Saturday, August 9, 2014

Animal Senses Compared to the Human Sense of Time

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Animal Senses Compared to the Human Sense of Time
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New findings about animal senses are being announced in the scientific media on a regular basis. In only the last month, for example, it was reported in National Geographic that: Elephants Have 2,000 Genes for Smell, Most Ever Found and Bats Set Their Internal Compass at Dusk, A First Among Mammals. In addition, about a year ago, National Geographic reported that Dung Beetles Navigate Via the Milky Way, First Known in Animal Kingdom

In all three reports the findings were groundbreaking with phrases like "first known" and "most ever."

The range and sensitivity of senses and the different information being sensed -- in all of the animal kingdom -- is mind boggling and goes far beyond the traditional five human senses of taste, touch, smell, hearing and sight. National Geographic, for example, wrote, "Greater mouse-eared bats set their internal magnetic compass using the pattern of light polarization -- light that vibrates in one direction." 

Human ears (left) with stereo capability can hear a broad range of sound but other animals have more complex and sensitive ears and can hear a wider or different range of frequencies. This young antelope (middle) has large ears which it can move to focus sounds. Bats (right) depend on their antennae-like ears to determine distances using echolocation, i.e. bouncing changing sounds off of objects.

But understanding animal senses does not stop with the raw data that is sensed. Often this data is processed by the animal's brain, making it much more sensitive. So while a dog has 300 million smell sensors vs. 6 million for humans (a factor of 50), it also has proportionally 40 times more of its brain devoted to analyzing smell than human beings. This means that a dog is 10,000 times more sensitive to smell than humans according to the latest research reported by NOVA on PBS.

Human smell (left) is one of our weakest senses, far surpassed by dogs (middle) who are 10,000 times more sensitive and bears (right) whose ability to smell is 7 times more sensitive than dogs.

Senses are also used in combination with other abilities of an animal, such as the duck-billed platypus who can sense tiny electric impulses in its prey -- and then can zero in on the location by moving its bill in a sweeping manner.

"The platypus can determine the direction of an electric source, perhaps by comparing differences in signal strength across the sheet of electroreceptors. This would explain the characteristic side-to-side motion of the animal's head while hunting." (
But defining and describing animal senses is only part of how senses operate in a living organism, which brings us to the classic subjective/objective debate. While the stimuli that a sense perceives is clearly outside the organism, the way that the stimuli is interpreted and acted on is determined by the animal, i.e. it is subjective.

With human eyes for example:
"Almost all higher order features of vision are influenced by expectations based on past experience. This characteristic extends to color and form face and object recognition...and to motion and spatial awareness..."

Eyesight is probably the strongest human sense (left) with full color stereoscopic vision and a remarkable ability for edge detection. But other animals such as eagles (middle) have 3.6 times the human visual acuity. Some insects (right) have a compound eye with a fisheye view (180 degrees) of the world that can see objects in focus both near and far at the same time.

In addition, many parts of the brain are often involved in processing the data that is sensed. With face recognition, for example. 
"Until now, scientists believed that only a couple of brain areas mediate facial recognition. However scientists have discovered that an entire network of cortical areas work together to identify faces.'This research will change the types of questions asked going forward because we are not just looking at one area of the brain," said Nestor...lead author of the study. "Now, scientists will have to account for the system as a whole...:"
This means a sound that is objectively 261.6 Hz and 70 decibels will have a different meaning for a human than for a mouse, for example. This sound is middle C or a musical note played at the normal volume on a radio. To a human being it would carry a musical meaning, perhaps reminding him or her of a sweet song but to a mouse it might be a warning that a human was nearby.

And what is my point in this blog about the human experience of time? 

I believe that humans have a unique sense, a sense of time that only we possess. And given the wide range of animal senses, it should not be surprising that we might have a sense that other animals do not have. In addition we have the largest brain relative to our body size, a brain which we now know is quite flexible (neuroplasticity). It is capable of storing memories, imagining future events and learning and working with concepts such as long term time both past and future. I believe that this unique sense of time is the principle reason we have become the dominant species on the planet. 


Scientific findings have confirmed that there are unique parts of the human brain that deal with time.
"This ability to hold on to a piece of information temporarily in order to complete a task is specifically human. [ED: my emphasis] It causes certain regions of the brain to become very active, in particular the pre-frontal lobe. This region, at the very front of the brain, is highly developed in humans. It is the reason that we have such high, upright foreheads, compared with the receding foreheads of our cousins the apes. Hence it is no surprise that the part of the brain that seems most active during one of the most human of activities [ED: short term memory] is located precisely in this prefrontal region that is well developed only in human beings."Perhaps the most extreme example of short-term memory is a chess master who can explore several possible solutions mentally before choosing the one that will lead to checkmate."  SHORT-TERM MEMORY': McGill University, Montreal, Canada


I think it is quite possible that the human brain's unique ability to consider future actions in the short term became a model for time itself. This short term understanding of time could have been developed and expanded through language and symbolism to include time in the long term. So the skill of considering whether to go right or left in the heat of a hunt could -- over thousands of years -- be extended to considering whether to go to the river or the mountains by the next full moon. 

The problem with complex, sophisticated time perception in humans is that it is not based on a specific sensory organ. Moreover, it is inextricably tied to language and symbols which have given us the tools to conceptualize time and to work with time. 

MRI of human brain. (
Perception not based on a specific sensory organ

Chronoception refers to how the passage of time is perceived and experienced. Although the sense of time is not associated with a specific sensory system, the work of psychologists and neuroscientists indicates that human brains do have a system governing the perception of time, composed of a highly distributed system involving the cerebral cortex, cerebellum and basal ganglia.
NOTE: It is quite significant that the most used noun in the English language is *time* according to the Concise Oxford English Dictionary, with the words year, day and life not far behind. While I can document this for English, I don't have the resources to document this in other languages -- but I assume that time is the most used noun in other languages as well.
While we cannot go back tens of thousands of years to reconstruct how a long term sense of time came about, there is perhaps another way to understand how it developed. When our children are young, they only live in the moment, but over years, especially as a result of education, they learn a long term sense of time. This process occurs starting with childhood, continues until adulthood and can be observed and studied.
Measures of performance on tests of working memory increase continuously between early childhood and adolescence; theorists have argued that the growth of working-memory capacity is a major driving force of cognitive development.

School Teaches Cultural Assumptions About Time

During the twenty year 'long childhood' of humans, young people learn their culture's expectations about time. While I will write a full blog about this, suffice it to say students in school learn about time more than any other subject. They learn to arrive on time, to not be late to each of their classes and to manage time such as doing their homework or studying for a final exam. These time demands become more stringent as a student gets older.


So what exactly is this different sense of time, you might ask? Well, it turns out it is quite simple. We are the only animal that understands 'when'. 

But don't take my word for it, read the detailed article, Are Animals Stuck in Time?, that compares the animal sense of time to the human sense of time. The article concludes that in fact animals are stuck in time whereas we humans can work with and manipulate time. 

Humans are not 'stuck in time' because understanding 'when' allows us to time-travel back to our past and also to an imagined future. It allows us remember our personal story and to shape ourselves and our civilization. Furthermore it allows us to take control, to plan for the future based on our knowledge of the past. 

The TARDIS time machine from the science fiction TV show, Dr. Who
"People can time-travel cognitively because they can remember events having occurred at particular times in the past (episodic memory) [ED: e.g. the sense of when] and because they can anticipate new events occurring at particular times in the future. The ability to assign points in time to events arises from human development of a sense of time and its accompanying time-keeping technology." William RobertsAre Animals Stuck in Time?
As we go though our lives, we order and organize what we do with a sense of 'when':  when in the past, when in the present and when in the future.
Take, for example, this very simple sentence that anyone of us might say -- yet which is extremely sophisticated:
"When I finish this job in about an hour, I will be done for the day."
This sentence which includes past, present, future and future perfect (a past that is in the future at the present time but will be past at a future point), is something we humans understand, but cannot be understood by any other animal.
However, I believe that we have made a critical mistake in our thinking. Most people -- in fact virtually all people I have talked to -- think of time as an objective condition that exists independently.

While time does exist objectively -- the sun will rise every morning no matter what we do -- our sense of time is particularly and perhaps peculiarly human. The way that we work with time, remember time, conceive of time is related to the way that our brains function. 

Therefore while the objective nature of time can be sensed, humans deal with it in a subjective manner. For example, as I have pointed out in my blog about 'human meta-time', we humans have the unique ability to move in a virtual world of space and time at warp speed. We can travel in our minds from past and current events and past and current houses, schools and jobs to places and activities we imagine we will do soon in the present and in the future.

And although civilization has developed a highly sophisticated way of marking and telling time such as clocks and calendars, when people remember the past it is rare that they can give dates. Instead they relate the past to things that happened before and after, i.e. when something occurred in their personal history. So our personal memory is not tied to the artificial time-telling and timekeeping devices of our cultures but rather the natural human sense of memory. See William Roberts, Are Animals Stuck in Time?
While we have all learned to live with clocks and show up on time, our personal sense of 'when' is not tied to man-made artificial timekeeping.
My point is that our inborn human sense of 'when' is separate from the man-made clocks and calendars that rule our workaday lives. Understanding when is a major part of being human. 'When' is our own personal story, knowing 'when' and how things happened in the past is how we became what we are, and thinking about 'when' in the future maps out who we hope to be.


The concept of 'when' adds a new dimension to time. Time is not just one dimensional, i.e. always in the moment or subject to an immediate need, or two dimensional, i.e. cyclical such as breakfast and dinner, night and day, and yearly migrations -- which are the way time is perceived by all the other animals. Instead 'when' adds a third dimension to time, a linear dimension of past, present and future.  We are the only animal that perceives and uses this dimension of time.

Data that is sensed is often multidimensional but not every animal can detect all of the dimensions. Sharks not only have a far better sense of smell which can detect a small amount of blood in the ocean 1/3 of a mile away but also a more dimensional sense of smell than humans have. Once having sensed the presence of blood, for example, they can locate the direction of the source of the blood with their two nares (snouts) in much the same way that our two ears are used to locate the source of a sound.
"Sharks smell through a pair of nostril-like holes, called nares...When its olfactory sensors detect the odor of a potential catch, the shark will turn into the current that is carrying the chemical. In addition, a shark's olfactory talents are so refined that it can often tell which of its nares is getting the stronger scent signal, guiding it even more precisely toward its prey."

As I pointed out in my blogs about moderncentric thinking (the often superior attitude modern people have about historic cultures), we humans are also guilty of humancentric thinking. We, unknowingly, have assumed that animals possess the same basic senses we have -- only with some changes. Yet if we want to really understand how animals sense, we need to see the world from their point of view. For example, how does a dolphin perceive its world? I won't say 'see' because even though sight may be involved, the echolocation ability of dolphins goes far beyond anything we have experienced either as humans or in our labs and perhaps beyond anything we can yet imagine.

"A recent discovery we made is that dolphins appear capable of directly perceiving the shapes of objects through echolocation. Prior to this finding, it had been generally assumed that dolphins learned to identify and recognize objects through echolocation by a process of associative learning -- by comparing the echoes returning from targets with the visual appearance of those targets."
"The sounds they [ED: dolphins] hear create a kind of holographic image in their minds...they perceive echoes as 3-D shapes and textures...Their ultrasonic clicks penetrate flesh, giving them an X-ray view of your bones and innards."

Understanding other types of animal senses has led to major scientific breakthroughs in the past, such as the development of radar which came about in part due to the study of how bats navigated in the dark and which also led to the development of sonar and ultrasound technology. (

And once we can see the world from the point of view of a different species, we may begin to understand our own world better. This is because the particular senses we humans possess have led us to build this world that we live in.

Because humans have hands that are free along with good vision, 
eye-hand skills have been critical to the creation of civilization. (

Because of our intelligence, we have been able to enhance our ability to sense through our technology. In this photo from the 1920's, a man is listening to the radio 
through ear phones, listening to music that is being played hundreds of miles away. (


The incredibly intuitive ancient Greeks said most of what I have written about the human sense of time through their mythology. 

Detail: "The creation of man by Prometheus. Marble relief, Italy, 3rd century CE." Louvre Museum, Paris, France. ( 


"Prometheus was said to be wise and possessed the gift of foresight and often considered what would be needed several years in the future." 

The brother of Prometheus, Epimetheus, who was rash and impulsive, was given the job of creating the animals, fishes and birds. Prometheus, a god who was wise and had the power of foresight, took his time making man out of clay. Yet when it came to giving man attributes, it turned out that this brother of Prometheus had already given most qualities away. 

 "Epimetheus began by giving the best traits to the animals — swiftness, courage, cunning, stealth, and the like — and he wound up with nothing to give to man. So Prometheus took the matter in hand and gave man an upright posture like the gods."

Yet since the natural qualities of fur, flight and strength etc. and had been taken, Prometheus went a step further to help mankind. He famously stole fire from the gods.

"Fire was bestowed upon mankind by Prometheus and with it came the beginning of civilization. Prometheus taught man how to craft tools from iron ore. He showed them how to plant crops and live through agriculture. Man learnt to craft weapons to defend themselves from wild animals. With fire they learnt to survive cold winters and defy the seasons. With fire man began to thrive and became superior to the animals of the wild."

In stealing fire from the gods, Prometheus also taught humans how to think ahead because starting a fire, keeping a fire going, cutting wood for the winter -- all took forethought, the skill needed to master time.

By stealing fire from the gods, teaching men crafts and agriculture, Prometheus, the god of forethought, gave man the gift of long term time, a quality more powerful than claws and sharp teeth. He taught humans about planning, about steps in a process, about the concept of 'when'. So only humans were given the ability to understand this dimension of time -- something the creatures impulsively made by his brother, Epimetheus, did not have.