Memorandum by QinetiQ
QinetiQ has undertaken considerable recent
analysis of research data on the ageing process, specifically
in the context of assessing the physical performance and potential
of Service personnel as they age. We regard this research as having
an important bearing on the population as a whole, and consequently
on the Committee's area of inquiry. As a result of the studies,
details of which are set out below, QinetiQ believes that further
research is necessary in the following areas:
— The effects of ageing on the physical
performance of women.
— Ageing and task performance, concentrated
on those tasks involving heavy loads on working memory, selective
attention, information processing and rapid reactions to presented
material.
— How and why attitudes and motivation
change in the work place with increasing age.
INTRODUCTION
The age structure of the European workforce
is changing. The birth rate is falling, which means that from
around 2011 onwards those in the age group 15-29 will represent
a decreasing proportion of the population. By 2010, it is estimated
that over 40 per cent of the working population will be aged 45
and over and by 2020 the modal value for working age will have
increased from 35-39 to 50-54 years of age.
In 2003 QinetiQ undertook a study to review
the research evidence that related the physical, cognitive and
non-cognitive (psychological) factors associated with the ageing
process to performance of military or analogous tasks1. The study
also attempted to identify gaps in our current knowledge and identify
strategic research that should be undertaken.
The approach adopted was to undertake separate
reviews of the published literature on the effects of ageing on
physical performance and the psychological effects of ageing on
performance. This included the effects of ageing on cognitive
performance, (ie thinking, decision making etc) and non-cognitive
factors such as attitudes and motivation towards work.
Ageing and physical performance
"Physical Fitness" encompasses a variety
of diverse factors, but can be described generally in terms of
four component parts: strength, speed, endurance and flexibility.
These can be measured in different ways but the ability to utilise
oxygen is commonly used as a measure of "fitness" as
high levels of this "aerobic capacity" are necessary
for speed and endurance. A measure, known as VO2max, (which is
a measure of maximal aerobic power) is often regarded as the best
indicator of general fitness.
Maximal aerobic power reaches a peak level at
around 20 years of age, then declines throughout the rest of life
at a rate of around 1 per cent each year.
However, this rate of decline can be reduced.
Studies of endurance athletes have shown the effect of prolonged
training on aerobic capacity well into later life. The decline
appears to be more directly related to a reduction in the amount
of training, rather than any factor directly related to the ageing
process itself. Aerobic capacity appears related much more directly
to activity levels than to age. The aerobic capacity of active
individuals declines more slowly if they maintain a regular exercise
programme. Sedentary individuals decline at a rapid rate during
their 20s and 30s, followed by a slower rate of decline of their
VO2max as they age further. It is likely that gradual increases
in training levels could counteract the ageing process and allow
an individual to maintain a constant level of aerobic fitness
for many years.
Peak muscle strength is generally achieved between
the ages of 20-30 years. It deteriorates from around the age of
30, but is subject to an increase in the rate of deterioration
towards later middle age. The cause of this progressive loss of
strength is an age-related loss of muscle mass, at an average
rate of 0.5 per cent per year. A fall of 25 per cent in peak isometric
force is usually observed between 30-65 years, but much of this
loss will occur after 55 years of age. However, evidence from
industry of older workers suffering strength-related problems
is limited. It appears that reduced muscle function with increased
age is not inevitable, and that resistance training can improve
muscle recruitment and maintain, or even increase, muscle mass
throughout life.
In 1999, the Research and Technology Organisation
(RTO) of NATO held a symposium on the operational issues of ageing
crewmembers, which investigated the case for a re-evaluation of
age policies for military crewmembers and covered operational,
psychological and physiological aspects2. Three significant conclusions
were drawn:
— During these times of preventive
medicine, health promotion and healthy lifestyles, physiological
age of individuals appears to be more important than chronological
age of groups;
— Knowledge, behaviour and experience
seem to adequately compensate for ageing among crewmembers in
military environments; and
— These factors, combined with new
medical and surgical therapies, and technological advances (in
equipment designs, etc) appear to justify seriously re-examining
current age policies for military crewmembers.
Fitness and diversity
Men and women appear not to differ, in most
respects, in the ageing process. Generally, women have a lower
aerobic capacity, but some of this difference is attributable
to societal norms that are gradually being eroded. Muscular strength
is less in women, but specific training can lessen this difference.
Major differences between men and women appear in the mid-50s,
when a marked fall in muscular strength has been reported in women,
but not in men. It is possible that this is brought about by hormonal
changes, but that other factors such as cultural expectations
may heighten this deterioration. More work may be required in
this area. This study found no reported differences in the response
to the ageing process by populations of different ethnicity.
Maintaining fitness
A study on the self-perception of fitness levels
among fire-fighters showed no correlation between how fit personnel
think they are and how fit they actually are. However, a supervised
fitness programme restored aerobic capacity and strength levels
in unfit fire fighters to the required levels, irrespective of
age. A study of Finnish police officers showed that, whilst muscular
strength declined over the 15 years of the study as the group
aged, the absolute aerobic capacity of the officers remained constant.
It concluded that the physical fitness of middle-aged police officers
depended on the level of physical activity in young adulthood,
and that age, in itself, was not related to reduced physical performance
on the job. However, the sporadic nature of the high levels of
physical performance associated with fire-fighting was shown to
be insufficient to maintain a high enough training drive in itself
(ie simply doing the job itself might not keep you fit enough
to meet the demands it imposes).
Studies that have looked at older groups show
that the response to a training stimulus appears to be unrelated
to age, and that significant increases in aerobic capacity, strength
and flexibility can be achieved in people well past normal working
age.
Ageing and cognition
Psychologists generally consider two aspects
of intelligence supported by experimental evidence: "fluid
intelligence" and "crystallised intelligence".
Fluid intelligence is held to be unaffected by experience (being
largely determined by hereditary factors) and to depend on the
integrity and efficiency of physiological and neurological functioning.
Therefore, it is likely to be subject to decline from early adulthood
onwards. Crystallised intelligence, in contrast, is a function
of accumulated experience, knowledge and training, and is largely
independent of fluid intelligence after early and middle adulthood.
It can be expected to increase through adulthood into old age.
Studies have shown that, on average, the older worker performs
less well than their younger counterparts on tests of fluid intelligence.
However, since the development of crystallised intelligence depends
on the exercise of fluid intelligence, the rate of growth would
be expected to diminish with age. Generally speaking, the pattern
of susceptibility, or resistance, of intelligence sub-tests to
the effects of ageing is in line with these hypotheses in that
scores on sub-tests which appear to be primarily measuring crystallised
intelligence are more stable with age than are sub-tests measuring
fluid intelligence.
Specific cognitive abilities
Laboratory studies have shown that ageing affects
performance on many information-processing tasks. These include:
memory for previously presented material, divided attention, working
memory, dual-task activities, and rapid reaction to presented
information. The decrease in performance has been attributed to
impairment of working memory, reduced processing speed or a combination
of both. Although these decrements are strongly correlated with
age throughout adulthood, they become more apparent after the
age of 50 years.
Although early research suggests older workers
have greater difficulty in learning new material, recent research
has shown factors which can remove some or all of these difficulties
so that there are little or no decrements associated with age.
If the material to be learned is contextual, ie the environment
supports the process, then older workers are just as adept at
learning as their younger counterparts.
Additionally, if the learning is implicit in
the task, ie unconscious learning, then little or no age decrements
are found. For example, in a task involving planning the best
route between two points on a map, older workers will later recognise
presented place-names, on that map, just as well as younger workers
do. This might indicate that working memory decrements are not
as extensive as first suggested.
Many of the studies are open to criticism on
methodological grounds. Although research has shown that the above
decrements exist, they are quite small. Typically, the range of
scores around the mode is much greater for older participants
in this research than for younger participants. This means that
any cited average score is less of an indication of any individual
score among older people than among younger ones. That is, there
is a large within group variation with, for example, many older
people outperforming many younger ones.
Another point of note is that, by the very nature
of this area of study, the majority of studies are cross sectional
(ie comparisons are made between separate groups of individuals
of particular age groups), not longitudinal (repeated studies
undertaken on the same group of individuals at different ages).
Those studies that have been longitudinal have produced results
that show a less marked decline in cognitive ability as one ages.
Non-laboratory studies
If the measured outcomes of any test of cognition
are actual work, or simulated work tasks, then age-related defects
disappear. Although research into the cognitive effects of ageing
goes back nearly 40 years, research upon how any age related cognitive
decrements actually affect work performance has only begun in
earnest within the last 10 years or so.
Most of these studies show that within middle
adulthood work performance is rarely affected by age. In fact,
older workers often show higher performance levels than their
younger colleagues. This is not a total surprise given that older
workers tend to be more experienced and so have much more crystallised
job knowledge than do younger workers. It is likely that the older
worker uses their wealth of expertise to develop more efficient
"routines" to overcome any cognitive deficits they may
experience.
Experience, usually measured by tenure, or length
of service that is correlated with age, would be expected to counteract
the effects of age on performance. Some studies of industrial
and clerical jobs have shown that when length of service is controlled,
age effects on performance disappear; conversely when age is controlled,
the effects of experience remain. Experience is a stronger predictor
of job performance than age.
Research into how older workers cope with training
is an area of concern for the recruitment of older people. If
experience is the mediator of age-related cognitive deficits,
employers need to know how commercially viable the training of
inexperienced older workers is. A great deal is known about the
training procedures most appropriate for and acceptable to older
workers. For example, older workers only show reduced ability
to learn if the pace of learning is forced. Older workers also
take longer to complete training, although if more time is given
to learn, they can achieve the same level of attainment as their
younger counterparts. This time limited deficit is not strictly
an age-dependent feature. If the training course is intensive
or difficult, then younger workers can be just as likely to show
achievement decrements in post-training tests. It may be that
the perceived workload in training can affect the effectiveness
of the training as older trainees may feel they have to invest
a lot more effort into achieving an accepted standard.
Non-cognitive factors
Research evidence in the field of personality
and ageing is, at present, limited. Some studies suggest that
older people score higher on scales of self-control, conscientiousness,
tolerance, modesty, wellbeing and achievement via conformance,
but lower on sociability, outgoingness, affiliativeness, extraversion,
change orientation, conceptual thinking, and achieving via independence.
Despite these findings, there is no evidence that any age differences
within personality affect work performance.
It is possible that, even if the underlying
personality does not change, as individuals age they conform to
an age norm or that they become the stereotypical older person.
The notion of an age norm seems odd, as it suggests that individuals
take on age as an identity or role. Yet research suggests that
this happens.
Research has identified both positive and negative
stereotypes of older workers. Stereotypes can be overcome by direct
experience with individual members of the group; however they
guide initial behaviour and, thereby, shape subsequent interaction.
Since it is a widely held stereotype that older workers are poor
learners, they are less likely to gain access to training schemes
and it is likely that the stereotype becomes a self-fulfilling
prophecy.
Recently, this notion of age norms has been
questioned. While there is broad agreement as to expectations
of career achievements by certain ages, there is no clear indication
that these expectations affect behaviour. There is no indication
of sanctions being applied if one does not conform to the supposed
norm.
However, like people at other stages in their
lives, older people come to understand what is expected of them
by looking for cues and role definitions provided by others. Age-related
norms regarding matters such as when to retire may be general
for a society or specific to an organisation. Such norms shape
the way other employees, including supervisors, treat older workers
and may lead to differences in the methods used to evaluate older
and younger people and to the creation of "incentives"
to retire. Despite stereotypes to the contrary, workers at midlife
and beyond are capable of changing and adjusting to changes in
their environments.
CONCLUSIONS
1. Differences within age groups, particularly
older groups from middle adulthood to the sixth decade, are almost
as great as those between younger and older groups. Therefore,
generalising from mean performance levels for older groups could
be misleading. The implication is that there will be older people
who outperform those considerably younger and this is true for
recruits as much as for job incumbents. Conversely, it is highly
unlikely that there is a measure of physical performance, achievable
by 30 year olds that will not be achievable by at least some people
of twice this age.
2. Previously accepted age-related decrements
in performance would appear to be related to lifestyle changes
associated with ageing, rather than physical limitations.
3. It would be correct to state that ageing
is associated with a decline in strength, endurance and reaction
time. However, it appears that this is neither as steep as has
been thought previously, nor as rooted in physiological origins
as might be thought. Furthermore, as the majority of people—even
those considered "fit" in comparison to their peers—are
not achieving their maximal possible fitness level, there exists
a reserve potential to utilise to counteract the ageing process.
4. Studies linking age and physical performance
suggest that "Biological Age" rather than "Chronological
Age" is a more satisfactory indicator of the ability to work
at certain jobs.
5. Surprisingly, the age-related decline
in physical fitness appears to be more related to expectation
than to biology. As we age, we expect to be less fit, so we exercise
less, worry less about weight gain, and attempt less demanding
roles. This is culturally reinforced as others' perceptions of
us get coloured by our age, so it becomes increasingly difficult
to maintain the activity levels that would maintain the levels
of fitness we had in our youth.
6. The evidence on physical performance
suggests, for those already trained to the required standard,
that with constant practice performance levels can be maintained
to a fitness level of a VO2max figure of 45-50 ml/kg up to 55
years and beyond. Some research suggests that even for physically
demanding jobs normal professional activity might not be sufficient
to maintain peak fitness requirements and therefore additional
supplementary training may be required. Research with older groups
suggests that response to physical training appears unrelated
to age. This would suggest that, with training, older groups but
below 55, could still regain physical fitness levels. However,
the appropriate training regimes required to maintain and re-gain
physical standards for older groups is an area that needs further
research.
7. This study supports the recent conclusion
by the US Rand Corporation3 that "Age is a poor predictor
of the decline of stamina, strength, reasoning and comprehension".
Age has some effect on most, if not all human capacities, but
our research indicates that age-deficits are not found to any
significant degree until the sixth, seventh and eight decades.
The studies examined suggest that for a typical working life (age
20 to 60 years), there is little evidence that older workers are
incapable of performing equally well in most job situations,
military and civil. Exceptions are likely to be related to some
military jobs that require superior visual acuity, strength or
reaction time.
8. Evidence from cognitive research shows
that the results of laboratory studies do not hold in the work
situation. There seem to be very few occupations that cannot be
performed by job incumbents up to 55 years and beyond. Experience
appears to compensate for what little performance decrement would
be expected as a consequence of ageing. For some high level tasks,
experience may be the most significant factor. A separate study
into the relationship between length of service and experience
being undertaken by QinetiQ as part of the MoD's Corporate Research
Programme will be of relevance to this question.
9. However, for tasks that involve heavy
loads on working memory, selective attention information processing
and rapid reactions to presented materials, performance decrements
might be much more susceptible to the effects of ageing.
10. In terms of physical and cognitive performance
there appears to be no biological reason why most people should
not perform effectively in a wide range of occupations, at least
up until the sixth decade. The evidence from the research on non-cognitive
factors indicates that evidence for personality changes as a result
of ageing is flawed through the lack of longitudinal studies.
There is no evidence that if personality changes that it has an
influence on work performance. However, everyday observation suggests
that behaviour appears to change with age.
11. Stereotypes of the older worker exist,
some positive and some negative. Little evidence exists as to
the validity of these assumptions. The concept of a norm has been
suggested and there is some evidence that older people adopt behaviour
congruent with expectations. It is also possible that some stereotypes
become self-fulfilling. If the expectation is that older workers
are more difficult to train then they may be offered fewer training
opportunities. How expectations and motivation of the older working
population are shaped and change over time is an area that requires
substantial additional research. With recent political comment
concerning the need to increase the age of retirement for economic
reasons, this would appear long overdue.
REFERENCES
1 Elshaw C,Kelm DM, Traynor ML Ageing and
Military performance: Final Report. QinetiQ/KI/CHS/CR031826 June
2003.
2 RTO meeting Proceedings 33 (papers presented
at the RTO Human Factors and Medicine Panel (HFM) Symposium, Toulon,
France, 11-14 October 1999). RTO-MP-33.
3 Goldich R L (1995). Military retirement
and personnel management: Should active duty careers be lengthened?
CRS Report for Congress. US Library of Congress.
October 2004
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