“Two Minds Don’t Blink Alike”: The Attentional Blink Does Not Occur in a Joint Context

Typically, when two individuals perform a task together, each partner monitors the other partners' responses and goals to ensure that the task is completed efficiently. This monitoring is thought to involve a co-representation of the joint goals and task, as well as a simulation of the partners' performance. Evidence for such "co-representation" of goals and task, and "simulation" of responses has come from numerous visual attention studies in which two participants complete different components of the same task. In the present research, an adaptation of the attentional blink task was used to determine if co-representation could exert an influence over the associated attentional mechanisms. Participants completed a rapid serial visual presentation task in which they first identified a target letter (T1) and then detected the presence of the letter X (T2) presented one to seven letters after T1. In the individual condition, the participant identified T1 and then detected T2. In the joint condition, one participant identified T1 and the other participant detected T2. Across two experiments, an attentional blink (decreased accuracy in detecting T2 when presented three letters after T1) was observed in the individual condition, but not in joint conditions. A joint attentional blink may not emerge because the co-representation mechanisms that enable joint action exert a stronger influence at information processing stages that do not overlap with those that lead to the attentional blink

Probing the time course of facilitation and inhibition in gaze cueing of attention in an upper-limb reaching task

Previous work has revealed that social cues, such as gaze and pointed fingers, can lead to a shift in the focus of another person’s attention. Research investigating the mechanisms of these shifts of attention has typically employed detection or localization button-pressing tasks. Because in-depth analyses of the spatiotemporal characteristics of aiming movements can provide additional insights into the dynamics of the processing of stimuli, in the present study we used a reaching paradigm to further explore the processing of social cues. In Experiments 1 and 2, participants aimed to a left or right location after a nonpredictive eye gaze cue toward one of these target locations. Seven stimulus onset asynchronies (SOAs), from 100 to 2,400 ms, were used. Both the temporal (reaction time, RT) and spatial (initial movement angle, IMA) characteristics of the movements were analyzed. RTs were shorter for cued (gazed-at) than for uncued targets across most SOAs. There were, however, no statistical differences in IMAs between movements to cued and uncued targets, suggesting that action planning was not affected by the gaze cue. In Experiment 3, the social cue was a finger pointing to one of the two target locations. Finger-pointing cues generated significant cueing effects in both RTs and IMAs. Overall, these results indicate that eye gaze and finger-pointing social cues are processed differently. Perception–action coupling (i.e., a tight link between the response and the social cue that is presented) might play roles in both the generation of action and the deviation of trajectories toward cued and uncued targets

Do you see what I see? Co-actor posture modulates visual processing in joint tasks

Interacting with other people is a ubiquitous part of daily life. A complex set of processes enable our successful interactions with others. The present research was conducted to investigate how the processing of visual stimuli may be affected by the presence and the hand posture of a co-actor. Experiments conducted with participants acting alone have revealed that the distance from the stimulus to the hand of a participant can alter visual processing. In the main experiment of the present paper, we asked whether this posture-related source of visual bias persists when participants share the task with another person. The effect of personal and co-actor hand-proximity on visual processing was assessed through object-specific benefits to visual recognition in a task performed by two co-actors. Pairs of participants completed a joint visual recognition task and, across different blocks of trials, the position of their own hands and of their partner's hands varied relative to the stimuli. In contrast to control studies conducted with participants acting alone, an object-specific recognition benefit was found across all hand location conditions. These data suggest that visual processing is, in some cases, sensitive to the posture of a co-actor

Eye movements may cause motor contagion effects

When a person executes a movement, the movement is more errorful while observing another person’s actions that are incongruent rather than congruent with the executed action. This effect is known as “motor contagion”. Accounts of this effect are often grounded in simulation mechanisms: increased movement error emerges because the motor codes associated with observed actions compete with motor codes of the goal action. It is also possible, however, that the increased movement error is linked to eye movements that are executed simultaneously with the hand movement because oculomotor and manual-motor systems are highly interconnected. In the present study, participants performed a motor contagion task in which they executed horizontal arm movements while observing a model making either vertical (incongruent) or horizontal (congruent) movements under three conditions: no instruction, maintain central fixation, or track the model’s hand with the eyes. A significant motor contagion-like effect was only found in the ‘track’ condition. Thus, ‘motor contagion’ in the present task may be an artifact of simultaneously executed incongruent eye movements. These data are discussed in the context of stimulation and associative learning theories, and raise eye movements as a critical methodological consideration for future work on motor contagion

It is not in the details: Self-related shapes are rapidly classified but their features are not better remembered

Self-prioritization is a robust phenomenon whereby judgments concerning self-representational stimuli are faster than judgments toward other stimuli. The present paper examines if and how self-prioritization causes more vivid short-term memories for self-related objects by giving geometric shapes arbitrary identities (self, mother, stranger). In Experiment 1 participants were presented with an array of the three shapes and required to retain the location and color of each in memory. Participants were then probed regarding the identity of one of the shapes and subsequently asked to indicate the color of the probed shape or an unprobed shape on a color wheel. Results indicated no benefit for self-stimuli in either response time for the identification probe or for color fidelity in memory. Yet, a cuing benefit was observed such that the cued stimulus in the identity probe did have higher fidelity within memory. Experiments 2 and 3 reduced the cognitive load by only requiring that participants process the identity and color of one shape at a time. For Experiment 2, the identity probe was memory-based, whereas the stimulus was presented alongside the identity probe for Experiment 3. Results demonstrated a robust self-prioritization effect: self-related shapes were classified faster than non-self-shapes, but this self-advantage did not lead to an increase in the fidelity of memory for self-related shapes’ colors. Overall, these results suggest that self-prioritization effects may be restricted to an improvement in the ability to recognize that the self-representational stimulus is present without devoting more perceptual and short-term memory resources to such stimuli

The role of transients in action observation

A large number of studies have now described the various ways in which the observation of another person’s dynamic movement can influence the speed with which the observer is able to prepare a motor action themselves. The typical results are most often explained with reference to theories that link perception and action. Such theories argue that the cognitive structures associated with each share common representations. Consequently, action preparation and action observation are often said to be functionally equivalent. However, the dominance of these theories in explaining action observation effects has masked the potential contribution from processes associated with the detection of low-level “transients” resulting from observing a body movement, such as motion and sound. In the present review, we describe work undertaken in one particular action observation phenomenon (“social inhibition of return”) and show that the transient account provides the best explanation of the effect. We argue that future work should consider attention capture and orienting as a potential contributing factor to action observation effects more broadly

Susceptibility to the fusion illusion is modulated during both action execution and action observation

Many researchers have proposed that when an individual observes the actions of another individual, the observer simulates the action using many of the same neural areas that are involved in action production. The present study was designed to test this simulation hypothesis by comparing the perception of multisensory stimuli during both the execution and observation of an aiming action. The present work used the fusion illusion - an audio-visual illusion in which two visual stimuli presented with one auditory stimulus are erroneously perceived as being one visual stimulus. Previous research has shown that, during action execution, susceptibly to this illusion is reduced early in the execution of the movement when visual information may be more highly weighted than other sensory information. We sought to determine whether or not a non-acting observer of an action showed a similar reduction in susceptibility to the fusion illusion. Participants fixated a target and either executed or observed a manual aiming movement to that target. Audiovisual stimuli were presented at 0, 100, or 200 ms relative to movement onset and participants reported the number of perceived flashes after the movement was completed. Analysis of perceived flashes revealed that participants were less susceptible to the fusion illusion when the stimuli were presented early (100 ms) relative to later in the movement (200 ms). Critically, this pattern emerged in both execution and observation tasks. These findings support the hypothesis that observers simulate the performance of the actor and experience comparable real-time alterations in multisensory processing

The influence of location, ownership, and the presence of a coactor on the processing of objects.

Humans operate in complex environments where social interactions require individuals to constantly attend to people and objects around them. Despite the complexity of these interactions from a visuomotor perspective, humans can engage and thrive in social settings. The purpose of the current study was to examine the simultaneous influence of multiple social cues (i.e., ownership and the presence of a coactor) on the processing of objects. Participants performed an object-based compatibility task in the presence and absence of a coacting confederate. Participants indicated whether pictures of mugs (that were either self-owned or unowned) were upright or inverted. The pictures appeared at one of 2 locations (a near or far location relative to the participant) on a computer screen laid flat on (parallel to) the tabletop. When present, the coactor stood on the opposite side of the screen/table. Analysis of response times (RTs) indicated that the processing of objects was influenced by the object’s ownership status, the presence of the coactor, and where the object was located on the screen. Specifically, RTs for pictures of self-owned mugs were shorter than unowned mugs, but only when the pictures were located at the near location. Further, the presence of a confederate resulted in shorter RTs for pictures located at the near but not the far location. These findings suggest that when objects were placed at the far location, the additional social cues of ownership and social context did not influence visuomotor processing of the objects

Multiparametric MRI for assessment of early response to neoadjuvant sunitinib in renal cell carcinoma.

Funder: NIHR Cambridge Biomedical Research CentreFunder: Addenbrooke’s Charitable TrustFunder: National Institute for Health Research (NIHR)Funder: Mark Foundation For Cancer ResearchFunder: Cambridge Commonwealth, European and International TrustFunder: Cancer Research UKFunder: Cambridge Clinical Trials UnitFunder: Cancer Research UK Cambridge CentreFunder: Engineering and Physical Sciences Research Council Cancer Imaging Centre in Cambridge and ManchesterFunder: Cambridge Experimental Cancer Medicine CentrePURPOSE: To detect early response to sunitinib treatment in metastatic clear cell renal cancer (mRCC) using multiparametric MRI. METHOD: Participants with mRCC undergoing pre-surgical sunitinib therapy in the prospective NeoSun clinical trial (EudraCtNo: 2005-004502-82) were imaged before starting treatment, and after 12 days of sunitinib therapy using morphological MRI sequences, advanced diffusion-weighted imaging, measurements of R2* (related to hypoxia) and dynamic contrast-enhanced imaging. Following nephrectomy, participants continued treatment and were followed-up with contrast-enhanced CT. Changes in imaging parameters before and after sunitinib were assessed with the non-parametric Wilcoxon signed-rank test and the log-rank test was used to assess effects on survival. RESULTS: 12 participants fulfilled the inclusion criteria. After 12 days, the solid and necrotic tumor volumes decreased by 28% and 17%, respectively (p = 0.04). However, tumor-volume reduction did not correlate with progression-free or overall survival (PFS/OS). Sunitinib therapy resulted in a reduction in median solid tumor diffusivity D from 1298x10-6 to 1200x10-6mm2/s (p = 0.03); a larger decrease was associated with a better RECIST response (p = 0.02) and longer PFS (p = 0.03) on the log-rank test. An increase in R2* from 19 to 28s-1 (p = 0.001) was observed, paralleled by a decrease in Ktrans from 0.415 to 0.305min-1 (p = 0.01) and a decrease in perfusion fraction from 0.34 to 0.19 (p<0.001). CONCLUSIONS: Physiological imaging confirmed efficacy of the anti-angiogenic agent 12 days after initiating therapy and demonstrated response to treatment. The change in diffusivity shortly after starting pre-surgical sunitinib correlated to PFS in mRCC undergoing nephrectomy, however, no parameter predicted OS. TRIAL REGISTRATION: EudraCtNo: 2005-004502-82