Martin Groen

The Effect of Substituting Discourse Markers on Their Role in Dialogue

There is general agreement that discourse markers help dialogue partners to highlight or locate available goal- or coherence-related information. There is, however, less agreement with regard to how the nature of the relation between the marked stretch of discourse and the rest of the dialogue should be defined. Recent work (Louwerse & Mitchell, 2003) has used a substitution test to characterize the relation a discourse marker expresses. It is unclear, however, what the effects are of substitution on the suggested role of discourse markers. In this article, 7 experiments are reported. Four experiments examine the suggested role of discourse markers across a variety of topics, domains, languages, and media formats. The results indicate that discourse markers are helpful to localize the stretches of discourse that are believed to contain pragmatic information pertaining to discourse coherence and dialogue goals. Three experiments investigated the effect of the substitution of discourse markers on their suggested role. The results show that substitution has a differential effect on the localization and assessment of coherence and dialogue goals. Based on these results, it is recommended that care needs to be taken when substituting discourse markers because the functional relation between the marker and the marked stretch of dialogue could be compromised.

Improving video-mediated communication with orchestration

Video-mediated communication (VMC) has become a popular communication medium. However, research to date suggests that the inherent constraints of VMC impair effective and efficient communication and task performance. We propose that these negative findings could be attributed to how the technology was used and propose the novel concept of communication orchestration aimed at mitigating some of the signaled limitations. Orchestration is a selection process for displaying information that is deemed relevant for accomplishing an effective and efficient task performance and communicative experience. We report an experiment that confirmed this suggestion. The results indicate that orchestration could be an important novel feature to aid humans when communicating via VMC, but also suggest that there is potential for further improvements in orchestration.

Automatic orchestration of video streams to enhance group communication

Unlike legacy video-conferencing, which connects two nodes each equipped with a camera, recent systems facilitating for video-mediated group communication deal simultaneously with a large number of video streams. This highlights the need for orchestration,, i.e. the intelligent selection of the most adequate camera views to be displayed on each screen. In this paper we present the initial results of a study that evaluates the effects of orchestration on communication within a specific context; that of two remote groups playing a collaborative board game. The results of the experiment indicate that automatic orchestration can provide improvements similar to the ones achieved when live video mixing is performed by human editors.

On the edge: haptic discrimination of edge sharpness.

The increasing ubiquity of haptic displays (e.g., smart phones and tablets) necessitates a better understanding of the perceptual capabilities of the human haptic system. Haptic displays will soon be capable of locally deforming to create simple 3D shapes. This study investigated the sensitivity of our haptic system to a fundamental component of shapes: edges. A novel set of eight high quality shape stimuli with test edges that varied in sharpness were fabricated in a 3D printer. In a two alternative, forced choice task, blindfolded participants were presented with two of these shapes side by side (one the reference, the other selected randomly from the remaining set of seven) and after actively exploring the test edge of each shape with the tip of their index finger, reported which shape had the sharper edge. We used a model selection approach to fit optimal psychometric functions to performance data, and from these obtained just noticeable differences and Weber fractions. In Experiment 1, participants performed the task with four different references. With sharpness defined as the angle at which one surface meets the horizontal plane, the four JNDs closely followed Weber’s Law, giving a Weber fraction of 0.11. Comparisons to previously reported Weber fractions from other haptic manipulations (e.g. amplitude of vibration) suggests we are sufficiently sensitive to changes in edge sharpness for this to be of potential utility in the design of future haptic displays. In Experiment 2, two groups of participants performed the task with a single reference but different exploration strategies; one was limited to a single touch, the other unconstrained and free to explore as they wished. As predicted, the JND in the free exploration condition was lower than that in the single touch condition, indicating exploration strategy affects sensitivity to edge sharpness.

Using eye tracking to evaluate usability of user interfaces: Is it warranted?

Abstract The evaluation of the usability of user interfaces is a crucial element in the design of computer software and other products with user interfaces. Owing to the availability of good quality, affordable eye tracking equipment and the arguable visual nature of interacting with user interfaces, the use of this methodology in usability evaluation is increasing. However, recent studies indicate that the relationship between eye movements and task performance is not as straightforward as has been suggested previously. It was found that careful alterations in the design of user interfaces did not lead to the expected improvement in task performance. This calls into question the use of eye tracking as a tool to assess usability.

User-Centred Design as a Risk Management Tool

Numerous risks have been identified to and from the design process. The most prominent approach to address design shortcomings is user-centred design (UCD); however, current implementations of UCD tend to overemphasise differences between users which make it less acceptable as a viable approach to the process of design and the goal of risk management. Three cases are discussed that illustrate a progression of design approaches from a lack of consideration of the user (accommodation; Control room design) to a more limited consideration of user needs through the consultation of guidelines (e-commerce website design) to an attempt to consider user needs through detailed study (assimilation; Consumer product design). It is proposed that the assimilation of user task behaviour in the design life-cycle will ensure the inclusion of usability considerations, thereby enabling UCD to be utilised as a risk management tool.

Establishing Goals and Maintaining Coherence in Multiparty Computer-Mediated Communication

Communicating via text-only computer-mediated communication (CMC) channels is associated with a number of issues that would impair users in achieving dialogue coherence and goals. It has been suggested that humans have devised novel adaptive strategies to deal with those issues. However, it could be that humans rely on “classic” coherence devices too. In this study, we investigate whether relevancy markers, a subset of discourse markers, are relied on to assess dialogue coherence and goals. The results of two experiments showed that participants oriented systematically on the relevancy markers and that substitution of the original markers for other (dis)similar words affected eye movements and task performance. It appears that, despite the loosely connected dialogue contributions, the multiple concurrent dialogues, and the multiparty nature of text-only CMC dialogues, humans are able still to locate coherence- and goal-related information by relying on the presence of the relevancy markers.