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Journal of Health Communication: International Perspectives Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/uhcm20

Using Virtual Pets to Promote Physical Activity in Children: An Application of the Youth Physical Activity Promotion Model a

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Sun Joo (Grace) Ahn , Kyle Johnsen , Tom Robertson , James Moore , Scott Brown , Amanda d

Marable & Aryabrata Basu

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Department of Advertising and Public Relations, Grady College of Journalism and Mass Communication, University of Georgia, Athens, Georgia, USA b

Driftmier Engineering Center, College of Engineering, University of Georgia, Athens, Georgia, USA c

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College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA

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College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA Published online: 28 May 2015.

To cite this article: Sun Joo (Grace) Ahn, Kyle Johnsen, Tom Robertson, James Moore, Scott Brown, Amanda Marable & Aryabrata Basu (2015) Using Virtual Pets to Promote Physical Activity in Children: An Application of the Youth Physical Activity Promotion Model, Journal of Health Communication: International Perspectives, 20:7, 807-815, DOI: 10.1080/10810730.2015.1018597 To link to this article: http://dx.doi.org/10.1080/10810730.2015.1018597

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Journal of Health Communication, 20:807–815, 2015 Copyright # Taylor & Francis Group, LLC ISSN: 1081-0730 print/1087-0415 online DOI: 10.1080/10810730.2015.1018597

Using Virtual Pets to Promote Physical Activity in Children: An Application of the Youth Physical Activity Promotion Model SUN JOO (GRACE) AHN1, KYLE JOHNSEN2, TOM ROBERTSON3, JAMES MOORE3, SCOTT BROWN3, AMANDA MARABLE4, and ARYABRATA BASU2 1

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Department of Advertising and Public Relations, Grady College of Journalism and Mass Communication, University of Georgia, Athens, Georgia, USA 2 Driftmier Engineering Center, College of Engineering, University of Georgia, Athens, Georgia, USA 3 College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA 4 College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA

A virtual pet was developed based on the framework of the youth physical activity promotion model and tested as a vehicle for promoting physical activity in children. Children in the treatment group interacted with the virtual pet for three days, setting physical activity goals and teaching tricks to the virtual pet when their goals were met. The virtual pet became more fit and learned more sophisticated tricks as the children achieved activity goals. Children in the control group interacted with a computer system presenting equivalent features but without the virtual pet. Physical activity and goal attainment were evaluated using activity monitors. Results indicated that children in the treatment group engaged in 1.09 more hours of daily physical activity (156% more) than did those in the control group. Physical activity self-efficacy and beliefs served as mediators driving this increase in activity. Children that interacted with the virtual pet also expressed higher intentions than children in the control group to continue physical activity in the future. Theoretical and practical potentials of using a virtual pet to systematically promote physical activity in children are discussed.

Childhood obesity has become one of the most serious public health challenges of the 21st century. Data suggest that children 7–12 years of age may be at great risk of obesity because of an increase in sedentary behavior (Basterfield, Pearce, Parkinson, Adamson, & Reilly, 2011; Corder, van Sluijs, Ekelund, Jones, & Griffin, 2010). Consequently, children in this age group should be considered a priority in interventions for promoting physical activity (PA). Pets may be a valuable but underused resource for promoting PA in children (Yam et al., 2012). Although some correlational studies have demonstrated that pet ownership is associated with higher levels of PA (Cutt, Giles-Corti, Knuiman, Timperio, & Bull, 2008; Yabroff, Trolano, & Berrigan, 2008), few studies have explored systematic applications of pets to promote PA. Also, the success of pet-based interventions is qualified by the fact that one must

Address correspondence to Sun Joo (Grace) Ahn, Department of Advertising and Public Relations, Grady College of Journalism and Mass Communication, University of Georgia, 120 Hooper Street, Athens, GA, 30602, USA. E-mail: sjahn@ uga.edu Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/uhcm.

first own a pet. This poses a potential barrier to the large number of people who do not own pets. The present study proposes the use of virtual pets to promote PA in children and aims to contribute to health behavior research in several ways. First, a virtual pet was developed based on the theoretical framework of the youth physical activity promotion model (Welk, 1999) as a means to promote PA in children regardless of actual pet ownership. This theory-driven development enables a systematic approach to using the virtual pet as a vehicle for health communication and health behavior change while taking advantage of the demonstrated benefits of pet ownership in increasing PA. In addition, exploring the underlying mechanisms of virtual pets that drive changes in PA levels will yield further insights to the motivations of PA in children, thereby increasing the translatability of the findings. The Youth Physical Activity Promotion (YPAP) Model Across several theoretical models that have been proposed to promote PA in children (Ajzen, 1991; Bandura, 1976), three common determinants may be found: psychological, social=cultural, and environmental characteristics. The YPAP model (Welk, 1999) attempts to reorganize these determinants into a model that delineates the process of

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S. J. Ahn et al. Some recent studies have provided empirical data that validates the predictive potentials of YPAP (Heitzler et al., 2011; Rowe, Raedeke, Wiersma, & Mahar, 2007; Spence & Lee, 2003), but the numbers are few due to the relative nascency of the model. The present study aims to extend earlier findings by applying the YPAP model in a novel context of pet ownership, wherein the source of reinforcement is a pet rather than family members and peers. Pets and Physical Activity in Children

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Fig. 1. Constructs of the YPAP model. YPAP ¼ Youth Physical Activity Promotion.

predisposing, enabling, and reinforcing children to engage in PA. Consequently, the YPAP model (see Figure 1) presents a comprehensive and mature framework that integrates earlier conceptualizations of health behavior change. Because YPAP was developed to guide PA promotion programs for children, it better serves the purposes of evaluating the success of the current virtual pet intervention compared to health behavior theories that are abstract in their conceptualization and do not target children. The predisposition factor in the YPAP model is defined as variables that collectively increase the likelihood that a child will be physically active; arguably, this is the most influential element. Welk (1999) argued that most theories of behavior change are based on some self-evaluative construct, wherein the individual perceives different degrees of ability or control over the behavior (e.g., self-efficacy, Bandura, 1977). The YPAP model has operationalized this construct as a subfactor under predisposition, distilled into the question, ‘‘Am I able?’’ Another construct often used in theories of behavior change is the cognitive assessment of perceived outcomes, wherein the individual decides whether or not to engage in behavior change based on a cost-benefit analysis (e.g., beliefs about PA; Strauss, Rodzilsky, Burack, & Colin, 2001). YPAP operationalizes this construct as the second subfactor of predisposition, distilled into the question, ‘‘Is it worth it?’’ The predisposition of the child is supported by the second factor driving PA, reinforcing factors, such as family influences. Several studies have demonstrated that children of active parents are more active than children of less active parents (Schaben, Welk, Joens-matre, & Hensley, 2006; Welk, Wood, & Morss, 2003). Research has determined that socialization forces, such as parental encouragement of PA (Brustad, 1996), rather than role modeling, significantly predicted children’s perceived competence and attraction to PA. Enabling factors that support the predisposition for PA, such as access to an environment that facilitates PA and biological factors such as physical skills, also serve to determine PA levels in children. Welk (1999) posited that enabling factors may directly predict PA levels based on environmental factors (e.g., easy access to PA facilities), or indirectly affect PA levels based on an individual’s biological factors that influence the ‘‘Am I Able?’’ question (e.g., fitter individuals are more confident of their PA capacity and thus engage in more PA).

Scholars have posited about a human–animal bond between a pet and its owner (Horowitz, 2008), wherein the owner would feel that the pet’s psychological and physical well-being are tightly linked to the self’s well-being. Confirming these ideas, the American Heart Association recently released a scientific report demonstrating the positive correlation between pet ownership and PA levels in both adults and children (Levine et al., 2013). However, the level of PA as a result of pet ownership would be contingent on a variety of factors, such as the child’s relationship with the pet or the activity needs of the pet, and it would be premature and impractical to recommend pet ownership as a means to increase PA in children. The American Heart Association (Levine et al., 2013) also discourages the purchase, rescue, and adoption of pets for the sole purpose of increasing PA for obvious ethical reasons. Furthermore, a pet would not be able to administer a systematic PA regimen that allows children to confidently answer the two questions of ‘‘Am I able?’’ and ‘‘Is it worth it?’’ Such a systematic approach would only be possible with pets that behave exactly, and every time, as they are told. This may be why the results of recent attempts at creating an intervention program to increase PA with dogs have yielded mixed results: some successful (Rhodes, Murray, Temple, Tuokko, & Higgins, 2012) and some not so successful (Kushner, Blatner, Jewell, & Rudloff, 2006). Thus, earlier research on pets and children’s PA demonstrates promise but scholars and practitioners have yet to harness this potential. Using Virtual Pets to Promote Physical Activity Developing a virtual pet based on the framework of YPAP would allow children to work with a programmable virtual pet that systematically promotes PA while still benefiting from the human-animal bond. Table 1 provides a summarized layout of the tenets of YPAP and how they are operationalized in the virtual pet. The right-hand column discusses the YPAP factors that inspired the development of a virtual pet feature described in the left-hand column. The middle column discusses how the feature reflecting the YPAP construct was operationalized in the interactions between the virtual pet and the child. By systematically encouraging children to set PA goals and offering appropriate reinforcements, the virtual pet will aim to not only promote favorable health attitudes, but ultimately to increase daily PA in children. Conceptually, existing video games aiming to promote healthy attitudes and lifestyle choices may appear to be

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Virtual Pets to Promote Physical Activity Table 1. Operationalization of YPAP model tenets in the virtual pet Virtual pet feature

Operationalization

YPAP model construct

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Goal setting

The virtual pet asks the child to set an activity goal attainable in the near future (e.g., 30 min, 1 hr, 1.5 hr). The child repeatedly sets a new activity goal after attaining the goal. Teaching tricks, 1. If the child does not attain the goal, the virtual pet physical provides feedback and encourages further physical appearance activities. 2. If the child does attain the goal, the virtual pet allows the child to practice tricks with the pet. The number of goals attained (i.e., total amount of physical activity) directly correlates to the sophistication of the tricks. A child who has not attained many goals will be able to teach relatively simple tricks (e.g., sit, stay) whereas a child who has attained many goals will be able to teach sophisticated tricks (e.g., fetch, moonwalk). 3. The physical appearance of the pet becomes leaner when children engage in more physical activity. Human–animal The human-animal bond is encouraged by allowing bond children to personalize the pet (e.g., choose a name, choose a collar). The pet is also interactive, responding in real-time to the children’s verbal and gestural inputs with verbal and gestural outputs. Finally, the virtual pet tracks and responds to each child’s progress by syncing its system to the child’s unique activity monitor code. Mobile kiosk The kiosk setup allows the virtual pet to be easily setup transportable.

Predisposition (‘‘Am I able?’’): Each time a goal is attained, the experience of mastery will increase self-efficacy. Predisposition (‘‘Is it worth it?’’): Outcomes are not simply positive (teaching tricks) or negative (not being able to teach tricks), but also offer differing degrees of rewards (i.e., sophistication of tricks) contingent on the number of total goals attained.

Social influence=reinforcement: The virtual pet’s health is linked to the physical activity of the child through a system that syncs to an activity monitor. The child must engage in physical activity to keep the virtual pet healthy and fit.

Enabling environment

Note. YPAP ¼ Youth Physical Activity Promotion.

similar to the development of virtual pets. However, a key difference is that the latter approach would promote PA away from the screen, whereas video games would contribute to increasing screen time. Although some studies have shown that active video games lead to higher energy expenditure than playing sedentary video games (Lanningham-Foster et al., 2006), overall screen time has been linked to the lack of PA and obesity (Anderson, Economos, & Must, 2008). Furthermore, a recent study found that, controlling for the total amount of PA, outdoor PA led to a host of favorable

outcomes including positive mood and attitudes compared to indoor PA (Thompson Coon et al., 2011). Thus, the virtual pet was developed to increase PA away from the screen by ensuring that children only spent minimal time interacting with the virtual pet, as depicted in Figure 2. In this preliminary test of the virtual pet’s effectiveness, the first question should focus on the effect of the interaction between children and the virtual pet on PA. A computer system that offers equivalent goal setting and verbal feedback features may be just as effective without incorporating a

Fig. 2. Interaction cycle between children and the virtual pet system.

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virtual pet. However, earlier studies do suggest that if a child is involved with the pet’s daily activities, pet ownership meaningfully increases the level of PA (Cutt et al., 2008; Yabroff et al., 2008). Thus, we hypothesized the following:

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Hypothesis 1: Children interacting with the virtual pet will demonstrate significantly higher levels of PA compared to children interacting with a computer system without the virtual pet.

In addition to the changes in PA immediately following interactions with the virtual pet, we were interested in whether the experience would increase intentions for future PA, even in the absence of the virtual pet. Recent studies have found that increasing the frequency of present engagement in PA significantly increases the likelihood of future engagement in PA (Fleig et al., 2013). Because we anticipate that the children interacting with the virtual pet will engage in PA more frequently than will the children interacting with the computer system alone, we expect that this experience will help increase the possibility of PA becoming a lifestyle habit in the future, even without the assistance of the virtual pet: Hypothesis 2: Children interacting with the virtual pet will demonstrate greater intentions for future PA compared to children interacting with a computer system without the virtual pet.

Mediators of Physical Activity Self-efficacy, or the confidence in one’s ability to perform a given behavior (Bandura, 1977), is a key predictor of the initiation and maintenance of PA regimens (Marcus, Selby, Niaura, & Rossi, 1992). According to the tenets of social cognitive theory (Bandura, 1976), setting a goal is an important source of motivation and serves as a standard against which to evaluate performance (i.e., ‘‘Am I able?’’). When the goal is attained, individuals perceive a rewarding sense of accomplishment at mastering the goal, and then go on to set higher goals. The experience of mastering a goal is one of the main drivers of self-efficacy (Ozer & Bandura, 1990). In the YPAP model, self-efficacy is an element that answers the ‘‘Am I able?’’ question, indirectly influencing overall PA. Beliefs about PA outcomes also serves as one of the strongest predictors of PA in children (Trost et al., 1997). These beliefs refer to the children’s perceptions of the consequences of PA (Saunders et al., 1997; Strauss et al., 2001). In the YPAP model, beliefs about PA is theorized as the cost-benefit assessment of PA wherein children consider the cognitive and affective consequences of engaging in PA and the value they place in them. The result of this assessment influences the final decision to engage in PA. Thus, beliefs about PA serve to answer the ‘‘Is it worth it?’’ question, indirectly influencing overall PA. The YPAP model proposes that PA self-efficacy and PA beliefs share a bidirectional relationship wherein one

influences the other. Logically, it seems more likely that confidence in the ability to engage in PA may strengthen a child’s beliefs about positive benefits of PA, than the other way around—positive PA beliefs leading to an increase in confidence. However, as the model does not provide further guidance on the order of variables in this causal relationship, a multiple mediation model will be tested to answer the following research questions: Research Question 1a: Will the virtual pet elicit greater PA self-efficacy, and as a result, more positive PA beliefs, ultimately leading to greater PA than the computer system? Research Question 1b: Will the virtual pet elicit more positive PA beliefs, and as a result, greater PA self-efficacy, ultimately leading to greater PA than the computer system?

Also, in line with Hypothesis 2 that tests future intentions to continue PA after interactions with the virtual pet, we explored whether PA self-efficacy and beliefs would mediate the relation between children’s experiences with the virtual pet and their intentions for future PA: Research Question 2a: Will the virtual pet elicit greater PA self-efficacy, and as a result, more positive PA beliefs, ultimately leading to greater intentions for future PA than the computer system? Research Question 2b: Will the virtual pet elicit more positive PA beliefs, and as a result, greater PA self-efficacy, ultimately leading to greater intentions for future PA than the computer system?

Method Participants A sample of 59 children (27 male, 32 female; 21 African American, 38 White Caucasian) between the ages of 9 and 12 years (age M ¼ 10.73, SD ¼ 0.78) was recruited from a summer camp in the South. Children in the camp are divided into tribal groups that compete with each other in various camp activities. Children in the current sample were recruited from a single tribal group and were from counties with similar median household income (approximately $38,900). Design and Stimuli As depicted in Figure 3, a virtual dog was introduced to the children in the treatment condition (n ¼ 32) in the form of a mobile kiosk with a television displaying a life-sized virtual dog, a motion and voice detection device (Kinect for Windows) set up on top of the television, and a laptop computer. The software was designed so that each child would be limited to about 5–10 min of interaction with the virtual dog as he or she set a PA goal or returned for an evaluation, feedback, and reinforcement. Thus, each kiosk was able to handle up to 12 children per hour. Two separate

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Virtual Pets to Promote Physical Activity

Fig. 3. Set up of the virtual pet kiosk. The Microsoft Kinect for Windows device stationed on top of the television detected the voice and gesture commands of the child as he or she taught the virtual dog tricks. The virtual dog responded and interacted in real time to the inputs.

kiosks were set up at the camp to ensure fluid interactions between the virtual dog and the children. During the first interaction, children had the opportunity to name the virtual dog and choose the color of its collar and tag. The virtual dog then asked children to set their PA goal in 30-min increments—30 min, 1 hr, and 1.5 hr. Activity monitors (www.zamzee.com) with an embedded three-axis accelerometer recording PA on a retractable USB interface were used to assess the child’s PA. The computer system developed for the kiosk was programmed to automatically recognize the unique marker for each activity monitor, and to evaluate the success or failure to meet the goal each child had set. This meant that each child interacted only with his or her personalized virtual dog. If the child met his or her goal, the virtual dog offered verbal praise and allowed the child to teach a trick from the list of 11 tricks preprogrammed into the dog. The list of tricks was designed to begin with basic moves (e.g., sit, lay down) and become progressively more sophisticated as more goals were reached (e.g., spin around, moonwalk). The idea was that because the virtual dog had become more fit with more activity goals that the child attained, it was able to perform more sophisticated tricks. The physical appearance of the virtual dog also shifted to appear leaner with increased PA. To optimize the realism of the interactions between the child and the dog, the tricks were taught using both voice and gesture commands captured by the Kinect for Windows device. For example, in order to teach the dog to fetch a ball, the child would vocally command ‘‘fetch’’ or ‘‘ball’’ and a ball would appear in the screen. The child was able to throw the ball by pulling back and projecting the hand forward. The virtual ball was designed to follow the trajectory of the hand, and the virtual dog would run after it to bring the ball back. If the child did not meet his or her goal, the virtual dog indicated that the goal had not been met and encouraged

the child to engage in further PA. Every time the activity monitor was plugged into the computer, the data were compiled in an activity log that tracked each child’s activity levels. In the control condition (n ¼ 27), children interacted with desktop computers using the same goal setting and feedback features. Again, the computer system automatically recognized the unique marker for each activity monitor, and evaluated the success or failure to meet the goal each child had set when the activity monitor was plugged in. In addition to tracking the activity data for each child, the computer system also prevented the child in the control group from interacting with the virtual dog even if he or she were to attempt to plug in the activity monitor in the kiosk’s computer. At the desktop computer, the children received the same prompt that required them to set an activity goal. If the child met the goal, the computer issued the same congratulatory message used for the treatment condition; if the child did not meet the goal, the same prompt for more PA was issued. The software for the control condition was also similarly designed to limit the screen time per child to about 5–10 min per interaction. Three desktop stations were set up at the camp to ensure fluid interactions between the computer system and the children. The only difference from the treatment condition was that the child did not interact with the virtual pet at the kiosk. Children in both conditions were free to set and meet as many goals as they wished. Procedure The experiment began on Monday afternoon and terminated on Thursday afternoon. PA in the camp was comprised of free play and loosely structured programs shared by all attending children. Parental permission and minors’ assent were obtained before participation. Children in the treatment and control groups participated in separate orientation sessions. During both groups’ orientation sessions, researchers trained children in the basic rules of wearing the activity monitor. Children in the treatment group received training in interacting with the virtual pet kiosk and children in the control group received training in using the desktop computer system. Both systems in the treatment and control conditions were self-sustained at the experimental site and the researchers tracked the real-time compilation of data offsite. After the third day, researchers visited the experimental site and administered a self-report survey in a computer laboratory setting. Children in each condition were called in separately and received a brief orientation on how to answer interval type items. Measures PA Hours The total amount of PA in hours that the children engaged in during the 3 days was tracked by an activity monitor. PA Self-Efficacy Following the guidelines established by Bandura (2006), Saunders and colleagues (1997), and Strauss and colleagues (2001), three interval scale items ranging from 1 (not confident

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Table 2. Descriptive statistics for dependent measures (N ¼ 59)

Physical activity hours (3-day total) Self-efficacy Beliefs Future intentions

Control

Treatment

M

SD

M

SD

5.86 3.58 3.95 3.85

2.95 0.81 0.72 1.03

9.14 4.01 4.36 4.25

2.63 0.56 0.62 0.84

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at all) to 5 (extremely confident) assessed the level of confidence that the children had about PA despite barriers including, asking parents to sign up for a PA; fatigue; and outside weather. The three items displayed moderate reliability, Cronbach’s a ¼ .57. PA Belief Following the guidelines of Saunders and colleagues (1997) and Strauss and colleagues (2001), four Likert scale items ranging from 1 (don’t agree at all ) to 5 (completely agree) assessed the extent to which children agreed with statements about the consequence of being physically active: ‘‘It would be fun,’’ ‘‘It would help me be healthy,’’ ‘‘It would give me energy,’’ and ‘‘It would help me spend more time with my friends.’’ The four items displayed moderate reliability, Cronbach’s a ¼ .53. Future PA Intention A single interval scale item, reported on a 5-point scale ranging from 1 (I am sure I will not be physically active) to 5 (I am sure I will be physical active), assessed the extent to which children intended to engage in PA after leaving the camp.

Results Table 2 provides means and standard deviations by condition for all measures. First, an independent t test was conducted with experimental condition as the independent variable and PA hours as the dependent variable. The Levene’s test for equality of variances was not significant (p ¼ .55) and equal variances was assumed. Results indicated that the children that interacted with virtual pets engaged in significantly higher levels of PA than children that interacted with the computer system only, t(57) ¼ 4.51, p ¼ .001, d ¼ 1.17. Hypothesis 1 was supported. Another independent t test was conducted with experimental condition as the independent variable and future PA intention as the dependent variable. The Levene’s test was not significant (p ¼ .76) and equal variances were assumed. Results indicated that the children that interacted with virtual pets had marginally higher intentions to engage in future PA after leaving the camp, t(57) ¼ 1.64, p ¼ .10, d ¼ .43. Therefore, Hypothesis 2 was marginally supported. Multiple Mediation Analyses Multiple mediation analyses were conducted with the PROCESS path-analysis macro for SPSS (Hayes, 2012). The first model tested the effect of experimental condition (0 ¼ control; 1 ¼ treatment) on PA hours. Experimental condition was entered as the independent variable, PA self-efficacy and belief as the mediators, and total PA hours as the dependent variable. The inclusion of all mediators in the same model is recommended as it facilitates the estimation of the magnitudes of the indirect effects associated with all relevant mediating variables (Preacher & Hayes,

Table 3. Regression weights, indirect effects showing mediation, bootstrap 95% confidence interval, lower and upper bounds Bootstrap 95% CI Regression weights

Coefficient

SE

Lower

Upper

Direct effects Condition ! Self-Efficacy Condition ! Belief Self-Efficacy ! Belief Condition ! Physical Activity Condition ! Intention Self-Efficacy ! Physical Activity Self-Efficacy ! Intention Belief ! Physical Activity Belief ! Intention Indirect effects Condition ! Self-Efficacy ! Physical Activity Condition ! Self-Efficacy ! Intention Condition ! Self-Efficacy ! Belief ! Physical Activity Condition ! Self-Efficacy ! Belief ! Intention Condition ! Belief ! Physical Activity Condition ! Belief ! Intention

0.43 0.23 0.40 3.15 0.04 1.05 0.37 1.44 0.50 Effect size .45 .16 .25 .09 .33 .12

.18 .17 .12 .75 .87 .57 .17 .58 .18 Bootstrap SE .37 .14 .20 .05 .34 .09

0.072 0.104 0.167 1.655 0.413 2.185 0.025 0.267 0.153

0.788 0.568 0.641 4.641 0.484 0.093 0.710 2.609 0.856

1.404 0.003 0.011 0.029 0.083 0.015

0.016 0.542 0.833 0.241 1.228 0.339

Note. Bootstrap resampling ¼ 1000.  p < .01.  p < .05.

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Virtual Pets to Promote Physical Activity 2008). Bootstrapping methods were used and results of the direct and indirect effects are reported in Table 3. On the basis of the upper and lower boundaries of confidence intervals that did not include zero values, the results indicated that children who interacted with the virtual pet developed an increased perception of PA self-efficacy. The increased self-efficacy, in turn, led to more favorable beliefs about the consequences of PA. Ultimately, the favorable belief led to an increase in the total number of hours spent engaged in PA. Data in Table 3 also indicate that because self-efficacy does not have a direct effect on the total number of PA hours, the order of mediators cannot be reversed. A second multiple mediation model was tested with experimental condition as the independent variable, PA self-efficacy and belief as the mediators, and future PA intention as the dependent variable. On the basis of the upper and lower boundaries of confidence intervals that did not include zero values, the results indicated that children who interacted with the virtual pet developed an increased perception of PA self-efficacy. Increased level of self-efficacy led to both an increase in intentions for future PA and more favorable beliefs about the consequences of PA. Furthermore, the favorable belief ultimately led to an increase in future PA intention. Data in Table 3 also indicate that self-efficacy has a direct effect on future PA intention, and further analysis revealed that belief also directly predicts self-efficacy, b ¼ .43, p ¼ .001. Thus, changing the order of the mediator would also lead to significant indirect effects of PA beliefs on self-efficacy, ultimately leading to high future PA intention.

Discussion Recent studies suggest that technology may serve an important component of multilevel interventions designed to combat obesity (Ahn, 2015; Coons, Roehrig, & Spring, 2011). The present study offers a novel source of social influence in the form of a virtual pet to promote PA in children. Children that interacted with the virtual pet for three days had significantly higher PA levels than children that interacted with just a computer system. The increase in PA was driven by increased levels of PA self-efficacy and favorable beliefs about PA. The experience with the virtual pet also led to marginally higher intentions for future PA, implying that the effects of the virtual pet may linger even in the absence of the virtual pet. Although some correlational studies have suggested that there is a relationship between pet ownership and PA (Cutt et al., 2008; Yabroff et al., 2008), only a limited number of studies have investigated causal relationships and even fewer have looked at underlying mechanisms. The present study extends the possibility explored in these earlier studies of employing pets as vehicles of PA promotion. In addition, PA self-efficacy and beliefs were found to be the underlying processes that drive PA, echoing the results found in other studies without pets involved (Annesi, Unruh, & Whitaker, 2007; Strauss et al., 2001). This further validates the use of virtual pets in that the underlying mechanisms leading to PA are similar to those found in earlier studies.

813 The results also echo the tenets of YPAP (Welk, 1999), which argues that self-evaluation (‘‘Am I able?’’; e.g., self-efficacy) and decision balancing (‘‘Is it worth it?’’; e.g., belief) both influence the predisposition of a child to engage in PA. In addition to providing further empirical support for YPAP, particularly in the context of an emerging digital media platform, the current results indicate that for PA, there is a significant relationship between self-efficacy and belief in that increased self-efficacy (as a result of interacting with the virtual pet) leads to increased favorable beliefs about PA, but not vice versa. This implies that health promotion efforts that merely focus on increasing favorable beliefs about PA (e.g., ‘‘PA is good for you!’’) may be ineffective if it is not preceded with efforts to increase self-efficacy (e.g., ‘‘You can do it!’’). Furthermore, because the health and fitness of the virtual pet was tightly linked to the physical activities performed by the child, the virtual pet likely served as an effective reinforcement factor of the YPAP model. The virtual pet encouraged PA through an interactive feedback system that was able to promote PA in a more systematic manner than a family member or a friend. Because the virtual pet is completely programmable and personalizable, it allows for children to receive consistent, as well as tailored feedback that monitors and adapts dynamically to the child’s changing needs for reinforcement. The current results imply a wide range of practical applications of the virtual pet. One of the many strengths of using a virtual agent rather than a physical toy as an intervention tool is the malleability of the virtual pet that allows for sophisticated tailoring of the virtual pet to match the behavioral changes in each user. Future studies may explore the effects of pets that change in appearance and behavior to look happier and healthier as children meet more PA goals, reflecting the achievement of each child. Also, the virtual pet was presented in a mobile kiosk, wherein children were able to interact with a life-sized pet that responded in real-time to their voice and gesture commands. The high mobility of the kiosk would allow for the virtual pet to be deployed at any location of choice, for example, school classrooms, work places, or physicians’ offices. This satisfies the enabling environment factor of YPAP in a novel way—instead of the children having to find an enabling environment for PA, the enabling environment can actively follow the children. Welk (1999) noted that the enabling environment is a necessary element of PA because without it, children would not have the opportunity to engage in any PA, even with high predisposition and reinforcement factors. Further adding to the strength of the virtual pet as an intervention tool is the translatability and scalability of the modality used for interaction. The kiosk used in the present study was built using a television and the Microsoft Kinect system for Windows. The Microsoft Kinect Xbox console has sold more than 24 million units since its launch in late 2010 (Epstein, 2013). The fitness progress of the virtual pet and the child was linked together using the Zamzee activity monitor, another widely available device. Thus, the kiosk

814 used in the present study is affordable and accessible. As so many households already own a Microsoft Kinect infrastructure, it would be possible to deliver the content for the virtual pet system so that children may benefit from owning the virtual pet in the comforts of their own homes.

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Limitations and Future Directions Although this preliminary test of virtual pets yielded promising results while also providing further support for the YPAP model, the results are qualified by several limitations. First, the children who participated in the present study were appropriate representatives of our target population but the sample size was relatively small. Moreover, the sample characteristics were unique in that they were participants of a summer camp, which promoted a high baseline of PA among all children through camp activities. The fact that significant results with moderate to strong effect sizes were obtained with a small sample indicates the strong potential of the virtual pet. Nevertheless, future studies should expand the sample by including participants from a wider range of ages, socioeconomic levels, and family backgrounds to increase the generalizability the results. Although interactions with the virtual pet led to greater intentions for future PA, the mean difference from the control group’s intentions was only marginal. One explanation may be that children have limited abilities to make decisions using future time perspectives (Friedman, 2002). Survey items that ask children to self-report intentions for future behavior may not be sufficiently sensitive to detect large differences. This limitation may be resolved with a longer term study with accurate and objective observations of PA over time. In sum, the present study is one of the first attempts to test the effectiveness of a theoretically driven virtual pet to promote PA in children. Although the results are preliminary, the study yields meaningful theoretical and practical contributions for future research of virtual pets as tools for both prevention and intervention. Children that had the opportunity to interact with the virtual pet for three days engaged in, on average, 1.09 hr of more PA each day (equivalent to 156% more) than children who interacted with a similar computer system without the virtual pet. As the Centers for Disease Control and Prevention recommends 1 hr of daily PA for children, the present results suggest virtual pets may successfully encourage children to meet these guidelines. These results yield compelling reasons to continue pursuing the development of a primary prevention program for children using virtual pets to promote PA. We hope that these results serve as impetus for further advancements of multilevel and multicomponent approaches in the battle against childhood obesity.

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