Aging and Older Adults
Understanding of human behaviors relevant to design helps designers produce better outcomes. When developing an application for older adults, it is important to consider human factors, the science of understanding interaction between people, products, and environment, while they are doing tasks (Fisk et al., 2009) in safe, efficient, and effective ways (Czaja & Lee, 2012). To a designer, understanding target audiences is an important factor in improving human-centered design which is based on usability in order to create designs that work effectively with natural human movements and behaviors. The population of older adults has specific needs based on changes that occur due to the aging process such as sensory, cognition, mobility, and spatial abilities. Learning about fundamental, physical, and psychological characteristics of older adults provides correct affordance for more effective use of an application. All characteristics that pertain to older adults are a part of the science of human factors. This section gives a background on what defines older adults in society and provides details on that population and physical and cognitive conversions that happen during the process of aging. It is critical that these definitions and changes be discussed to understand carefully who the target audience is for appropriate design of an application.
The United States is experiencing tremendous growth in the population of older adults. “In 2050, the number of Americans aged 65 and older is projected to be 88.5 million, more than double its projected population of 40.2 million in 2010” (Vincent & Velkoff, 2010, p.1). By 2050, 27 percent of the population will be located within the age group 60 and older in the United States (Vincent & Velkoff, 2010). That result generates another assumption that more older adult population will become larger than the total population of children under 14 years of age (Deen, 2012). It would also affect the Potential Support Ratio (PSR) (UN, 2015), a measurement of how many younger people are available to support the welfare of older people. Baby boomers, aged between 51 and 70 years in 2016, will contribute to the impact on the PSR because they began entering into the older population category in 2011 (Vincent & Velkoff, 2010). They were born between 1946 and 1964 and have been responsible for remarkable development in the marketing industry. In 1960 when they turned 18 boomers were the greatest target audiences with respect to fashion, new technology, industry, and consumer products such as Pepsi, Levis, and Coca-Cola (Nielsen & Agers, 2012). Today’s older adults are healthier and live longer “due to the improvement in public health, nutrition, medicine and personal hygiene” (Deen, 2012, p.573), and the sudden increase in aging population has made it impossible to develop economical solutions for “well-being, health care, and social needs of older adults.” (Deen, 2012, p.573)
According to the report of the most recent U.S. Census (West, Cole, Goodkind, & He, 2014) nearly 80% of the older population was living independently alone or with spouse only in the United States. Homebound older adults tend to encounter feelings of isolation, depression, loneliness, and disability (Holt & Komlos-Weimer, 1999). Those feelings affect individuals’ health (Berkman, 1995). Before designing products for older adults, there are several considerations that designers should recognize regarding functional abilities relative to age-related changes in this population.
Rowe and Kahn (1997) defined successful aging as physical and functional health with a relative absence of disease, high cognitive physical health, and active and dynamic involvement in society. Bohlmeijer, et al., (2007, p.291) “defined successful aging as the maximization and attainment of positive outcomes and the minimization or avoidance of negative outcomes.” Moreover, as Fisk, et al., (2009) stated, aging is not an illness, not a diagnosis, it is associated with a progressive decline in physical and mental health in both males and females after maturity.
A noticeable decline in one’s ability typically starts in the mid-forties (Hawthorn, 2000), but there are no specific age boundaries for dividing younger and older adults because each individual has a different rate of aging that can be categorized in terms of four dimensions: “chronological, biological, psychological, and social ageing” (Phillips, Ajrouch, & Hillcoat-Nallétamby, 2010, p.12). Although most developed countries have used the chronological age of 65 or older as describing older adults, and no UN standard criterion existed, the UN has now agreed to describe persons of age 60 years or older as older adults because of shorter life expectancy in developing countries (Czaja & Lee, 2012; WHO, 2013). Therefore, the term older adults in this research will mean those in the age range 60 years and older. This description covers an enormous variety of biological and psychological conditions.
Vision: When people age, vision impairment typically starts to increase in their early forties (Fisk et al., 2009). Contrast sensitivity, especially color sensitivity, declines in the blue-green range (Hawthorn, 2000). Declining sensitivity makes the eye lenses appear like a yellow filter, diminishing the difference between blue and green. Yellowing eye lenses see objects as if a person wears yellow filter lensed glasses, making it relatively easy to see red, orange, and yellow, but difficult to see blue, green, and violet (Agelight, 2001). Seven out of ten people over the age of 65 need to wear eyeglasses. Vision impairment also affects sensitivity to glare, large changes in illumination, and speed of processing, all of which are related to the reaction time from speed changes (Fisk, et al., 2009). The ability to accurately estimate an object’s depth may also rapidly decline with age. It can be difficult for older adults to recognize fragmented or incomplete objects and target locations in an unstable field (Hawthorn, 2000).
After researching differences in vision, we can decide how to help older adults find items with ease and hold their attention on those items. The most recommended design guideline principles are layout simplicity, clarity, consistency, and bolder search cues (Hawthorn, 2000). The distance between eyes and screen while wearing bifocals may cause blurred vision (Hawthorn, 2000) because bifocals are designed for print materials and not for screens (Agelight, 2001). Most such impairment can tire older people and diminish their cognitive attention while doing tasks (Hawthorn, 2000). For example, clicking on a small button on the website requires older adults more intense attention, so designers should give older adults more time to read text blocks before moving to other pages and should avoid moving texts to prevent distraction while concentrating on reading content (Hawthorn, 2000). Computer Vision Syndrome (CVS) can also easily occur in older adults because of their decreasing vision sensitivity. Dry eyes, caused by lack of blinking, or headaches, eyestrain, and eye irritation are common symptoms of CVS (Agelight, 2001).
Taste and Smell: Although individual abilities are varied, most people over the age of 60 report a decreasing sense of taste: sweet, sour, bitter, and salty, and a diminishing sense of smell often is accompanied by diminishment in taste.
Speech and Hearing: Aging is also related to the sense of hearing. A gradual declination in auditory ability is usually the result of a loss of sensitivity for high-pitched alert sounds such as those from alarm and emergency systems, as well as difficulty in understanding synthetic speech distinguished by some degree of distortion (Arch, 2010; Czaja & Lee, 2012). Older adults tend to not register sound frequencies over 2500 Hz (Hawthorn, 2000), so they may miss smoke alarms frequencies of about 4000 Hz that would be effective for younger users (Berkowitz & Casali, 1990). Older adults tend to have a harder time hearing higher-pitched female voices than male voices (Hawthorn, 2000). Designers must be aware of older people’s auditory deficiencies that affect their ability to detect tones, sounds, or general ability to understand speech (Fisk, et al., 2009). Designers should consider the provision of permission to adjust sound volume, avoidance of frequencies over 4000 Hz, frequency ranges between 500 and 2000 Hz, and sound intensities of at least 60dB. Both visual and auditory information is easier to understand if background music or noise is minimized, especially when a person is trying to concentrate on spoken language while performing tasks.
Haptics: Study of haptic ability for older adults generally refers to the sense of touch, including various sensory abilities such as identifying body parts with the eyes closed. It relates to using devices of assistive technology for everyday life. The term haptic refers to kinesthetic sensitivity associated with automatic integration dealing with movement and maintaining balance using muscles, joints, and skin (Fisk et al., 2009). Declining balance, encountered by many older adults every day, may cause postural instability and unintentional falls (Fisk et al., 2009). Skin and muscles, in processing haptic information, may be influenced by temperature and vibration information. Older adults tend to have privative touch, so either a visual sign, or some auditory or vibratory clues can be used as warnings.
Interactions with products require users to use various cognitive processes that, in turn, involve a broad range of mental processes. Age-related change in cognition is necessary for designers in that older adults tend to perform technology-based tasks in a declining status of cognition ability (Czaja & Lee, 2012). While mentally processing the information they may tend to respond slowly or find it difficult to do new or unfamiliar tasks (Fisk et al., 2009). They also cannot easily ignore attractive but unimportant stimuli, thus resulting in disruption of concentration on tasks (Holt & Komlos-Weimer, 1999). Automated behavior is a brain activity that decreases effort in use of applications. Designers should consider automated reactions that are difficult to form by older adults (Hawthorn, 2000) and should carefully deal with menus, tool buttons, and input locations (Hawthorn, 2000).
Working Memory (Short-term Memory)
Working memory relates to the processing of items from short-term memory that significantly declines with aging. It holds immediate memories of the events from short-term memory until we use them, but they are then rapidly replaced by new information. People use working memory every day to retain temporal information for everyday tasks (Fisk et al., 2009). When stimuli information flows through the perceptual system into sensory memory it is briefly memorized or raised to awareness, and then items are delivered to “working memory, sometimes called short-term memory” (Fisk et al., 2009, p.20). Items held in working memory for an extended time through rehearsal are then, through a few different mechanisms, selected for transport to long-term memory; this is similar to recall of memories from high school years and memorable experiences that may have occurred a few years ago (Atkinson & Shiffrin, 1968). Working memory is the age-related memory, associated with a gradual decline in processing items (Hawthorn, 2000; Salthouse, 1994), text comprehension (Light, Birren, & Schaie, 1990), and visual information (Hoyer & Rybash, 1992) in short-term memory.
Semantic Memory (Long-term memory)
Semantic Memory is a kind of permanent space for information that gradually declines with aging. It refers to a long-term memory, including behaviors, learned movements, and population stereotypes. Recall of the meaning of words, historical facts, memory related to art and music, and general knowledge is related to semantic memory (Fisk et al., 2009). Older adults may tend to have difficulty searching for memories of such experiences or otherwise exhibit slow access to stored information, but they do not lose easily most such information (Fisk et al., 2009).
Prospective memory is memory related to future plans (Einstein & McDaniel, 1990), “remembering to do something in the future” (Fisk et al., 2009, p.21). Time-based prospective memory, such as taking medication in two hours, and event-based prospective memory, such as taking medication after having lunch, are examples of prospective memory. Event-based prospective memory is easy for older adults in that it has a cue as a reminder for the future plan ( Einstein & McDaniel, 1990; Fisk et al., 2009) because a cue such as taking medicine after dinner will provide older users with a precise time when the activity needs to occur.
Procedural memory is another kind of long-term memory that involves recalling how to execute activities such as riding a bike or driving (Fisk et al., 2009). It is difficult for older adults in developing automatic processes such as forming new habits to be performed without thinking. Overlearned automated activities before aging allow people to perform without any conscious thought; however, well-practiced activities are age-insensitive even for older adults (Fisk et al., 2009).
Attention is our ability to focus on required task processes (Hawthorn, 2000). There are several specific attention and all declines with age. Selective attention is tasks that search and choose relevant information from all sources. Dynamic visual attention is successful interaction with products or environment. When reorienting the location of attention from one item to another, older adults often need more time to reorient items. Divided attention pays attention to multiple tasks at the same time. Older adults find it difficult when things move fast and increased time must be spent on multitasking activities.
Spatial orientation is the capacity to understand “where [objects] are positioned and oriented relative to objects in their environment” (Thompson, Fleming, Creem-Regehr, & Stefanucci, 2011, p.327). The ability perceiving nearby objects to complex direction-finding in an unfamiliar space is crucial to understand spatial surroundings (Thompson, Fleming, Creem-Regehr, & Stefanucci, 2011). “Spatial properties include location, size, distance, direction, separation and connection, shape, pattern, and movement” (Smelser & Baltes, 2001, p.14771). The spatial ability also declines with age (Cherry, Park, & Donaldson, 1993).
Mobility is the ability to move oneself by walking, by means of transportation, or operating devices. Mobility is directly related to one’s health and quality of life during later life (Webber, Porter, & Menec, 2010) because as people grow old, their body structure and control of movement become degraded (Fisk et al., 2009). Maintaining mobility allows older adults to stay active, energetic, and live independently (WHO, 2014). As movement and response time slow in older adults, there is increased difficulty maintaining continuous movement, loss of accuracy, and limited moving distance, all primary features of mobility (Czaja & Lee, 2012). Additionally, laboratory-based research proved “age-related performance decline as a combination of poorer perceptual feedback, increased noise in the motor pathway, and strategy differences in approaching the task” (Fisk et al., 2009, p.24), affecting their capability to use accessible devices such as cursor-positioning performance that tend to require considerable attention in older adults. Pointing time with a mouse was longer for older adults, but there were no significant age-related differences between older and younger adults in pointing time with touch-based devices (Czaja & Lee, 2012; Jagacinski, Liao, & Fayyad, 1995). The response time of older adults is usually 1.5 to 2 times slower compared to younger adults (Fisk et al., 2009; Jagacinski et al., 1995).
Designers should think about the moving time of a cursor, target size, and click time for actions like double-clicking. Although older adults may encounter motor, cognitive, and physical limitations for socializing, the technology could be an effective solution in alleviating their problems.
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