\subsection{Goal-setting and Feedback}

Goal-setting is considered a key feature of technologies intended to encourage physical activity \cite{Consolvoetal06}. The most prominent approach to determining physical activity goals can be found in Chick-Clique \cite{ToscosFaber06}, where users set their own daily step-count goals. In this example, the locus of control remains with the user, who has to determine the degree of change that he or she wants to make. One potential problem with this approach is that it relies on the user to set an appropriately challenging goal. If users set goals are either too difficult or too easy, they can fail to inspire change \cite{Pearson2012}. To avoid setting inappropriate goals, Houston \cite{Consolvoetal06} and Fish’n’Steps \cite{Linetal06} automatically create each user’s step-count goal based on their baseline step-count. UbiFit Garden \cite{Consolvoetala08,Consolvoetalb08}, a mobile fitness app, consists of a fitness device, an interactive application and a glanceable display. The goal attainment in this system is tracked through the glanceable display (i.e., how well the garden is looked after). The interactive application includes detailed information about an individual's physical activities and a journal where activities can be added, edited, and deleted. The study showed that participants who had an awareness display were able to maintain their physical activity level better than did participants who did not have such a display.

Feedback in Chick-Clique was presented to users in the form of text messages, whereas Houston, Fish’n’Steps and UbiFit Garden provided visual feedback to the users when daily goals were achieved. Feedback varied and ranged in complexity from an asterisk annotation in Houston to the development of animated characters in Fish`n’Steps. The motivation behind the development of a character goes beyond the straightforward mechanism of feedback, aiming to cultivate “a strong internal locus of control through care of pet or plants”. In the case of UbiFit Garden the individual’s level of physical activity was reflected in the “liveliness” of a garden environment visualised on the individual’s mobile phone screen. 

Other researchers have started to investigate the potential for the use of ambient persuasion, in which visual feedback about physical activity levels is presented peripherally, such as through an augmented mirror\footnote{A technology that uses a one-way mirror to achieve an intuitive augmented reality environment}  \cite{FujinamiRiekki08} or using tablet-based information visualisation methods \cite{fan2012}. In all the technologies reviewed in this paper, feedback either through a visual or a music/haptic display has been present and has shaped a significant part of the choice architecture depending on the negative or positive nature of the feedback. In the other hand, goal-setting is rarely used as a standalone motivational tool. More commonly, it is framed within the context of games \cite{Ahtinenetal10,Berkovskyetal09a,Gasseretal06,Linetal06} or social awareness applications \cite{Consolvoetal06,Toscosetal08} that explicitly introduce aspects of teamwork, competition and social facilitation into the process of behavioural change.
