Identifying Hedonic Factors in Long-Term User Experience

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1 Identifying Hedonic Factors in Long-Term User Experience Sari Kujala 1, Virpi Roto 1,2, Kaisa Väänänen-Vainio-Mattila 1, Arto Sinnelä 1 1 Tampere University of Technology, P.O.Box 589, FI Tampere, Finland 2 Nokia Research Center, P.O.Box 407, Nokia Group, Finland sari.kujala@tut.fi, virpi.roto@gmail.com, kaisa.vaananenvainiomattila@tut.fi, arto@sinnela.fi ABSTRACT User experience (UX) arises from the user s interaction with a product and its pragmatic and hedonic (pleasure) qualities. Until recently, UX evaluation has focused mainly on examining shortterm experiences. However, as the user-product relationship evolves over time, the hedonic aspects of UX eventually seem to gain more weight over the pragmatic aspects. To this end, we have developed a UX Curve method for evaluating long-term user experience, particularly the hedonic quality. In this paper, we present a study in which the UX Curve was used to retrospectively evaluate the UX of Facebook and mobile phones. The results show that compared to a questionnaire, the UX Curve method is more effective for identifying the hedonic aspects of UX. This method can be used by practitioners and researchers who want to understand evolving UX and to design better products. This straightforward method is especially suited for industrial contexts where resources are limited. Categories and Subject Descriptors H.5.2: User interfaces, User-centered design. General Terms Human Factors Keywords User experience, long-term user experience, delight, mobile phone, Facebook. 1. INTRODUCTION User experience (UX) refers to the user s perceptions and responses in regard to their interaction with a system or product [11]. As Hassenzahl and Tractinsky [8] describe, user experience goes beyond the task-oriented approach of traditional HCI and focuses on hedonic aspects such as fun and pleasure. These hedonic aspects of user experience satisfy universal human needs but do not necessarily have utility value. The hedonic aspects create delight, which has been found to increase customer loyalty more than satisfaction alone does [1]. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Designing Pleasurable Products and Interfaces, June 22 25, 2011, Milan, Italy. Copyright 2011 ACM /00/0010 $ According to Karapanos et al. [13], when users make product goodness judgments the pragmatic aspects of the user experience (i.e. utility and usability) seem to be dominant only for the initial experiences with a product; thus the relevance of the hedonic aspects (particularly what a product expresses about its owner) increases over time. Therefore, it is interesting to study long-term user experience how the user's experience and relationship evolve over time from the early learning and enthusiasm about a product through to it simply becoming a part of daily life. While momentary experiences can be seen to influence the overall product experience [2], the user's overall evaluation of UX is not merely a simple sum of the individual experiences [9]. Retrospective evaluations of long-term user experiences are based on memories of the user and they can be vulnerable to biases [18]. However, both Norman [18] and Karapanos et al. [16] argue that these memories will be reported to others and guide the future behavior of the individual. The word of mouth that users pass on about the product to others is related to company success [20], while future consumer behaviors such as repurchase intentions are directly linked to customer loyalty [1]. Therefore, the users reconstructed memories of use are very relevant to the manufacturer. Based on Vermeeren et al. s [24] data, most of the current UX methods focus on single behavioral episodes and short-term evaluations. There are only a few published user studies with longterm UX as the primary focus [15, 25]. Longitudinal user studies are rare because they are expensive and impractical especially in product development contexts. Long-term UX evaluation methods that are easier to apply are therefore needed. In addition to the lack of methods for measuring long-term UX, there are few methods for evaluating hedonic aspects of user experience. Yet, the hedonic aspects seem to be the most relevant in the long run. Semantic differential questionnaires [5] are sometimes used to evaluate hedonic aspects but they produce only numeric results of how interesting, costly, exciting, exclusive etc. the product feels. These quantitative results do not explain the reasons behind the ratings, which would provide developers direct input on how to improve their designs. Our aim was to understand how qualitative data on hedonic aspects of user experience changing over time can be identified in industrial contexts. There have been a few attempts to develop a method for evaluating long-term user experience without the investment and delay of a multi-month field study. In a similar vein, we have developed a retrospective user experience evaluation method called the UX Curve that can be used to qualitatively investigate user experience and to provide feedback

2 on product features and qualities for design purposes. First, users are allowed to express their experiences freely before they are asked to consider their experiences from different points of view representative of various dimensions of UX: attractiveness, ease of use, utility, and degree of usage. The users are asked to recall and express significant reasons for changes in their experience while drawing a curve on a timeline. These reasons reveal meaningful issues that can be addressed in the further design iterations of the products under study. We tested the UX Curve method with 40 users to evaluate the user experience of two different types of communication tool: Facebook and mobile phones. We describe the reasons found for changing UX over time and compare the results of the UX Curve to the results of a questionnaire. 2. RELATED RESEARCH This section presents related work from two main areas: namely hedonic product quality and evaluating long-term usage. 2.1 Hedonic Product Quality Hassenzahl [5] describes hedonic quality as being related to the users' self, in contrast to pragmatic quality which is related to the users' need to achieve goals. Hedonic quality comprises quality dimensions that have no obvious relation to the task the user wants to accomplish with the system but instead are related to noninstrumental qualities such as, esthetics, innovativeness and originality [3]. Further, Hassenzahl [4, 5] subdivides hedonic attributes into stimulation, identification and evocation. A product provides stimulation by its challenging and novel character, identification by expressing one's self and personal values to relevant others, and evocation by one's formation of memories [4, 5]. Experimental research shows that both pragmatic and hedonic qualities contribute to the appeal of a product [4, 6]. Schrepp et al. [22] show that both qualities also have an impact on the attractiveness of business management software that is used for work purposes. The relative weights of the pragmatic and the hedonic quality in forming an overall evaluation of a product are dependent on the users' motivational orientations and the context of evaluation [7]. However, the results of Chitturi et al. [1] show that the importance of hedonic quality increases in the long run. Their experiments with both imagined experience scenarios and real usage experience of car owners show that delighting customers with hedonic quality improves customer loyalty as measured by word of mouth and repurchase intentions more than utilitarian quality does. Our interest in this paper was to explore whether the UX Curve method could provide feedback on the experience of hedonic quality in particular and its changes over several months of use. 2.2 Approaches to Long-Term UX Evaluation There are two primary ways to evaluate long-term user experience: repeated evaluation of UX over a period of time in a longitudinal field study; or retrospective evaluation by asking users to recall their long-term experience. Karapanos et al. [15] used the Day Reconstruction Method (DRM) to repeatedly evaluate the experiences of iphone users over five weeks. DRM is a retrospective diary method, in which participants are asked to reconstruct their experiences daily. However, even these kinds of longitudinal studies are very rare because of their expensive and laborious nature [14]. Retrospective recall of personally meaningful experiences is more lightweight than a longitudinal field study for both the respondent and the researcher. The problem of retrospective studies is that the human memory produces biases in any recollections. However, as Shiffman et al. [23] point out, retrospective impressions are very relevant to a person and can have a greater effect on later behavior, since they represent the information they use to make subsequent decisions. One example of a retrospective UX evaluation method is CORPUS developed by Von Wilamowitz-Moellendorff et al. [25]. CORPUS is an interview technique used for reconstructing changes in UX over a period of more than one year. However, it provides only rough descriptions of the trends of user experience and few reasons explaining the causes of any changes. Karapanos et al. [14, 16] developed iscale, a (not publicly available) online survey tool to minimize retrospective bias by assisting users to recall their experiences with a product by sketching a curve over time. The goal of the study [16] was to compare the effectiveness of two versions of iscale and free recall without any form of sketching. The study shows that sketching increases the amount and the richness of the recalled information. However, the study did not include qualitative or interpersonal analysis of the results. Thus, how the remembered experiences relate to the assessment of the product is still an open question. Although memories are rarely accurate they nevertheless seem to be very meaningful to humans and they do affect product success. As shown in the psychological studies [e.g. 19], individual experiences have less relevance to humans than the retrospective memories. In this study, we use the UX Curve method to evaluate long-term user experiences of Facebook and mobile phones and analyze the amount and quality of UX information gained from their hedonic qualities. The results are also compared to findings elicited by a questionnaire. 3. METHOD To test whether the UX Curve method is useful in revealing longterm hedonic experiences 40 users were asked to describe their experiences by means of the UX Curve method and a questionnaire. The effectiveness of the questionnaire and of the UX Curve method in revealing hedonic experiences was then compared. 3.1 Participants Twenty Facebook users and twenty mobile phone users from Finland participated in the study. These product categories were chosen as they represent two different purposes of use: Facebook is a hedonic service including social aspects, games, and other amusements and it is used mainly during free time. A mobile phone is more pragmatically oriented and used both for workrelated utility reasons and for free-time hedonic reasons. The 21 female and 19 male users were recruited through notices in a newspaper, Facebook groups and some also from the Nokia customer database. Their mean age was 36.0 years (SD=10.6) and they had been using Facebook or their mobile phones for periods ranging from 3 to 12 months (mean 9.0 months, SD=2.6). 3.2 Procedure The individual session with each participant consisted of an initial background questionnaire, the curve-drawing session using the UX Curve method, and a final questionnaire. The users participated individually in the 1.5 hour sessions. After being welcomed, the participants filled in an initial questionnaire

3 before the curve-drawing session started. First, the researcher asked participants to recall the moment when they began using Facebook or the mobile phone. The researcher handed out the first empty template (Figure 1) for the general UX curve and advised participants to draw a curve describing how their relationship towards Facebook or the phone had changed from the first time they used it until today. After drawing the general curve and freely expressing their experiences, each participant was asked to draw four other curves from different UX perspectives. We asked the participants to mark the reasons at their approximate locations on the curve, but they also explained their marking orally and were allowed to describe the reasons to the researcher as well. At the end of the evaluation sessions, participants filled in the final questionnaire. The researcher asked them for feedback on the curve drawing method and rewarded them with two movie tickets. Figure 1. An example of a UX curve template. 3.3 Materials Initial questionnaire We collected background information about the participants with an initial two-page questionnaire. In addition to the basic demographic data, we asked questions about their Facebook or mobile phone usage UX Curve templates The UX Curve templates included an empty two-dimensional graph area along with lines for writing on and briefly describing the reasons for the changes in the curve. The participants were told that the horizontal axis represents the time dimension from the beginning of the use to the current moment and that the vertical axis represents the intensity of their experience. They were also told that the horizontal zero line in the middle of the graph divides it into a positive upper part and a negative lower part. The vertical axis was labeled accordingly with + and signs. The first UX Curve template was about the participant s general relationship and user experience with Facebook or the phone. The four consecutive templates addressed specific dimensions of UX: attractiveness, ease of use, utility, and degree of usage. The first general curve presented did not have any heading, but the other curves were presented with headings, as follows: Attractiveness: The product is attractive and interesting in your own eyes and those of your friends. ; Ease of use: The product is easy and effortless to use (as in Figure 1); Utility: The product has an important function for you. ; Degree of usage: Degree of usage over time. The degree of usage curve graph did not have a negative area since this aspect obviously cannot be negative. For the Facebook users "the product" was changed to "Facebook" in the curve templates. We chose these four UX dimensions because we believed they form a representative set of central UX dimensions which users can reflect upon [cf. 3, 6, 17]. Attractiveness was selected to represent overall appeal and non-instrumental qualities (esthetics, symbolic and motivational aspects), although these were not specified to the users. Our assumption was that users may have not understood the variety of abstract non-instrumental qualities and there would have been too many curves to be drawn Final questionnaire At the end of the session, participants were asked to fill in a twopage questionnaire giving their overall evaluation of Facebook or their phone. The questionnaire included the following questions about meeting expectations: Did the product/service meet your expectations? loyalty: How likely it is that you will continue to purchase products/the usage of the services from the same manufacturer? [20] willingness to recommend: If your friend was planning to purchase a similar kind of a product, how likely is it that you would recommend this product to him/her? (adapted from [20]) and importance: How important is this product/service to you? We also asked for reasons for their answers, along with asking open-ended questions about surprising, best, and worst qualities of the product or service. 3.4 Data Analysis The curve drawing sessions were audio recorded and transcribed. The reasons explaining the curve trend changes mentioned during the interview and written down in the curve template were picked out from the text document and content-analyzed. First, open coding was used to identify themes in the data without ready categories. Second, the identified set of phenomena was categorized using the user experience model by Hassenzahl [3, 4]. The model categorizes user experience issues into pragmatic (utility and usability) and hedonic or non-instrumental. Utility means that the product provides relevant functionality for performing tasks and manipulating environment and usability refers to the ways to access this functionality easily and efficiently [4]. The hedonic categories adapted from Hassenzahl [3, 4] were stimulation, identification, beauty and evocation (see the definitions in 2.1). The analysis was performed by one of the authors and then checked by one of the other authors. The first themes identified by

4 open coding fit very well with Hassenzahl's categories [3, 4] and the two evaluators agreed with the categorization. Only a few reasons needed to be categorized as "miscellaneous" as they did not fit the categories and seemed to describe more practical issues or the change of the user-product relationship over time. In addition, for Facebook, many reasons mentioned were related to sociability and privacy and not directly related to instrumental needs, so they were used as additional hedonic categories. In addition to the qualitative analysis, the curve drawings were categorized according to their trends. First, we tested 10 categories to classify all the curve trends, for example U-form curve, improving negative, improving positive, and changeable, but we found them difficult to utilize. We therefore simplified the categorization and focused on the curves three primary trends: improving, deteriorating, or stable. The categorization was performed on the basis of whether the starting point of the curve was higher or lower compared to the end point. For example, the curve in Figure 2 was categorized as improving as its starting point was lower than its ending point, even though the curve deteriorates in the middle. If the starting and ending points were at the same level, the curve was categorized as stable. The hand drawn curves were moved to Excel by using 11 coordinate points per curve. The coordinate points were then used to calculate the means of curves. The relationships between the curve types and the key questionnaire results were investigated by statistical analysis. As the size of the sample was small, we used the non-parametric Mann-Whitney U test. 4. RESULTS A total of 200 curves were collected, including 40 general UX curves and 40 for each of the four specific UX dimensions: General, Attractiveness, Ease of Use, Utility and Usage volumes. This paper mostly focuses on the Attractiveness curve which elicited the highest number of hedonic reasons for evolving user experience. 4.1 Trends of the curves Figure 2 shows an example of a general UX curve drawn by a mobile phone user. The curve shows a typical beginning improving through learning in trend, and the reasons for the changes. The users marked the main reasons for the changes on the curve or below it and then explained the experiences more verbally. Figures 3 and 4 show the mean Attractiveness curves categorized according to the curve form and the application. (The means of the curve types were calculated as described in 3.4. The stable curves were left out of the figures as there were only five of them.) The improving attractiveness of Facebook continued over time, whilst the improving attractiveness of mobile phones was faster in the beginning of use but became steady soon after. The reasons for the differences are illuminated by the users' explanations of the reasons for the changes in long-term user experience, as reported in the next section. Figure 2. An example of a general UX curve drawn by a mobile phone user, with annotated reasons for changes. Figure 3. The mean Attractiveness curves of the improving and deteriorating curves of the Facebook users (The x axis shows the timeframe of 3-12 months). Figure 4. The mean Attractiveness curves of the improving and deteriorating curves of the mobile phone users (The x axis shows the timeframe of 3-12 months).

5 4.2 Reasons for the Changing UX All in all, the Facebook users reported 466 reasons for the changing user experience, 297 positive and 169 negative. The mobile phone users reported 574 reasons of which 351 were positive and 223 negative. As the Attractiveness curve focuses on hedonic issues, it also elicited the highest number of hedonic reasons among both the Facebook and mobile phone users; however the General curve also disclosed hedonic reasons, as can be seen in Table 1. Table 1. The number of reported pragmatic and hedonic reasons for changing user experience Curve type Facebook users Mobile phone users Pragm. Hed. Pragm. Hed. General Attractiveness Ease of use Utility Usage volumes Mean The negative stimulation-related reasons included lack of interest in Facebook and decreasing amount of content provided by friends. The sociability-related reasons mainly included communicating with friends and hearing from old friends. One of the users explained, for example, that "I can share social nonsense". Sociability-related negative reasons were few, but included factors such as dividing one s friends into two groups (those who use Facebook and those who do not) and taking time away from being with family. The less common reasons, which were not included in Figure 6, were positive reasons related to identification; these were mentioned by eight users. For example, the users mentioned that they liked joining Facebook groups that support their own ideas and to express their thoughts through the service. In addition, privacy issues were reported by five users. These included both insecurity about the visibility of their own material and unclear terms of intellectual property. Two users mentioned that Facebook is too American and one was irritated by the advertisements. Facebook is used mainly for hedonic reasons, so Facebook users expressed more hedonic reasons for changes than the mobile phone users did. The overall proportion of hedonic reasons mentioned was 49.6% for Facebook users and 26.0% for the mobile phone users. Figures 5 and 6 show the pragmatic reasons and the most common hedonic reasons mentioned as changing the Attractiveness curve over time. Figure 5 shows that the mobile phone users mentioned the most hedonic reasons related to identification and beauty. The identification-related reasons were mainly about social identification including the phone s attractiveness in the eyes of other people and superiority over someone else s phone. 13 out of 20 users mentioned how good the phone looked in the eyes of others, how they showed the phone to others, or how their friend had the same model. A negative reason mentioned by ten users was the availability of new and better phone models, a factor affecting identification. The beauty-related reasons referred, naturally, to design and visual appearance. For example, it was mentioned that "the moving background picture is a brilliant and charming property". As a drawback, four users mentioned that wearing out caused the looks of the phone to deteriorate over time. The next most common reasons, not included in Figure 5, were the charm of novelty mentioned by ten mobile phone users and aesthetics and pleasure of interaction mentioned by ten mobile phone users. On the negative side, familiarisation, losing the charm of novelty, or the availability of new and better phone models were mentioned by 18 users. Figure 6 shows that the most common hedonic reasons improving the user experience of Facebook were related to stimulation and sociability. The stimulation-related reasons referred to many aspects of which the most common ones were interesting content including social information, photographs, applications and games, curiosity and interest in the service and its undiscovered functions. For example, a user described how "It increases attractiveness that I know there are aspects that I don't know yet". Figure 5. The relative proportions of the four most common reasons for changes in the Attractiveness curve, as mentioned by mobile phone users. Figure 6. The relative proportions of the four most common reasons for changes in the Attractiveness curves, as mentioned by Facebook users.

6 4.3 Comparing the results of the UX Curve method and the questionnaire Figures 7 and 8 show the relative proportions of the users' response categories when they were asked to name the three best and three worst product qualities in the final questionnaire. It can be seen that the qualities mentioned in the questionnaire resemble those mentioned while drawing the Attractiveness curve (Figures 5 and 6). Figure 7. The relative proportions of the three best and worst product qualities, as named by mobile phone users in the questionnaire. compared to the 15 mentioned in the questionnaire. The reason may be that 7 users had already mentioned privacy issues in the General curve. 4.4 The role of hedonic reasons in the longterm UX In addition to number of hedonic reasons, it is interesting to know how these reported hedonic qualities affect long-term user behavior. The responses of mobile phone users revealed that the improving trend of Attractiveness is related to user satisfaction and recommending to friends (see Table 2). On the other hand, the other curve types (general, ease of use, and utility) did not have the same statistical relation. This suggests that the hedonic reasons play an important role in user satisfaction and customer loyalty. Table 2. The effect of the trend of the attractiveness curve on user satisfaction and recommendation (scale 1-7, 1= highly unlikely, 7=highly likely) Question Trend Mean p Is this a good product for you? Do you think that the product has met your expectations? If your friend was planning to purchase a similar kind of a product, how likely is it that you would recommend this product to him/her? Improving 6.2 Deteriorating 4.7 Improving 6.2 Deteriorating 4.1 Improving 6.3 Deteriorating Figure 8. The relative proportions of the three best and worst product qualities, as named by Facebook users in the questionnaire. Remarkably, when participants were directly asked to prioritize the most important qualities, they seemed to focus on issues that are practical or otherwise easy to rationalize, but when drawing the Attractiveness curve, they disclosed both pragmatic and hedonic issues. The mobile phone users focused on pragmatic issues in the questionnaire but also brought up hedonic issues related to beauty and aesthetics in interaction when drawing the Attractiveness curve. One difference between the curve drawing and the questionnaire was that the Attractiveness curve revealed only five privacy issues All except one of the Facebook users were very satisfied and thus, their answers could not be analyzed to identify the most relevant reasons behind user satisfaction and recommending. 4.5 Factors influencing the long-term UX Figure 9 summarizes the competing factors influencing improving and deteriorating long-term UX of Facebook and the mobile phones. This is done by combining the reasons for changes mentioned in the UX curves. Learning to use the product was naturally an important factor that improved UX over time. As a person learns to use a product, it becomes more pleasant to use and the functions can be utilized more effectively. The other factors behind improving UX were related to hedonic quality, such as beauty of mobile phones or stimulation in Facebook. New content, services and applications seem to be ways to avoid the level of interest going down after the initial excitement. The deficiencies in pragmatic qualities such as technical faults and long-term usability problems seem to be common reasons for deteriorating UX. Good usability is also a precondition to learning, which helps users to utilize the functions and enjoy using the product. The physical wearing out of mobile phones reduces their beauty and social status value. Finally, losing the charm of novelty and comparison with newer products will force the UX down. Users did not compare mobile phones only with newer products, they also compared their phone with those owned by their friends and family members. Users were proud if they found their own phone to be better than someone else s.

7 5. DISCUSSION AND CONCLUSIONS In this study, we investigated the usefulness of the UX Curve method in identifying factors influencing long-term user experience and in particular, the hedonic aspects of user experience. The practical goal of the method is to gather user feedback for design purposes. The UX Curve method was tested with 40 users to evaluate the user experience of two different types of product: Facebook and mobile phone. The results show that the UX Curve, and in particular the Attractiveness curve, is effective in providing concrete user feedback and revealing the number of hedonic aspects of user experience changing over time. When the validity of a method is evaluated, the first and the most important criterion is that the method should predict real-world behavior. Our results show good validity in that respect as the improving trend of the Attractiveness curve had a statistically significant association with users' satisfaction, their met expectations, and their willingness to recommend the product to others. Furthermore, those users willing to recommend the product had also told positive stories to their friends. Revealing the factors that drive recommendation and loyalty is important to companies as the return on investment of user experience work comes via a loyal and growing customer base. When we asked the participants to list the best and worst qualities of Facebook or their mobile phone in a traditional questionnaire, they focused on pragmatic and rational issues. When the participants were asked to draw the Attractiveness curve and explain the reasons for changes, most of the reasons given were hedonic ones. This is an important finding, since methods capable of revealing the hedonic qualities are needed for designing pleasure aspect of user experience. One could ask why the UX Curve better supports users describing the hedonic aspects of their user experience when compared to a questionnaire. One possible explanation is that while drawing the curve they are not being directly asked about the qualities of the product and their prioritization and as such they are instead focusing on recalling their experiences. It may also be more socially acceptable to simply describe hedonic experiences rather than prioritize them as more important than pragmatic ones. Thus, users may find it easier to rationalize and describe the pragmatic issues when directly asked in a questionnaire [cf. 10]. This explanation is also supported by Richins' [21] findings that for social desirability reasons, status or prestige issues are not mentioned in self-reports. The users remembered more experiences with the UX Curve compared to the interviewing technique of CORPUS [25]. The number of individual experiences described per user was 26 in a 1.5 hour session (including two questionnaires) compared to 3.4 experiences in a 45 minute session with CORPUS. Otherwise, the results of the two methods were similar. The trends of the usability curves were improving in both studies. Other curves (utility, stimulation, beauty, and identity) had more stable or deteriorating trends in CORPUS than in the UX Curve, but also the periods of use were longer. In addition to revealing hedonic issues, the benefit of the UX Curve method is that it reveals how user experience evolves over time and shows the various relevant competing forces involved. Pragmatic issues are related to necessities and if a product does not meet the expectations related to pragmatic quality, the attractiveness will deteriorate over time. However, most of the issues influencing the long-term user experience are related to the hedonic quality. Issues related to pleasure, such as beauty, esthetics in interaction, stimulation and social status improved the attractiveness of the products over time. Facebook differs from mobile phones in that it evolves over time as new content, services, applications and games are provided. This is visible in our results where the attractiveness of Facebook was constantly improving while the attractiveness of the phones became steady over time. Based on the feedback provided in this study, designers could improve Facebook by developing inspiring new applications, supporting social presence and different forms of content as well as improving users' control of their privacy. The mobile phones were functionally richer products compared to Facebook and learning to use these functions took longer in the beginning. After the user became familiar with all the functionality and new mobile phones models became available, the mobile phones became unavoidably less exciting and their attractiveness decreased. On the basis of our results, new services, applications and content could maintain the attractiveness of the phones. The UX Curve method, and particularly the Attractiveness curve, promisingly discloses qualitative information about the hedonic aspects of long-term user experience that participants do not often bring out in evaluations. In addition, the identified UX trends can be used for comparing products and predicting their users loyalty. The method is also reasonably easy compared to longitudinal methods like the Day Reconstruction Method [12] and thus, it is more practical in product development contexts. One UX Curve session took about 1.5 hours instead of the months DRM can take. The session could be even shorter, as our session included two questionnaires and five different curve types. In future, designers could select fewer curve types based on the particular product type and what is relevant to it. Effective user experience evaluation and analysis tools are needed in industry especially, but also in academia. The UX Curve is a promising method to reveal long-term aspects of user experience, information about the memories of the most meaningful emotional experiences and their reasons. Other methods are needed to provide data on more exact user interface details. In our future work, we will look at the possibilities of utilizing software tools such as iscale [14, 16] and automatic semantic analysis in making the UX Curve study applicable in different UX evaluation cases. 6. REFERENCES 1. Chitturi, R., Raghunathan, R., Mahajan, V. Delight by design: The role of hedonic versus utilitarian benefits. Journal of Marketing, 2008, 72, Forlizzi, J. and Battarbee, K., Understanding experience in interactive systems. 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