Kirsten Cater

Using crowdsourcing to support pro-environmental community activism

Community activist groups typically rely on core groups of highly motivated members. In this paper we consider how crowdsourcing strategies can be used to supplement the activities of pro-environmental community activists, thus increasing the scalability of their campaigns. We focus on mobile data collection applications and strategies that can be used to engage casual participants in pro-environmental data collection. We report the results of a study that used both quantitative and qualitative methods to investigate the impact of different motivational factors and strategies, including both intrinsic and extrinsic motivators. The study compared and provides empirical evidence for the effectiveness of two extrinsic motivation strategies, pointification - a subset of gamification - and financial incentives. Prior environmental interest is also assessed as an intrinsic motivation factor. In contrast to previous HCI research on pro-environmental technology, much of which has focused on individual behavior change, this paper offers new insights and recommendations on the design of systems that target groups and communities.

Selective quality rendering by exploiting human inattentional blindness: looking but not seeing

There are two major influences on human visual attention: bottom-up and top-down processing. Bottom-up processing is the automatic direction of gaze to lively or colourful objects as determined by low-level vision. In contrast, top-down processing is consciously directed attention in the pursuit of predetermined goals or tasks. Previous work in perception-based rendering has exploited bottom-up visual attention to control detail (and therefore time) spent on rendering parts of a scene. In this paper, we demonstrate the principle of Inattentional Blindness, a major side effect of top-down processing, where portions of the scene unrelated to the specific task go unnoticed. In our experiment, we showed a pair of animations rendered at different quality levels to 160 subjects, and then asked if they noticed a change. We instructed half the subjects to simply watch our animation, while the other half performed a specific task during the animation.When parts of the scene, outside the focus of this task, were rendered at lower quality, almost none of the task-directed subjects noticed, whereas the difference was clearly visible to the control group. Our results clearly show that top-down visual processing can be exploited to reduce rendering times substantially without compromising perceived visual quality in interactive tasks.

Parallel worlds: immersion in location-based experiences

This paper analyses the stages and circumstances for immersion based on quantitative and qualitative feedback from 700 people who took part in a three week long public trial of a location-based audio drama. Ratings of enjoyment, immersion and how much history came alive all scored highly and people often spent up to an hour in the experience. A model of immersion as a cycle of transient states triggered by events in the overall experience is defined. This model can be used to design for immersion in future experiences.

Reorientation in the Real World: The Development of Landmark Use and Integration in a Natural Environment

An influential series of studies have argued that young children are unable to use landmark information to reorient. However, these studies have used artificial experimental environments that may lead to an underestimation of the childrens ability. We tested whether young children could reorient using landmarks in an ecologically valid setting. Children aged between 3 and 7 years completed a reorientation task in open parkland, and the properties of the search array (size and distinctiveness) were manipulated in a within-subjects design. Responses were recorded using Global Positioning Systems technology. All age groups performed above chance level, demonstrating that young children can reorient using natural landmarks. This behaviour was modulated by the nature of the search array: children were more accurate when the locations were spaced in a large array, and when the search locations were distinctively coloured. This suggests that the integration between landmarks and search locations, at different spatial scales, is a key factor in characterising human reorientation in the real world.

Visual attention models for producing high fidelity graphics efficiently

Despite the ready availability of modern high performance graphics cards, the complexity of the scenes being modelled and the realism required of the images means that rendering high fidelity computer images is still simply not possible in a reasonable, let alone real-time. Knowing that it is a human that will be looking at the resultant images can be exploited to significantly reduce the computation time required for high fidelity graphical images, for although the human visual system is good, it does have limitations. The key is knowing where the user will be looking in the image.This paper describes high level task maps and low level saliency maps. For a large number of applications, these visual attention models can indeed determine where the user will be looking in scene with high accuracy. This information is then used to selectively render different parts of a complex scene at different qualities. We show that viewers performing a known visual task within the environment consistently fail to notice the difference in rendering quality between benchmark high quality images and the selectively rendered images that were rendered at a fraction of the computational cost.

Resonant Bits: Harmonic Interaction with Virtual Pendulums

This paper presents the concept of Resonant Bits, an interaction technique for encouraging engaging, slow and skilful interaction with tangible, mobile and ubiquitous devices. The technique is based on the resonant excitation of harmonic oscillators and allows the exploration of a number of novel types of tangible interaction including: ideomotor control, where subliminal micro-movements accumulate over time to produce a visible outcome; indirect tangible interaction, where a number of devices can be controlled simultaneously through an intermediary object such as a table; and slow interaction, with meditative and repetitive gestures being used for control. The Resonant Bits concept is tested as an interaction method in a study where participants resonate with virtual pendulums on a mobile device. The Harmonic Tuner, a resonance-based music player, is presented as a simple example of using resonant bits. Overall, our ambition in proposing the Resonant Bits concept is to promote skilful, engaging and ultimately rewarding forms of interaction with tangible devices that takes time and patience to learn and master.

Location aware interactive applications

In this sketch we describe two novel location aware interactive applications; Riot! 1831, an interactive historical play, and Moulinex, an interactive ambient sound piece. Both of the applications discussed have the common trait of using GPS to calculate the users location which is then used to control the participants interaction with the application. Thus the users interface is their whole body movement through the physical environment around them.

An investigation into the use of spatialised sound in locative games

This paper shows how spatialised sound can be used to guide users around a located gaming environment. Thus far, despite growing interest in delivering location-relevant media information to users, accurate delivery of virtual spatialised sound using limited-processing portable devices, such as Personal Digital Assistants (PDAs), has not yet been explored. The use of spatialised sound allows users to judge accurately which direction a virtual sound is coming from through a pair of stereo headphones. The initial findings of this research demonstrates that spatialised sound can be used to navigate users in a locative game running on a PDA.

Going the distance: spatial scale of athletic experience affects the accuracy of path integration

Evidence suggests that athletically trained individuals are more accurate than untrained individuals in updating their spatial position through idiothetic cues. We assessed whether training at different spatial scales affects the accuracy of path integration. Groups of rugby players (large-scale training) and martial artists (small-scale training) participated in a triangle-completion task: they were led (blindfolded) along two sides of a right-angled triangle and were required to complete the hypotenuse by returning to the origin. The groups did not differ in their assessment of the distance to the origin, but rugby players were more accurate than martial artists in assessing the correct angle to turn (heading), and landed significantly closer to the origin. These data support evidence that distance and heading components can be dissociated. Furthermore, they suggest that the spatial scale at which an individual is trained may affect the accuracy of one component of path integration but not the other.

TopoTiles: Storytelling in Care Homes with Topographic Tangibles

In this paper we present our initial ethnographic work from developing TopoTiles, Tangible User Interfaces designed to aid storytelling, reminiscence and community building in care homes. Our fieldwork has raised a number of questions which we discuss in this paper including: How can landscape tangibles be used as proxy objects, standing in for landscape and objects unavailable to the storyteller? How can tangible interfaces be used in an indirect or peripheral manner to aid storytelling? Can miniature landscapes aid recollection and story telling through embodied interaction? Are ambiguous depictions conducive to storytelling? Can topographic tangibles encourage inclusivity in group sharing situations? In this paper we share our initial findings to these questions and show how they will inform further TopoTiles design work.