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Presentation of the dissertation project and the research results to date (Graf) Print E-mail

Presentation of the dissertation project and the research results to date:

Initial Questions and Goal of the Project

The long perspective goal of the workgroup’s investigations is to unfold the relation of tactile maps and verbal annotations to convey spatial meaning. One necessary prerequisite is to know how tactile primitives convey meaning in an ensemble such as a tactile map. Instead of investigating the sensory properties of tactile maps and what requirements they impose, my focus is to investigate the properties of tactile maps on the cognitive level. The open question is how different topologic parameters, different geometric parameters, the realisation of Gestalt principles, and the interplay of all factors contribute to the cognitive complexity of tactile maps. The goal of this dissertation project is to provide guidelines on (a) which cognitive complexity is induced by which parameters in a tactile map and (b) at which level of complexity there is the need to include a second modality to provide enough information so that visually impaired map users can obtain survey knowledge of the environment.

Approach & Method

Even if visually impaired people outperform sighted people in the discriminating tactile entities, they lose their gain fast (Postma et al., 2008) and do not perform as well when active elaboration is required (Vecchi, 1998). The research questions introduced here depend on cognitive abilities that demand the tacit and procedural knowledge of how to interpret a map. As visually impaired people are often not trained in reading maps, sighted and blind-folded people are our test subjects during this stage of the experiments. One way of investigating the representations acquired from tactile maps is to evaluate what people can do with these representations. As one cannot directly evaluate survey knowledge, a mixture from tasks that require survey knowledge is used to assess the performance that can be achieved when using maps made from different inventories. These tasks are (1) sketch drawing to activate visuo-spatial mental models which are believed to capture an allocentric view of the world and (2) verbalization of route descriptions which are believed to capture an egocentric view of the world. Thus one can evaluate if test subjects could infer some route knowledge or survey knowledge from the map.

Experiments – Past and Future

In this dissertation project, the focus is on a special class of external representations, namely You-Are-Here (YAH) maps (Levine, 1982; O’Neill, 1999). A YAH map is a static display that represents the immediate environment in which it is mounted. The position of the map is designated by the YAH symbol in the map space.

Appropriate Support for Using Tactile YAH Maps

I assume two processes with a tactile YAH map: in the beginning map users search for the YAH symbol to find the representation of their current position in the map. Having found this position, map users explore the map to gain an understanding of the environment. Two questions arise: Which type of (tactile) indicator to the YAH symbol results in the smallest search time when looking for it? Which type of indicator is the least hindering in exploring the map after the YAH symbol is found?

From the first experiment I can conclude that both the behavioural data as well as the data from cognitively orientated task indicate that using a guiding line or border marks might be a cognitively adequate solution to the problem of indicating the YAH symbol in the map tactually. The results from the survey about what users find more useful and least hindering support that conclusion as test subjects showed a strong tendency to prefer the border marks to the guiding line. These results can be used as baseline condition in further experiments.

Building an Cognitively Motivated Inventory for Outdoor Environments structured by Paths

From the first experiment I have gained some hints in the experiment that it might make a cognitive difference how the same topologic configuration is used in the realization of a route (here, we consider only outdoor environments). Considering intersections, it makes a difference of how T and X-intersections are travelled. Going straight seems to be the default operation, but turning involves the decisions against a different amount of options. This should be accounted for when a route is realized. The same holds true for the succession of straight segments composing a long straight track. This is the preferred option according to the Gestalt principle of continuation. Any (correct) decision against that preferred option should be considered of higher value than simply following the preferred option. I will investigate how different topologic, geometric, and Gestalt parameters influence the cognitive complexity of a tactile map.

Complexity Threshold for Tactile YAH Maps

Using artificial maps with a limited amount of tracks and landmarks might be a factor that makes it questionable if I could generalize the findings to more complex maps. I hypothesize that there is a certain cognitive complexity that demarcates the upper limit of content that can be conveyed through standard tactile maps to support knowledge acquisition about the environment. I will run experiments with abstracted maps of real environments that are of different cognitive complexity (realized with the inventory found in the former experiments) and check at what level the majority of people cannot grasp the structure from the tactile map any more. The inventory which was developed in the second experiment will be used to check which complexity of environmental features could be displayed in tactile YAH maps. The aim is to investigate the relation between inventory, complexity and understanding under the objective that the YAH maps will be still useful and useable, i.e. it could be used to gain an overview of the environment.

Expected Results

I will be able to give a set of design recommendations for cognitively appropriate tactile maps based on a tested inventory of entities and the effects of relationships amount them. It will be possible to give an estimate for which cognitive task a tactile map alone will probably be enough and for which task the user would need another support. The results from the investigations about an inventory for tactile YAH maps in combination with the results from the investigations into the complexity threshold will give some insights into the mutual dependencies of these factors and might shed some light onto other aspects, e.g. prerequisites for the application of these recommendations in a computer controlled process for the production of tactile maps. An extension to these results would be to find out if the recommendations are applicable for other contexts and if yes under which modifications.

Links to Other Internal & External Projects

Cengiz Acartürk, Doctoral Candidate at the Department for Informatics, works on the interaction of language and graphics in text-graph documents. If maps are seen as a special type of graph it becomes evident that his dissertation project and my dissertation project share some characteristics. We have had an inspiring exchange of thoughts through the whole time of our collaboration as colleagues at the same institute.

The project is linked with Kris Lohmann’s CINACS project, which is about how to convey map knowledge through the interaction of tactile maps and spoken language. I provided him with video taped tactile map explorations, which he used to gain insight and inspiration for his work. As we are using the set up and laboratory that I established for experiments, he could make use of my work and experience with the EmPrint Spot Dot Printer to produce tactile maps. We regularly talk about topics concerning tactile maps and often share literature or exchange hints on relevant publications. Kris and I plan to establish further collaborations concerning the cognitive processing of tactile maps.

As part of the cooperation with our Chinese partners my visit to China in 2009 included a research visit to Prof. Sun’s group and collaborations with Prof. Cai and with Prof. Wang. Prof. Cai is a member of CINACS and I worked with members of his research group after the CINACS Summer School 2009. One of his interests is utilizing speech act theory to structure language understanding. The aim of this collaboration was to analyse if and how speech act theory could be used to analyse existing verbal map descriptions and to develop recommendations on how to best construct such descriptions, i.e. descriptions that may not be misunderstood.

The CINACS Spokesperson Prof. Zhang recommended Prof. Wang to me. He is a robotics researcher with interest in multimodal interaction. Prof. Wang’s research interests are simulations of haptic experiences with force display technology. It was interested to discuss other applications of haptic technology and which conceptual inventories could be used in the tactile domain to not exceed the human cognitive abilities. This would help in the planning of the transfer from some visual application to the haptic equivalent.