Implicit visuospatial sequence representations are accessible in both the practice and the transfer hand.

A serial reaction time task was used to test whether the representations of a probabilistic second-order sequence structure are (i) stored in an effector-dependent, effector-independent intrinsic or effector-independent visuospatial code and (ii) are inter-manually accessible. Participants were trained either with the dominant or non-dominant hand. Tests were performed with both hands in the practice sequence, a random sequence, and a mirror sequence. Learning did not differ significantly between left and right-hand practice, suggesting symmetric intermanual transfer from the dominant to the non-dominant hand and vice versa. In the posttest, RTs were shorter for the practice sequence than for the random sequence, and longest for the mirror sequence. Participants were unable to freely generate or recognize the practice sequence, indicating implicit knowledge of the probabilistic sequence structure. Because sequence-specific learning did not differ significantly between hands, we conclude that representations of the probabilistic sequence structure are stored in an effector-independent visuospatial code.

Let's do it: Response times in Mental Paper Folding and its execution.

Action imagery is the ability to mentally simulate the execution of an action without physically performing it. Action imagery is assumed to rely at least partly on similar mechanisms as action execution. Therefore, we expected that imagery and execution durations would be constrained by the number of folds in a Paper Folding Task. Analogously, individual differences in execution durations were expected to be reflected in imagery durations. Twenty-eight participants performed two imagery conditions (computer vs. paper) and one execution condition (paper) where two-dimensional grids of a three-dimensional cube were (mentally) folded to determine whether two selected edges overlapped or not. As expected, imagery performance and execution performance were strongly correlated and decreased with the number of folds. Further, the number of folds influenced imagery durations even more than execution durations. This may be due to the additional cognitive load in imagery that emerges when tracking the folds to follow up with the next ones. The results indicate that Mental Paper Folding predominantly involves dynamic visual representations that are not functionally associated with one's own movements as in action imagery.

Sharing and Receiving Eye-Contact Predicts Mate Choice After a 5-Minute Conversation: Evidence from a Speed-Dating Study.

In popular narratives, the first date with a potential mate often centers on their gaze as embodiment of interest and attraction. However, evidence is still lacking on the role of eye-contact as a potent signal in human social interaction in the context of dating. In addition, behavioral mechanisms of mate selection are not well understood. In the present study, we therefore examined mutual eye-contact and its influence on mate choice by applying dual mobile eye-tracking during naturalistic speed-dates. A total of 30 male and 30 female subjects attended four speed-dates each (N = 240). Subjects were more likely to choose those dating partners with whom they shared more eye-contact with. In addition, perceived attractiveness played an important role for mate choice. Interestingly, receiving but not giving eye-contact also predicted individual mate choice. Eye-contact thus acts as an important signal of romantic attraction when encountering a dating partner.

Swift attenuation of irrelevant features through feature consistency: Evidence from a capture-probe version of the contingent-capture protocol.

In the present two experiments, we explore the possibility of swift attenuation of capture by irrelevant features in the contingent-capture protocol. Some prior research suggests that feature attenuation might be most efficient for fixed, anticipated irrelevant features and that varying irrelevant features from trial to trial can undermine their successful attenuation. Here, we exploited this dependence of attenuation on feature certainty to test if attenuation contributed to contingent-capture effects in a capture-probe version of the contingent-capture protocol. In line with the swift attenuation of irrelevant features, salient but target-dissimilar singleton cues that were consistently coloured diminished recall of probes at their locations. This was in comparison to inconsistently coloured target-dissimilar singleton cues. Nonetheless, probe-recall was still better at target-dissimilar cue locations than at non-singleton locations in the cueing display, indicating attenuation of task-irrelevant features rather than their complete suppression.

Individual differences in sensory processing sensitivity amplify effects of post-learning activity for better and for worse.

Sensory processing sensitivity (SPS) is a biologically-based trait associated with greater reactivity to both positive and negative environments. Recent studies suggest that the activity following learning can support or hinder memory retention. Here, we employed a within-subject experiment to examine whether and how individual differences in SPS contribute to differences in memory retention. Sixty-four participants encoded and immediately recalled two word lists: one followed by 8-min of eyes-closed, wakeful resting; and the other by a distraction task. After 7 days, participants completed a surprise free recall test for both word lists. If participants wakefully rested after encoding, memory retention increased as a function of higher SPS. However, in the distraction condition, a negative curvilinear relationship indicated that memory retention was especially hindered for highly sensitive individuals. These results suggest that individual differences in SPS are an important factor to consider when examining the effects of environmental conditions on learning and memory.

Task-synchronized eye blink modulation neither requires visual stimulation nor active motor response and is modulated by task predictability.

It has been repeatedly shown that temporal task features are reflected in eye blink dynamics during attention tasks. Eye blinks occur with increased likeliness particularly when demands on external attention allocation are low. Both predictive, top-down and reactive, bottom-up processes were shown to be involved in blink regulation. However, whether temporal stimulus prediction is a generally active component of the attention system or rather specific to the visual domain has not been fully elaborated yet. By monitoring eye blinking of 99 students during an auditory attention task and analyzing particularly the dynamics of eye blink onsets relative to stimuli timings, we show here that prediction does, in principle, not require visual stimulation, and is also not merely a consequence of the involvement of manual responses during the task. We further show that both the inclusion of manual response to stimuli and elevated task predictability enhance the prediction component reflected in eye blink dynamics, whereas for the latter we experimentally manipulate objective task predictability by adjusting the frequency dependence of the power spectral densities of the series of inter-stimulus time intervals. This allows us finally to explain why, for specific choices of experimental conditions, the generally active and present prediction component involved in attention can become difficult to detect in non-visual, auditory tasks. Conversely, this comes with the important implication that, if tasks aim for elaborating particularly temporal prediction, distributing stimuli over time such that inter-stimulus-intervals conform to a sample of Gaussian noise represents a specifically unfavorable choice.

Wakeful resting and listening to music contrast their effects on verbal long-term memory in dependence on word concreteness.

Wakeful resting and listening to music are powerful means to modulate memory. How these activities affect memory when directly compared has not been tested so far. In two experiments, participants encoded and immediately recalled two word lists followed by either 6 min wakefully resting or 6 min listening to music. The results of Experiment 1 show that both post-encoding conditions have a similar effect on memory after 1 day. In Experiment 2, we explored the possibility that less concrete words, i.e. lower in imageability than in Experiment 1, are differently affected by the two post-encoding conditions. The results of Experiment 2 show that, when words are less concrete, more words are retained after 1 day when encoding is followed by wakeful resting rather than listening to music. These findings indicate that the effects of wakeful resting and listening to music on memory consolidation are moderated by the concreteness of the encoded material.

Cardiovascular reactivity during sadness induction predicts inhibitory control performance.

Higher negative affectivity has an association with decreased executive function and cognitive control. Heart rate variability (HRV) serves as an index of cardiac vagal regulation differences in the autonomic nervous system for both cognition and emotion. The current study investigates this association using a classic as well as emotional antisaccade paradigm to study inhibitory control performance. Ninety participants completed affective questionnaires (Beck Depression Inventory-II, and Mood Scale), a 6-minute baseline electrocardiogram, and two different antisaccade tasks. After the baseline, subjects were presented with a video sequence with either neutral, sad, or emotionally arousing content. By subtracting the baseline from the video sequence, we computed HRV reactivity and tested whether the reactivity score could predict inhibitory control performance. We hypothesized that this would be the case in both the sadness and arousal group, but not in the neutral one. Furthermore, we awaited significant performance differences between experimental groups. Contrary to our assumption, inhibitory control performance did not differ between experimental groups. Moreover, there was no significant relation between affective measures and task performance. Nevertheless, cardiovascular reactivity in terms of HRV was predictive of error rates in both antisaccade tasks in the sadness group. We could find this effect neither in the neutral nor in the arousal group. In addition, BDI scores moderated the effect in the emotional task. Results indicate that emotional reactivity to a sad video stimulus as indexed by HRV as well as the interaction with current emotional state predict inhibitory control performance.

Early lifetime experience of urban living predicts social attention in real world crowds.

More than half of the world's population is currently living in cities, with more and more people moving to densely populated areas. The experience of growing up and living in crowded environments might influence the way we explore our social environment, mainly how we attend to others. Yet, we know little about how urbanicity affects this vital function of our social life. In two studies, we use mobile eye-tracking to measure participants' social attention, while walking through a shopping mall. Results show that social density of participants' native place impacts how frequently they look at passing strangers. People who experienced more city living from birth to early adolescence, attend more to strangers' faces than their rural counterparts. Our findings demonstrate that the early experience of urban upbringing configures social attention in adulthood. The urbanicity-related bias towards social gazing might reflect a more efficient processing of social information in urban natives.

Variation in antisaccadic response latencies investigated with the hierarchical LATER process model.

The antisaccade paradigm is frequently applied to measure inhibitory control. Typically, simple, perceptually neutral stimuli are used as cues. Recently, emotional versions of this paradigm have also been employed. In our study, we used both versions of the paradigm. In addition, scrambled faces served to control for stimulus size and emotional valence. We applied a hierarchical extension to the Linear Approach to Threshold Ergodic Rate (LATER) process model, which allows the estimation of two latent cognitive parameters: speed of information accumulation (accretion rate) and the amount of information needed before a saccadic movement (caution threshold). We hypothesized a faster accretion rate and lower caution threshold for circular and scrambled compared to emotional face stimuli as well as meaningful differences between individual emotions. Our results showed a faster accretion rate and lower caution threshold for emotional compared to circular stimuli, though. In contrast, scrambled faces had a lower accretion rate and lower caution threshold. Furthermore, the LATER model uncovered subtle differences between different emotions. Happy faces tend to receive a faster accretion rate and higher caution threshold than neutral ones, while for fearful faces it was the other way around. Our results contradict earlier research on emotional stimuli interfering inhibitory control.

Sensory processing sensitivity predicts performance in an emotional antisaccade paradigm.

Sensory Processing Sensitivity (SPS) is a common, heritable, and evolutionarily conserved trait, describing inter-individual differences in responsiveness and a more cautious approach to novel stimuli. It is associated with increased activation of brain regions involved in awareness, integration of sensory information, and empathy during processing of emotional faces. Furthermore, SPS is related to better performance in a visual detection task. Even though SPS is conceptualized to be closely related to traits characterized by pausing before acting, no study to date has assessed the relation between SPS and inhibitory control in a behavioral inhibition task. The present study fills this gap by investigating how SPS influences individual performance on two different antisaccade paradigms including emotional face stimuli. In addition, we assessed self-reported mood, anxiety, and depressiveness. Results showed that SPS was related to faster processing speed on the emotional, but not the classic antisaccade paradigm. Moreover, SPS predicted inhibitory control speed above mood and depressiveness. Our results provide evidence that higher SPS participants show superior inhibitory abilities, especially during the processing of emotional stimuli. This is in line with earlier findings showing better performance in a visual detection task as well as increased brain activation during emotional face processing.

Patterns of eye blinks are modulated by auditory input in humans.

Previous studies could elaborate a link between attentional processes and eye blinking in both visual and auditory attention tasks. Here we show that this link is active at a fundamental level of perception: presentation of a series of bare sine tones is sufficient to induce a modulation of temporal blink patterns, allowing to determine which series was presented to participants even when they are not required to interactively engage in processing the auditory input. In particular, we monitored eye blinking during an auditory attention task using two series of sine tones, differing in the predictability of the timing of tone onsets. Whereas inter-onset intervals in one tone series corresponded to uncorrelated samples from a normal distribution, they were distributed according to a Gaussian random walk in the other tone series. We find that blink patterns are dynamically modulated by both purely auditory inputs. The magnitude, form, and coherence of the temporal associations between tone onsets and blink events depend strongly on the requirement to respond to the presented stimuli. The predictability of the tone series appears to modulate pre-stimulus blink inhibition given that a response is required. Altogether, these findings suggest eye blink as a readily available, non-invasive behavioral marker for context-sensitive, moment-to-moment allocation of attention.

Do emotional stimuli interfere with response inhibition? evidence from the antisaccade paradigm.

When it comes to measuring cognitive control and inhibition, the antisaccade paradigm is a popular task to apply. Usually, simple, perceptually and affectively neutral stimuli, e.g. white circles, are used. Recently, researchers also employed a version of the paradigm displaying emotional faces. Differences in cognitive processing due to stimulus size and emotional valence have not been investigated yet. Thus, in the present study, we applied both versions of the antisaccade paradigm in a healthy sample. In addition, we used scrambled faces to control for stimulus size and emotional valence. We hypothesised slower reaction times and higher error rates for emotional face stimuli compared to circular and scrambled ones as well as significant differences between individual emotions. In contrast to our hypotheses, results showed faster reaction times fewer errors for emotional faces compared to circular and scrambled stimuli. Furthermore, ANOVA models showed no meaningful differences between different emotions. Our study shows specific patterns in inhibitory control due to stimulus size and valence in an antisaccade eye-tracking task.

Investigating Object Files in Spatial Cueing.

In spatial cueing, cues presented at target position (valid condition) can capture visual attention and facilitate responses to the target relative to cues presented away from target position (invalid condition). If cues and targets carry different features, the necessary updating of the object representation from the cue to the target display sometimes counteracts and even reverses facilitation in valid conditions, resulting in an inverted validity effect. Previous studies reached partly divergent conclusions regarding the conditions under which object-file updating occurs, and little is known about the exact nature of the processes involved. Object-file updating has so far been investigated by manipulating cue-target similarities in task-relevant target features, but other features that change between the cue and target displays might also contribute to object-file updating. This study examined the conditions under which object-file updating could counteract validity effects by systematically varying task-relevant (color), response-relevant (identity), and response-irrelevant (orientation) features between cue and target displays. The results illustrate that object-file updating is largely restricted to task-relevant features. In addition, the difficulty of the search task affects the degree to which object-file updating costs interact with spatial cueing.

Sense and Sensitivity - Using Spatial Response-Compatibility Effects to Investigate Ambiguous Word Meaning.

We investigated sensitivity for the vertical meaning of the German particle ab by means of stimulus-response compatibility effects. In German, the particle ab is ambiguous and can take on a vertical meaning (downward) as in Auf und Ab (engl. up and down), but it can also take on nonvertical or nonspatial meanings as in Ab und An (engl. from time to time). We show that the particle ab only creates a spatial compatibility effect relative to the German particle auf (Experiment 1) but not relative to the particle an (Experiment 2). Furthermore, as participants executed upward versus downward responses in both Experiments 1 and 2, the mere vertical antagonism of the responses was insufficient to instill a verticality-based compatibility effect. In addition, the compatibility effect was restricted to the transparent version of the particle. If a letter sequence corresponding to the particles was presented in a semantically and morphologically opaque way (e.g., the letters ab were embedded in the German word knabe, engl. boy), no compatibility effect was found, underlining that the effect was due to word meanings rather than visual features. The results underscore the boundary conditions for using compatibility effects in investigating lexical and semantic spatial processing in humans.

How We Perceive Others Resembling Us.

Eye contact is essential for social cognition, acting as an important tool for social communication. While differences in face scanning patterns concerning familiarity have been thoroughly investigated, the impact of facial similarity on gaze behavior has not been examined yet. We addressed this topic by recording subjects' eye-directed gazing while looking at faces that were individually created systematically varying in terms of similarity to the self-face and familiarity. Subjects' self-faces were morphed into three other faces including a close friend of the same sex. Afterwards, they rated similarity to their self-face of those morphed face stimuli in a separate rating task. Our results show a general preference for the eyes' area as well as differences regarding fixation patterns depending on similarity to the self-face. The lower the similarity to the self-face, the more fixations on the eyes' area. Subjects' ratings followed a linear line, indicating well-pronounced face perception. Nevertheless, other faces were rated faster than the self-face independent of familiarity, while morphed faces got the slowest ratings. Our results mirror the importance of similarity to the self-face as a factor shaping the way we look at the eyes of others explaining variance apart from familiarity.

Individual differences in working memory capacity moderate effects of post-learning activity on memory consolidation over the long term.

Similar to sleeping after learning, a brief period of wakeful resting after encoding new information supports memory retention in contrast to task-related cognition. Recent evidence suggests that working memory capacity (WMC) is related to sleep-dependent declarative memory consolidation. We tested whether WMC moderates the effect of a brief period of wakeful resting compared to performing a distractor task subsequent to encoding a word list. Participants encoded and immediately recalled a word list followed by either an 8 min wakeful resting period (eyes closed, relaxed) or by performing an adapted version of the d2 test of attention for 8 min. At the end of the experimental session (after 12-24 min) and again, after 7 days, participants were required to complete a surprise free recall test of both word lists. Our results show that interindividual differences in WMC are a central moderating factor for the effect of post-learning activity on memory retention. The difference in word retention between a brief period of wakeful resting versus performing a selective attention task subsequent to encoding increased in higher WMC individuals over a retention interval of 12-24 min, as well as over 7 days. This effect was reversed in lower WMC individuals. Our results extend findings showing that WMC seems not only to moderate sleep-related but also wakeful resting-related memory consolidation.

Factors modulating the effects of waking rest on memory.

Study results indicate that moments of unoccupied rest immediately after learning serve an essential cognitive function: memory consolidation. However, there also are findings suggesting that waking rest after learning has similar effects on delayed memory performance as an active wake condition, where participants work on a cognitive distractor task. Based on these studies, we highlight several potentially modulating factors of the so-called resting effect.

Assessment of Fractal Characteristics of Locomotor Activity of Geriatric In-Patients With Alzheimer's Dementia.

INTRODUCTION: Many physiological signals yield fractal characteristics, i.e., finer details at higher magnifications resemble details of the whole. Evidence has been accumulating that such fractal scaling is basically a consequence of interaction-dominant feedback mechanisms that cooperatively generate those signals. Neurodegenerative diseases provide a natural framework to evaluate this paradigm when this cooperative function declines. However, methodological issues need to be cautiously taken into account in order to be able to provide reliable as well as valid interpretations of such signal analyses. METHODS: Two conceptually different fractal analyses, i.e., detrended fluctuation analysis (DFA) and analysis of cumulative distributions of durations (CDDs), are applied to actigraphy data of 36 geriatric in-patients diagnosed with dementia. The impact of the used time resolution for data acquisition on the assessed fractal outcome parameters is particularly investigated. Moreover, associations between these parameters and scores from the Mini-Mental-State-Examination and circadian activity parameters are explored. RESULTS: Both analyses yield significant deviations from (mono-)fractal scaling over the entire considered time range. DFA provides robust measures for the observed break-down of fractal scaling. In contrast, analysis of CDDs results in measures which highly fluctuate with respect to the time resolution of the assessed data which affects also further derived quantities such as scaling exponents or associations with other (clinically relevant) assessed parameters. DISCUSSION: To scrutinize actigraphic signal characteristics and especially their (deviations from) fractal scaling may be a useful tool for aiding diagnosis, characterization, and monitoring of dementia. However, results may, besides contextual aspects, also substantially depend on specific methodological choices. In order to arrive at both reliable and valid interpretations, these complications need to be carefully elaborated in future research.

Wakeful resting and memory retention: a study with healthy older and younger adults.

Studies indicate that a brief period of wakeful rest after learning supports memory retention, whereas distraction weakens it. It is open for investigation whether advanced age has a significant effect on the impact of post-learning wakeful rest on memory retention for verbal information when compared to a cognitively demanding distraction task. In this study, we examined (1) whether post-learning rest promotes verbal memory retention in younger and older adults and (2) whether the magnitude of the rest benefit changes with increasing age. Younger adults and older adults learned and immediately recalled two consecutive word lists. After one word list, participants rested wakefully for 8 min; after the other list, they solved matrices. Memory performance was again tested in a surprise free recall test at the end of the experimental session. We found that, overall, younger adults outperformed older adults. Also, memory retention was higher following a wakeful rest phase compared to distraction. A detailed analysis revealed that this wakeful rest benefit was significant for the older adults group, whereas the younger adults group retained a similar amount of information in both post-encoding conditions. We assume that older adults can profit more from a wakeful rest phase after learning and are more prone to distraction than younger adults. With increasing age, a short break immediately after information uptake may help better retain the previously learned information, while distraction after learning tends to weaken memory retention.