cognitive flexibility underlying time-based expectancy and offer important theoretical implications, challenging future research on the timing mechanisms involved in time-based expectancy.