Why do People Carry Mobile Phones?

Why do people carry phones?
Why do people carry what they carry?
And if we can understand why, how can we use this knowledge in the design of future products, applications and services?

Why people carry phones might seem like a rather basic question for someone who works for a mobile phone manufacturer, but the journey to try and understand the answer has been an interesting one.

A couple of years back I carried out a multi-cultural research project with Per Persson and a number of other colleagues to figure out what objects people consider to be essential when they leave home. We spent time studying 17 urban dwellers in San Francisco, Berlin and Shanghai and Tokyo with shadowing, home-interviews, plus 129 street interviews and numerous observation sessions. One of our screening criteria for in-depth subjects was that people had to own a mobile phone although during the screening process we made no assumptions about whether they considered the phone a necessity or not.

In the cultures we studied 3 objects were considered essential across all participants, cultures and genders were keys, money and mobile phone. Whilst this may seem obvious the interesting part of the study was in understanding the reasons why people considered these objects essential (largely survival, safety & security), why they were not always present (forgetting, awareness, making a conscious decision to be out of touch) and strategies people adopted to help them remember to take these objects. A lot of times money will be carried in a wallet or purse, but when it comes down to it, the money (cash and notes) are considered the essential objects before the other objects that are also contained there.

Some of the material from this study was presented in the DUX 2005 paper - 'Mobile Essentials - Field Study and Concepting' (download paper, 0.4mb). The paper introduces three interrelated ways to understand human behaviour to explain what we learned, and at some point I'll use Future Perfect to expand on some of these issues.

Firstly the Center of Gravity describes the most likely place where you are likely to cluster and consequently find these objects. In the home the Center of Gravity is likely to be the edge of a desk, a chair and often in the case of women, a bag. Objects don't stay in the center of gravity but over time they gravitate there.

The second idea is the Point of Reflection - the moment when leaving a space when you pause current activities turn back into an environment and check you have the mobile essentials. Typically this involves looking at the Center of Gravity, sometimes tapping pockets, sometimes speaking aloud. Not seeing the objects where they are supposed to be (the Center of Gravity) can be a sign that they are already carried.

The last behavioural concept is something we call the Range of Distribution - essentially the degree to which essential objects are likely to stray from the person, or from the person's line of sight/range of touch. Range of distribution is largely based on perceived risk of theft - the higher the perceived risk the further away objects are likely to be placed be allowed to 'stray'. This way of thinking about objects is important because the more likely an object is to be out of sight the more likely it is to be forgotten, and a mobile essential that is forgotten has little use in solving emergencies. In addition as mobile phones that take on functions associated with other mobile essentials for example access/identity (key, smart-card) or payment (money) can affect where and how they are carried.

As a private, relatively safe environment the home has a large range of distribution, whilst spaces like cafes or public transport have a relatively low range of distribution. The lowest range of distribution we observed was bus commuting in Shanghai rush-hour. The most extreme example of range of distribution was given to us by a vice cop in Berlin who explained about a drug dealer that double wrapped his produce which was then stored it his mouth - if the cops tried to bust them swallowed. Waiting for the produce to clear the digestive system was often too much hassle for low level busts, and was presumably rather unpleasant and messy.

Taxis are interesting environments in that they are often treated as a temporary private space - in which people can relax and objects are likely to spread out within the natural boundaries of the environment. When combined with other parameters such as: people using taxi's whilst tired or impaired e.g. drunk/high; the likelihood of using the mobile phone in the taxi; placing objects on the seat/out of sight after use; and a pressured sequence of tasks at the end of the journey such as thinking what to do next on arrival at the destination and paying the driver, help explain why mobile phones are often left in taxis.

There are naturally many other reasons why people carry a mobile phones - for entertainment, projecting status, a sense of belonging, or capturing and communicating an experiences using a camera phone to name a few, but the commonality was essentially their ability to help us survive.

Most people consider other objects essential - driver's license (particularly in the US), medication, travel pass and lip-stick are just some that have been mentioned but these can change over the course of the day and according to context. I would argue that nearly all objects that people carry are essential, because the carrier has already gone through a conscious and subconscious selection process to select those objects from all the objects they own or have access to. Nobody carries stuff just for the hell of it. Well actually that's not strictly true - many people carry things that they are not aware they are carrying - phones increasingly have features that the owner considers useful, is not aware are on the device. In these instances the smart question is what situations trigger initial awareness of a feature, and many researchers are working on contextual understanding in part to present the user with the right feature/knowledge at exactly the right time that it is useful.

The exceptions to why people don't carry these objects are in some ways more interesting than the fact they do in the first place. Designing solutions that meet a user needs are relatively easy, but for a product to be adopted into the flow of someone's life takes a good understanding of exceptions. Mobile essentials are often forgotten, despite the strategies for remembering. Keys are not necessarily needed if you live in an extended family or in areas of high unemployment. Some people like to 'switch off' and talk about quality time without the interruption of the mobile phone (I expect there to be different attitudes towards constant connectivity with younger generations). There is also the issue of at what point in a person's life they are entrusted to carry these essentials and in the case of children, if they are lost, who is responsible to replace them?

In one sense the easiest way never to ever forget anything ever again is to have nothing to remember. This is not as glib as it first sounds - it is possible to delegate responsibility to remembering to other people or indeed to technology. (The concept of delegating can be considered as a solution to many problems except entertainment and bodily functions).

A number of interesting avenues have come out of this research:

Why people make a conscious effort to leave mobile essentials behind and in the case of their mobile phone - switched off. This loosely comes under the heading connecting people, dis-connecting people, and re-connecting people.

My colleagues have initated a study of where people in Helsinki carry their phones and whether they notice incoming communication. A paper, drawing on data from follow up studies in Milan and New York will be presented at the Mobility Conference 2005 in Guangzhou China. (I'll post it when its available)

Another theme is the role of the phone in supporting and on occasion triggering personal crisis. Not life threatening events but things like being locked out of home, being lost late at night, breaking up with boyfriend/girlfriend and yes, mobile phone theft and loss. Notice the overlap between mobile essentials and personal crisis?.