Target Acquisition in Multiscale Electronic Worlds

Since the advent of graphical user interfaces, electronic information has grown exponentially, whereas the size of screen displays has stayed almost the same. Multiscale interfaces were designed to address this mismatch, allowing users to adjust the scale at which they interact with information objects. Although the technology has progressed quickly, the theory has lagged behind. Multiscale interfaces pose a stimulating theoretical challenge, reformulating the classic target-acquisition problem from the physical world into an infinitely rescalable electronic world. We address this challenge by extending Fitts’ original pointing paradigm: we introduce the scale variable, thus defining a multiscale pointing paradigm. This article reports on our theoretical and empirical results. We show that target-acquisition performance in a zooming interface must obey Fitts’ law, and more specifically, that target-acquisition time must be proportional to the index of difficulty. Moreover, we complement Fitts’ law by accounting for the effect of view size on pointing performance, showing that performance bandwidth is proportional to view size, up to a ceiling effect. The first empirical study shows that Fitts’ law does apply to a zoomable interface for indices of difficulty up to and beyond 30 bits, whereas classical Fitts’ law studies have been confined in the 2-10 bit range. The second study demonstrates a strong interaction between view size and task difficulty for multiscale pointing, and shows a surprisingly low ceiling. We conclude with implications of these findings for the design of multiscale user interfaces

Polar and Cartesian Structure in the Data of Fitts's (1954) Classic Experiments-With a Criterion for Distinguishing a Strong and a Weak Version of Fitts' Law

International audienc

On the Measurement of Movement Difficulty in the Standard Approach to Fitts' Law

Fitts' law is an empirical rule of thumb which predicts the time it takes people, under time pressure, to reach with some pointer a target of width W located at a distance D. It has been traditionally assumed that the predictor of movement time must be some mathematical transform of the quotient of D/W, called the index of difficulty (ID) of the movement task. We ask about the scale of measurement involved in this independent variable. We show that because there is no such thing as a zero-difficulty movement, the IDs of the literature run on non-ratio scales of measurement. One notable consequence is that, contrary to a widespread belief, the value of the y-intercept of Fitts' law is uninterpretable. To improve the traditional Fitts paradigm, we suggest grounding difficulty on relative target tolerance W/D, which has a physical zero, unlike relative target distance D/W. If no one can explain what is meant by a zero-difficulty movement task, everyone can understand what is meant by a target layout whose relative tolerance W/D is zero, and hence whose relative intolerance 1–W/D is 1 or 100%. We use the data of Fitts' famous tapping experiment to illustrate these points. Beyond the scale of measurement issue, there is reason to doubt that task difficulty is the right object to try to measure in basic research on Fitts' law, target layout manipulations having never provided users of the traditional Fitts paradigm with satisfactory control over the variations of the speed and accuracy of movements. We advocate the trade-off paradigm, a recently proposed alternative, which is immune to this criticism

Understanding the Three-Dimensional Conceptual Space of Fitts' Aimed-movement Paradigm

Unpublished manuscript, 48 pages.Fitts' law is a well known empirical relation which predicts aimed-movement time (MT) from target distance (D) and target width (W). Fitts' demonstration that MT, within limits, depends essentially on the ratio D/W implies a scale invariance that reduces the paradigm from three dimensions (MT, D, and W) to two (MT and D/W). This reduction, however, is legitimate only for narrow ranges of scale variations, a limitation that appears to have been overlooked so far. This paper advocates an explicit three-dimensional construal of Fitts' paradigm involving not only the speed (MT) and the relative amplitude (D/W), but also the absolute amplitude (D), or scale of movements. Not only is this three-dimensional description of Fitts' paradigm a technical necessity for the classic study of Fitts' law, but it paves the way for a more complete modelling of aimed-movement performance and suggests a promising adaptation of Fitts' paradigm to the recently emerged problem of target selection in zooming interfaces

Quantifying Degree of Goal Directedness in Document Navigation: Application to the Evaluation of the Perspective-Drag Technique

International audienceThis article pursues a two-fold goal. First we introduce degree of goal directedness (DGD), a novel quantitative dimension for the taxonomy of navigation tasks in general. As an attempt to operationalize the DGD concept in the context of electronic documents navigation, we introduce the serial target-acquisition (STA) experimental paradigm. We suggest that DGD and the STA paradigm may usefully enrich the conceptual toolkit of HCI research for the evaluation of navigation techniques. Our second goal is to illustrate the utility of the DGD concept by showing with a concrete example, Perspective Drag, the refinement it allows in evaluating navigation techniques. We report data obtained from two experiments with the STA paradigm that cast light on what Perspective Drag is specifically good for: it is particularly suitable in realistic task contexts where navigation is less than 100% directed by its terminal goal, that is, where the user wants not only to reach a particular item but also to pick up information from the document during document traversal

Not Just Pointing: Shannon's Information Theory as a General Tool for Performance Evaluation of Input Techniques

This article was submitted to the ACM CHI conference in September 2017, and rejected in December 2017. It is currently under revision.Input techniques serving, quite literally, to allow users to send information to the computer, the information theoretic approach seems tailor-made for their quantitative evaluation. Shannon's framework makes it straightforward to measure the performance of any technique as an effective information transmission rate, in bits/s. Apart from pointing, however, evaluators of input techniques have generally ignored Shannon, contenting themselves with less rigorous methods of speed and accuracy measurements borrowed from psychology. We plead for a serious consideration in HCI of Shannon's information theory as a tool for the evaluation of all sorts of input techniques. We start with a primer on Shannon's basic quantities and the theoretical entities of his communication model. We then discuss how the concepts should be applied to the input techniques evaluation problem. Finally we outline two concrete methodologies, one focused on the discrete timing and the other on the continuous time course of information gain by the computer

New Mexico Lobo, Volume 046, No 32, 3/10/1944

New Mexico Lobo, Volume 046, No 32, 3/10/1944https://digitalrepository.unm.edu/daily_lobo_1944/1006/thumbnail.jp

The additivity of stimulus-response compatibility with the effects of sensory and motor factors in a tactile choice reaction time task

A tactile, two-choice, reaction time experiment is reported in which the effects of stimulus-response compatibility, response repertoire, and stimulus intensity are found to be additive. The implication of these results for the underlying information processing stage structure is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27727/1/0000119.pd

Nouvelles interactions physiques pour dispositifs mobiles

Soixante pour cent de la population mondiale possède aujourd'hui un téléphone portable. Les modèles récents, qui tendent à devenir de petits ordinateurs portables, sont jusqu à 10 000 fois plus puissants et 300 000 fois moins lourds que le premier ordinateur, apparu voici 60 ans. Malgré cette puissance, et les ressources offertes par les équipements dont ils sont munis (écran tactile multitouch, accéléromètres et autres capteurs...), les mobiles souffrent de certaines limitations du fait de la disparition de nombreux périphériques d'entrée classiques tels que le clavier et la souris. Afin d'augmenter la bande passante interactionnelle de ces dispositifs et de tirer partie de ces capteurs, nous nous sommes intéressé dans cette thèse aux possibilités offertes par l'interaction gestuelle en considérant deux axes de recherche : les mouvements sur le mobile et les mouvements du mobile. Après avoir proposé un espace de classification nous avons conçu et développé plusieurs techniques d'interaction gestuelle destinées à enrichir et faciliter l'interaction de l'utilisateur avec ces dispositifs.Concernant les mouvements sur le mobile, nous nous sommes intéressé à l'amélioration du Flick, une technique de défilement largement popularisée ces dernières années. Après avoir étudié son anatomie , nous avons proposé d'exploiter plusieurs ressources interactionnelles jusqu'à présent inutilisées. Ce travail a donné naissance à trois nouvelles techniques: Flick-and-brake et LongFlick, qui utilisent respectivement la pression sur l'écran et les caractéristiques du geste de lancer pour mieux contrôler le défilement, et 'Semantic Flicking' qui exploite la sémantique du document pour faciliter la lecture. Dans un second temps nous avons considéré les possibilités offertes par l'interaction 3D, en déplaçant le dispositif mobile dans l'espace. Cette voie de recherche vise à permettre d'augmenter le vocabulaire d'interaction sans parasiter les interactions tactiles déjà existantes. Tirant parti des capteurs intégrés dans les mobiles, en particulier les accéléromètres, nous avons proposé deux nouvelles techniques d'interaction 3D : TimeTilt qui utilise des gestes fluides et impulsifs pour naviguer aisément entre différentes vues et JerkTilt qui introduit la notion de gestes 'auto-délimités' pour accéder rapidement à des commandes. Ces gestes auto-délimités ayant également la particularité de pouvoir être facilement combinés avec des interactions sur l'écran, nous avons enfin considéré la combinaison des modalités offertes par les gestes bi- et tri-dimensionnels.Sixty percent of the world's population now owns a mobile phone. Recent models, which tend to become small laptops are up to 10 000 times more powerful and 300 000 times less heavy than the first computer, appeared 60 years ago. Despite this power and all the resources provided by modern equipment (touchscreen, accelerometer and other sensors...), mobile phones suffer from certain limitations due to the lack of conventional input such as keyboard and mouse. To increase the interaction bandwidth of these device and take advantage of these sensors, we investigate the potential offered by gestural interaction by considering two lines of research: movements on the mobile and movements of the mobile. After defining a classification space we conceived and developed several gestural interaction techniques to enrich and facilitate interaction between the user and these devices. For the movements on the mobile we have proposed to improve the flick, a scrolling technique widely popularized in recent years. We first studied his anatomy of this technique, then we proposed to exploit multiple interactional resources hitherto unused. This work gave birth to three new techniques: Flick-and-Brake and LongFlick, that respectively use the pressure on the screen and the characteristics of the throwing action to better control scrolling, and Semantic Flicking which leverage on document semantics to facilitate reading. In a second stage we considered the potential of 3D interaction, by moving the mobile device in the space. This line of research aims at expanding the interaction vocabulary while avoiding interferences with existing touch interactions. Leveraging on integrated sensors such as accelerometers, we proposed two new techniques for 3D interaction: TimeTilt, which uses smooth and impulsive gestures to easily navigate between different views, and JerkTilt, which introduced the notion of self-delimited gestures for accessing quickly to commands. An interesting property of these self-defined gestures is their ability to be combined with common interactions on the screen. We thus finally considered the combination of modalities offered by the two and three-dimensional gestures.PARIS-Télécom ParisTech (751132302) / SudocSudocFranceF