How Time Flies!

When I was a kid, summer vacations lasted forever followed by a very long school year. I could pack a lot of fun into a 15-minute recess. Exploring a creek and woods behind my house had no crisp beginning or end. Time stretched to accommodate whatever I set out to do. 

So why does January suddenly become July in my 75th year? Why do the days between placing the trash curbside evaporate so quickly now? Researchers have answers thanks to recent investigations using technologies and techniques that explore the bodies and minds of people and animals. And the research suggests we can dilate our perceptions of time at any age. I can't enjoy a grade-school-long summer again but I can stretch time a bit -- from time to time.

Time Is An Illusion

We don’t experience reality directly. Instead, our brains evolved to selectively display and highlight whatever was required to stay alive and reproduce. Our experiences are generated by electrical signals oscillating between millions of coordinated groups of neurons in the dark recesses of our skull. Physical time passes with the precision of a ticking clock but we only perceive time and events manufactured by our neurons. 

There are occasions when time stands still. Before we were born, time, as we know it, didn't exist. If you have been in a medically-induced coma during general anesthesia, time likely passed unnoticed; you awakened with no idea how long your medical procedure lasted.

During sleep, unlike general anesthesia, we have a subliminal awareness of time and sensory input. We process and prioritize words according to one sleep study. In one ear subjects wearing headphones heard unfamiliar “Jabberwocky” (nonsense that sounds like french but has no translation). Familiar English words were played in the other ear. Using a technique called stimulus reconstruction, brainwaves were monitored to determine which set of words attracted the majority of subliminal attention. When both sets of words were played simultaneously, familiar words stimulated significantly more neural activity than did jabberwocky. When only Jabberwocky was played, all the subliminal attention was devoted to Jabberwocky. Even in sleep, we are alert to familiar sounds.

The level of subliminal awareness and recall during sleep varies from person to person. An insomnia study determined that insomniacs perceive nights to last longer compared to sound sleepers; insomniacs substantially underestimated sleep time and overestimated waketime.

Follow on studies confirm that insomniacs and sound sleepers differ less due to time asleep than due to the perception of time asleep. Ongoing research is exploring the relationship between retroactive memory upon waking and states of mentation while sleeping. 

Biological Clocks

The master clock in humans resides in a portion of the brain called the SCN near where optic nerves coordinate impulses arriving from each of our two eyes.  The SCN is like an orchestra conductor coordinating all the instruments to produce a symphony; almost every cell in our bodies has its own timekeepers that work together to regulate our bodily cravings and functions. Our biological clocks determine when we get hungry and sleepy, our body temperature, our metabolism, and the release of energy into our bloodstream. Without specialized proteins called "clock proteins", our organs would not coordinate with one another to keep us alive. And the entire orchestra affects our subjective perception of time.

An experiment with mice demonstrated how time can seem to flow faster or slower when our biological clocks are altered. Mice were rewarded when they correctly distinguished between two intervals of time: intervals greater than, and less than, 15 seconds. Knowing that people with Parkinson's disease often have a hampered ability to perceive time due to degenerating dopamine-releasing neurons, the researchers developed a technique to use light to stimulate the dopamine-releasing neurons in the trained mice.

The scientists were able to design light stimulations to cause mice to either underestimate or overestimate the 15-second time intervals they previously knew well. Dopamine-releasing neurons were thus confirmed to play a central role in short-term time perception.

Using cleverly constructed experiments and advanced technologies scientists have determined that other animals have biological differences in time perception due to differences in sensory organs, brain function, physical size, metabolic rates, reaction time, and other factors. For example, flies appear to experience time passing nearly seven times slower than the human experience (a fly would perceive one second as if it lasted 6.8 seconds -- this gives them plenty of time to avoid a swat). The chart to the right shows how humans compare to other animals regarding time perception.

Evolution provided us with biological clocks consisting of dozens of electrical and chemical processes combining to help us eat, sleep and otherwise survive and reproduce. In evolutionary processes, physical time per se was less important than the cycles of the sun and moon, seasons, hormones, and electrical oscillations that allow us to extract useful information from the past and to predict the future. The perception of time varies throughout our lives for good reasons. For example, over time unimportant information is discarded or largely concealed in shortened time segments giving priority to more consequential experiences. 

Short-Term Time Perception

We experience time slowing down under specific circumstances. I had an auto accident nearly ten years ago. The windshield appeared to crack in slow motion. There is no shortage of anecdotes about others experiencing time slowing during an intense experience: a near-death experience ("My life flashed before my eyes"), or a spectacular sports feat ("I was in the zone").

David Eagleman, an adjunct professor at Stanford University, determined that during an ominous situation we don't actually experience events in slow motion but we perceive the events as if they occur in slow motion. To test whether threatening encounters slow our sensory abilities, our perception of time, or both, Eagleman dropped 15 research subjects into an adrenaline-fueled freefall on an amusement park ride and showed them rapidly changing images as they fell. 

Contrary to Eagleman's initial hypothesis the subjects did not see the images in slow motion any more than in a normal situation. But in retrospect, they recalled the experience as if the images were displayed in slow motion. Physical time marches on but our perception of time shrinks and stretches according to circumstances.

It is well established that specialized areas of the brain turn on and off as our attention fluctuates. For example, in a prior post, I explained that fMRI studies identify separate areas of the brain that activate and deactivate as one's attention shifts from science to religion. This explains how individuals look to logic and science to understand and predict physical phenomenon yet turn to religion for comfort when stressful situations are out of their control.
Electrophysiological measurements show that when someone is taking orders, their brain devotes fewer mental resources to, and spends much less time considering, the outcome of their actions; people will do things under orders that they would never do voluntarily. When people are ordered by an authority to torture or administer punishment to another person most will act against their morals and principles and comply. 

People also devote fewer mental resources to performing routine activities out of habit. Such activities barely register in one's brain and they may minimize or not remember the activity thereby compressing perceived time. By contrast, mindfulness practice stretches time, it intensifies and focuses attention making time seem to pass more slowly. 

Try an exercise used in a mindfulness class I attended. While you are focused on a routine activity (e.g., doing dishes or mowing the lawn) eat two raisins one at a time. Later when you are relaxed and can devote your attention to one task eat them one at a time paying close attention to details like taste, texture, the tactile sensations on your tongue, and your jaw muscles chewing. You will experience time slowing and sensations in your mouth will intensify as your brain devotes more resources to the activity.  The difference in time perception will be evident. 

Long-Term Time Perception

Short-term time perception embodies a continuous flow of experiences stored in short-term memory. Long-term time perception is formed from fragmented memories that are not necessarily sequentially organized; there are big gaps between memorable episodes that are unreliably organized along a timeline. 

As we age, we recall things that happened a handful of years ago only to realize a "handful" has become a double-digit number. Our cute young relatives rapidly became middle-aged. Our memory of each school year condenses into a few remnants of noteworthy experiences.

Over time we tend to remember past events by association rather than by time of occurrence. An odor reminds of an event, we recall a vacation when we encounter memorabilia acquired during a trip, we remember when something occurred because it coincided with an important date like a graduation or a special anniversary. Our perception of time as a whole becomes vague and dispersed over time. But none of this entirely explains why time seems to pass more quickly when we get older. There is more to long term time perception than how memories are stored.

If time perception were simply proportional to time, a six-year-old child would double his or her perceived time by age 12. In that same six-year period I would experience only 12% more time. But long term time perception is not proportional to the above chart, it is more proportional to unique experiences. Our brain is more heavily engaged in the more meaningful situations; survival and security demand we assess a new situation in terms of past experiences and predictions of its consequences. 

It is well established that time perception is greatly influenced by the amount of energy and mental resources devoted to comprehending and reacting to a particular experience; the more critical and engaging the event, the more prominent will be its place in our long-term memory and time perception. 

A child is constantly having unfamiliar experiences and must devote enormous mental resources to understanding and prioritizing the importance of each moment; almost no segment of time is unimportant enough to disregard. Young minds are constantly evaluating how the present relates to the past, how the future might relate to the present, and what the present has in common with other experiences. External time becomes relevant when you are called in for dinner or the sun has set.

As an older adult, a large proportion of our experiences are repetitive, habitual, and have predictable consequences, we can safely discard them. The excess baggage is dropped from our long-term perception of time and life feels like it is passing quickly. But research on time perception provides a few ways to stretch and therefore capture that which otherwise might be lost.

Slowing Perceptions Of Time

The first two suggestions temporarily dilate time, the remainder affect longer-term time perception

1. Be afraid. I don't recommend having an auto accident but "safe fear" like rock climbing with ropes, skydiving, or even reading or watching a suspenseful episode can slow the passage of time. But it is fear more than excitement that has the greatest effect -- perhaps because of all emotions that we have evolved to experience, fear has been throughout human evolution most important to our ability to survive. We "create" the time needed to survive the threat. A classic study sent 60 people skydiving for the first time. Each participant rated their level of fear and, separately, their excitement as they embarked on the plane. Those who rated fear higher than excitement reported the longest time estimates of the dive.

2. Have an awe-inspiring experience. As we experience or witness awe-inspiring activities time feels more abundant. For example, watch a video of an extraordinary feat (climbing Mount Everest, helping children in a primitive village, or saving a baby elephant's life). Research suggests you may feel more "in-the-moment" and perceive time to slow.

3. Spend more time in Nature. Some research subjects were taken for walks in nature while others took walks in an urban setting. Each subject was then asked to estimate the duration of the walk. Those walking in nature felt more relaxed and consistently overestimated time walking while those in urban settings consistently underestimated time spent walking. 

Recall dogs experience two minutes for each human one minute

4. Alter your routines. Take a different route to work, experiment with new restaurants or meals. Change the times and ways you perform daily activities. Volunteer to help others. Explore places you otherwise might never see. Change where you perform daily tasks (exercise in a park, write letters in a coffee shop, or make your grocery list in your patio or yard). There are endless ways to transform habits, routines, and behavior patterns into physical and mental activities that activate more mental resources. Novel experiences and deviations from mundane behaviors are effective ways to add bonus time to your life. The more drastic the change in routine, the more time seems to slow down. People moving to a different country, for example, report time to pass very slowly for weeks after the move.

5. Practice mindfulness meditation. Don't expect overnight results, however. In one experiment, people who meditated every day for weeks experienced the most dramatic slowing of perceived time. A likely explanation is that mindfulness training focuses attention on the present. To get a glimpse of the effect without waiting weeks, during a daily routine (driving, walking in public, etc.) pay attention to as much of your surroundings as possible. Sustain awareness of the plants, structures, activities, clouds, -- every detail large and small -- for as long as you can. Reject distracting thoughts.

6. Avoid multitasking, it is the antithesis of mindfulness. We multitask thinking it saves time but over time it can have the opposite effect.

7. Make daily recollection a habit. Pay extra attention to a couple of situations you want to recall later. At the end of each day recall one or two particularly salient events including as much detail as possible. With practice, you may find yourself becoming more attentive to the present moment throughout the day. You will find time passing more leisurely and generally feel more relaxed.

I don't include drugs as a recommended way to manage time perception but one can't research time perceptions without encountering many studies about the effects of drugs. Both recreational and medicinal drugs can significantly affect time perception. Drugs such as cocaine, methamphetamine, and alcohol appear to make time speed up, whereas haloperidol, LSD, and marijuana appear to slow time down. Other drugs used in medical treatments such as dopamine and serotonin affect time perceptions.