摘要:

We describe marking menus, an extension of pie menus, which are well suited for stylus-based interfaces. Pie menus are circular menus subdivided into sectors, each of which might correspond to a different command. One moves the cursor from the center of the pie into the desired sector. Marking menus are invisible pie menus in which the movement of the cursor during a selection leaves an "ink trail" similar to a pen stroke on paper. The combination of a pie menu and a marking menu supports an efficient transition from novice to expert performance. Novices can "pop-up" a pie menu and make a selection, whereas experts can simply make the corresponding mark without waiting for the menu to appear. This article describes an experiment in which we explored both articulatory and cognitive aspects of marking menus for different numbers of items per menu and using different input devices (mouse, trackball, and stylus). The articulatory aspects are how well subjects could execute the physical actions necessary to select from pie marking menus. Articulatory aspects were investigated by presenting one group of subjects with the task of selecting from fully visible menus. Because one feature of marking menus is that users should be able to select from them without seeing the menus (by making a mark), we also ran two groups of subjects with invisible pie menus: one group with an ink trail and one without. These subjects were therefore faced with the task of either mentally representing the menu or associating marks with the commands they invoked through practice. These then are the cognitive aspects to which we refer. Our results indicate that subjects' performance degraded as the number of items increased. When menus were hidden, however, subjects performance did not degrade as rapidly when menus contained even numbers of items. We also found subjects performed better with the mouse and stylus than with the trackball.

ISSN:0737-0024    

DOI:10.1207/s15327051hci0801_1

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1993

数据来源: Taylor

摘要:

Four experiments were performed to test the relationship between instructionally derived knowledge and practice in the use of a simple device. Using a derivative of Kieras and Bovair's (1984) device, we show that different subjects can be given instructions that convey equivalent information but that lead to crossovers in the time to perform different tasks (i.e., one task is easier with one set of instructions, a second task is easier with other instructions). Experiment 1 shows that the performance crossover between question types perseveres when subjects relinquish the instructions, after they have been committed to memory. Experiment 2 shows that the performance crossover perseveres over considerable experience using the device. Experiment 3 shows that the crossover can disappear if sufficient practice is given with the particular question types. Experiments 2 and 3 taken together suggest that subjects may only be able to overcome the computational disadvantages of their initial instructional material by adopting task-specific strategies. Experiment 4 shows that when new problems are introduced after the point at which the crossover disappears then a new crossover appears, implying that, even with extended practice of operating the device and solving problems on the device, some features of the initial instructional device description are preserved and continue to determine the users' behavior. We argue that a definition of internalization coupled with Anderson's (1983, 1987) ACT* theory of skill acquisition provides a good account of these results.

ISSN:0737-0024    

DOI:10.1207/s15327051hci0801_2

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1993

数据来源: Taylor

摘要:

To guide the design of advice-offering user-assistance software, "Wizard of Oz" techniques were used to observe the interaction between users of a graphical statistical package and a human playing the role of a simulated intelligent advisory system. The results emphasize the complexities of advisory processes. Video data for 34 cases of advice seeking, giving, and following were analyzed in detail. The evidence indicates that clients followed prescriptive advice effectively and efficiently in slightly more than half the cases. For other cases, clients performed twice as many actions as needed in three times as much time and never reached prescribed states. A hypothesis that observed advice-following difficulties were correlated with advice abstractness was not supported. Rather, it seems advice did not match well with client's knowledge of the system. Impacts on advisory system design are discussed.

ISSN:0737-0024    

DOI:10.1207/s15327051hci0801_3

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1993

数据来源: Taylor