Sensing Time

ddl's picture

What is time?   For most, it seems to be a means of measuring one’s existence; in a sense, an external entity that dictates all of our experiences, encounters, and ultimately our lifespan.  This eternal force even appears to supersede our own consciousness and preside over the span of one’s experiential lifetime, as we have a finite beginning and end to our ability to perceive, be coherent, and endure within the physical realm.   Surely the existence of a time before ours can be shown by the fact that there are documented records chronicling the existence of our predecessors and, conversely, our offspring can attest to the continuance of time as a means of overseeing life well after our own personal demise.  If this is the case, then we are disconnected from time; it does not seem to be a construction of our thoughts and mental processes, but rather something that interacts with us, and is present for us to interact with.  Do our nervous systems then have a means of sensing time and, if so, what implications can time have on our psyches?  These are the topics that I hope to explore in more depth within the contents of this analysis.
To address the first of these quandaries, whether our bodies have a means of sensing time, one must look to his or her own personal experiences. Many times, we rely on objectively observing clocks, calendars, and other temporal measurement devices to give us our conceptions of how much time we have experienced over the course of set period of action or thought. In many other cases, we have developed the ability to look at the progressions or changes of other objects, like a sun setting over the horizon, or on a longer scale, a butterfly undergoing metamorphosis from a caterpillar to a butterfly or the orbit of a planet around its axis, to trace the passage of time. As the tangible objects within these situations undergo the changes to their physical states or locations within space, we can sense that a certain amount of time has come and gone over the course of watching these events.  The use of time has become so rudimentary in everyday life that people have actually begun to structure many aspects of their human experience around this temporal progression.  We have developed concepts like birthdays which celebrate the date of our initial entry into the world, expected life spans which predict the amount of time before our last breaths, and histories which count back to the ‘beginnings of time’, marking eras and important events with their associated dates on a timeline.  Even our everyday schedules have become encapsulated and dependent upon such time courses. Our bodies require a certain amount of sleep and thus each individual’s cycles of waking consciousness and slumber are alternated accordingly.  Because we have been dependent on these patterns of action for so long, effective deviations to these time allotments dictate our actions, (i.e. we become cranky and lethargic if we haven’t slept in a long time or if we don’t get our accustomed amounts of sleep).  Even relative success in executing function is directly proportional to the time that is spent training or honing that particular skill set via practice.  We know when it’s our bedtime, just as we realize when we have to wake up partially because these actions have long been a part of our routines.  

Even though these all appear to be examples of the body’s ability to perceive and be impacted, from a neurological standpoint, by time, this may not actually be the case.   As we discussed in our Neurobiology and Behavior class, in order to sense or have a conception of an external stimulus, we must have a receptor for it (1).  However, in all of these aforementioned cases, it doesn’t necessarily have to be time that our nervous systems are reacting to.  Instead, the inputs may be other external patterns or factors that our brains then use to paint the idea of time progression. For example, the body does not actually sense the progression of time over the course of a sunset, but rather may have interpreted the changes in light sensory input data (light to dark, etc.) that are produced by the setting sun as being related to the conception of this action taking time to occur.  Similarly, extra time taken to practice a given activity translates to more repetition of the activity, which is stimulating more frequently the various neuronal pathways that allow for a given person to exercise that action.  This, in turn, would allow a person to develop more muscle memory for that activity and to execute it more rapidly and effectively in future instances.   Also, recognizing when it is time for bed may be linked to the fact that a person has become tired, has less energy, and begins to feel heir eyelids getting heavy.  In this light, our body does not appear to be sensing time.  Rather, receptors responsible for detecting other sensory information are producing input signals to our nervous system.  Our brain then associates these trends and changes in what we are sensing with time allotments due to the fact that this concept of time is so engrained within our culture.  Authors Matthieu Ricard and Trinh Xuan Thuan speculate on the mechanism of this mental process that is responsible for generating the feeling that time is passing from a collection of associated sensory input information in their work, The Quantum and the Lotus.  They state:
Data concerning the external world are transmitted by our sensory organs to our brain, which     incorporates them into a mental picture. This cerebral activity brings into play simultaneously several   separate regions of the brain with different functions.  According to the neurobiologist Fransisco Varela, it’s the complexity of bringing together and integrating these various parts of the brain that gives us the sensation of time. This orchestrated, synchronous activity of large, discrete sets of neurons, among the hundreds of billions in the human brain, creates what scientists call an “emergent” biological state, that is to say a state, in this case the consciousness of time, that is more than the sum of its parts. Since this state lasts from a few tens to a few hundreds of a millisecond, we have the sensation of “now,” of a present with a duration. But this synchronization of neurons is unstable and doesn’t last. Its instability sets off other synchronous groupings of neurons, producing a succession of emergent states. They then give us the sensation of time passing. Each emergent state forks off from the preceding one, so that the previous one is still present in the succeeding one. This gives us the impression that time is continuous (3).

This could very well explain the reasons that our nervous systems can perceive time from a set of seemingly unrelated sensory data.  In general, this process is providing us with a means of better making sense of a given situation and organizing the vast arrays of experiences and perceived concepts that we encounter in a chronological fashion.
However, this may not necessarily rule out the existence of time receptors within our bodies.  There are also other experiences which may in fact cause the nervous system to generate outputs based strictly on time.  For example, personally, I routinely find myself waking up out of a dead sleep on days in which I have an appointment or an assignment to get done, without the aid of an alarm clock or any other outside stimulus.   This has been my savior countless times when I have neglected to set an alarm or accidently fell asleep after being up late studying, thus allowing me to effectively rush off to get done what I had planned (under circumstances where I would not normally have woken up otherwise).   Is this because my body is actually subconsciously aware of the time of day it is and that temporal point’s relationship to the time associated with the task at hand?  I’m convinced that this may be possible.  In her lecture, “The Philosophy of Time”, Cheryl Chen of the Bryn Mawr College Psychology Department also provided another interesting example of this by presenting the fact that people typically rush (or alter their behavior in uncharacteristic manners) when faced with an eminent deadline appointment  (2).  The worry associated with not getting the required work accomplished within the given time parameters seems to be directly related to the fact that the body can sense the rapidly approaching time restriction.  In this way, it is able to determine that there is not much temporal space left to run its course before this situation is upon him or her.  Time in this sense can very clearly manipulate or influence one’s behavior.  So such phenomena would lead one to believe that he or she must have a time receptor somewhere on his or her body, which unlike the receptors responsible for their five other major senses (touch, taste, sight, sound, and smell) does not pass through their ‘I’ Function (the space within the brain that allows one to take ownership over particular actions)  (1).  This would allow for it to escape being a product of conscious awareness and exist as something that cannot intentionally be regulated.
In closing, from the observations presented in this study, it seems very probable that the body does in fact have set receptors that can allow the nervous system to recognize and react to perceptions of time flow.  This ability simply adds to the already stunning repertoire of sensory capabilities that we know the nervous system to possess, showing that the human capacities to develop input signals from the surrounding environment in actuality extend well beyond the abilities to perceive simply with the five primary senses of touch, sight, smell, sound, and taste.


Works Cited
1.)  Bio 202 Home Page, on the Serendip web site,
http://serendip.brynmawr.edu/exchange/courses/bio202/s09/notes.  Accessed 9 April 2009.
2.)  Chen, Cheryl.  The Philosophy of Time, on the Serendip web site,
http://serendip.brynmawr.edu/local/scisoc/time/chennotes.html.  Accessed 10 April 2009.
3.)  Ricard, Matthieu and Trinh Xuan Thuan.  The Quantum and the Lotus.:  A Journey
to the Frontiers Where Science and Buddhism Meet.  New York:  Three Rivers Press, 2001. pg.132.

Comments

Serendip Visitor's picture

time

I find this very interesting. Are there known instances, medically speaking, of individuals who lack this internal time keeping mechanism? Also, it seems that all motor events have a time component as well as a spacial component. Driving a car is a good example. If you are traveling a certain speed and want to make a turn, there is certainly a timing aspect to that action as with anything we do.

Paul Grobstein's picture

the brain and time

Interesting issue.  People do, of course, talk about a time "sense."  But it had never occurred to me to think about "receptors" for it.  Yes, we could in principle have such receptors but, like proprioception, the inputs don't  get to the I-function/consciousness. But why presume receptors at all?  Perhaps time isn't "out there" at all but is instead a construction of the brain?

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