Sichtweisen auf das Altern und deren Relevanz für Mensch-Maschine Interaktion

24. Januar 2016, von Carolin Makus und Bart-Jan van Putten
Dieser Artikel ist zurzeit nur in Englisch verfügbar.

A person’s chronological age, e.g. ‘50’ or ‘65’, is a weak predictor for how the person uses interactive products. If we want to design products that fit to the needs and behavior of seniors, we therefore need to look at aging in a more sophisticated way. In this article we introduce five perspectives on aging and indicate how relevant they are for man-machine interaction.


What does it mean to be old, to feel old or to be seen as an elderly member of our society? First of all, like the term ‘growing old’ implicates, aging is a process. Aging is based on changes in our bodies, in our minds and in our environment. These changes determine what we can and can’t do, what we believe we can and can’t do and what others believe we can and can’t do. In this article, we will shine some light on these changes from five different perspectives:

Chronological Age

The chronological age is used to organize ourselves by the amount of time that we have spent on planet earth, to e.g. allow or forbid people from doing certain things. Do you want to drive a car? You better have at least 6.570 days on your clock. You want to enjoy a beer or two? Well, make it 5.840 days. These numbers vary by country and culture. They do not tell how capable and responsible a driver really is. Chronological age is a model which describes how likely it is that one is a capable and responsible driver. Such a model makes things simpler, but often too simple: some 80-year olds are excellent drivers, while others can not cross the street by themselves. When we only know the chronological age of a person, we can guess how likely it is that that person can drive a car, but this likelihood comes with a large uncertainty.

Biological Age

Scientists have discovered that there are biogenetic processes that make us ‘grow old’, constantly. These are some examples of biological changes:

  • The changing transcriptional activity of our genes
  • Mutations as a consequence of poor DNA-repair
  • ‘Exhausted’ cell renewal, caused by the shortening of the telomeres
  • Apoptosis: the programmed cell death, in order to prevent an endless replication of possibly defective cells

A person’s biological condition strongly affects how (s)he uses interactive products. For example, reduced eyesight under low-light conditions is very common among people over 50. This is one of the reasons why older people often do not like to drive at night.

Functional Age

The functional age defines the capability of a person to execute the tasks of daily life. Can a person still do her own shopping, clean her own house or travel to visit friends and family? Functional age plays a major role when it comes to the question, whether a person is able to live at home independently.

When we know a person’s functional capabilities, we have a starting point for designing better products and services. However, this information is not sufficient. We may know if the person can still drive a car, but we do not know if she prefers comfort functions, such as a parking aid and cruise control, or if she prefers the more classical and manual way of operating the car. The psychological perspective on aging can then be helpful.

Psychological Age

“You are only as old as you feel.” This saying sums up the meaning of psychological age. It’s all about the self-assessment of a person: her belief in her capabilities and her motivation to do new things or continue to do things she used to do. It is also about well-being and satisfaction with her life until that date. The more honest someone is about her own (age-concerned) feelings, the more likely it is that she will act need-oriented and become predictable as a potential customer of age-sensitive products.

When designing products for seniors, psychological age is often just as important as functional age. For example, there are seniors who are courageous enough to try out new things. A senior who used to be driven around by her late husband, may take a few driving lessons and start driving again, as long as the car has an automatic transmission. Other seniors may be less courageous (or more responsible) and prefer to use public transportation.

Sociological Age

Whereas psychological age is about how one assesses oneself, sociological age is about the external assessment. What do other people think about the older adult’s capabilities and which behavior do they expect or desire? What is the person’s role? Is she expected to play an active role in mentoring new employees, shaping politics, taking care of her grandchildren? There must be a reason why most of us want to reach old age but do not want to be seen as old people. This attitude can be found in many western cultures. In other countries, such as Thailand, being old is a thing to be proud of.

When we understand how society sees a person, this may help us to design better products. Imagine for example a courageous senior driving relatively slowly on the highway in the right lane. When another driver approaches the car from behind, he may be surprised by the speed difference and overtake rather roughly. The senior in turn may be annoyed by the ‘careless driving of the younger generation’. Instead, we could design a mechanism in the overtaker’s car which gives a timely warning about the speed difference. This would not just improve safety but also provide everyone with a better driving experience.


When speaking about age, people have an image in mind (a simplification, a model) of an average person who is 50, 60, 70, etc. years old, based on prior experiences with such persons. In reality, nobody ages alike. It is a gradual process, which manifests itself on many different levels.

The different perspectives on aging are correlated. For example, when a person believes (psychological age) that she is no longer able to drive a car safely at night, she will drive less and less until one day she will no longer remember how to operate a car at all (functional age). The neighbors will notice that she never uses her car and may tell her that this is good because “she shouldn’t be driving at her age” (sociological age).

Chronological age is a simple and objective perspective and is therefore frequently used to define the expected or desired behavior of people. Unfortunately, it is not a powerful predictor for how people use interactive products. Other perspectives, such as functional age, psychological age and sociological age are much more helpful. In a future article we will describe how user research can focus on these perspectives to provide valuable insights for designing better interactive products for seniors.

Further reading