The second part of ‘Theories on People and Things’ explores a thing and its properties and looks into the kind of meaning relations people have with it. It ends with the implications these findings have for design.
What things are
The definition of a thing given by material culture scholar Judy Attfield will be used here as a starting point: ‘a thing is the basic entity our entire material world is build up from’.(1)J. Attfield, Wild Things. The Material Culture of Everyday Life, New York 2000, p. 12. Because this is a rather broad definition, a closer look at the various categories of things that can be discerned from the literature and studies that are referred to in part 1 of this article, is needed. This will help make clear what kinds of things are included when researching the human-object relation and what kinds are not.
A distinction can be made between natural things and man-made things. The first come into being without any human interference and depend solely on the processes of nature. Man-made things are intentionally made by human beings.(2)H. Arendt, The Human Condition, Chicago 1958, pp.147-148; M. Csikszentmihalyi and E. Rochberg-Halton, The Meaning of Things. Domestic Symbols and the Self, Cambridge 1981, p. 14. Without human effort they would not exist. All the literature and research referred to here is based on the interaction between human beings and man-made things. What makes them interesting is that humans are responsible for their creation and get to interact with them.(3)Csikszentmihalyi/Rochberg-Halton 1981, p. 16. Knowledge about this process of producing and using is valuable, because it might help us in designing a material world that fits our needs better.
When talking about the relation between people and things, things are the totality of man-made entities that make up the material world. But not all things made by mankind are of interest here. Take for instance a train. A train is man-made, but it is not the type of thing the literature and studies used here are dealing with. This is because individuals have no influence on a train being there and functioning or not. An individual cannot dispose himself of a train as he can with his bike or car. This is not because of the sheer size of the train, but because they don’t own the train. So the second consideration in the relationship between people and things is the personal ownership. For this study things that are personally possessed by individuals are relevant.
Things have a lifespan. At some moment in time they enter our material world, eventually followed by a moment when they are no longer part of this world. The ‘death’ of a thing can be caused by material transience, meaning that things can break beyond repair. More often things ‘die’ by becoming prematurely obsolete in the lives of their owners. Between the moment of production and of being thrown away, things have a life during which they can take on different roles.(4)I. Kopytoff, ‘The Cultural Biography of Things: Commoditization as Process’ in: A. Appadurai (ed.) The Social Life of Things, Cambridge 1986, p. 66. In this respect, anthropologist Kopytoff distinguishes commodities and singularities. A commodity is a thing that has both use value as exchange value. A singularity is priceless, either because it is so common that humans do not find it worthy of a price at all, or because it is extremely special – for instance a crown jewel – that no price can possibly be attached to it. Once a commodity is exchanged, the new owner can either exchange it again or keep it off the market. In the latter case the thing is now singularized. But it does not mean it cannot re-enter the world of commodities in a later stage. For example, a can of beans is a commodity while waiting on the shelf of the supermarket, but turns into a singularity as soon as it is bought by someone who plans to eat the beans. This can of beans can become a commodity again, for instance during a situation of war. It can then be traded for other things that are of need. Another example of singularized goods are homemade and handmade craftworks. People often make these as a hobby without any intention of selling them. For the study of the attachment of people to things, both commodities and singularities are of interest.
The example of handmade products resulting from an individual’s hobby leads us to another categorization of things: that between handmade and machine made things. Before the industrial revolution things were made by hand with the use of various tools. This way of making things still exists, but since the industrial revolution machines have taken over most of the work. Handmade things have a different character than machine made ones. Machines produce the same things in large quantities, whereas handmade things are unique. Both are the subject of research concerning the relation between people and things.
The last differentiation that can be made is the distinction between digital and non-digital things. Digital technologies have developed rapidly over the last twenty years, leading to completely new types of products that did not even exist in earlier times. In 2011 not owning a mobile phone is a rarity, whereas owning one in 1990 was almost unheard of. The research and literature used here stems from the period between 1980 en 2011. They map the time when non-digital things were most common, but also that time when people have become so used to digital things, they cannot imagine living without them.(5)Csikszentmihalyi/Rochberg-Halton 1981; M. Wallendorf and E. Arnould, ‘My Favourite Things: A Cross-Cultural Inquiry into Object Attachment, Possessiveness and Social Linkage’, Journal of Consumer Research 14:4 (1988); M. Richins, ‘Valuing Things: The Public and Private Meanings of Possessions’, Journal of Consumer Research 21:3 (1994); P. Verbeek, What Things Do, Pennsylvania 2005; D. Miller, The Comfort of Things, Cambridge 2008; W. Odom, J. Pierce, E. Stolterman and E. Blevis, ‘Understanding Why We Preserve Some Things and Discard Others in the Context of Interaction Design’, CHI 2009. Proceedings of the 27th international conference on human factors in computing, New York 2009.
Things: form and function
So a thing is a man-made entity that an individual has ownership over, that is either a commodity or a singularity, that can be either handmade or machine made and that has a digital or non-digital nature. But what about the actual physicality of a thing?
According to Plato, a thing is an idea turned into matter.(6)In: Verbeek 1998. What material is used and how the thing is given shape, are decisions made by the designer. Modernists in the Twenties and Thirties of the previous century believed that the form of a thing should be dictated by its function. Their credo ‘form follows function’ has given way to the conviction that it is not so much function that gives shape to things, but meaning.(7)Verbeek 1998; Modernism and the belief in ‘form follows function’ was influential until after World War II. In the 1960s though, the modernist influence started to fade with the introduction of Pop Design. The Pop design aesthetic was about funny instead of functional designs, preferring decoration over minimalism and ‘less is more’. The definite break from modernism came with the emergence of post modern design. Postmodernists saw things not as functional but as carriers of meaning. Verbeek: ‘Form Follows Function has been replaced by Form Follows Fun.’
In any case, the form that is decided upon by the designer is part of the physical properties of that thing. Physical properties are inherent and objective qualities and humans perceive these properties by using their senses.
Things not only have a shape or form, but also a function. The primary function of a thing is determined by the designer, but this does not imply that the thing will be used to perform this function first and foremost. Only the interaction between an individual and an object will determine which function the object will fulfil in which situation.(8)N. Crilly, ‘The Roles that Artefacts Play: Technical, Social and Aesthetic Functions’, Design Studies 31:4 (2010), p. 313. The primary function is usually a so-called technical function. Take for instance a car. Its primary function is transportation. But a primary function can also be of symbolic nature. Plastic souvenirs that represent the Eiffel tower, have the primary function of reminding its owner of the city of Paris.
How does the human-object relation come about?
Before exploring the different functions things can fulfil in the lives of human beings, a closer look is needed at how the human-object relation can come about, or how things can come to mean something for us. As described above things have physical and functional properties that are inherent and objective to the thing itself. These properties are present, independent of a person interacting with the thing or not. What a particular thing can come to mean for someone depends on the process of interaction between the individual and some or all of the thing’s properties.(9)Csikszentmihalyi/Rochberg-Halton 1981, p. 172.
Ethnologists Mihaly Csikszentmihalyi and Eugene Rochberg-Halton recognize three types of interactions between people and things through which things can acquire meaning: the experience of the aesthetic quality of the thing, the attention devoted to the thing by its user and the outcome or goal the user wants to achieve with the transaction. In other words, interaction between people and things begins with how a thing feels, looks or smells to someone. Secondly, things that cannot function autonomously need people in order to fulfil their function. Interaction has to take place, whereby people invest attention into the thing. And lastly, people often have an idea of who they want to become in the future or how they want to present themselves to others. Things can play a role in both these processes. So, the expression of present or future ideas of self can be the goal of interacting with things. These three types of interaction are connected to the three levels of the brain that cognitive scientist Donald Norman describes.(10)D. Norman, Emotional Design, New York 2004.
He discerns the visceral level. This level is pre-consciousness and pre-thought. The brain reacts to sensorial stimulation by the appearance of a thing. Often it invokes feelings of intense longing, sometimes without knowing what to do with the thing. The second level is the behavioural level, which is about use and the experience of functionality. The behavioural level is also pre-conscious. Humans can do something while thinking about something else. An experienced driver can drive a car and at the same time talk to someone. The third level of the brain is connected to thinking. It is the reflective level and has to do with interpreting situations. It is our consciousness. The reflective level is connected to the transactions between humans and things that are guided by the desired goals and outcomes of this transaction. People know what they want to achieve and choose the things they want to interact with, based on achieving that future goal.
When a person interacts with an object through one of these three types, the object will start to mean something to this person. What kind of meaning, depends on specific individual interactions. Professor of Marketing Marsha Richins has shown with her study on meaning that there are public and private meanings and that they interact.(11)Richins 1994. Public meanings are shared by a large group of people and are shaped by societal norms and values. Objects with which someone has no personal experience, are often attributed with a publicly accepted meaning. Private meaning is the meaning a thing has for an individual and is based on personal interactions. A combination of both public and private meanings can also occur. Take for instance a diamond necklace given by a husband to his wife. What this necklace means to the wife may contain the public meaning that diamonds, because of their monetary value are a very special gift, and also the possible private meaning that diamonds symbolize a loving relationship between husband and wife.
Types of meaning relations
Besides the distinction between public and private meanings, researchers have also found various types of private meanings.(12)Csikszentmihalyi/Rochberg-Halton 1981; D. Prentice, ‘Psychological Correspondence of Possessions, Attitudes and Values’, Journal of Personality and Social Psychology 53:6 (1987); Wallendorf /Arnould 1988; Richins 1994; Miller 2008; Odom/Pierce/Stolterman/Blevis 2009. The schemes used to classify these meaning relations differ between these studies, but an attempt can be made to present a summary of the sort of meanings people most commonly attribute to their favourite things.
Symbolic meanings are based on what things symbolize for their owners. These meanings are not intrinsic to things, but are attributed to them by their users. All three types of interaction described above (visceral, behavioural and reflective) can lead to symbolic meanings. Data from various studies show that relations between people and things are usually based on symbolic meanings.(13)Csikszentmihalyi/Rochberg-Halton 1981, p. 84; Arnould 1988, p. 537; Richins 1994, p. 511; D. Miller and F. Parrot, ‘Loss and Material Culture in South London’, Journal of the Royal Anthropology Institute 15 (2009).
Most common are symbolic meanings connected to a sense of self. Material possessions are then used to invoke a feeling about one’s present, future or past self. Things can play an important role in the expression of the self to others, take for instance clothing, but a journal or diary to write in can also be important for a more private expression. Besides for their self-expressiveness, things are valued for their ability to represent some sort of personal achievement of or a source of pride for the owner. Objects that somehow remind the owner of himself in earlier times, are often treasured as well.(14)Prentice 1987, p. 996; Richins 1994, p. 511.
Another common type of symbolic meaning has to do with interpersonal relationships. Things that remind one of relationships with family or friends are treasured. These things can be a gift from someone close or any other object that somehow has come to be associated with a specific person or relationship. In the case of the death of a loved one, things can play a role in the grieving process. Anthropologists Miller and Parrott have shown how people use things to deal with emotions of loss.(15)Miller/Parrott 2009. Objects that are associated with a deceased person can be important for relatives and friends while grieving for that person. It is not uncommon for those left behind to hang on to all material possessions of a loved one who has died. As time goes by, they slowly let go of some things until only a few things are left. Whereas humans can not control death, they can control how and when they part with material things associated with the deceased.(16)E. Myer, ‘Phenomenological Analysis of the Importance of Special Possessions: An Exploratory Study’, Advances in Consumer Research 12 (1985), p. 563; Miller/Parrott 2009, p. 509.
Another type of symbolic meaning is connected to history and personal memories.(17)Wallendorf/Arnould 1988, p. 537; Odom/Pierce/Stolterman/ Blevis 2009, p. 4. People value objects because they remind them of certain times in their lives or of relationships with people that lay in the past. The best example would be heirlooms, for they are kept within families specifically to keep memories of family members alive. But a piece of furniture can just as well function as a symbol for times or people gone by.
The last type of symbolic meaning that was mentioned by respondents from various studies was connected to prestige or status.(18)Prentice 1987, p. 995; Richins 1994, p. 564. Things can function as status symbols, representing a certain social status that reflects on the thing’s owner. Objects that are attributed meanings of prestige are used to show others how well off one is.
What all these types of symbolic meaning have in common is that they are not inherent to products, but are attributed to them through the process of individual interactions. Predicting what kind of symbolic meaning will be attributed to what thing is very difficult and depends on the variables of the thing, the individual and the context of the interaction.
When meaning is attributed to a thing because of what it does technically, one speaks of utilitarian meanings. Things are valued when they provide some sort of necessity in a more general way, such as prescribed eyeglasses in order to see properly.(19)Csikszentmihalyi/Rochberg-Halton 1981, p. 85; Wallendorf/Arnould 1988, p. 427; Richins 1994, p. 511. Objects that perform their technical function over and over again or that perform a very specific function, are often loved for it. Utilitarian meaning mostly comes about through interaction on the behavioural level, as described by Norman, and is the second most common type of meaning besides symbolic ones.
Authors Odom, Pierce, Stolterman and Blevis, who have researched the nature of human-object relations concerning digital artifice, describe two kinds of utilitarian meanings that are unique to their specific study. The first is that of engagement. The authors found that when an object invites and promotes physical engagement from its owner during use, the attachment between owner and thing will be stronger than when an object can function autonomously.(20)Odom/Pierce/Stolterman/Blevis 2009, p. 4. So this is meaning based on the way in which an object functions and not so much on what it does. The second meaning type the authors discern is that of augmentation. By this they mean the extent to which an object can be (re)modified, repaired or altered by its owner. Through this process of changing and adapting the object, it is augmented with the energy of its owner. An augmented object then becomes more valuable. A person is less likely to part ways with an object to which he has dedicated his time and energy.
Meanings based on intrinsic qualities: perceived durability and aesthetics qualities
Another popular category of meaning is based on the appreciation of the intrinsic qualities of things. This is the case when something is valued by its user because of the so-called ‘perceived durability’ of the thing or because of its aesthetic qualities. Sometimes people simply like something because of the way it looks or feels. They value the aesthetic quality of that thing. This appreciation can be based on the materials that were used, the style of the design, or the way it was produced. Handmade things for instance often show traces of the production process that give the object a unique feel and therefore make it special. The object’s aesthetics can also be appreciated for their timeless appearance or because of the object’s style being in fashion.
Perceived durability Odom et al discovered, is the belief of an object’s owner in the expected duration of either the object’s materiality or its ability to fulfil its function. Objects that are expected to have long lifespans are valued by their owners precisely for that characteristic. They collected their data around 2009, at a time when digital things were a big part of almost everyone’s life. While digital technologies can make life easier in some ways, they are also known to be vulnerable. Digital things are fragile and often difficult and expensive to repair, certainly in comparison to anything analogue. We would expect that people value digital objects, but in another study they discovered that people rarely feel strong attachments to digital things and that they hardly believe digital things to improve with age.(21)W. Odom & J. Pierce, ‘Improving with Age: Designing Enduring Interactive products’, in: CHI 2009. Proceedings of the 27th international conference on human factors in computing systems, New York 2009, p. 3795. When one’s house is filled with digital things, analogue things in comparison can be perceived as more durable and will therefore be more appreciated. So in a time when people’s possessions very often have a digital character, the concept of perceived durability can play an important role in establishing relations between people and things, be they digital or not.
The final important category of meaning is recreational meaning. Things that give the owner some sort of pleasure while using it, are valued precisely for that quality.(22)Richins 1994, p. 511. Musical instruments, sports equipment, toys and collections of things are often attributed with recreational meanings. Recreational meaning is not based on the utility of things, but on the pleasure one gets from interacting with these things. Like utilitarian meanings, recreational meanings are mostly connected to things that people interact with on a behavioural level.
When looking at the human-object relation, the various types of meaning as distinguished by research and scholars are of interest. Knowing what kind of objects these meanings are attached to, is also valuable. Some of the studies into the attachment of people to things have tried to answer questions about specific connections between types of meaning and types of products. Their results indicate that it is very difficult to predict exactly what something will come to mean to someone.
Types of meanings and types of things
People attach meaning to objects in a very flexible way as the case of symbolic meanings has shown. Any one thing can become the carrier of every possible symbolic meaning depending on the individual. Take for instance a novel. It can have recreational meanings for some, while for others it can refer to memories of being in high school and reading it for English literature class. Or it can remind them of their grandfather, who gave the book as a present. Because symbolic meanings are completely dependent on individual experiences and interactions with things, it is almost impossible to predict relations that might come about between human beings and things.
In the case of utilitarian meanings predictions are less difficult to make. Designers are likely to incorporate the primary function of an object into their design in such a way that it becomes a denotative aspect. In that way a chair will most likely be used to sit on. Of course the user is still free to use the chair in any other way he pleases, but chances are he will indeed use it as a seat. It is not per se true that a thing with an obvious primary function, will only be attributed with a utilitarian meaning. A thing such as a chair can be used in various other ways than the designer intended and it can also become imbued with every possible symbolic meaning.
The influence of age and gender
It is almost impossible to predict what an object will come to mean for an individual. Age and gender however seem to indicate what kind of things people will value for recreational purposes. For instance, children tend to prefer so called active things over more contemplative things.(23)Csikszentmihalyi /Rochberg-Halton 1981, p. 95. Active things invite some sort of kinetic interaction. They can carry this type of interaction as a primary function, like a football or a bike. Both are intended to be used in an active way and are not made only to be looked at. But children also use more static things like furniture or cutlery for playing purposes. A dining room table can for instance function as a tent or a boat.
Older people often have stronger relations with more contemplative things like photo albums and books.(24)Ibidem, p. 96. Things that symbolize earlier times are highly appreciated by them. This difference between young and old can be explained by looking at the different stages of life. When you are younger, interaction with things plays an important role in discovering who you are and what you can achieve with your physical energy. Young children therefore value things more for their recreational and functional meanings and less for their symbolic meanings. For adolescents the symbolic meaning of things will become more important. Adolescents who are slowly turning into their own person independent of their parents can, through the use of things, communicate to others their own developing identity.(25)Myers 1985, p. 565. Things can become symbols for the person they want to become. The ability of things to represent parts of a personal history becomes a plus when one gets older. Things then are representative of what one has done in life.
According to Csikszentmihalyi/Rochberg-Halton and to Wallendorf/Arnould, gender also plays a role in predicting what kind of things a person will love. They saw differences between men and women in types of preferred objects. Men tend to like things that are more active, like sports equipment, electronics and vehicles, while women name more contemplative things like photographs, art and books as their favourite things. Their research explained this difference by the expected gender roles of men and women in society. Men are often seen as providers and protectors, while women take on more nurturing roles. Active and contemplative things comply with these roles. But even though age and gender seem to be indicators, it is important to remember that predictions of what things will actually mean to someone are still difficult to make.
For designers who want to turn the human-object relation into a more durable one, this knowledge is useful. It gives an insight into how a meaningful relation between someone and something can come about. So what can designers do to give their designs a better chance of being loved by their owners?
Looking at the reasons respondents in the various empirical studies mentioned for liking certain things, the category of symbolic meaning stands out as the most important one. Apparently symbolic meanings make strong human-object relations. These relations can be based on self-expression, interpersonal relationships, history or even matters of prestige and status. So things that enable people to attach symbolic meanings to them, are more likely to be loved and cherished. But these empirical studies also show that it is almost impossible to predict which things will get attributed with what symbolic meaning. This process is completely dependent on unique, individual interactions between people and things. Designers therefore cannot possibly know beforehand if their design will be used for self-expression, or if it will symbolize some sort of interpersonal relationship. It might not even get attributed with meaning at all.
The category of utilitarian meanings seems more promising for designers wanting to design objects with long lifespans. Things that function well, are obviously appreciated more than things that perform badly. Designing strong, proper functioning objects that are a pleasure for people to use and appeal to their sense of action might help creating strong attachments between people and things. Things that require some form of engagement from their user to function well, are liked more than things that function autonomous. Another way to strengthen the human-object relation, is to enable people to repair or modify the thing themselves. Objects that are invested with the individual’s time and energy – either by repairing them or adjusting their functioning to specific personal needs – are valued more than objects that can only be worked on by specialists. So things that are transparent in their functioning, are preferred over those that are opaque.
Besides symbolic and utilitarian meanings, there are also intrinsic qualities of things to be considered. In the case of aesthetics, objects can be loved for their feeling of ‘nowness’ or for their timeless look. The risk of designing fashionable things is of course that they are prone to fall out of fashion within a short period of time. In order to encourage enduring human-object relations a design should not be too time specific in its style. Choosing more mute colours and not adding too much elaborate detailing will give a design a better chance of surviving different fashions.
Objects that their owners expect to have a long life, are preferred over objects that feel to be of lesser quality. This means that designers should think about the quality and the durability of materials, but also about the object’s construction. Perceived durability is connected to transparency. When someone understands how something works and can personally alter or repair it, it will probably be perceived as more durable than something that is opaque in its functioning. Understanding brings with it a feeling of control over the object.
Because young people prefer active things over contemplative things, adding the possibility of kinetic interaction to a design increases the chance that a young person will like it. When designing for older people, creating contemplative things is more successful. The same goes for men and women. Men are more likely to like things they can actively interact with, whereas women prefer things that are more contemplative.
The difference in liking between the young and old, learns us that people’s preferences of certain things over others are not static in time. With today’s indestructible synthetic materials the tendency exists to design indestructible things. The problem with these things is that they might very well outlive our need for them. Summarizing, designing for durable human-object relations is not about attaching meaning to designs, but about making designs as susceptible as possible to meaning giving by their users. To accomplish this, requires the use of durable materials and leaving enough room for interaction between user and thing.
Dorien Duivenvoorden, 2012.
noten [ + ]
|1.||↑||J. Attfield, Wild Things. The Material Culture of Everyday Life, New York 2000, p. 12.|
|2.||↑||H. Arendt, The Human Condition, Chicago 1958, pp.147-148; M. Csikszentmihalyi and E. Rochberg-Halton, The Meaning of Things. Domestic Symbols and the Self, Cambridge 1981, p. 14.|
|3.||↑||Csikszentmihalyi/Rochberg-Halton 1981, p. 16.|
|4.||↑||I. Kopytoff, ‘The Cultural Biography of Things: Commoditization as Process’ in: A. Appadurai (ed.) The Social Life of Things, Cambridge 1986, p. 66.|
|5.||↑||Csikszentmihalyi/Rochberg-Halton 1981; M. Wallendorf and E. Arnould, ‘My Favourite Things: A Cross-Cultural Inquiry into Object Attachment, Possessiveness and Social Linkage’, Journal of Consumer Research 14:4 (1988); M. Richins, ‘Valuing Things: The Public and Private Meanings of Possessions’, Journal of Consumer Research 21:3 (1994); P. Verbeek, What Things Do, Pennsylvania 2005; D. Miller, The Comfort of Things, Cambridge 2008; W. Odom, J. Pierce, E. Stolterman and E. Blevis, ‘Understanding Why We Preserve Some Things and Discard Others in the Context of Interaction Design’, CHI 2009. Proceedings of the 27th international conference on human factors in computing, New York 2009.|
|6.||↑||In: Verbeek 1998.|
|7.||↑||Verbeek 1998; Modernism and the belief in ‘form follows function’ was influential until after World War II. In the 1960s though, the modernist influence started to fade with the introduction of Pop Design. The Pop design aesthetic was about funny instead of functional designs, preferring decoration over minimalism and ‘less is more’. The definite break from modernism came with the emergence of post modern design. Postmodernists saw things not as functional but as carriers of meaning. Verbeek: ‘Form Follows Function has been replaced by Form Follows Fun.’|
|8.||↑||N. Crilly, ‘The Roles that Artefacts Play: Technical, Social and Aesthetic Functions’, Design Studies 31:4 (2010), p. 313.|
|9.||↑||Csikszentmihalyi/Rochberg-Halton 1981, p. 172.|
|10.||↑||D. Norman, Emotional Design, New York 2004.|
|12.||↑||Csikszentmihalyi/Rochberg-Halton 1981; D. Prentice, ‘Psychological Correspondence of Possessions, Attitudes and Values’, Journal of Personality and Social Psychology 53:6 (1987); Wallendorf /Arnould 1988; Richins 1994; Miller 2008; Odom/Pierce/Stolterman/Blevis 2009.|
|13.||↑||Csikszentmihalyi/Rochberg-Halton 1981, p. 84; Arnould 1988, p. 537; Richins 1994, p. 511; D. Miller and F. Parrot, ‘Loss and Material Culture in South London’, Journal of the Royal Anthropology Institute 15 (2009).|
|14.||↑||Prentice 1987, p. 996; Richins 1994, p. 511.|
|16.||↑||E. Myer, ‘Phenomenological Analysis of the Importance of Special Possessions: An Exploratory Study’, Advances in Consumer Research 12 (1985), p. 563; Miller/Parrott 2009, p. 509.|
|17.||↑||Wallendorf/Arnould 1988, p. 537; Odom/Pierce/Stolterman/ Blevis 2009, p. 4.|
|18.||↑||Prentice 1987, p. 995; Richins 1994, p. 564.|
|19.||↑||Csikszentmihalyi/Rochberg-Halton 1981, p. 85; Wallendorf/Arnould 1988, p. 427; Richins 1994, p. 511.|
|20.||↑||Odom/Pierce/Stolterman/Blevis 2009, p. 4.|
|21.||↑||W. Odom & J. Pierce, ‘Improving with Age: Designing Enduring Interactive products’, in: CHI 2009. Proceedings of the 27th international conference on human factors in computing systems, New York 2009, p. 3795.|
|22.||↑||Richins 1994, p. 511.|
|23.||↑||Csikszentmihalyi /Rochberg-Halton 1981, p. 95.|
|24.||↑||Ibidem, p. 96.|
|25.||↑||Myers 1985, p. 565.|