Deborah M. Clawson

Prospective Memory and the Efficacy of a Memory Strategy in Multiple Sclerosis

Prospective memory (PM), which is the ability to remember to carry out actions that are planned for the future, plays an important role in professional and social life as well as in activities of daily living. This study examined PM performance among adults with multiple sclerosis (MS) and evaluated the efficacy of a mnemonic strategy, implementation intentions. Compared to controls, adults with MS were impaired on PM, both in terms of acting when encountering the correct circumstances (prospective component) and in terms of remembering the correct action to perform (retrospective component). The prospective-component deficit was greater for tasks that depended on more resource-demanding cognitive processes and smaller on tasks that could be performed more automatically. Use of implementation intentions improved MS-group performance on the prospective component, particularly on the more resource-demanding tasks, consistent with the explanation that implementation intentions improved performance by allowing the use of more automatic processes to perform these PM tasks. Implications for providing environmental support to encourage the use of mnemonic strategies are discussed.

Prompt comprehension in UNIX command production.

We hypothesize that a cognitive analysis based on the construction-integration theory of comprehension (Kintsch, 1988) can predict what is difficult about generating complex composite commands in the UNIX operating system. We provide empirical support for assumptions of the Doane, Kintsch, and Poison (1989, 1990) construction-integration model for generating complex commands in UNIX. We asked users whose UNIX experience varied to produce complex UNIX commands, and then provided help prompts whenever the commands that they produced were erroneous. The help prompts were designed to assist subjects with respect to both the knowledge and the memory processes that our UNIX modeling efforts have suggested are lacking in less expert users. It appears that experts respond to different prompts than do novices. Expert performance is helped by the presentation of abstract information, whereas novice and intermediate performance is modified by presentation of concrete information. Second, while presentation of specific prompts helps less expert subjects, they do not provide sufficient information to obtain correct performance. Our analyses suggest that information about the ordering of commands is required to help the less expert with both knowledge and memory load problems in a manner consistent with skill acquisition theories.

The long-term retention of knowledge and skills

Abstract : We received three classes of guidelines we found to optimize long-term retention. The first class concerned ways to optimize the conditions of training. We discussed three general guidelines in this class. The first concerned the contextual interference found, for example, with random sequences of tasks as opposed to fixed or predictable sequences. The second concerned training parts of a task versus the whole task. The third concerned the distinction between generating and reading. The second class of guidelines concerned ways to optimize the strategies used. We found that in tasks that require deliberate retrieval from memory, training that promotes efficient encoding strategies maximizes long-term retention. The third class of guidelines concerned ways to attain direct access, or automatic retrieval, from memory. We found in several domains that achieving automaticity requires extensive practice. Further, even when retrieval appears automatic after extensive practice, mediators may still continue to exert their influence.

Navigational Training in Virtual and Real Buildings

Three experiments explored aspects of virtual reality (VR) that may influence its utility for training in navigating architectural spaces. Taken together, these experiments suggest that the utility of virtual reality depends on characteristics of the user-virtual environment interface. In experiments testing the importance of movement control, full participant control of rotational and forward movement in VR led to nearly optimal training on a medium-sized building, but limited control in VR was worse than no control. Transparent walls, a VR possibility that goes beyond real-world options, were beneficial during training and on a direct measure of learning spatial layouts. Finally, in an experiment examining both training and transfer, VR training was similar to real-world training, and was quicker and transferred better to navigating a real-world building than floor-plan training. However, this held only when the testing route was traveled in the trained direction.

Interface design for inducing and assessing immersion in virtual reality

The prospect of individual virtual reality workstations pose new challenges for design of an interface that can provide an immersive experience in a relatively confined space. CyberSeat II is one strategy that provides a compelling virtual environment (VE) under these circumstances. This approach, as well as the tools for assessing spatial location in and out of a VE, are described.

Long-Term Retention of Spatial Knowledge Acquired in Virtual Reality

Retention of spatial knowledge was compared after acquisition using virtual reality (VR), a map, and a real building. Participants were trained to navigate a route and to note the locations of landmarks. Two weeks later they were tested on their ability to navigate the route and to point to the landmarks they had learned. They were tested in either an aligned or contra-aligned orientation. The orientation specificity for VR observed immediately after training in our previous experiment (Clawson, Miller, Knott, & Sebrechts, 1998) was magnified after retention. On the route test, the VR group performed better than the map group, but only when tested in the aligned orientation. On the survey test, the VR group was less accurate than the map or real building groups, especially in the contra-aligned condition. Potential cognitive and perceptual causes of this orientation specificity are discussed.

Initial Planning Benefits Complex Prospective Memory at a Cost

The effect of initial planning on complex prospective memory was investigated using a virtual environment and a sample of healthy young adults (N = 34). Participants were assigned to either an initial planning or a control condition and were asked to complete a series of time- and event-based prospective memory tasks. The planning group completed the tasks more quickly and accurately than the control group. However, the total time spent, including both planning and task execution, was comparable for the two groups. Within the planning group, tasks that were planned were more likely to be completed than unplanned tasks, but inclusion of overly detailed information in the plans resulted in poorer performance. These results suggest that although initial planning can be beneficial to task completion, the complexity of a plan may contribute to decrements in performance.