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The UK, in line with most of the EU and developed world, has an ageing population: in 1985 15% of the population was over 65 years old. This rose to 17% by 2010 with a predicted growth to 23% by 2035 (Office for National Statistics, 2012). In recent years, mobile technologies have had a massive impact on working life, for example it is estimated that over 25% of emails are now opened on mobile devices (Knotice, 2012). As the older working population rises, due to both ageing population demographics and increasing retirement age, a growing number of digital economy workers will require to continue to use mobile technologies for work into their mid/late 60s. Furthermore, many people will want to continue professional, social and lifestyle usage into their late retirement as the technologies can support increased community involvement and personal independence. Unfortunately, the ageing process can interfere considerably with mobile technology usage. The normal ageing process typically involves a decline in visual and auditory abilities together with a decline in working memory, selective attention, and motor control (Fisk, Rogers, Charness, Czaja, & Sharit, 2012). For example, many people in their 40s start to have vision changes that affect their near focus while, as a rule-of-thumb, older people require 1.5 to 2.0 times longer to perform a motor action compared to younger people (Fisk et al., 2012).
Text entry is core to mobile interactions such as emailing, social networking, instant messaging and interacting with services such as web or map searching. The majority of smartphones now do not have any physical keyboard but rely on on-screen touch keyboards. These have been shown to be slower and more error-prone than traditional mini-physical keyboards in studies such as Hoggan, Brewster, & Johnston (2008), and Lee & Zhai (2009a), but are popular as they allow for larger mobile screens. While there have been numerous studies into text entry usage on touchscreens, there has been very little work studying the effects of ageing on text entry, particularly on modern touchscreen phones where reduced visual acuity, reduced motor control and reduced working memory are all likely to have an impact. The most notable work is that of Nicolau & Jorge (2012) who examined the role of hand tremor in input by older adults on touchscreen phones and tablets. Younger users have been shown to be faster in text entry studies since the early days of personal digital assistant devices (Wright et al., 2000). The main reasons for this are the effects of age on both our vision and on the accuracy and speed of movement. In an example checklist for design of push buttons for a stereo, (Fisk et al., 2012) included the following key recommendations when designing for older (65+) users:
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To accommodate older users with tremor and arthritic conditions, avoid combinations of low force (< 0.35 N) and low travel (< 0.2 mm);
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Ensure that there is adequate spacing between buttons to prevent inadvertent activation of controls;
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Ensure that surfaces have sufficient frictional resistance to prevent finger sliding;
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Ensure that there is proper illumination for activation under conditions of dim lighting.
Smartphone touchscreen keyboards provide an extreme counter-example of these principles:
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Soft keys require almost zero force to activate and have zero travel;
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Soft keyboards typically have no gap between keys (any visible gap is ignored by the underlying software that uses predictive technology to guess which key was intended);
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Surfaces are high gloss low resistance glass;
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Keyboards are often reduced contrast to aid styling with strong sunlight and high reflection levels further reducing contrast.