Matthijs Leendert Noordzij

Exploring the brain basis of joint action: co-ordination of actions, goals and intentions.

Abstract Humans are frequently confronted with goal-directed tasks that can not be accomplished alone, or that benefit from co-operation with other agents. The relatively new field of social cognitive neuroscience seeks to characterize functional neuroanatomical systems either specifically or preferentially engaged during such joint-action tasks. Based on neuroimaging experiments conducted on critical components of joint action, the current paper outlines the functional network upon which joint action is hypothesized to be dependant. This network includes brain areas likely to be involved in interpersonal co-ordination at the action, goal, and intentional levels. Experiments focusing specifically on joint-action situations similar to those encountered in real life are required to further specify this model.

Brain Mechanisms Underlying Human Communication

Human communication has been described as involving the coding-decoding of a conventional symbol system, which could be supported by parts of the human motor system (i.e. the “mirror neurons system”). However, this view does not explain how these conventions could develop in the first place. Here we target the neglected but crucial issue of how people organize their non-verbal behavior to communicate a given intention without pre-established conventions. We have measured behavioral and brain responses in pairs of subjects during communicative exchanges occurring in a real, interactive, on-line social context. In two fMRI studies, we found robust evidence that planning new communicative actions (by a sender) and recognizing the communicative intention of the same actions (by a receiver) relied on spatially overlapping portions of their brains (the right posterior superior temporal sulcus). The response of this region was lateralized to the right hemisphere, modulated by the ambiguity in meaning of the communicative acts, but not by their sensorimotor complexity. These results indicate that the sender of a communicative signal uses his own intention recognition system to make a prediction of the intention recognition performed by the receiver. This finding supports the notion that our communicative abilities are distinct from both sensorimotor processes and language abilities.

Differences between Early-Blind, Late-Blind, and Blindfolded-Sighted People in Haptic Spatial-Configuration Learning and Resulting Memory Traces

The roles of visual and haptic experience in different aspects of haptic processing of objects in peripersonal space are examined. In three trials, early-blind, late-blind, and blindfolded-sighted individuals had to match ten shapes haptically to the cut-outs in a board as fast as possible. Both blind groups were much faster than the sighted in all three trials. All three groups improved considerably from trial to trial. In particular, the sighted group showed a strong improvement from the first to the second trial. While superiority of the blind remained for speeded matching after rotation of the stimulus frame, coordinate positional-memory scores in a non-speeded free-recall trial showed no significant differences between the groups. Moreover, when assessed with a verbal response, categorical spatial-memory appeared strongest in the late-blind group. The role of haptic and visual experience thus appears to depend on the task aspect tested.

The Influence of Visual Experience on Visual and Spatial Imagery

Differences are reported between blind and sighted participants on a visual-imagery and a spatial-imagery task, but not on an auditory-imagery task. For the visual-imagery task, participants had to compare object forms on the basis of a (verbally presented) object name. In the spatial-imagery task, they had to compare angular differences on the basis of the position of clock hands on two clock faces, again only on the basis of verbally presented clock times. Interestingly, there was a difference between early-blind and late-blind participants on the visual-imagery and the spatial-imagery tasks: late-blind participants made more errors than sighted people on the visual-imagery task, while early-blind participants made more errors than sighted people on the spatial-imagery task. This difference suggests that, for visual (form) imagery, people use the channel currently available (haptic for the blind; visual for the sighted). For the spatial-imagery task in this study reliance on haptic processing did not seem to suffice, and people benefited from visual experience and ability. However, the difference on the spatial-imagery task between early-blind and sighted people in this study might also be caused by differences in experience with the analogue clock faces that formed the basis for the spatial judgments.

A dissociation between linguistic and communicative abilities in the human brain

Although language is an effective vehicle for communication, it is unclear how linguistic and communicative abilities relate to each other. Some researchers have argued that communicative message generation involves perspective taking (mentalizing), and—crucially—that mentalizing depends on language. We employed a verbal communication paradigm to directly test whether the generation of a communicative action relies on mentalizing and whether the cerebral bases of communicative message generation are distinct from parts of cortex sensitive to linguistic variables. We found that dorsomedial prefrontal cortex, a brain area consistently associated with mentalizing, was sensitive to the communicative intent of utterances, irrespective of linguistic difficulty. In contrast, left inferior frontal cortex, an area known to be involved in language, was sensitive to the linguistic demands of utterances, but not to communicative intent. These findings show that communicative and linguistic abilities rely on cerebrally (and computationally) distinct mechanisms.

Haptic orientation perception benefits from visual experience: Evidence from early-blind, late-blind, and sighted people

Early-blind, late-blind, and blindfolded sighted participants were presented with two haptic allocentric spatial tasks: a parallel-setting task, in an immediate and a 10-sec delay condition, and a task in which the orientation of a single bar was judged verbally. With respect to deviation size, the data suggest that mental visual processing filled a beneficial role in both tasks. In the parallel-setting task, the early blind performed more variably and showed no improvement with delay, whereas the late blind did improve, but less than the sighted did. In the verbal judgment task, both early- and late-blind participants displayed larger deviations than the sighted controls. Differences between the groups were absent or much weaker with respect to the haptic oblique effect, a finding that reinforces the view that this effect is not of visual origin. The role of visual processing mechanisms and visual experience in haptic spatial tasks is discussed.

What is the link between language and spatial images? Behavioral and neural findings in blind and sighted individuals

In order to find objects or places in the world, multiple sources of information, such as visual input, auditory input and asking for directions, can help you. These different sources of information can be converged into a spatial image, which represents configurational characteristics of the world. This paper discusses the findings on the nature of spatial images and the role of spatial language in generating these spatial images in both blind and sighted individuals. Congenitally blind individuals have never experienced visual input, yet they are able to perform several tasks traditionally associated with spatial imagery, such as mental scanning, mental pathway completions and mental clock time comparison, though perhaps not always in a similar manner as sighted. Therefore, they offer invaluable insights into the exact nature of spatial images. We will argue that spatial imagery exceeds the input from different input modalities to form an abstract mental representation while maintaining connections with the input modalities. This suggests that the nature of spatial images is supramodal, which can explain functional equivalent results from verbal and perceptual inputs for spatial situations and subtle to moderate behavioral differences between the blind and sighted.

Topic familiarity and information skills in online credibility evaluation

With the rise of user-generated content, evaluating the credibility of information has become increasingly important. It is already known that various user characteristics influence the way credibility evaluation is performed. Domain experts on the topic at hand primarily focus on semantic features of information e.g., factual accuracy, whereas novices focus more on surface features e.g., length of a text. In this study, we further explore two key influences on credibility evaluation: topic familiarity and information skills. Participants with varying expected levels of information skills i.e., high school students, undergraduates, and postgraduates evaluated Wikipedia articles of varying quality on familiar and unfamiliar topics while thinking aloud. When familiar with the topic, participants indeed focused primarily on semantic features of the information, whereas participants unfamiliar with the topic paid more attention to surface features. The utilization of surface features increased with information skills. Moreover, participants with better information skills calibrated their trust against the quality of the information, whereas trust of participants with poorer information skills did not. This study confirms the enabling character of domain expertise and information skills in credibility evaluation as predicted by the updated 3S-model of credibility evaluation.

Neural correlates of intentional communication

We know a great deal about the neurophysiological mechanisms supporting instrumental actions, i.e., actions designed to alter the physical state of the environment. In contrast, little is known about our ability to select communicative actions, i.e., actions directly designed to modify the mental state of another agent. We have recently provided novel empirical evidence for a mechanism in which a communicator selects his actions on the basis of a prediction of the communicative intentions that an addressee is most likely to attribute to those actions. The main novelty of those findings was that this prediction of intention recognition is cerebrally implemented within the intention recognition system of the communicator, is modulated by the ambiguity in meaning of the communicative acts, and not by their sensorimotor complexity. The characteristics of this predictive mechanism support the notion that human communicative abilities are distinct from both sensorimotor and linguistic processes.

Health empowerment through activity trackers

The increasing popularity of activity trackers has shown a remarkable shift in human computer interaction; individuals seem willing to wear a device that constantly tracks health related metrics such as movement, exercise, sleep, and calorie burn. Using the insights derived from their activity trackers, individuals are expected to be more empowered to set and stick to personal health goals. Whereas the outcome of using activity trackers is of great importance to both individuals and society at large, there are no empirical studies substantiating this presumption. This study aims to contribute to filling this research gap. Making use of self-regulation theory as theoretical framework, we developed a model that proposes six system specific elements (attractiveness, monitoring, feedback, privacy protection, readability, and gamification) as determinants of health empowerment, and thereof health commitment. Using survey data collected from individuals wearing smart wristbands (Nź=ź210), the model was validated. Overall, the results provide strong support for the health empowering capabilities of smart wristbands. The paper concludes with implications for theory and practice, and some suggestions for future research. We test the influence of smart wristband characteristics on health empowerment.Attractiveness, gamification, readability, feedback, and privacy drive empowerment.Perceived monitoring does not contribute to health empowerment.Health empowerment contributes to both affective and normative commitment.