Empirical studies on MLA

1.6.1

In virtual space

The importance of MLA in virtual environments has not been widely addressed with user studies. Most of the existing work about it focused on the first kind of MLA interface we describe in section 1.5.2: verbal description of MLA in the context of text-based virtual reality.

Dillenbourg and Traum (1997) however investigated the effects of MLA in a text- based virtual reality (MOO environment). In this context, pairs of participants had to collaborate in finding a killer in a virtual and closed environment by gathering various clues located in different rooms. The authors found that location awareness supported implicit coordination. Indeed, the subjects did not check systematically where their partner was, but rather maintained this knowledge without explicit acts. MOO features correspond to several MLA tools. One of these is the fact that the MOO environment automatically provides information about mutual positions: every time a message was received in the chat, every time users met or separated, plus every time when one saw the consequence of an action being performed by one's partner, and so forth. The authors describe how MLA supported implicit coordination: since each partner could observe where the other went without asking him explicitly, it eased the game resolution given that each visited room meant that the clues had been collected. The user path indeed reflected his or her strategy (at least if it seemed to follow a direction) and one partner might have anticipated the other’s intentions by tracing his or her spatial path (if the user knows that the upper corridor has 4 aligned rooms and that his partner had visited the three first ones, he would have certainly expected the partner to visit the fourth room). Mutual understanding was also improved by knowing where one's partner has been. For instance, if A knew that B had gone to room 5 and that a suspect was located in room 5, then A might infer that B had probably collected information from the suspect. This was due to the direct mapping between virtual space (rooms) and the problem space (one suspect or object was located in each room). MLA then helped to know what one’s partner knew, a first step in building a shared understanding of the task.

Other results from the experiment accounted for the importance of spatial features in collaboration. For instance, the authors describe how space was the main criterion for division of labor among the participants of groups. The subjects had to collect information from 12 suspects located in different rooms. All of the 20 pairs coordinated their work on a spatial basis (e.g. one member explores the rooms in the upper corridor and the other does the same in the lower corridor). A final lesson from the experiment was that MLA supports grounding through the creation of a micro- context: when the users met, they expected their partner to say something about the suspects or the objects located in that room. This micro-context helped to establish mutual understanding: knowing what one’s partner knows is a first step in building a shared comprehension of the task.

Montandon (1996) also dealt with virtual textual environments. In her experiment, pairs of participants had to find four letters that constituted a word. To do that, they

had to answer to questions located in MOO rooms: each letter was obtained by answering questions and each question was located in a room. For each question, a clue was available in another room. The subjects had to explore the rooms to get the questions and, if necessary, the clues. However, if the two players met in a room, they were punished and sent to a room far away. They hence needed good coordination to avoid accidental meetings. Montandon found that users performed lots of explicit acts of spatial coordination when they were not provided with MLA. She described explicit acts of coordination as communication regarding the current position, the future position and use of the “who” command which allows one to see who is where.

A usability study of MLA in groupware has also showed the benefit groups can draw upon when using telepointers and a map (Gutwin and Greenberg, 1998). The authors tested how the presence of “workspace miniatures” (map and telepointers) would affect the group task performance. They compared two conditions (having or not having these MLA interfaces) in three tasks using a shared workspace that consisted of a virtual representation of a pipeline construction kit. Each of the tasks was a variation on the pipeline collaborative construction. What Gutwin and Greenberg found was that in two tasks completion time was lower with the MLA interface, and in the third one, communication was less efficient. The authors counted the visual communication provided by the map as a factor in success, as well as the potentiality of the tool to provide a continuous feedback to the others (people did not have to wait the end of the interaction to see the what was being done).

1.6.2

In physical space

It is in the field of mobile computing that MLA usage has recently drawn more attention, because of the frenzy of development of location-based systems (LBS). A relatively important part of the features developed for LBS concern collaborative components enabling people to be aware of others' location. Mostly technology- driven, the exploration of MLA's roles and influences has been done to test the potential of LBS applications. The investigations of how LBS applications would be used have been conducted in different contexts using field experiments, ethnomethodological studies and surveys. Three recurrent kinds of tasks have been used in pervasive computing for that matter: games in which participant had to find people and/or objects (Benford et al., 2004, 2004; Licoppe & Inada, 2005), simple real-world tasks such as rendezvousing and navigation (Dearman et al., 2005; Axup et al., 2005) and museum exhibit exploration (Brown et al., 2003). Note that these studies only address synchronous and “position-based” MLA interfaces (information about partners’ in space, shown on a map in real-time), delineating the different roles such systems play in collaboration.

Based on a review of how MLA was used in the pervasive environment described above, four roles stood out: initiation of communication, a resource for conversation, an “ambient virtual copresence” tool, and finally a means to monitor the task completion. With regards to the interfaces described in section 1.5 , all the studies about MLA only address synchronous location-awareness conveyed by maps (scrollable or not).

Mutual Location-Awareness indeed influences different moments of verbal interactions in pervasive games. For instance, Licoppe and Inada (2005) studied a

location-based game, deployed in Japan called Mogi Mogi, in which players have to collect virtual localized artifacts in Tokyo. Players had a MLA interface in the form of a map on cell-phones similar to the Botfighters version showed in section 1.5.5. The authors noticed that knowing the others’ positions on the cell phone screen created an affordance for social encounters and led to specific forms of conversational openness. Location awareness in this context was often used to trigger a conversation. For Brown et al. (2003), a different component of verbal interactions was influenced by the presence of MLA: the content of the conversation. They explored how a mixed reality system would augment visits to museums by allowing voice communication and sharing information concerning location and orientation (represented as a map). Their experiment of this location-awareness tool showed that MLA was a powerful resource for conversation, easing referential communication (the understanding that an item which is present in an individual’s vicinity is the topic of the conversation). Knowing the partners’ location indeed helped to derive deictic cues: it enabled participants to understand what the partner was looking at and thus encouraged either talk about it or incited the partner to look at the same thing. Similarly, in a study of the pervasive game “Uncle Roy All Around You” Benford et al., (2004) demonstrated that MLA (in the form of a map) provided cues that can be perceived as “deictical” linguistic elements to give directions or tell one’s location. In this game, on-line and street players have to collaborate to find an elusive character called “Uncle Roy”. In this context, MLA was used to indicate direction in two ways: either by using the known location to derive possible directions (“you are very close now, stay on that side of the road”) or by giving directions using absolute geographical references (such as landmark: “Go to 12 Waterloo Place”).

Additionally, when studying how location-aware technology impacts social behavior within the context of rendezvousing (meeting at an agreed upon time and location), Dearman et al., (2005) compared three different technology conditions: using a mobile phones, using a PDA displaying MLA as a scrollable map and using both devices. All of the groups were able to complete the rendezvous tasks without much difficulty but participants exhibited very different behaviors depending on the technology used. The phone appeared to be relevant for discussing actions (“what are you doing?”) and intentions (“where are you planning to go?”) but the MLA displayed on the PDA was more efficient to find partners and to provide users with a feeling of “ambient virtual copresence”; MLA was, in the authors’ words, a “background communication channel to monitor their partner” (Dearman et al., 2005, p. 561). Furthermore, by seeing in an unobtrusive manner people’s position and movement, the MLA feature provided information about partner’s contribution to the task, as well as their progress.