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Social Transmission of Experience of Agency: An Experimental Study.
The sense of controlling one's own actions is fundamental to normal human mental function, and also underlies concepts of social responsibility for action. However, it remains unclear how the wider social context of human action influences sense of agency. Using a simple experimental design, we investigated, for the first time, how observing the action of another person or a robot could potentially influence one's own sense of agency. We assessed how observing another's action might change the perceived temporal relationship between one's own voluntary actions and their outcomes, which has been proposed as an implicit measure of sense of agency. Working in pairs, participants chose between two action alternatives, one rewarded more frequently than the other, while watching a rotating clock hand. They judged, in separate blocks, either the time of their own action, or the time of a tone that followed the action. These were compared to baseline judgements of actions alone, or tones alone, to calculate the perceptual shift of action toward outcome and vice versa. Our design focused on how these two dependent variables, which jointly provide an implicit measure of sense of agency, might be influenced by observing another's action. In the observational group, each participant could see the other's actions. Multivariate analysis showed that the perceived time of action and tone shifted progressively toward the actual time of outcome with repeated experience of this social situation. No such progressive change occurred in other groups for whom a barrier hid participants' actions from each other. However, a similar effect was observed in the group that viewed movements of a human-like robotic hand, rather than actions of another person. This finding suggests that observing the actions of others increases the salience of the external outcomes of action and this effect is not unique to observing human agents. Social contexts in which we see others controlling external events may play an important role in mentally representing the impact of our own actions on the external world.
Slow oscillating transcranial direct current stimulation during sleep has a sleep-stabilizing effect in chronic insomnia: a pilot study.
Recent evidence suggests that lack of slow-wave activity may play a fundamental role in the pathogenesis of insomnia. Pharmacological approaches and brain stimulation techniques have recently offered solutions for increasing slow-wave activity during sleep. We used slow (0.75 Hz) oscillatory transcranial direct current stimulation during stage 2 of non-rapid eye movement sleeping insomnia patients for resonating their brain waves to the frequency of sleep slow-wave. Six patients diagnosed with either sleep maintenance or non-restorative sleep insomnia entered the study. After 1 night of adaptation and 1 night of baseline polysomnography, patients randomly received sham or real stimulation on the third and fourth night of the experiment. Our preliminary results show that after termination of stimulations (sham or real), slow oscillatory transcranial direct current stimulation increased the duration of stage 3 of non-rapid eye movement sleep by 33 ± 26 min (P = 0.026), and decreased stage 1 of non-rapid eye movement sleep duration by 22 ± 17.7 min (P = 0.028), compared with sham. Slow oscillatory transcranial direct current stimulation decreased stage 1 of non-rapid eye movement sleep and wake time after sleep-onset durations, together, by 55.4 ± 51 min (P = 0.045). Slow oscillatory transcranial direct current stimulation also increased sleep efficiency by 9 ± 7% (P = 0.026), and probability of transition from stage 2 to stage 3 of non-rapid eye movement sleep by 20 ± 17.8% (P = 0.04). Meanwhile, slow oscillatory transcranial direct current stimulation decreased transitions from stage 2 of non-rapid eye movement sleep to wake by 12 ± 6.7% (P = 0.007). Our preliminary results suggest a sleep-stabilizing role for the intervention, which may mimic the effect of sleep slow-wave-enhancing drugs.
Modulating human sense of agency with non-invasive brain stimulation.
Human voluntary actions are accompanied by a distinctive subjective experience termed "sense of agency". We performed three experiments using transcranial direct current stimulation (tDCS) to modulate brain circuits involved in control of action, while measuring stimulation-induced changes in one implicit measure of sense of agency, namely the perceived temporal relationship between a voluntary action and tone triggered by the action. Participants perceived such tones as shifted towards the action that caused them, relative to baseline conditions with tones but no actions. Actions that caused tones were perceived as shifted towards the tone, relative to baseline actions without tones. This 'intentional binding' was diminished by anodal stimulation of the left parietal cortex [targeting the angular gyrus (AG)], and, to a lesser extent, by stimulation targeting the left dorsolateral prefrontal cortex (DLPFC), (Experiment 1). Cathodal AG stimulation had no effect (Experiment 2). Experiment 3 replicated the effect of left anodal AG stimulation for actions made with either the left or the right hand, and showed no effect of right anodal AG stimulation. The angular gyrus has been identified as a key area for explicit agency judgements in previous neuroimaging and lesion studies. Our study provides new causal evidence that the left angular gyrus plays a key role in the perceptual experience of agency.
Endogenous Action Selection Processes in Dorsolateral Prefrontal Cortex Contribute to Sense of Agency: A Meta-Analysis of tDCS Studies of 'Intentional Binding'.
BACKGROUND: Sense of agency is the experience of being in control of one's own actions and their consequences. The role of frontal cortex in this aspect of action control and awareness remains unclear. OBJECTIVE/HYPOTHESIS: Given the role of dorsolateral prefrontal cortex (DLPFC) in action selection, we predicted that DLPFC may contribute to sense of agency when participants select between multiple actions. METHODS: We performed a series of experiments by manipulating a range of task parameters related to action selection and action outcomes while participants were exposed to tDCS stimulation of the left DLPFC. We measured the temporal association between a voluntary action and its outcome using the intentional binding effect, as an implicit measure of sense of agency. RESULTS: Fixed-effect meta-analysis of our primary data showed a trend towards a frontal tDCS, together with considerable heterogeneity between our experiments. Classifying the experiments into subsets of studies, according to whether participants endogenously selected between alternative actions or not, explained 71% of this heterogeneity. Anodal stimulation of DLPFC increased the temporal binding of actions towards tones in the subset of studies involving endogenous action selection, but not in the other studies. CONCLUSIONS: DLPFC may contribute to sense of agency when participants selected between multiple actions. This enhanced feeling of control over voluntary actions could be related to the observed therapeutic effects of frontal tDCS in depression.
I could have done otherwise: Availability of counterfactual comparisons informs the sense of agency.
Personal control and agency are closely associated with the counterfactual notion that a person could have done otherwise (CDO). In both philosophy and law, this counterfactual evaluation determines responsibility and punishment, yet little is known about its influence on agents' experience during action. We used a risky decision-making task to study how counterfactual evaluations influenced participants' sense of agency. Two factors were manipulated independently: the presence/absence of counterfactual comparisons between actions and the presence/absence of counterfactual comparisons between outcomes of these actions. Perceived agency was highest when both counterfactual comparisons were available. Interestingly, this pattern persisted even when counterfactual information was only revealed after action, suggesting a purely reconstructive evaluation effect. These findings allow a more precise phrasing of the CDO element of personal agency: a person feels most control when she could have performed another action, thereby obtaining another outcome.
Subliminal modulation of voluntary action experience: A neuropsychological investigation.
Human voluntary actions are often associated with a distinctive subjective experience termed 'sense of agency'. This experience could be a reconstructive inference triggered by monitoring one's actions and their outcomes, or a read-out of brain processes related to action preparation, or some hybrid of these. Participants pressed a key with the right index finger at a time of their own choice, while viewing a rotating clock. Occasionally they received a mild shock on the same finger. They were instructed to press the key as quickly as possible if they felt a shock. On some trials, trains of subliminal shocks were also delivered, to investigate whether such subliminal cues could influence the initiation of voluntary actions, or the subjective experience of such actions. Participants' keypress were always followed by a tone 250 ms later. At the end of each trial they reported the time of the keypress using the rotating clock display. Shifts in the perceived time of the action towards the following tone, compared to a baseline condition containing only a keypress but no tone, were taken as implicit measures of sense of agency. The subliminal shock train enhanced this "action binding" effect in healthy participants, relative to trials without such shocks. This difference could not be attributed to retrospective inference, since the perceptual events were identical in both trial types. Further, we tested the same paradigm in a patient with anarchic hand syndrome (AHS). Subliminal shocks again enhanced our measure of sense of agency in the unaffected hand, but had a reversed effect on the 'anarchic' hand. These findings suggest an interaction between internal volitional signals and external cues afforded by the external environment. Damage to the neural pathways that mediate interactions between internal states and the outside world may explain some of the clinical signs of AHS.
Extending experiences of voluntary action by association.
"Sense of agency" refers to the experience that links one's voluntary actions to their external outcomes. It remains unclear whether this ubiquitous experience is hardwired, arising from specific signals within the brain's motor systems, or rather depends on associative learning, through repeated cooccurrence of voluntary movements and their outcomes. To distinguish these two models, we asked participants to trigger a tone by a voluntary keypress action. The voluntary action was always associated with an involuntary movement of the other hand. We then tested whether the combination of the involuntary movement and tone alone might now suffice to produce a sense of agency, even when the voluntary action was omitted. Sense of agency was measured using an implicit marker based on time perception, namely a shift in the perceived time of the outcome toward the action that caused it. Across two experiments, repeatedly pairing an involuntary movement with a voluntary action induced key temporal features of agency, with the outcome now perceived as shifted toward the involuntary movement. This shift required involuntary movements to have been previously associated with voluntary actions. We show that some key aspects of agency may be transferred from voluntary actions to involuntary movements. An internal volitional signal is required for the primary acquisition of agency but, with repeated association, the involuntary movement in itself comes to produce some key temporal features of agency over the subsequent outcome. This finding may explain how humans can develop an enduring sense of agency in nonnatural cases, like brain-machine interfaces.
Altered balance of excitatory and inhibitory learning in a genetically modified mouse model of glutamatergic dysfunction relevant to schizophrenia.
The GluA1 AMPAR subunit (encoded by the Gria1 gene) has been implicated in schizophrenia. Gria1 knockout in mice results in recently experienced stimuli acquiring aberrantly high salience. This suggests that GluA1 may be important for learning that is sensitive to the temporal contiguity between events. To test this, mice were trained on a Pavlovian trace conditioning procedure in which the presentation of an auditory cue and food were separated by a temporal interval. Wild-type mice initially learnt, but with prolonged training came to withhold responding during the trace-conditioned cue, responding less than for another cue that was nonreinforced. Gria1 knockout mice, in contrast, showed sustained performance over training, responding more to the trace-conditioned cue than the nonreinforced cue. Therefore, the trace-conditioned cue acquired inhibitory properties (signalling the absence of food) in wild-type mice, but Gria1 deletion impaired the acquisition of inhibition, thus maintaining the stimulus as an excitatory predictor of food. Furthermore, when there was no trace both groups showed successful learning. These results suggest that cognitive abnormalities in disorders like schizophrenia in which gluatamatergic signalling is implicated may be caused by aberrant salience leading to a change in the nature of the information that is encoded.
Touch, taste, & smell user interfaces: The future of multisensory HCI
© 2016 Authors. The senses we call upon when interacting with technology are very restricted. We mostly rely on vision and audition, increasingly harnessing touch, whilst taste and smell remain largely underexploited. In spite of our current knowledge about sensory systems and sensory devices, the biggest stumbling block for progress concerns the need for a deeper understanding of people's multisensory experiences in HCI. It is essential to determine what tactile, gustatory, and olfactory experiences we can design for, and how we can meaningfully stimulate such experiences when interacting with technology. Importantly, we need to determine the contribution of the different senses along with their interactions in order to design more effective and engaging digital multisensory experiences. Finally, it is vital to understand what the limitations are that come into play when users need to monitor more than one sense at a time. The aim of this workshop is to deepen and expand the discussion on touch, taste, and smell within the CHI community and promote the relevance of multisensory experience design and research in HCI.
Space-based bias of covert visual attention in complex regional pain syndrome.
See Legrain (doi:10.1093/awx188) for a scientific commentary on this article. Some patients with complex regional pain syndrome report that movements of the affected limb are slow, more effortful, and lack automaticity. These symptoms have been likened to the syndrome that sometimes follows brain injury called hemispatial neglect, in which patients exhibit attentional impairments and problems with movements affecting the contralesional side of the body and space. Psychophysical testing of patients with complex regional pain syndrome has found evidence for spatial biases when judging visual targets distanced at 2 m, but not in directions that indicate reduced attention to the affected side. In contrast, when judging visual or tactile stimuli presented on their own body surface, or pictures of hands and feet within arm's reach, patients with complex regional pain syndrome exhibited a bias away from the affected side. What is not yet known is whether patients with complex regional pain syndrome only have biased attention for bodily-specific information in the space within arm's reach, or whether they also show a bias for information that is not associated with the body, suggesting a more generalized attention deficit. Using a temporal order judgement task, we found that patients with complex regional pain syndrome processed visual stimuli more slowly on the affected side (relative to the unaffected side) when the lights were projected onto a blank surface (i.e. when no bodily information was visible), and when the lights were projected onto the dorsal surfaces of their uncrossed hands. However, with the arms crossed (such that the left and right lights projected onto the right and left hands, respectively), patients' responses were no different than controls. These results provide the first demonstration of a generalized attention bias away from the affected side of space in complex regional pain syndrome patients that is not specifically related to bodily information. They also suggest a separate and additional bias of visual attention away from the affected hand. The strength of attention bias was predicted by scores on a self-report measure of body perception distortion; but not by pain intensity, time since diagnosis, or affected body side (left or right). At an individual level, those patients whose upper limbs were most affected had a higher incidence of inattention than those whose lower limbs were most affected. However, at a group level, affected limb (upper or lower) did not predict bias magnitude; nor did three measures designed to assess possible asymmetries in the distribution of movements across space. It is concluded that inattention in near space in complex regional pain syndrome may arise in parallel with a distorted perception of the body.10.1093/brain/awx152_video1awx152media15495542665001.
Comparing audiovisual semantic interactions between linguistic and non-linguistic stimuli
We examined the time-courses of the crossmodal semantic congruency effects elicited by naturalistic sounds or spoken words on the processing of visual pictures and printed words. Auditory primes were presented at seven stimulus onset asynchronies (SOAs) with respect to the visual targets, ranging from auditory leading by 1000 ms to auditory lagging by 250 ms. Participants made speeded categorization judgments (living vs. non-living) regarding the visual targets. Three common effects were observed for both types of visual targets: Both naturalistic sounds and spoken words induced a slow facilitatory effect when leading by 250 ms or more in the congruent condition, but induced a rapid inhibitory effect when leading by 250 ms or less in the incongruent condition. Only spoken words that did not match the visual targets elicited an additional inhibitory effect when leading by 100 ms or when presented simultaneously. As compared to non-linguistic stimuli, the priming effects associated with linguistic stimuli occurred over a wider range of SOAs, and the interactions occurred at a more specific level of the category hierarchy (i.e., the basic level) than required by the task. These results suggest different routes to semantic access: Linguistic stimuli accessed meaning mediated by the lexical representation that activated semantic representations at the corresponding level of the category hierarchy precisely, whereas non-linguistic stimuli accessed their meaning rapidly and directly, but first accessed meaning at a higher-level of semantic hierarchy. We propose a comprehensive framework to provide a dynamic view regarding how meaning is extracted during the processing of linguistic and non-linguistic stimuli presented in the visual and auditory modalities, therefore contributing to our understanding of the human semantic system.
Social touch
© 2016 Springer Science+Business Media New York. The more social aspects of touch, despite their relevance to numerous domains of human behavior, from cultural anthropology to cognitive neuroscience, and from virtual reality through to linguistics, have not been extensively studied by scientists. That is, psychologists and neuroscientists are only now beginning to uncover some of the neurocognitive mechanisms responsible for these important real-world interactions. In this chapter, we summarize the latest developments in this field of research. In particular, we highlight a number of studies where touch, no matter whether direct or mediated by technological devices, has been shown to affect our behavior, as well as our physiological reactions. We show how this sensory modality often acts as a powerful interface allowing us to interact socially and emotionally with the world around us. The available research also suggests that touch plays an important role in supporting our well-being.
Cognitive Function in Low-Income and Low-Literacy Settings: Validation of the Tablet-Based Oxford Cognitive Screen in the Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI).
Objectives: 1. Assess validity of the Oxford Cognitive Screen (OCS-Plus), a domain-specific cognitive assessment designed for low-literacy settings, especially in low- and middle-income countries (LMIC); 2. Advance theoretical contributions in cognitive neuroscience in domain-specific cognitive function and cognitive reserve, especially related to dementia. Method: In a cross-sectional study of a sample of 1,402 men and women aged 40-79 in the Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI), we administered OCS-Plus along with health and sociodemographic assessments. HAALSI is a representative sample of older adults in Agincourt, South Africa contributing to normative understanding of cognition in LMIC. We report measure distributions, construct and external validity of the OCS-Plus. Results: OCS-Plus has excellent construct and external validity. Intra-class correlations between similar basic measures of orientation in OCS-Plus and in HAALSI assessments was 0.79, and groups of people performing well on the OCS-Plus verbal memory also showed superior performance on HAALSI verbal memory. The OCS-Plus scores showed consistent associations with age and education and domain-specific associations with alcohol and depression. Younger respondents and the more educated did better on all assessments. Discussion: The OCS-Plus represents a major methodological advance in dementia studies in LMICs, and enhances understanding of cognitive aging.
Typical integration of emotion cues from bodies and faces in Autism Spectrum Disorder.
Contextual cues derived from body postures bias how typical observers categorize facial emotion; the same facial expression may be perceived as anger or disgust when aligned with angry and disgusted body postures. Individuals with Autism Spectrum Disorder (ASD) are thought to have difficulties integrating information from disparate visual regions to form unitary percepts, and may be less susceptible to visual illusions induced by context. The current study investigated whether individuals with ASD exhibit diminished integration of emotion cues extracted from faces and bodies. Individuals with and without ASD completed a binary expression classification task, categorizing facial emotion as 'Disgust' or 'Anger'. Facial stimuli were drawn from a morph continuum blending facial disgust and anger, and presented in isolation, or accompanied by an angry or disgusted body posture. Participants were explicitly instructed to disregard the body context. Contextual modulation was inferred from a shift in the resulting psychometric functions.Contrary to prediction, observers with ASD showed typical integration of emotion cues from the face and body. Correlation analyses suggested a relationship between the ability to categorize emotion from isolated faces, and susceptibility to contextual influence within the ASD sample; individuals with imprecise facial emotion classification were influenced more by body posture cues.
Crossmodal Classification of Mu Rhythm Activity during Action Observation and Execution Suggests Specificity to Somatosensory Features of Actions.
The alpha mu rhythm (8-13 Hz) has been considered to reflect mirror neuron activity because it is attenuated by both action observation and action execution. The putative link between mirror neuron system activity and the mu rhythm has been used to study the involvement of the mirror system in a wide range of socio-cognitive processes and clinical disorders. However, previous research has failed to convincingly demonstrate the specificity of the mu rhythm, meaning that it is unclear whether the mu rhythm reflects mirror neuron activity. It also remains unclear whether mu rhythm suppression during action observation reflects the processing of motor or tactile information. In an attempt to assess the validity of the mu rhythm as a measure of mirror neuron activity, we used crossmodal pattern classification to assess the specificity of EEG mu rhythm response to action varying in terms of action type (whole-hand or precision grip), concurrent tactile stimulation (stimulation or no stimulation), or object use (transitive or intransitive actions) in 20 human participants. The main results reveal that above-chance crossmodal classification of mu rhythm activity was obtained in the central channels for tactile stimulation and action transitivity but not for action type. Furthermore, traditional univariate analyses applied to the same data were insensitive to differences between conditions. By calling into question the relationship between mirror system activity and the mu rhythm, these results have important implications for the use and interpretation of mu rhythm activity.SIGNIFICANCE STATEMENT The central alpha mu rhythm oscillation is a widely used measure of the human mirror neuron system that has been used to make important claims concerning cognitive functioning in health and in disease. Here, we used a novel multivariate analytical approach to show that crossmodal EEG mu rhythm responses primarily index the somatosensory features of actions, suggesting that the mu rhythm is not a valid measure of mirror neuron activity. Results may lead to the revision of the conclusions of many previous studies using this measure, and to the transition toward a theory of mu rhythm function that is more consistent with current models of sensory processing in the self and in others.
Children reading spoken words: interactions between vocabulary and orthographic expectancy.
There is an established association between children's oral vocabulary and their word reading but its basis is not well understood. Here, we present evidence from eye movements for a novel mechanism underlying this association. Two groups of 18 Grade 4 children received oral vocabulary training on one set of 16 novel words (e.g., 'nesh', 'coib'), but no training on another set. The words were assigned spellings that were either predictable from phonology (e.g., nesh) or unpredictable (e.g., koyb). These were subsequently shown in print, embedded in sentences. Reading times were shorter for orally familiar than unfamiliar items, and for words with predictable than unpredictable spellings but, importantly, there was an interaction between the two: children demonstrated a larger benefit of oral familiarity for predictable than for unpredictable items. These findings indicate that children form initial orthographic expectations about spoken words before first seeing them in print. A video abstract of this article can be viewed at: https://youtu.be/jvpJwpKMM3E.
Stimulus-parity synaesthesia versus stimulus-dichotomy synaesthesia: Odd, even or something else?
In stimulus-parity synaesthesia, a range of stimuli-for example, letters, numbers, weekdays, months, and colours (the inducers)-elicit an automatic feeling of oddness or evenness (the concurrent). This phenomenon was first described by Théodore Flournoy in 1893, and has only recently been "rediscovered." Here, we describe an individual who experiences a comparable phenomenon, but uses the labels negative and positive rather than odd and even. Stimulus-parity synaesthesia may be broader than first supposed, and it is important that assessments are sensitive to this breadth.