P SY R EC: Psychological Concepts to enhance the Interaction with Recommender Systems Gerhard Leitner1 Abstract. Although recommender systems are already a successful carried out and showing concrete possibilities for combining psy- part of many online systems, there are still areas of research which chological knowledge and recommender technologies are exempli- are unexploited. One of them is the appropriate consideration of psy- fied. The paper concludes with a discussion and an outlook on future chological theories which could be beneficial for the interaction be- work. tween a computerized system and an online consumer, particularly in the financial services sector. This paper emphasizes the potentials of integrating psychological knowledge into the further development of 2 Theoretical Background recommender systems on the basis of psychological theories and ba- In the history of online sales many examples of online platforms exist sic decision processes. The enumerated concepts have been demon- which were characterized by high technical quality and innovative- strated to be influential in consumer buying behaviour in numerous ness but lost market share or even disappeared because they did not studies and therefore are used as a theoretical basis of the presented appropriately consider user needs. For example, the first company work. A conceptual framework is build upon the technology accep- offering books online was superseded by competitors who provided tance model (TAM) which offers the possibility of integrating psy- better user experience. Another example showing the importance of chological knowledge in the further development of online financial considering user needs is Boo.com, which was based on cutting edge services. Possible applications and implementations are shown on the technology but showed bad usability, see, for example, [5]. Recom- basis of empirical work that has been carried out in the past years. mender systems can be considered as state of the art technologies supporting online interaction and purchase and have demonstrated 1 Introduction their benefits and capabilities in numerous studies. However, as [7] pointed out, decision support tools such as recommender systems The utility of recommender systems to enhance the quality of deci- consist of three parts:”...database management capabilities, mod- sion processes and their outcome has been approved many times, ac- elling functions, and a powerful yet simple user interface..”. Specif- cording to [1] they are among the most successful applications in Ar- ically the latter offers high potentials for enhancement, by consider- tificial Intelligence. Although recommenders have such a successful ing human capabilities such as attitudes, emotions, and other factors history, there are still unexploited potentials for advancement [2, 3]. influencing their behaviour in their design. The goal to achieve is Specifically promising in this regard is knowledge from psychology an enhanced quality of interaction between the human user and the and research aiming to integrate it into recommender systems. This computerized part of a system resulting in a better outcome for both, area of research is, taking the words of [4], still in its infancy. This the user and the provider. paper opens new perspectives on the potentials of psychological con- Recommender systems can be seen as the technical counterpart cepts and theories to enhance the interaction with recommender sys- of real shopping environments. For about a century research in con- tems in general and in the context of financial services in particular. sumer psychology has been influential in advertising, marketing, and The emphasis is put on interface and interaction aspects, because sales. Speaking of the offline world it does not surprise any more recommender systems are typically characterized by highly sophis- that the design of supermarkets in regard to shopping paths, light- ticated algorithmic and technical basis. However, investigating also ing conditions or sound exposure is not left to chance and consumer efforts in the enhancement of the interface is important, or, as Louis psychology is omnipresent [8]. In comparison, psychological knowl- [5] formulated it: ”No matter how good your back-end systems are, edge applied in the online sector is limited, although an increased the users will only remember your front end. Fail there and you will consideration could be beneficial on different levels [9]. Specifically fail, period.” phenomena addressed in consumer and decision psychology are of The rest of the paper is structured as follows. In the first sections interest in this regard [10, 11]. The challenge addressed in this paper an introduction into the theoretical background with an emphasis on is to take this knowledge to optimize recommender operated plat- psychological concepts is given. This part is followed by a detailed forms in a way that consumers can, on the one hand, benefit from the discussion on decision phenomena and how these are related to rec- advantages of information and communication technologies (ICT). ommender systems. Afterwards a framework based on the TAM, the This is possible because recommender systems are able to dynam- technology acceptance model [6] is presented serving as a research ically adapt to the individual user. This can constitute a meaningful basis for future research activities. In Section 6 studies which were alternative to offline purchase situations where an average sales assis- 1 Alpen-Adria-Universität Klagenfurt, Institute for Informatics- tant can be assumed to base his recommendations only on a limited Systems, Universitätsstrasse 65-67, 9020 Klagenfurt, Austria, set of alternatives. On the other hand it is important to make the user email:gerhard.leitner@aau.at forget about the disadvantages online systems could have compared to real shopping experiences. These are, for example, the possibil- and value. Expectancy refers to the degree to which a person is ity to touch and investigate a product physically and to communicate capable of reaching a goal. Value refers to the importance the goal with a human counterpart, negotiate a price or ask questions. The has for the person. Example theories of this group are the theory of challenge for the service-provider is the increased difficulty to con- planned behaviour (TPB) or the theory of reasoned action (TRA) vince an online user about the benefits of a product or even persuade and they are important in the context of online buying. Besides him or her to buy it, because there are limited possibilities to estab- personal aspects (i.e., attitude to a behaviour), social aspects play lish a pleasant atmosphere. In the following a spotlight is put on a an important role and influence the value. For example, how peo- selection of psychological concepts and theories which have a direct ple from relevant groups such as peer groups, family and friend relation to buying behaviour and therefore build a promising basis would judge a certain behaviour (e.g., the purchase of a certain for further research and to enhance recommender systems in a way product) [18, 19]. that they are capable of supporting all facets and phases of human • Need for Cognition / Elaboration Likelihood Model, NfC consumer behaviour. This is neither easy nor possible in just one it- NfC implies that depending on the importance of the domain eration. (”personal involvement”) a person tends to process information on different elaboration routes. In domains which are of high impor- tance for the person information is processed on the central route, 3 Basic Psychological Theories characterized by a high level of elaboration (extensive collection The following list of theories is not intended to be exhaustive, it of information, comparison, outweighing of pros and cons, etc.) should just point out the potentials of psychological concepts which The alternative way of processing, the peripheral route, is char- have, as demonstrated in numerous studies, a direct relation to hu- acterized by low involvement of the person and, as an effect, an man behaviour and insofar could also be useful for the enhancement intentional low investment of efforts in processing information. of online behaviour in general and in regard to financial services in The type of elaboration is, for example, of interest when an online particular. Some of the elements of the theories have been either anal- platform is intending to include persuasive technologies [20, 21]. ysed for applicability or actually used within own studies [12, 13, 1], • Cognitive Dissonance, CD others are planned to be integrated in our future work. CD is assuming a mental model that a person establishes about a certain area of life, a behaviour or other relevant issues. The • Prospect Theory, PT model only includes ”consonant” information, which means that PT is of interest in regard to the behaviour of consumers in situ- information present in the model should not be contradictory. For ations characterized by uncertainty and and risk. These are, when example, if a person thinks about financing a holiday trip with a considering the work of [10] demonstrating that the assumptions loan this may contradict with a negative attitude towards taking of economic theory do not hold, almost all situations. Because out a loan for things that do not have a material value (such as of limitations in human information processing, systematic biases cars or real estates) . In this case dissonance occurs and, accord- in rating situations and decision making are observable. For ex- ing to the model, mental efforts are invested to restore consistency ample, humans act risk seeking when a loss is probable, or risk [22]. For the concrete example an argument could be that the ex- averse when a profit can be expected [11, 14]. This asymmetry is, change rate of country’s currency where the journey is heading is for example, one explanation why people invest additional money favourable and insofar money is saved. into loss-making investments. • Reactance Theory, RT • Locus of Control Theory, LoC Implies that humans are driven by the assumption that they can LoC implies that behaviour depends on the interpretation of a per- behave and act unrestrictedly. If a behaviour or an ”object of de- son whether she has control over a situation or interaction and the sire” is not available or difficult to reach, its subjective value is outcome of an interaction (internal locus of control). When a situ- increased and the reactant user tries to overcome this shortage by ation or outcome is beyond influence (e.g. the user has the feeling increased efforts [23]. Online platforms try to induce reactance that the system or external forces have the control), then external by indicating limitations in product or service availability. In re- locus of control is the case [15]. gard to financial services, for example, special offers for loans or • Attribution Theories, AT financing models are made available for limited time periods. Attribution theories are, as LoC, assuming internal/external con- • Flow, F trol as one important dimension, but also include other dimen- The central concept of the theory is the state of flow which is sions, for example stability vs. flexibility. It is not only of rele- characterized by an immersion of the user with the system. Flow vance whether control is perceived as internal or external but also is, for example, observable on computer game players, musicians if it is stable, depending on the domain or a particular situation or craftsmen who smoothly interact with their tools without ob- [16, 17]. An example for the influence of LoC and AT in the con- servable disruptions [24]. A platform offering financial services text of financial services is that a person may assume that it makes should aim at supporting flow by enabling a smooth interaction sense to actively control her financial portfolio (internal control) to dialogue between user and system and giving the possibility to increase prosperity. A person who observes herself as externally ”play” with alternatives. controlled may think that anyway only governments with taxa- tion policies and financial service providers are responsible for How elements of the enumerated theories and concepts could af- the financial status of the individual. This attitude can be stable fect the interaction with a financial services platform is illustrated in or flexible, the latter, for example, by observing the own financial the following example. situation as depending on the global economy and the possibility Example. Imagine a potential consumer is using an online sys- to change when the financial crisis is overcome. tem to inform herself about loan opportunities. Based on her attribu- • Expectancy-Value Theories, EVT tional patterns (AT, LoC) she has a certain understanding of whether This group of theories is based on the two dimensions expectancy she is able to use an online platform and can control the outcome of the product search. We assume that she is self-confident in the usage mean that the outcome of the decision is better. One of the reasons is of the system (EVT, expectancy) and the system is appropriately de- that the dimensions consulted for a decision are often unconscious. signed that she can ”play around” and easily evaluate alternatives An a posteriori justification is done on dimensions which can be ra- (and eventually reaches a kind of ”flow”, F). Depending on the per- tionalized but those may not be the ones which were responsible for sonal importance (EVT, value) of the product she is searching for the decision. (loan for a holiday trip, a car or a house) she will put low or high Limited Decision. Another person having in mind to rent an apart- efforts in the evaluation, comparison, and selection of the product ment and just needs money for new furniture may be less passionate (NfC). When she knows what she wants and has good experiences and would apply other criteria to the decision process. She applies with a certain brand or provider (PT, CD) she will not care that much the second type of decision, which is limited decision. Decisions fol- what others say about her decision (EVT, peers). If she is uncertain, lowing this strategy are based on experiences (positive and negative doesn’t want to make a mistake or wants a product with a high status ones) and heuristics which were derived from these experiences, such she will orient herself on information of other users (EVT, peers) and as ”Brand A is better than brand B” or, ”The more expensive, the bet- in what percentage they purchased what product (for example based ter a product”. The person may choose the company for financing on online ratings or discussions with her peer groups). If the product furniture based on an advertisement she recently saw. In this case the or service she has finally chosen is not available immediately, she availability heuristic, described by [11, 14], is applied (e.g., brands will try to solve the problem by finding other sources from where to and companies that are commonly known are better). Following this get the product (PT, RT) or she will resign and decide not to buy any heuristic could lead to choosing a financing the furniture shop offers product (AT). to his customers (an alternative the first person probably would not think about). An influence could also have the social environment (subjective norm, [18, 19]). Recommendations of relatives or friends 4 Decisions as the Connecting Element which have good experiences with a bank can be taken into account. The direct application of the theories and concepts enumerated above Habitual Decision. The third type of decision, habitual decision, can is difficult because many of them are too abstract. It is therefore nec- be seen as a combination of extensive and limited decision. Based on essary to investigate the ”atomic” element of consumer behaviour previous experiences a mental model has been established, on the which is decision. Each purchase or even browsing for information basis of which consumer behaviour follows a routine sequence and to prepare a purchase is characterized by a singular decision or a se- may not involve explicit decisions. This strategy mainly is applied in quence of decisions. They are made on the basis of gathered informa- routine behaviour when no extraordinary investment is planned (such tion, the consultation of different information sources, the outweigh- as in the previous examples). For example, if a person has to trans- ing of alternatives, etc. Economic theory has assumed that humans fer money to a country where the receiver still requires conventional can be considered as omniscient and make decisions on the basis of paper based transfer, she typically goes to her familiar bank branch optimal rationality. Since the work of Simon [10] it is commonly and transfers the money there although there might be another com- agreed that this assumption does not hold for most decision situa- pany who offers cheaper transfers to the target country. In the past tions. The majority of human decision processes is characterized by the selection of the best bank might have involved extensive deci- limited information use, biased mental models and routines either sion strategies. When these efforts were successful and resulted in because of missing capabilities or a low level of motivation to invest selecting an appropriate bank, a mental model is build which drives cognitive efforts. Depending on the kind of limitation, technological future behaviour. If the combination of services, price and reputation means supporting the basic decision processes have to be designed has been working satisfactorily in the past it would not have a seri- in different ways. ous impact, if it did not work any more (e.g., prices for services are Felser [25], based on the work of [26], categorizes decisions in slightly increased) - in terms of financial loss or well-being. consumer behaviour into 4 types, namely extensive, limited, habitual Impulsive Decisions. The last form - impulsive buying - is character- and impulsive decisions. What type of decision is actually applied is ized as a ”reaction” to environmental stimuli rather active behaviour depending on the type of product or service, the degree of personal and may not include decisions at all. This form of occurs in the con- involvement, and emotional contribution (activation) to the domain text of financial services, for example, when a credit card is used for and other personality traits. For example, searching for an appropri- buying things. This also involves investing money, but the investment ate loan for an apartment can have very different characteristics and is hidden and partly unconscious. motives. The previous paragraph was describing decisions on a general Extensive Decision. If a person is planning to buy the apartment level. Beckett et al.[27] have focused their work on financial prod- this is a long term investment that influences the financial life of the ucts and present their findings in the form of a four-field decision person for decades. Therefore the person is probably highly involved, matrix which has parallels to the four types of decisions described activated, and will invest high efforts to find out the best financing al- by [25]. Additionally to involvement, which is part of the systematic ternative and therefore applies an extensive decision procedure until of [26, 25] and NfC [21], the authors point out confidence as another he gets the best financial plan which the smallest influence in the relevant dimension, which is a relevant dimension in LoC and AT current financial situation. The strategy followed has characteristics [17] as well as the EVT [18]. The first decision type included in the of the central route processing of need for cognition theory [20, 21]. matrix is repeat-passive decisions - which correspond to habitual de- Although this type of decision making is highly sophisticated, it has cision in the nomenclature of [25]. Based on positive experiences the some weaknesses. For example, the amount of information consid- consumer has developed loyalty to an enterprise (a bank or insurance) ered in the decision is not directly proportional to the amount of in- and does not explicitly search for alternatives. The rational-active de- formation available, which means that even if higher amounts of in- cision type corresponds to the extensive decision strategy. The third formation would be available, people prefer short cuts [25]. An em- type identified by [27], relational-dependent decisions corresponds pirical proof for this hypothesis could be shown in our own work [1]. to [25, 26]’s limited decision type and is based on heuristics regard- Another insight is that higher effort invested into a decision does not ing experience and brand. If this strategy has been successful, trust is developed which reduces search and information processing activ- and mobile first [33]. Not only the technology in the back-end (the ities. Finally, the impulsive type of [25] does not occur very often recommender system) has to be adaptive, but also the interface itself in the context of financial decisions. Therefore the matrix of [27] in- should adapt to the needs of users. Burke [34] proposes a hybrid so- cludes a fourth field labelled ”no purchase”. Figure 1 is showing the lution for recommender system technology, a similar approach could decision types of [25] and their counterparts described in the work of also be imagined for the user interface part. A one fits all approach [27]. seems not to be contemporary, different interface alternatives seem to be a proper way to provide an adaptive access to a recommender system for different groups of users in different contexts of use. One and the same user could be interacting with different views of the system, on different devices, depending on the task at hand, contex- tual aspects, and psychological factors such as involvement in the domain. This means that interfaces do not only have to be adaptive, but personalized, platform independent and customizable [35, 36]. The application of conventional usability engineering methods to ac- company the development is crucial [37, 38], integrated in a user centred design process and combined with frequent evaluations in- volving representatives of the intended user groups. 5 An Integrated Model as Basis of Research Figure 1. Comparison of decision types of [25] and [27] The aspects addressed in the previous sections characterizing con- sumer behaviour in general and online consumer behaviour in partic- ular are difficult to capture. Their comprehension would be easier if The matrix has been evaluated in a series of focus groups and a way could be found to operationalize them based on an integrated three product types are corresponding to the different decision types framework. The technology acceptance model (TAM) originally pro- shown in Figure 1: basic transaction services (existing accounts), ba- posed by Davis [39] could build a basis for this attempt. TAM and its sic insurances products (car, house), and investment services (stocks, derivates have been empirically validated in numerous studies, and shares, pensions, etc.). Repeat-passive decisions mainly take place in it optimally combines the two dimensions emphasized in the previ- the context of basic transaction services, when brand loyalty to bank- ous section. Content - meaning the psychological aspects related to ing institution and confidence in the decision is high. Rational-active a decision making and Presentation - aspects that related to human decisions are made when price is one of the most important criteria. computer interaction. The TAM has relations to many of the theories This strategy is characterized by the necessity to search for products, and concepts enumerated in the previous sections. Figure 2 shows an to deal with a big amount of information and to thoroughly analyse adapted version of the latest version of TAM, TAM 3, introduced by the outcome. This could be necessary because, for example, insur- [6]. The dimensions of TAM and their relation to the concepts and ance companies offer more or less the same services and products theories enumerated above are described in this section. The descrip- and deliberately make comparison to competitive products difficult. tions are partly taken from [6, 40]. Relational-dependent decisions are, according to the results achieved by [27] still strongly depending on personal communication and ad- • Experience vice, because of the inherent complexity of the products and services. Already having used a system or similar ones can have an influ- The previous paragraphs were devoted to the content of decision ence on many factors, such as the perceived usefulness and the processes involved in consumer behaviour. The second, similarly im- subjective norm. In relation to psychological theories, experience portant dimension in regard to online platforms based on recom- can increase, for example, the confidence and the assumption of mender systems is the presentation of information. We take the dif- internal control (LoC, AT). ferentiation of [9] who proposes to differentiate two roles an online • Voluntariness consumer has to assume, one as a shopper and the second as a com- The extent to which users perceive the usage of a system to be puter user. What characterizes and drives the shopper has been em- non-mandatory. This aspect relates to reactance theory (RT) - if a phasized above, in the next part the focus is put on the role of a person has the freedom to choose an online system for financial computer user. Supporting a user in decision making requires the services additionally to offline services this makes a difference provision of interfaces that is appropriate, an issue the research areas to being forced to use online services (because the nearby bank of human computer interaction (HCI), usability engineering and user branch has been closed). experience [28, 29, 30, 31] are dealing with. In regard to online con- • Subjective Norm sumer behaviour one of the major goals has to be to design interfaces A person’s perception that most people who are important think he in a way that they compensate the limitations an online system has in or she should or should not perform a behaviour or use a system. comparison to a to real world shopping situation and emphasize the There could, for example, be a conflict between the personal pref- advantages online systems have over real world shopping. The flex- erences and the attitude of the relevant others, which could lead to ibility, adaptiveness, and adaptability of recommender systems en- cognitive dissonance (CD) (”I would issue a credit for a holiday abling an individual support of each consumer is probably not avail- trip”.) able in typical shopping environments and insofar bear high poten- • Image tials but are also challenging in regard to user interface design. This The degree to which the use of an innovation is perceived to en- means, for example, that the development has to be based on state of hance one’s status in the social system. In regard to the provision the art interface design technologies, such as responsive design [32] of different platforms (desktop or mobile platforms) this aspect, Figure 2. Technology Acceptance Model Version 3, adapted from [40] and complemented with example relations to psychological theories for example, influences the usage of a mobile app. It is depend- • Computer Self-Efficacy ing on whether or not the platform is accepted by the peer group The degree to which a person beliefs that he or she has the abil- (Apple, Android, Windows mobile) and illustrates that the attitude ity to perform the intended task. This depends on the experience towards a system is not always based on functional requirements with computer systems in general, and on the experiences within (EVT). a specific domain (e.g. financial services) in particular (LoC, AT). • Task Relevance • Perceptions of External Control A person’s perception regarding the degree to which the target The degree to which a person believes that an organizational and system is relevant to his or her life. If a system offers enhanced technical infrastructure exists to support use of the system. This efficiency (e.g., not having to visit a bank branch for basic tasks) could also be influential in a negative way (according to LoC and without loosing quality (NfC) it will be used. AT) when a person feels that the organization behind a system • Output Quality limits his or her performance or degrees of freedom. The degree to which a person believes that the system offers the • Computer Anxiety same services and enables to achieve the same results as other The degree of a person’s fear, when she/he is faced with the need alternatives, for example, services offered in a bank branch (PT, of using computers to access services. Specifically in the context NfC). of financial services (or even online transactions with credit cards) • Result Demonstrability people are anxious because of the danger to lose money (PT). Tangibility of the results of using the system. This aspect has re- • Computer Playfulness lations to subjective norm and image, for example showing in- The degree of cognitive spontaneity in computer interactions. If a creased prosperity as a result of intelligent investments (EVT). system supports this kind of interaction, such as simulating differ- ent variants of financing, this supports persons engaging in exten- digital cameras (pixels, storage, zoom). Only the order of items was sive decision making processes (NfC). manipulated but this significantly increased their recall. • Perceived Enjoyment The extent to which using a specific system is perceived to be en- joyable, whereas enjoyment can have different dimensions. Feel- ing safe in the sense of nothing unexpected can happen when transferring money could be one form of enjoyment. Another one is developing trust towards an institution or a platform when the latter is characterized by transparency and comprehensibility (NfC). • Objective Usability A comparison of systems based on the actual level of effort re- quired to complete specific tasks. If it is faster to go to the bank branch to transfer money than using the computer interface, then the objective usability of an online system would be low (EVT). • Perceived Usefulness The degree to which a person believes that using the system will help him or her to attain gains in life quality. Saving money by us- ing an online system instead of personal services convinces people to adapt to new technologies (EVT). • Perceived Ease of Use Figure 3. Recall frequency in a manipulated item sequence (continuous line) and a familiar item sequence (dashed line) [1] The degree of ease associated with the use of the system. Besides the utility aspects of a system, the subjective usability is relevant. If people do not trust a system or are doubtful in their usage, they A more recent work which builds upon the work on serial position would not use it (LoC, AT). effects was carried out in the domain of group decision making [52]. • Behavioural Intention Making decisions in groups, for example choosing a dinner with a The degree to which a person has conscious plans to perform or business partner or deciding what movie to watch with friends in a not perform some specified behaviour. Only if the enumerated di- cinema always involves psychological phenomena on the individual mensions are fulfilled in a certain degree, a person will have the as well as on the group level. Decisions derived in group situations intention to use a system. The correlation between the intention are influenced by rhetoric skills of the participants, negotiation tech- and the actual use still is low (EVT). niques applied, leadership competency and other personality factors. • Use Behaviour When every aspect is, depending on the individ- In contrast to this real-time and synchronous approach, an online tool ual preferences, optimally fulfilled, then a flow experience could supports asynchronous and sequential decision procedures. Psycho- occur (F). logical concepts that could have an impact in this kind of decision process are, for example, originating from research groups who de- As emphasized in the enumeration of elements, the TAM has con- veloped the prospect theory [11, 14]. One group of effects are an- nections to the concepts and theories addressed in this paper [9] and choring or framing effects, or more general, context effects [53, 51]. would also allow the integration of additional aspects, for example A following small example illustrates their influence. To be able to trust, cf. e.g. [41, 42, 43, 44]. The TAM has also served as basis for sketch a financial plan it is necessary to have a starting point, the an- research in the financial services domain, cf. e.g. [45, 46, 47]. chor stimulus. This starting point is typically the amount of money that has to be financed. A strategy that is frequently used in adver- 6 Empirical Work tising is not to use the whole amount for evaluation (for example, 100.000 are needed + overhead costs) but the monthly rate (for exam- The theoretical concepts presented in this paper have been evaluated ple 500). Within the study we investigated alternatives of presenting in several empirical works. In this section a selection of these works information and were interest in the possibilities of manipulating se- and their relation to the theoretical parts of the paper is presented and rial position effects and other form of presentation, concretely based relations to the enumerated models and concepts are emphasized. on the multi attribute utility model (MAUT). The results showed that The first work in this regard is a paper on serial position effects. MAUT concepts can counteract serial position effects and insofar The effect, being one of the oldest phenomena in psychological ba- represent an appropriate means to steer decision processes. Figure 4 sic research [48, 49, 50], is characterized by the fact that items pre- is showing an example screen of the C HOICLA group decision sup- sented in a list or sequence are better memorized when presented at port tool on which preferences can be declared based on multiple the beginning or the end of the list. In our work [1] we could show attributes. that changing the sequence of items significantly influences the recall The last empirical work presented was focused on persuasion [54] of the items and this offers a possibility to influence the interaction and the potentials of the asymmetric dominance effect, better known between a consumer and a computer system on the level of presen- as decoy effect [55]. This concept has also a relation to anchoring and tation. Depending on the motives and needs that drive the consumer framing effects which can be manipulated. In contrast to the example (e.g. involvement, confidence, type of decision, willingness to invest above where information is hidden or presented in another form, the efforts) important information can be put in the sequence where it has decoy effect uses the influence of adding additional information to the highest probability to be perceived and memorized for further us- a decision situation. Adding a decoy element is intended to divert age. Figure 3 is shows the effect on the recall of items by simply or even disturb the attentive processes of a potential consumer and changing their order. The list used in the study contained features of open a new perspective to him or her to lead a decision in a certain computerised systems based on recommender technology. The the- oretical basis builds a selection of psychological concepts and the- ories which have been empirically investigated in numerous studies and proved themselves as being relevant in the context of consumer behaviour. An increased consideration of knowledge from psychol- ogy could enhance the quality of recommender systems, specifically on the level of the user interface. The different types of decisions related to consumer behaviour were discussed and possibilities of recommender systems to support such decisions were exemplified. The technology acceptance model serves as a basis for further re- search in this area because it already integrates many of the relevant psychological concepts and theories that have been demonstrated to be influential in the context of consumer behaviour. With an appro- priate consideration of this knowledge, recommender systems could overcome the disadvantages online system have in comparison to of- Figure 4. Choicla Screen to enter preferences for restaurants based on fline interaction between consumers and, for example, shop assis- MAUT [52] tants. The advantages of recommender systems such as their capabil- ities of processing huge amounts of data, selecting the correct prod- direction, to persuade a user to purchase a product or to initiate a ucts from millions of alternatives, and calculating the best product preference construction which would not have been started without for are consumer within a few seconds could be exploited in a better the distractive element. In our paper we investigated the asymmetric way if not only the back-end functionalities but also the front-end, dominance effect and could show possibilities how to integrate them the interface to the customer is enhanced in an appropriate way. into recommender systems. Figure 5 is showing a decoy situation. Although our work is addressing different domains, the concep- Before introducing the decoy element (D) two products are available tual work sketched and the empirical studies performed are also to the customer, C (competitor product) and T (target product). C is applicable to the financial sector. Specifically of interest in this re- characterized by a lower price, but also by lower quality than T. As gard are the different types of decisions driving potential customers price is one of the most important dimensions in purchase decisions and motivating them to use an online system, choosing a product or [26] consumers tend to buy C. With introducing the decoy D which service, changing parts of his or her financial portfolio. In the con- has a lower quality than T, but a higher price, the focus of attention is text of recent developments in the financial sector (e.g., merging of directed to quality. This new perspective is not only of advantage for banks and insurance companies, closing of branches) the importance the provider (because of higher revenue) but also for the consumer of online services will increase. Appropriate systems supporting the (because of higher quality and satisfaction with the product). different needs, motives of end consumers, and also respecting the different levels of efforts people are willing to invest into financial decisions will be more important than ever before. Recommender systems integrating psychological aspect and simulating a ”human image” [36] could fill the arising gaps. With the system M YLIFE, an award winning platform, we could demonstrate respective possi- bilities. M YLIFE is an online platform enabling insurance agents to- gether with end consumers to manage the consumer’s financial port- folio in a cooperative partnership instead of putting the consumer in the role of a ”supplicant” towards financial service providers. The system consists of an intelligent algorithmic basis FAST D IAG [56] and an appropriate user interface visualizing in an integrated fashion the finance portfolio of a customer. The empirical work presented can only be seen as the starting point in the endeavour of enhancing human recommender interac- tion in the emphasized way. An unresolved problem in this regard is, Figure 5. Showing the example for the asymmetric dominance (”decoy”) for example, how a recommender system could find out what strat- effect. Product C (competitor) is of lower quality than product T (the target egy a consumer is currently applying (e.g. extensive or limited de- product), but C is cheaper and price is typically the feature with the highest influence in purchase situations. People would therefore, in general, choose cision) and to change the presentation of information accordingly. product C. By introducing a product D (decoy) which is of higher quality There are of course domains where one strategy is the most proba- than C, but of lower quality than T and more expensive than both of them, ble one (e.g. financing a real estate are probably based on extensive the viewpoint (anchor, reference frame) changes, and product T is preferred and central route elaboration) but further research is necessary to ad- by the majority of consumers [54] dress this problem. Of course transferring services form offline to online does not only have advantages. 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