Michiel M. A. Spapé

Working memory and the attentional blink: blink size is predicted by individual differences in operation span.

The attentional blink (AB) is often attributed to resource limitations, but the nature of these resources is commonly underspecified. Recent observations rule out access to short-term memory or storage capacity as limiting factors, but operation bottlenecks are still an option. We considered the operation span of working memory (WM) as a possible factor and investigated the relationship between individual WM operation span (as measured by OSPAN), fluid intelligence (as measures by Raven’s SPM), and the size of the AB. WM operation span was negatively correlated with the AB, whereas fluid intelligence was associated with higher overall accuracy but not with AB magnitude. These results support the idea that individual processing limitations (with regard to either attentional allocation policies or the speed of global cortical integration processes) play a key role in the AB.

He said, she said: Episodic retrieval induces conflict adaptation in an auditory Stroop task

People respond more slowly if an irrelevant feature of a target stimulus is incompatible with the relevant feature or the correct response. Such compatibility effects are often reduced in trials following an incompatible trial, which has been taken to reflect increased cognitive control. This pattern holds only if two trials share some similarities, however, suggesting that it may be modulated by the episodic context. To look into this possibility, we had participants respond to high- or low-pitched tones by saying “high” or “low,” respectively, and ignore the simultaneously presented auditory word “high” or “low.” As expected, performance was impaired if the heard word was incompatible with the required response, and this Stroop-like effect was reduced after incompatible trials. This sequential modulation was observed, however, only if the voice in the two successive trials was the same, whereas no modulation was obtained when the speaker changed. The results suggest that sequential modulations are due to the automatic retrieval of episodic event representations that integrate stimuli, actions, and situational and task-specific control information, so that later reactivation of some elements of a given representation tends to retrieve the other elements as well.

Blinks of the eye predict blinks of the mind.

The Attentional Blink (AB)--a deficit in reporting the second of two target stimuli presented in close succession in a rapid sequence of distracters--has been related to individual processing limitations of working memory. Given the known role of dopamine (DA) in working memory processes, the present experiment tested the hypothesis that DA, and in particular the DA/D1 subsystem, plays a role in the AB. We present evidence that the spontaneous eyeblink rate (EBR), a functional marker of central dopaminergic function, reliably predicts the size of AB. Thus, in line with our hypothesis, these data point to a modulatory role for DA in the AB.

Intermodal event files: integrating features across vision, audition, taction, and action

Understanding how the human brain integrates features of perceived events calls for the examination of binding processes within and across different modalities and domains. Recent studies of feature-repetition effects have demonstrated interactions between shape, color, and location in the visual modality and between pitch, loudness, and location in the auditory modality: repeating one feature is beneficial if other features are also repeated, but detrimental if not. These partial-repetition costs suggest that co-occurring features are spontaneously bound into temporary event files. Here, we investigated whether these observations can be extended to features from different sensory modalities, combining visual and auditory features in Experiment 1 and auditory and tactile features in Experiment 2. The same types of interactions, as for unimodal feature combinations, were obtained including interactions between stimulus and response features. However, the size of the interactions varied with the particular combination of features, suggesting that the salience of features and the temporal overlap between feature-code activations plays a mediating role.

Predicting term-relevance from brain signals

Term-Relevance Prediction from Brain Signals (TRPB) is proposed to automatically detect relevance of text information directly from brain signals. An experiment with forty participants was conducted to record neural activity of participants while providing relevance judgments to text stimuli for a given topic. High-precision scientific equipment was used to quantify neural activity across 32 electroencephalography (EEG) channels. A classifier based on a multi-view EEG feature representation showed improvement up to 17% in relevance prediction based on brain signals alone. Relevance was also associated with brain activity with significant changes in certain brain areas. Consequently, TRPB is based on changes identified in specific brain areas and does not require user-specific training or calibration. Hence, relevance predictions can be conducted for unseen content and unseen participants. As an application of TRPB we demonstrate a high-precision variant of the classifier that constructs sets of relevant terms for a given unknown topic of interest. Our research shows that detecting relevance from brain signals is possible and allows the acquisition of relevance judgments without a need to observe any other user interaction. This suggests that TRPB could be used in combination or as an alternative for conventional implicit feedback signals, such as dwell time or click-through activity.

Compatibility-sequence effects in the Simon task reflect episodic retrieval but not conflict adaptation: Evidence from LRP and N2

Behavioral and psychophysiological studies on the Simon effect have demonstrated that stimuli automatically activate spatially corresponding responses, even if their location is irrelevant to the task. Interestingly, this Simon effect is attenuated after stimulus-response incompatible trials (Gratton effect or compatibility-sequence effect), a pattern that has often been attributed to online conflict adaptation, even though an account in terms of episodic binding and retrieval is just as plausible. Here we show that the compatibility-sequence effect can be eliminated and partly reversed by rotating the boxes in which stimuli are presented in between two given trials, a manipulation that is likely to affect episodic representation but not online control. Sequential modulations of electrophysiological indicators of automatic response priming were also eliminated (N2) or even reversed in sign (LRP), suggesting that these effects are due to episodic retrieval of stimulus-response bindings but not, or to only a negligible degree, to online adaptation.

From outcome prediction to action selection: developmental change in the role of action-effect bindings

Ideomotor theory considers bidirectional action-effect associations to be the fundamental building blocks for intentional action. The present study employed a novel pupillometric and oculomotor paradigm to study developmental changes in the role of action-effects in the acquisition of voluntary action. Our findings suggest that both 7- and 12-month-olds (and adults) can use acquired action-effect bindings to predict action outcomes but only 12-month-olds (and adults) showed evidence for employing action-effects to select actions. This dissociation supports the idea that infants acquire action-effect knowledge before they have developed the cognitive machinery necessary to make use of that knowledge to perform intentional actions.

Keep your opponents close: social context affects EEG and fEMG linkage in a turn-based computer game

In daily life, we often copy the gestures and expressions of those we communicate with, but recent evidence shows that such mimicry has a physiological counterpart: interaction elicits linkage, which is a concordance between the biological signals of those involved. To find out how the type of social interaction affects linkage, pairs of participants played a turn-based computer game in which the level of competition was systematically varied between cooperation and competition. Linkage in the beta and gamma frequency bands was observed in the EEG, especially when the participants played directly against each other. Emotional expression, measured using facial EMG, reflected this pattern, with the most competitive condition showing enhanced linkage over the facial muscle-regions involved in smiling. These effects were found to be related to self-reported social presence: linkage in positive emotional expression was associated with self-reported shared negative feelings. The observed effects confirmed the hypothesis that the social context affected the degree to which participants had similar reactions to their environment and consequently showed similar patterns of brain activity. We discuss the functional resemblance between linkage, as an indicator of a shared physiology and affect, and the well-known mirror neuron system, and how they relate to social functions like empathy.

Exploring Peripheral Physiology as a Predictor of Perceived Relevance in Information Retrieval

Peripheral physiological signals, as obtained using electrodermal activity and facial electromyography over the corrugator supercilii muscle, are explored as indicators of perceived relevance in information retrieval tasks. An experiment with 40 participants is reported, in which these physiological signals are recorded while participants perform information retrieval tasks. Appropriate feature engineering is defined, and the feature space is explored. The results indicate that features in the window of 4 to 6 seconds after the relevance judgment for electrodermal activity, and from 1 second before to 2 seconds after the relevance judgment for corrugator supercilii activity, are associated with the users perceived relevance of information items. A classifier verified the predictive power of the features and showed up to 14% improvement predicting relevance. Our research can help the design of intelligent user interfaces for information retrieval that can detect the users perceived relevance from physiological signals and complement or replace conventional relevance feedback.

The meaning of the virtual Midas touch: an ERP study in economic decision making.

The Midas touch refers to the altruistic effects of a brief touch. Though these effects have often been replicated, they remain poorly understood. We investigate the psychophysiology of the effect using remotely transmitted, precisely timed, tactile messages in an economic decision-making game called Ultimatum. Participants were more likely to accept offers after receiving a remotely transmitted touch. Furthermore, we found distinct effects of touch on event-related potentials evoked by (a) feedback regarding accepted and rejected offers, (b) decision cues related to proposals, and (c) the haptic and auditory cues themselves. In each case, a late positive effect of touch was observed and related to the P3. Given the role of the P3 in memory-related functions, the results indicate an indirect relationship between touch and generosity that relies on memory. This hypothesis was further tested and confirmed in the positive effects of touch on later proposals.