Background and Motivation

Our main goal with GROUPGARDENwas to develop a group mirror tailored to support face-

to-face brainstorming sessions and to investigate whether such a subtle intervention can im- prove brainstorming and facilitate social processes. There already exist group mirrors, which have been applied in brainstorming sessions. However, these are not specifically designed to support brainstorming. As described in Section 3.1, the original form of brainstorming by Osborn (1953) is based on a number of rules. Furthermore, a number of problems have been described in research in the context of co-located brainstorming. Our prototype aims at supporting these rules and at defying the described problems. It has been reported that balancing participation in brainstorming is beneficial for both quantity and quality of ideas (Oxley et al., 1996). We therefore included a mechanism that is designed to make group members aware of the balance of contributions during the brainstorming session.

GROUPGARDEN’s design uses metaphors derived from nature, in form of a garden scenery

with flowers, a tree and the sky with clouds and the sun. This choice is inspired by other work, which I will outline in the following. The second study deals with the factor of the display environment (table or wall). I will also summarize related work from this area of research.

The Garden Metaphor

The main reason why we chose a metaphorical visualization for the design of GROUPGAR- DENis a study conducted by Streng et al. (2009). This work is described in detail in Section

2.2.2, Figure 2.4 shows the metaphoric version during the study. The authors compared two versions of a group mirror with each other: a metaphoric and a diagrammatic visualiza- tion. The metaphors they used were trees and the weather, both representing the quality of contributions of different group members. The trees can change in gradation of five stages dependent on the quality of argumentation. These stages reach from a tree with leaves and fruits to a leafless tree. Similarly, the weather can change in five stages from cloudless sky to heavy rain. Furthermore, the times of day and night indicate different phases of the collab- orative task. When group members interrupt each other, a lightning covers the display. The diagrammatic visualization provides the same information. A column chart in five stages is used to represent the quality of the group members’ work. When collaborators interrupt

5 Supporting Brainstorming

each other, a red circle starts to flash. In a laboratory study, both versions were compared to each other. Results indicate that the metaphorical version supported self-regulative processes better than the diagram version and was further preferred by 70% of the participants.

Analogously to Streng et al. (2009), we relied on metaphors derived from nature because their effectiveness has been indicated in previous work. Furthermore, the metaphor of a garden is cross-culturally understandable and a relaxing and non-threatening environment, as Crossley et al. (1998) note. We presume that the organic nature of a garden is a feasi- ble metaphor for representing the highly dynamic process of a collaborative creativity task. Specifically, we chose flowers and a tree for visualizing the most important aspects of col- laborative brainstorming. Chau (2011) summarizes the advantages of the flower metaphor, which can be transferred to other plants such as trees as well. First, these metaphors are easy to understand (Lantin and Judelman, 2006; Xiong and Donath, 1999). Zhu (2002), for instance, could show that participants of her study showed a higher preference for the flower metaphor compared to a messenger without these metaphorical visualizations. Sec- ond, plants such as flowers and trees have a rich structure, which can represent different information that is not too difficult to be differentiated (Xiong and Donath, 1999). Third, positive and negative valuation can easily be encoded, for instance, by showing flourishing or withering plants.

We based the design of GROUPGARDENnot only on the work of Streng et al. (2009), but we

were also inspired by other projects that used natural metaphors (see for example, Section 5.1). Another approach using the metaphor of flowers and a garden is the PEOPLEGARDEN

by Xiong and Donath (1999). The concept of this work was already briefly described in Section 2.3.3. PEOPLEGARDENuses so-calleddata portraitsto represent individual partic-

ipants of online interaction environments (e.g., chats). Thesedata portraitsare clustered to visualizations resembling a garden (see Figure 2.6, bottom left), enabling group members to see their individual data as well as providing them with the possibility to compare mul- tiple group members. Xiong and Donath (1999) use the scenario of a Web-based message board. Flowers represent individual users. The petals of the flower represent the person’s postings, arranged in a temporal order. The color of the petals shows if a post starts a new conversation (magenta) or if it is a response to an already existing topic (blue). On top of the petals, pistil-like circles indicate the number of responses from other users. Furthermore, the saturation of the petals gives an indication of the time of a posting, as the color of the petals fades with time. The height of a flower represents how long someone has been a member of the message board, deploying the metaphor that older flowers already grew taller. The metaphor of a “healthy garden” is used, as bright flowers indicate an active discussion. Another example using flowers and trees as a metaphor for increasing motivation is the KNOWLEDGE GARDEN (Crossley et al., 1998). This is a 3D environment that uses the

metaphor of flowers to represent information, in their case automatically clustered Internet resources such as bookmarks.

The ITREE project (Nakahara et al., 2005) is a mobile phone application with the goal to

increase participation in online bulletin board systems (BBS). The flourishing of a tree and

Figure 5.1: Related work on metaphorical visualizations. The FLOWERGARDENby Lantin and Judelman (2006) (left), the UBIFITGARDENby Consolvo et al. (2008b) (middle) and two sketches of a flower visualization by Polleti et al. (2012) (right).

the color of a sky change dependent on the number of posts, number of times posts are read, number of replies to posts and the ratio of forum posts to replies. The authors could show that the metaphors could increase participation in the online board.

Another example, the FLOWERGARDEN(Lantin and Judelman, 2006), emerged from a col-

laboration of a designer and a computer scientist. Their concept comprises that each partici- pant is represented by a flower with petals that indicate conversation events that they entered in an online tool (see Figure 5.1, left). Participants had some freedom in designing their flowers as they could choose between differently colored and shaped petals. A studyin the wildrevealed that participants competed for the biggest and pretties flower.

The previously discussed systems have in common that they want to motivate group mem- bers in some sort of collaborative process. Streng et al. (2009) aim at increasing quality of contributions in a scripted collaborative scenario, Xiong and Donath (1999) have the goal to enhance participation in online interaction environments, Crossley et al. (1998) designed their system for a collaborative 3D information visualization tool, Nakahara et al. (2005) intend at increasing participation in a BBS and Lantin and Judelman (2006) both present a collaborative development process and designed the tool for a collaborative environment. Tools using metaphors derived from nature were also deployed in a number of other scenar- ios. The UBIFITGARDEN(Consolvo et al., 2008b) is designed for people who want to start

including regular physical activities in their daily lives. Here, a garden scenery is shown on a glanceable display on a mobile phone (see Figure 5.1, middle). Butterflies represent goal attainments and different types of flowers represent different types of physical activities. In two studies (see also Consolvo et al., 2008a), the authors could show that participants espe- cially perceived the glanceable display with the metaphors motivating. Results revealed that for participants without display, physical activity decreased over time and in phases in which maintaining physical activity is difficult (such as during holidays), which was not the case for participants that were made aware of their activities with the metaphorical visualization.

5 Supporting Brainstorming

Another tool using natural metaphors aims at visualizing Web search results (Chau, 2011). “Flower glyphs” represent different information and meta-information of search results: The petals represent keywords, the length of the stem resembles the document length, the number of leaves indicate external and internal outlinks and the size of the ground the flower is standing on represents the number of inlinks.

Lastly, I will briefly refer to a tool designed to lead to a continued engagement, in their ex- ample by reducing one’s personal carbon footprint (Polleti et al., 2012). Therefore, different design approaches were developed: visualizations using flowers (see Figure 5.1, right), pie charts, jelly fish and footprints. In summary, these studies and projects show that metaphors have found their way into a number of different technological tools with the goal to engage people in certain tasks. Usage scenarios reach from collaboration tools to systems designed for more engagement in physical activities. Several studies could show the benefits of these kinds of visualizations. However, the influence in a brainstorming scenario has not been investigated yet. A first prototype for this scenario is described in this section.

Comparisons of Table and Wall Displays

Another aspect that the study with GROUPGARDENinvestigates is a comparison of table and

wall displays. Evaluating the advantages of various types and sizes of displays has been a topic of research since these possibilities exist.

Mandryk et al. (2002) discuss seven different display factors, among them theorientation, theprivacy and thenumber of displays. The authors review the impact of these factors on group work. With the orientation of displays, Mandryk et al. (2002) refer to vertical (walls) and horizontal displays (tables). The main distinctions are that vertical displays offer the same view for all group members while people sitting around a table have different views. This can have an impact on several factors of the mechanics of collaboration described by Gutwin and Greenberg (2000), namely on coordinating, planning and monitoring of tasks. Besides that, particular objects may orient differently to the borders. On walls, objects frequently align with the lower edge while on horizontal surfaces, objects often do not align to the surface borders. Also, transient objects (such as mugs or notepads) can easily be placed on horizontal surfaces.

Inkpen et al. (2005) present a number of field studies investigating among other aspects the

display angle (referred to as display orientation by Mandryk et al. (2002)). They found differences regarding communication. Participants made more pointing gestures at a table display compared to a wall display. On the one hand, participants commented that sitting around a horizontal surface was more comfortable and natural than working with a vertical display. On the other hand, participants also reported that they were more focused on the task when working on the wall display. Other differences were found in regard to ergonomics. On the wall display, people tended to write larger and some of the participants stated that writing was more difficult. Furthermore, people tended to move more when working with a wall display.

Another direct comparison of horizontal and vertical displays was conducted by Rogers and Lindley (2004). Their results show that working on a tabletop display led to a more cohesive working style, while vertical displays are perceived as less beneficial for group work. However, their study only covered small groups, in their case, a group with three group members. For larger groups, vertical displays have a number of advantages, as more people can gather in front of a wall display compared to a tabletop display. Moreover, the task they chose required group members to create a number of different representations, meaning that interacting with the surface played an important role for the task. A comparison of table and wall displays in the specific context of a scripted collaboration has been conducted by Streng (2010). This study is described more in-depth in section 3.2.3. Figure 3.4 shows the setting of the system on table and wall displays.

The before described investigations of horizontal and vertical displays have in common that they anticipate displays with which group members can interact directly, for example, by touch or multi-touch gestures. Group mirrors, however, do not allow direct interaction as they are designed to stay in the periphery of the group’s attention. Considering that group members can influence the visual representation more indirectly by adapting their behavior, the focus of the study that is described in the course of this section focuses on the effects of horizontal and vertical displays that do not allow direct interaction.