Aging is defined by time.
Even though our bodies are in a constant process of change, some cells in our
bodies remain with us from conception. Our bodies have 37 trillion cells that
are constantly duplicating, updating, maintaining and replacing themselves.
Each cell contributes to a specific organ in the body. Jonas Frisen, a stem
cell biologist at the Karolinska Institute in Stockholm developed a method for
determining the age of each organ. Although some cells remain with us the
duration of our life—neurons of the cerebral cortex, cells of your inner lens
in our eyes, muscle and valve cells of your heart—the rest of our body is in a
constant frenzy of change and rejuvenation so that with time we get to replace
whole organs:
1. Intestines replaced every 2-3 days old,
2. Taste buds replenish themselves every ten days.
3. Skin and lungs (2-4 weeks)
4. Liver is replaced (5 months)
5. Nails (6-10 months).
6. Red Blood cells, every four months after travelling over 300
miles and going through the heart 170,000 times, 60 times per hour our red
blood cells are given respite and are renewed
7. Hair if the follicles have not fallen off every 3-6 years)
8. Bones (every 10 years) and lastly
9. Heart--most of it (every 20 years)
Despite this newness, we
measure our age by our chronology—how much measured time has elapsed. On
average our body is only eleven years old. However with each replication a
slight imperfection results. We see these imperfections and assign it to the
“aging” of our bodies. We resign ourselves to accepting our aging as an
indication of our chronological time but it isn’t. Physical aging are mistakes
that happen. But we mesh the two together. Aging and time are glued together
and only when we look closer do we see that each is unique and separate.
We have a story, a narrative
arc playing in the background of our life. Time is a special dimension, an
unrelenting linear and absolute progression. Although time seems intuitive, we
have a great difficulty even conceptualizing what time is, let alone explaining
what it is. We have ways of measuring sequences and flow of events that we call
time, but time remains elusive to explain.
A quick dive into quantum
physics dispel any such illusion that time is stable or linear. For example in
quantum entanglement two electrons remain connected, no matter how far apart
they are, in synchrony. The electrons remain attached in time but not space. In
this quantum universe, time doesn't exist at all. In the split slit experiment—where
electrons interfere with each other after going though two slits but only when
they are not being recorded—seems to suggest that electrons can go back in
time, or at best do not conform to our linear time. Whatever our linear time
means. Einstein called time a “stubbornly persistent illusion”. He was wrong,
time is our reality that fails to find evidence outside of our consciousness.
Time is something that we
create for ourselves and we do this by measuring it. And we measure time with
great relish. Other than external means of measuring time—an impressive and
historical array of clocks and watches, celestial movement, temples and
seasonal rituals—our mental representation of time is fundamentally linked to
our body. Our internal time is determined by our own biological, neurological
and emotional reality. Many theories attempt to explain how time emanates from
our mind and our body. But the biggest contributor to our sense of time is our
own sense of aging—time speeds up with age.
Internal Clock
Our bodies are sophisticated
watches—chronographs—that seem to get faster with age. The psychologist William
James at the turn of the 20th century observed that years seems to pass more
rapidly as we grow older. Many have attempted to prove this observation, but
with variable success. Then the French
biophysicist Lecomte du Nouy in 1937 associated this phenomenon of a racing
time with the slowing in cellular activity in aging bodies. He connected time with
our physiological processes. To this day, although there is much evidence
supporting this theory, the relationship between our physiological processes
and our estimate of time remains contested. Studies do not show clear-cut
outcomes. We have not found all of the mechanisms that control our sense of
time. But in our explorations, we are learning more about the variability of
how we judge time.
For example in 1958 Sanford
Goldstone, William Boardman and William Lhamon with Baylor University Houston,
Texas asked institutional older adults to count 30 seconds at a rate of one
count per second. Older adults (average age 69 years) tended to report a
shorter time interval then younger adults (average age 24 years). But the
evidence goes back and forth. In 2005 Marc Wittman and Sandra Lehnhoff with the
Ludwig-Maximilian University Munich, agree that despite the widespread belief
that the subjective speed of the passage of time increases with age, results
are inconsistent. They support the widespread belief that the passage of time
speeds up with age although they do point out that such incremental changes are
subtle. Despite stereotypes that even though older people see the
passage of time increasing, younger participants anticipated that time will be
slower when they get older. The authors also concede that there remain
other factors that conflict with a purely age-based interpretation of the
speeding of time.
Older adults switch from
"time lived since birth" to "time left to death.” One lag (since
birth) seems long while the other lag (left to death) seems short and is
getting shorter. Perhaps it is this sense of urgency, and our attempt to catch
up with our legacy when we see time as going too fast. In an experiment in 1961
Michael Wallach, and Leonard Green with MIT found that both the type and
quality of activity and the perceived time remaining makes time speed up. This
sense of urgency is what influences our impression of time accelerating. Our
activity and our sense of urgency determine time. Those older adults who are
dying and fearing death feel more pressured by the passage of time. Similarly
those who are busy also see time passing by faster. In contrast, Steve Baum
with Sunnybrook Medical Center, Toronto and his colleagues report that time
also moved slower for many institutionalized elders. People in institutions who engage in few daily
activities see time as going by more slowly. Older adults report both extremes;
time getting faster while others report time going slower.
Heteroscedasticity
This does not make sense. And
we are missing the first principle of gerontology—heteroscedasticity. Older
adults become more varied the older the group becomes.
We have older adults who are
catatonic in nursing homes while others remain in the community, active,
engaged and at the peak of their capacity.
Jacob Tuckman uncovered this fact in 1965 when he reported that although
there is a slight increase in the cadence of time among older adults (60 and
over) he reported that they were both the group that saw time pass quickly as
well as the group that saw time most slowly.
Older adults were just more aware of time and reacted to the perception
of time in “both directions.”
And we know that time is
flexible and malleable in our mind. The elaboration came when Richard Block
replicated a study that found that time intervals with many events are
experienced as longer than intervals filled with fewer events. In uneventful situations, such as in a
typical nursing home when a period of time is not filled with distracting
events, time seems to pass slower. For
those adults that are engaged and active, there is not enough time to complete
their activities, and therefore time goes by too fast. We might be measuring
time on the basis of events that happen. Our physiology not only dictates time,
but we look at the environment to tell us how fast or slow we need to move time.
The environment might provide a
metronome. We are looking for events that happen in order to synchronize our
internal time clocks. This is known as the Kappa Effect.
We intuitively measure time
by the space in between events—in this case, blinking lights. The experiment is
easy. Imagine you have a reference light that blinks once for a split second,
then spaced a few inches to the right another light blinks and then twice as
far to the right another light blinks. Even though the time lag between the
second blink and the third blink is the same, we always assume that the third
blink is delayed because it is further away from the first blink. Our internal
clock is sensitive to how objects appear in space. Events bunched together are seen as occupying
a shorter period of time while events that are spread out are seen as taking
longer time. But it is not just distance. There are numerous factors that
influence our timing.
Some of these factors include
the type of stimuli (visual, auditory, tactile), the intensity, size or
strength of stimuli, complexity, uniqueness, including background and contrast,
as well as speed and variance in speed all influence whether we perceive time
as slowing or speeding. Most importantly, we attach emotional meaning to
events. In 2007 Sylvie Droit-Volet and
Warren Meck reported how our sense of time is moderated by how we feel. So that
time seems short when we are having fun and extends when we are bored.
It could be that time does not
get faster with age but it seems that it does because we have an urgency to do
things before we die. We speed up time in order for us to coherently make sense
of our urgency. We tend to try and accomplish too many things despite perhaps
not having the energy to accomplish them. And it is not our perception that
slows down or speeds up but our memory of it.
Similar to the experience of
fear, where time seems to slow down, what speeds up n is our memory not our
attention. David Eagleman with Baylor College of Medicine, Houston, Texas
designed a clever experiment that conclusively showed that fear for example
does not actually increase how fast we are at noticing events, and therefore
slowing time. He found that instead what happens is that we gain improved
memory that packs that time unit with many details and events. Knowing this however does not explain
neurological conditions that results in both time speeding as in the
“zeitraffer” phenomenon, or the obverse experiences called “akinetopsia”, when
motion slows or stops altogether.
The fact that time perception
can reflect neurological problems indicate that something “mechanical” is
happening in the brain. It seems that motion and time are related
neurologically. This is not only how we think or memorize, it is how we are
built. The only other place this happens is in cinema: a movie that is
controlled by the timing of projecting individual frames. Likewise, our brain
records individual frames—many more than we are aware of, and perhaps with many
different layers, emotional, visual, auditory—and then like a film reel plays
them out for us on the basis of an internal time. The brain plays these memory
frames at speeds that make the story coherent. So if more detail is needed then
it slows the film down (fast time) and when the story is uneventful the brain
speeds it up (slow time). All of this is done in the visual cortex.
We are learning that time is
a complex psychological phenomenon. It is not an illusion, but a reality that
exists at the center of our consciousness. With time there are variances in the
context (busy vs bored), differences in individual experiences (older vs
younger) and there are also complexity of time (neurological vs external
measures.) Understanding that we have memories that are snapshots (some of
which remain in our subconscious) rather than a movie, elevates time to the
master conductor of our memories. Time orchestrates our memories. But this
still does not explain why older adults are more prone to speed time up.
The Logarithmic Time
Aging is like a logarithm, the older we get the short the percentage of time that has elapsed. It’s just mathematics. This was first estimated by Paul Janet (1823-1899). He found that the apparent length of an interval at a given time is proportional to the age of the observer. For a ten-year-old a year adds 10% to her life, but only half that value (5%) for a twenty-year-old. For a 90 year old, 10 years is an ninth of their life, while for a twenty year old 10 years is half their life., hence the perceived shortness of time as we get older. James Kenney wrote an interesting blog on this function and he estimated that time is perceived logarithmic, meaning that it gets shorter as we age. He referred to this function as Logtime. In estimating the length of a year we compare it to our age. We see time proportionally so that the older we are chronologically the smaller the proportion of a time unit. We are predisposed to see time going faster, regardless of all other factors. This observation is further supported by an earlier understanding of time by a German physician Karl von Vierordt (1868). Vierordt‘s Law states that short event are perceived as longer than they are and longer events as shorter. There is a convergence. This also applies to historical events as well where we estimate long past events as more recent than they were which gives the impression that time is speeding. For older adults, events that happened thirty years seem more recent. And we do this to help our memory.
Between two to five seconds seem to be the time where we are present,
and within this short period we have a fairly accurate time. While memory and
anticipation form the majority of our awareness. It helps therefore to have a
retrievable memory that assigns more importance to the more recent events (and
therefore more likely to be pertinent) and to bunch experiences into more
manageable time limits.
Conclusion
Again, Steve Baum and his colleagues report that among 296 institutionalized and community dwelling elderly (average age 75.4 years) faster time perceptions were associated with being healthier—less clinical depression, enhanced sense of purpose and control, and “younger” perceived age—while the opposite perception held true for older adults who were more frail and saw themselves as “older” where time was going slower.
If time orchestrates our
memory, dictating the speed and therefore the length of our life’s story then
it determines or at least indicates our expected life span. Logtime determines
that this period of perceived remaining time is experienced to be shorter the
older we get. That is the mathematics of the basis of our perceived shortening time.
If our Logtime is determined by how much time we believe we have remaining,
then the healthier we are the more accomplishments we want to achieve and the
faster time seems to pass. The more things that we want to accomplish, the
greater the urgency and therefore the shorter we feel our remaining time to be.
Time is faster.
We dictate time speed by our
urgency and our age. In return, our time metronome selects memories to make the
story, our narrative arc, coherent. The counter-intuitive prediction being that
the faster you think that time is going, the longer you are likely to live. How
we see time is an indication of our life story. We might be accessing cues from
both our body and the environment that tells us when that final curtain is
likely to be.
© USA Copyrighted 2017 Mario D. Garrett
References
Baum, S. K., Boxley, R. L.,
& Sokolowski, M. (1984). Time perception and psychological well-being in
the elderly. Psychiatric Quarterly, 56(1), 54-61.
Eagleman, D. M. (2008). Human
time perception and its illusions. Current opinion in neurobiology, 18(2),
131-136.
Goldstone, S., Boardman, W.
K., & Lhamon, W. T. (1958). Kinesthetic cues in the development of time
concepts. The Journal of genetic psychology, 93(2), 185-190.
Spalding, K. L., Bhardwaj, R.
D., Buchholz, B. A., Druid, H., & Frisén, J. (2005). Retrospective birth
dating of cells in humans. Cell, 122(1), 133-143.
Wittmann, M., & Lehnhoff,
S. (2005). Age effects in perception of time. Psychological Reports, 97(3),
921-935.
-->
No comments:
Post a Comment