108 ChapTer 3 Development Over the Life Span
Still, various aspects of intelligence, memory,
decision making, and several other forms of men-
tal functioning do decline with age. After roughly
age 65, adults usually begin to score lower on tests
of reasoning, spatial ability, and complex problem
solving than do younger adults. It takes them
longer to retrieve words and names, dates, and
other information; in fact, the speed of cognitive
processing in general slows down. However, older
people vary considerably in this respect, with
some declining significantly and others remaining
quite sharp (Lövdén et al., 2010; Salthouse, 2013).
Further, generational differences in education and
familiarity with tests may help account for some
of the cognitive differences between older and
younger people (see Chapter 1).
Moreover, not all cognitive abilities worsen
with age. Fluid intelligence is the capacity to reason
and use new information to solve problems. It re-
flects in part an inherited predisposition, and it par-
allels other biological capacities in its growth and
later decline (Bosworth & Schaie, 1999; Li et al.,
2004). Crystallized intelligence consists of knowledge
and skills built up over a lifetime, the kind of intel-
ligence that gives us the ability to do arithmetic,
define words, or take political positions. It depends
heavily on education and experience, and it tends
to remain stable or even improve over the life span.
This is why physicians, lawyers, teachers, farmers,musicians, insurance agents, politicians, psycholo-
gists, and people in many other occupations can
continue working well into old age (Halpern, 2008).
Also, older adults are often able to compensate
for age- related declines by recruiting parts of the
brain that are not commonly activated when young
people do the same tasks—an example of the brain’s
impressive flexibility (Huang et al., 2012).
Many of the physical and mental losses that do
occur in old age are physiologically and genetically
based and are seen in all societies, but others have to
do with cultural, be-
havioral, and psycho-
logical factors (Park
& Gutchess, 2006).
Psychologists have
made great strides in
separating conditions
once thought to be an inevitable part of old age
from those that are preventable or treatable:• Malnutrition and medications. Apparent
senility in the elderly is often caused by mal-
nutrition, prescription medications, harmful
combinations of medications, and over-the-
counter drugs (such as sleeping pills and anti-
histamines), all of which can be hazardous to
old people.About Mental Decline in
Old AgeThinking
CriTiCally
fluid intelligence The
capacity to reason and
use new information
to solve problems; it is
relatively independent of
education and tends to
decline in old age.
crystallized
intelligence Cognitive
skills and specific
knowledge acquired over
a lifetime; it is heavily
dependent on education
and tends to remain
stable.
The two images of old age: More and more old people are living healthy, active, mentally stimulating lives. But with^
increasing longevity, many people are also falling victim to degenerative diseases such as Alzheimer’s.