Varieties of Confidence Intervals

Different grasping experiences affect mapping effects but not correspondence effects between stimulus size and response location

The so-called spatial-size association of response codes (SSARC) effect denotes that humans respond faster and more accurately with a left response to physically small stimuli and a right response to physically large stimuli, as compared to the opposite mapping. According to an application of the CORE principle to the SSARC effect, the habit to grasp larger/heavier objects with one's dominant hand and smaller/lighter objects with one's non-dominant hand creates spatial-size associations. We investigated if grasping habits play a causal role in the formation of spatial-size associations by testing if the mapping of a preceding object-grasping task affects the size of the SSARC effect in subsequent choice-response tasks with keypress responses. In the object-grasping task, participants were instructed to grasp wooden cubes of variable size either according to a compatible (small-left; large-right) or according to an incompatible (small-right; large-left) mapping. In the choice-response tasks, participants responded with left or right keypresses to the size or color of a small or large stimulus. The results showed that participants with the compatible mapping in the object-grasping task showed a larger SSARC effect in the size discrimination task, but not in the color discrimination task, than participants with the incompatible mapping in the object-grasping task. Results suggest that a short period of practice with different size-location mappings can modulate size-location links used for controlled S-R translation, but not links underlying automatic S-R translation. In general, the results support the hypothesis that grasping habits play a causal role in the formation of spatial-size associations.

Post-error adjustments occur in both reaching and grasping

Post-error slowing (PES), the tendency to slow down a behavioral response after a previous error, has typically been investigated during simple cognitive tasks using response time as a measure of PES magnitude. More recently, PES was investigated during a single reach-to-grasp task to determine where post-error adjustments are employed in a more ecological setting. Kinematic analyses in the previous study detected PES during pre-movement planning and within the grasping component of movement execution. In the current study (N = 22), we increased the cognitive demands of a reach-to-grasp task by adding a choice between target and distractor locations to further explore PES, and other post-error adjustments, under different task conditions. We observed a significant main effect of task condition on overall reaction time (RT); however, it did not significantly impact PES or other post-error adjustments. Nonetheless, the results of this study suggest post-error adjustment is a flexible process that can be observed during pre-movement planning and within the onset and magnitude of the reaching component, as well as in the magnitudes of the grasping component. Considering the sum of the results in the context of existing literature, we conclude that the findings add support to a functional account of error reactivity, such that post-error adjustments are implemented intentionally to improve performance.

The reciprocity of spatial-numerical associations of vocal response codes depends on stimulus mode

Individuals make faster left responses to small/er numbers and faster right responses to large/r numbers than vice versa. This "spatial-numerical association of response codes" (SNARC) effect represents evidence for an overlap between the cognitive representations of number and space. Theories of the SNARC effect differ in whether they predict bidirectional S-R associations between number and space or not. We investigated the reciprocity of S-R priming effects between number and location in three experiments with vocal responses. In Experiments 1 and 2, participants completed a number-location task, with digits as stimuli and location words as responses, and a location-number task, with physical locations as stimuli and number words as responses. In addition, we varied the S-R mapping in each task. Results revealed a strong SNARC effect in the number-location task, but no reciprocal SNARC effect in the location-number task. In Experiment 3, we replaced physical location stimuli with location words and digit stimuli with number words. Results revealed a regular and a reciprocal SNARC effect of similar size. Reciprocal SNARC effects thus seem to emerge with verbal location stimuli and vocal responses, but not with physical location stimuli and vocal responses. The S-R associations underlying the SNARC effect with vocal responses thus appear bidirectional and symmetrical for some combinations of stimulus and response sets, but not for others. This has implications for theoretical accounts of the SNARC effect which need to explain how stimulus mode affects the emergence of reciprocal but not regular SNARC effects.

The visual size is enough to automatically induce the potentiation of grasping behaviours

Seeing objects usually grasped with a power or a precision grip (e.g., an apple vs a cherry) potentiates power- and precision-grip responses, respectively. An embodied account suggests that this effect occurs because object conceptual representations would lie on a motor simulation process. A new account, named the size-coding account, argues that this effect could be rather due to an overlapping of size codes used to represent both manipulable objects and response options. In this article, we investigate whether this potentiation effect could be merely due to a low-level visual feature that favours a size-coding of stimuli: the visual size in which objects are presented. Accordingly, we conducted two experiments in which we presented highly elementary and non-graspable stimuli (i.e., ink spots) either large or small rather than graspable objects. Our results showed that the mere visual size automatically potentiates power- and precision-grip responses that are in line with the size-coding account of the potentiation effect of grasping behaviours. Moreover, these results appeal to improve the methodological control of the size of stimuli especially when researchers try to support the embodied account.

Manipulable objects can potentiate pointing and unusual grasping besides habitual grasping behaviors

People are faster to perform a precision grip when they see a cherry (i.e., a small graspable object) than to perform a power grip, and the reverse holds true when they see an apple (i.e., a large graspable object). This potentiation effect supports that object representations could include motor components that would be simulated when a graspable object is seen. However, the nature of these motor components remains unclear. The embodied account posits that seeing an object only potentiates the most frequent actions associated with it (i.e., usual actions). In contrast, the size-coding account posits that seeing an object potentiates any actions associated to spatial codes compatible with those associated to the objects. We conducted three experiments to disentangle these two alternative accounts. We especially varied the nature of the responses while participants saw either large or small graspable objects. Our results showed a potentiation effect when participants performed the usual grasping actions (Experiment 1: power and precision grip) but also when they performed unusual grasping actions (Experiment 2: grasping between the thumb and little finger) and even when they had to perform non-grasping actions (Experiment 3: pointing actions). By supporting the size-coding account, our contribution underlines the need for a better understanding of the nature of the motor components of object representations and for using a proper control condition (i.e., pointing action) before arguing that the embodied account convincingly explains the potentiation effect of grasping behaviors.

Associations between physical size and space are strongly asymmetrical

The spatial-size association of response codes (SSARC) effect describes the phenomenon that left responses are faster and more accurate to small stimuli whereas right responses are faster and more accurate to large stimuli, as compared to the opposite mapping. The effect indicates associations between the mental representations of physical size and space. Importantly, the theoretical accounts of SSARC effects make different predictions about the reciprocity and/or symmetry of spatial-size associations. To investigate the reciprocity of SSARC effects, we compared compatibility effects in two verbal choice-response tasks: a size-location (typical SSARC) task and a location-size (reciprocal SSARC) task. In the size-location task, participants responded verbally to a small/large stimulus by saying "left"/"right". In the location-size task, participants responded verbally to a left-/right-side stimulus by saying "small"/"large". Participants completed both tasks with a compatible (small-left, large-right; left-small, right-large) and an incompatible (small-right, large-left; left-large, right-small) mapping. A regular SSARC effect emerged in the size-location task. However, no reciprocal SSARC effect emerged in the location-size task if outliers were excluded. If outliers were not excluded, small reciprocal SSARC effects occurred. Associations underlying the SSARC effect are thus strongly asymmetrical: Physical (stimulus) size can prime spatial responses much more strongly than spatial (stimulus) position can prime size-related responses. The finding of asymmetrical associations between size and space is in line with some theoretical accounts of the SSARC effect but at odds with others.

Spatial-numerical associations of manual response codes are strongly asymmetrical

The spatial-numerical association of response codes (SNARC) effect denotes the observation that humans respond faster and more accurately with a left-side response to smaller numbers and a right-side response to larger numbers, as compared to the opposite mapping. Existing accounts, such as the mental number line hypothesis or the polarity correspondence principle, differ in whether they assume symmetrical associations between numerical and spatial stimulus and response codes or not. In two experiments, we investigated the reciprocity of the SNARC effect in manual choice-response tasks with two conditions. In the number-location task, participants pressed a left or right key to a number stimulus (dots in Experiment 1, digits in Experiment 2). In the location-number task, participants made one or two consecutive keypresses with one hand to a left- or right-side stimulus. Both tasks were performed with a compatible (one-left, two-right; left-one, right-two) and an incompatible (one-right, two-left; left-two, right-one) mapping. In both experiments, results showed a strong compatibility effect in the number-location task, reflecting the typical SNARC effect. In contrast, in both experiments, there was no mapping effect in the location-number task when outliers were excluded. However, when outliers were not excluded, small reciprocal SNARC effects occurred in Experiment 2. Together, the findings suggest that priming of spatial responses by numerical stimuli is much stronger than priming of numerical responses by spatial stimuli. The results are consistent with some accounts of the SNARC effect (e.g., the mental number line hypothesis), but not with others (e.g., the polarity correspondence principle).

Tradeoffs of estimating reaction time with absolute and relative thresholds

Measuring the duration of cognitive processing with reaction time is fundamental to several subfields of psychology. Many methods exist for estimating movement initiation when measuring reaction time, but there is an incomplete understanding of their relative performance. The purpose of the present study was to identify and compare the tradeoffs of 19 estimates of movement initiation across two experiments. We focused our investigation on estimating movement initiation on each trial with filtered kinematic and kinetic data. Nine of the estimates involved absolute thresholds (e.g., acceleration 1000 back to 200 mm/s2, micro push-button switch), and the remaining ten estimates used relative thresholds (e.g., force extrapolation, 5% of maximum velocity). The criteria were the duration of reaction time, immunity to the movement amplitude, responsiveness to visual feedback during movement execution, reliability, and the number of manually corrected trials (efficacy). The three best overall estimates, in descending order, were yank extrapolation, force extrapolation, and acceleration 1000 to 200 mm/s2. The sensitive micro push-button switch, which was the simplest estimate, had a decent overall score, but it was a late estimate of movement initiation. The relative thresholds based on kinematics had the six worst overall scores. An issue with the relative kinematic thresholds was that they were biased by the movement amplitude. In summary, we recommend measuring reaction time on each trial with one of the three best overall estimates of movement initiation. Future research should continue to refine existing estimates while also exploring new ones.

Analysis of proportions using arcsine transform with any experimental design

Introduction

Exact tests on proportions exist for single-group and two-group designs, but no general test on proportions exists that is appropriate for any experimental design involving more than two groups, repeated measures, and/or factorial designs.

Method

Herein, we extend the analysis of proportions using arcsine transform to any sort of design. The resulting framework, which we have called Analysis of Proportions Using Arcsine Transform (ANOPA), is completely analogous to the analysis of variance for means of continuous data, allowing the examination of interactions, main and simple effects, post-hoc tests, orthogonal contrasts, et cetera.

Result

We illustrate the method with a few examples (single-factor design, two-factor design, within-subject design, and mixed design) and explore type I error rates with Monte Carlo simulations. We also examine power computation and confidence intervals for proportions.

Discussion

ANOPA is a complete series of analyses for proportions, applicable to any design.

Recommendations and publication guidelines for studies using frequency domain and time-frequency domain analyses of neural time series

Since its beginnings in the early 20th century, the psychophysiological study of human brain function has included research into the spectral properties of electrical and magnetic brain signals. Now, dramatic advances in digital signal processing, biophysics, and computer science have enabled increasingly sophisticated methodology for neural time series analysis. Innovations in hardware and recording techniques have further expanded the range of tools available to researchers interested in measuring, quantifying, modeling, and altering the spectral properties of neural time series. These tools are increasingly used in the field, by a growing number of researchers who vary in their training, background, and research interests. Implementation and reporting standards also vary greatly in the published literature, causing challenges for authors, readers, reviewers, and editors alike. The present report addresses this issue by providing recommendations for the use of these methods, with a focus on foundational aspects of frequency domain and time-frequency analyses. It also provides publication guidelines, which aim to (1) foster replication and scientific rigor, (2) assist new researchers who wish to enter the field of brain oscillations, and (3) facilitate communication among authors, reviewers, and editors.

Examining the Mechanisms of Internal and External Focus of Attention With Donders' Subtractive Method

The goal of the current study was to measure the processing demands on the stages of information processing with internal and external foci of attention. Participants completed simple and two-choice reaction time tasks with internal and external foci of attention. Donders' subtraction method was used to isolate the cumulative duration of stages unique to simple and choice reaction time tasks. Mean reaction time was comparable with internal and external foci of attention in simple and two-choice reaction time tasks. These results suggest that processing demands were comparable with internal and external foci of attention. We hypothesize that there was not a processing advantage for an external focus in simple reaction time because the required movements had low movement complexity.

The effects of eccentric exercise-induced fatigue on position sense during goal-directed movement

We investigated the impairment of position sense associated with muscle fatigue. In Exp. 1, participants performed learned eccentric extension (22 °/s) movements of the elbow as the arm was pulled through the horizontal plane without vision of the arm. They opened their closed right hand when they judged it to be passing through a target. Dynamic position sense was assessed via accuracy of limb position to the target at time of hand opening. Eccentric movements were performed against a flexion load (10% of flexion MVC). We investigated performance under conditions with and without biceps vibration, as well as before and after eccentric exercise. In Exp. 2, a motor was used to extend the participant's limb passively. We compared conditions with and without vibration of the lengthening but passive biceps, before and after exercise. In Exp. 1, vibration of the active biceps resulted in participants opening their hand earlier ( [95% CI] -5.52° [-7.40, -3.63]) compared to without vibration. Exercise reduced flexion MVCs by ~44%, and participants undershot the target more (-5.51° [-9.31, -1.70]) in the post-exercise block during control trials. Exercise did not influence the persistence of the vibratory illusion. In Exp. 2, vibration resulted in greater undershooting (-2.99° [-3.99, -1.98]) compared to without vibration, before and after exercise. Although exercise reduced MVCs by ~50%, the passive task showed no effects of exercise. We suggest that the CNS continues to rely on muscle spindles for limb position sense, even when they reside in a muscle exposed to fatiguing eccentric contractions.

Potential inflammatory biomarkers for tinnitus in platelets and leukocytes: a critical scoping review and meta-analysis

OBJECTIVE

To explore the association between platelets or leukocytes and tinnitus.

DESIGN

A meta-analysis and scoping review examining the association between tinnitus and platelets and leukocytes. All 11 studies included were critically appraised using the Joanna Briggs Institute (JBI) checklist (2017a). A random effects model was used to pool the results of the studies examining mean platelet volume (MPV) and tinnitus.

STUDY SAMPLE

1935 studies were identified in the initial search, 11 of which were included in the scoping review. 6 of the 11 studies had their MPV values pooled in the meta-analysis.

RESULTS

Pooled results of 818 subjects from 6 studies indicated that MPV was significantly higher in those with tinnitus compared to a comparison group without tinnitus. The overall mean difference was 0.43 fL with a 95% confidence interval (CI) from 0.31 to 0.55 and a p value of < 0.0001 which was statistically significant. MPV is the only haematological parameter which is reliably associated with tinnitus.

CONCLUSIONS

MPV could be a useful biomarker for tinnitus. Further studies should aim to standardise methodology with more rigorous exclusion criteria to reproduce and define this association. NLR, PLR, WBC count, RDW and PDW do not show a reliable association with tinnitus.

The acute effects of periodic and noisy tendon vibration on wrist muscle stretch responses

Mechanical muscle tendon vibration activates multiple sensory receptors in the muscle and tendon. In particular, tendon vibration tends to activate the Ia afferents the strongest, but also will activate group II and Ib afferents. This activation can cause three main effects in the central nervous system: proprioceptive illusions, tonic vibration reflexes, and suppression of the stretch response. Noisy tendon vibration has been used to assess the frequency characteristics of proprioceptive reflexes and, interestingly there appeared to be no evidence for proprioceptive illusions or tonic vibration reflexes during standing [9]. However, it remains unknown if noisy vibration induces a suppression of the muscle stretch response. Therefore, the purpose of this study was to investigate the effects of noisy and periodic tendon vibration on the stretch response in the flexor carpi radialis muscle (FCR). We examined FCR stretch responses with and without periodic (20 and 100 Hz) and noisy (∼10-100 Hz) tendon vibration. We additionally had participants perform the task under the instruction set to either not respond to the perturbation or to respond as fast as possible. The key finding from this study was that both periodic and noisy vibration resulted in a reduced stretch response amplitude. Additionally, it was found that a participant's intent to respond did not modulate the amount of suppression observed. The findings from this study provide a more detailed understanding of the effects of tendon vibration on the muscle stretch response.

Is perfectionism a killer of creative thinking? A test of the model of excellencism and perfectionism

The standards that a person pursue in life can be set in a rigid or flexible way. The recent literature has emphasized a distinction between high and realistic standards of excellence, from high and unrealistic standards of perfection. In two studies, we investigated the role of striving towards excellence (i.e., excellencism) and striving towards perfection (i.e., perfectionism) in relation to divergent thinking, associative thinking, and openness to experience, general self-efficacy, and creative self-beliefs. In Study 1, 279 university students completed three divergent thinking items, which called for creative uses of two common objects and to name original things which make noise. A measure of openness to experience was included. Results from multiple regression indicated that participants pursuing excellence tended to generate more answers and more original ones compared with those pursuing perfection. Openness to experience was positively associated to excellencism and negatively associated to perfectionism. In Study 2 (n = 401 university students), we replicated these findings and extended them to associative tasks requiring participants to generate chains of unrelated words. Additional individual differences measures included general self-efficacy, creative self-efficacy, and creative personal identity. The results suggested that excellencism was associated with better performance on divergent thinking and associative tasks, compared with perfectionism. Excellencism was positively associated with all four personality variables, whereas perfectionism was significantly and negatively associated with openness to experience only. Implications for the distinction between perfectionism and excellencism with respect to creative indicators are discussed. In addition, the paradoxical finding that perfection strivers had high creative self-efficacy and creative personal identity but lower openness to experience and poorer performance on objective indicators of creative abilities is discussed.

Anticipating the magnitude of response outcomes can induce a potentiation effect for manipulable objects

Merely seeing large objects (e.g., apples) potentiates power grip whereas seeing small objects (e.g., strawberries) potentiates precision grip. According to the embodied cognition account, this potentiation effect reflects automatic access to object representation, including the grip usually associated with the object. Alternatively, this effect might be due to an overlap between magnitude codes used to code manipulable objects and magnitude codes used to code responses outcomes. In Experiment 1, participants saw objects usually grasped with a power or precision grip and had to press keys either with their forefinger or with their palm, each response generating a low or high tone (i.e., a large vs. small perceptual outcome, respectively). Tones were automatically delivered by headphones after the responses have been made in line with the ideomotor theories according to which voluntary actions are carried out due to the anticipation of their outcomes. Consistent with the magnitude-coding hypothesis, response times were shorter when the object and the anticipated response outcome were of the same magnitude than when they were not. These results were also consistent with a between-experiment analysis. In Experiments 2 and 3, we investigated to what extent removing or switching the outcomes during the experiment influence the potentiation effect. Our results support that the potentiation effect of grasping behaviours could be due to the compatibility between magnitude codes rather than to the involvement of motor representations. Our results also suggest a spontaneous use of the magnitude of response outcomes to code responses, as well as the flexibility of this coding processes when responses outcomes are altered.

The effect of early list manipulations on the DRM illusion

The Deese-Roediger-McDermott (DRM) paradigm is widely used to study false memory in the laboratory. It tests memory for lists of semantically related words (correct list item memories) and their non-presented associates (false lure memories). Evidence suggests that early items in DRM lists could make an especially significant contribution to false memories of lures, as they may critically influence the underlying associative activation and/or gist extraction processes. The present study tested this suggestion by using two manipulations that were intended to affect processing of early DRM list items. The first was interpolation of a semantically unrelated distractor item among the list items (Experiments 1 and 2). The second was arranging for these items to be either the strongest or weakest associates of the lure (Experiment 2). In Experiment 1, a distractor item reduced both list item and lure recall when presented early in a DRM list, but selectively disrupted list item recall when presented late in the list. In Experiment 2, arranging for the early list items to be the weakest associates of the lure reduced false recall of the lure but had no effect on list item recall. The findings are discussed with respect to theories that explain false memory in the DRM protocol, including fuzzy trace theory (FTT) and activation-monitoring theory (AMT). They are also discussed with respect to general theories of memory and the potential role of category/context information in generating false memories.

Feasibility and Acceptability of a Digital Intervention to Support Shared Decision-making in Children's and Young People's Mental Health: Mixed Methods Pilot Randomized Controlled Trial

Background

Interventions to involve parents in decisions regarding children’s and young people’s mental health are associated with positive outcomes. However, appropriately planning effectiveness studies is critical to ensure that meaningful evidence is collected. It is important to conduct pilot studies to evaluate the feasibility and acceptability of the intervention itself and the feasibility of the protocol to test effectiveness.

Objective

This paper reports the findings from a feasibility and acceptability study of Power Up for Parents, an intervention to promote shared decision-making (SDM) and support parents and caregivers making decisions regarding children’s and young people’s mental health.

Methods

A mixed method study design was adopted. In stage 1, health care professionals and parents provided feedback on acceptability, usefulness, and suggestions for further development. Stage 2 was a multicenter, 3-arm, individual, and cluster randomized controlled pilot feasibility trial with parents accessing services related to children’s and young people’s mental health. Outcome measures collected data on demographics, participation rates, SDM, satisfaction, and parents’ anxiety. Qualitative data were analyzed using thematic analysis. Google Analytics estimates were used to report engagement with the prototype. Outcomes from both stages were tested against a published set of criteria for proceeding to a randomized controlled trial.

Results

Despite evidence suggesting the acceptability of Power Up for Parents, the findings suggest that recruitment modifications are needed to enhance the feasibility of collecting follow-up data before scaling up to a fully powered randomized controlled trial. On the basis of the Go or No-Go criteria, only 50% (6/12) of the sites successfully recruited participants, and only 38% (16/42) of parents completed follow-up measures. Nonetheless, health care practitioners and parents generally accessed and used the intervention. Themes describing appearance and functionality, perceived need and general helpfulness, accessibility and appropriateness, and a wish list for improvement emerged, providing valuable information to inform future development and refinement of the intervention.

Conclusions

Owing to the high attrition observed in the trial, proceeding directly to a full randomized controlled trial may not be feasible with this recruitment strategy. Nonetheless, with some minor adjustments and upgrades to the intervention, this pilot study provides a platform for future evaluations of Power Up for Parents.

Trial Registration

International Standard Randomized Controlled Trial Number (ISRCTN) 39238984; http://www.isrctn.com/ISRCTN39238984.

International Registered Report Identifier (IRRID)

RR2-10.2196/14571

Scene memory and spatial inhibition in visual search : A neural dynamic process model and new experimental evidence

Any object-oriented action requires that the object be first brought into the attentional foreground, often through visual search. Outside the laboratory, this would always take place in the presence of a scene representation acquired from ongoing visual exploration. The interaction of scene memory with visual search is still not completely understood. Feature integration theory (FIT) has shaped both research on visual search, emphasizing the scaling of search times with set size when searches entail feature conjunctions, and research on visual working memory through the change detection paradigm. Despite its neural motivation, there is no consistently neural process account of FIT in both its dimensions. We propose such an account that integrates (1) visual exploration and the building of scene memory, (2) the attentional detection of visual transients and the extraction of search cues, and (3) visual search itself. The model uses dynamic field theory in which networks of neural dynamic populations supporting stable activation states are coupled to generate sequences of processing steps. The neural architecture accounts for basic findings in visual search and proposes a concrete mechanism for the integration of working memory into the search process. In a behavioral experiment, we address the long-standing question of whether both the overall speed and the efficiency of visual search can be improved by scene memory. We find both effects and provide model fits of the behavioral results. In a second experiment, we show that the increase in efficiency is fragile, and trace that fragility to the resetting of spatial working memory.

The effect of good continuation on the contact order judgment of causal events

When a ball on a pool table moves to hit another ball, people feel the causal impression between the two balls: The first ball causes the second ball's motion, which is known as the launching effect. Previous research has shown that the causal impression becomes stronger when the two balls have a similar direction of movement. Here, we tested whether this good continuation influenced perception of the contact time between the causal object and the effect object. A variant of Michotte's visual collision event was used as a stimulus, consisting of two competing cause objects and one effect object. In the display, the two cause objects on the left begin to move and contact the effect object in the center, causing it to move. In Experiments 1 to 4, the contact order of the cause objects and the motion direction of the effect object were systematically varied. The observers were asked to judge which of the cause objects had a more causal relationship and made contact first. The results showed that the observers were more likely to judge a cause object as having a more causal relationship with the effect object when there was good continuation, and they often erroneously judged the cause object as having first contacted the effect object; this effect was maintained with up to approximately 100 ms of delay after contact. These results suggest that good continuation is an important cue that postdictively determines perception of the contact time of a cause object in a short time window.