perception and species specific worlds ?

7/27/2019 PERCEPTION AND SPECIES SPECIFIC WORLDS ?

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PERCEPTION AND SPECIES SPECIFIC WORLDS ?

Samuel S. Franklin

California State University, Fresno , Emeritus

There is a theory in modern physics called The ManyWorlds Hypothesis. It was conceived

by Hugh Everett III when he was 28 years old at Princeton University and served as his

doctoral dissertation. It is widely recognized and embraced by some of the most renowned

physicists in the world.

Everett claimed that subatomic particles like electrons can take an almost infinite number

of paths and each has a certain probability of occurring. Once the electron or other small

particle is measured it is realized or actualized; it comes into being. But, all the other paths

it might have taken are also actualized. We may measure the particle at position A but it

went elsewhere too: to positions B and C and n. Everett proposed that it goes to all the

positions but it does so in different worlds. A wave function describes all the possible

paths of the particle and while it may be observed in one place, it goes to all the others aswell. There are many worlds each as real as the observed.

Given our penchant for Newtonian physics and our assumptions about the macro physical

world it is not easy to comprehend the many worlds hypothesis but it has a large following

of very smart physicists who understand such things.

There is still another kind ofmany worlds hypothesis that may be easier for us non-

physicists to grasp. For almost forty years I studied and taught the psychology of

perception and have recently come to a surprising (for me) conclusion. In this paper I

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suggest that because our human brains differ from other animal brains the world we

perceive is probably very different from the worlds perceived by other animals. I think it is

likely that your dog and cat and the blackbird in the nearby tree all perceive very

different worlds from each other and from us. Given the variations in our brains I am

suggesting that each species has its own world. There are many worlds. There are as many

worlds as there are species.

In the following pages I will try to explain this view and discuss some of its implications.

CLASSICAL DUALISM

While the theory of many worlds is quite recent, belief in more than one world has been

with us for a long time. Plato's dualism proposed that the material world, the one that we

so trust now, is actually very untrustworthy. He left us with a wonderful story about his

dualistic universe: 'The Allegory of the Cave.'

We are asked to imagine a group of chained prisoners at the mouth of a cave. Because the

chains restrict their movements the prisoners can only see the back wall of the cave.

Behind them and off in the distance lies a mountain top where people walk holding giant

patterns in the shape of a tree or person or circle. Further out and behind the mountain top

lies the sun, low in the sky shining on the forms which in turn cast their shadows upon the

back wall of the cave. Thus, all the prisoners can see are the shadows of the forms.

However, the shadows are not truly representative of the forms. As the sun rises the

shadows become shorter and distorted and when the sun moves north or south the shapes

become further distorted. The prisoners see only likenesses that are at best

approximations to the true forms.

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As the allegory continues one of the prisoners breaks loose from his chains and from the

shadows he has known and makes his way toward the distant mountain top where the true

forms reside.

Plato's story tells us that we are like the prisoners chained to the cave of the physical world

which provides only distortions of the real, true and divine forms which exist in another

nonphysical world. The shapes carried by the people upon the mountain top are not of the

physical world, they represent perfect ideas, patterns, divine forms. The circles that we

see every day are imperfect, unlike those found the transcendental world. All the oak treesthat we see are but approximations to the perfect oak tree in the other world. The world of

matter and stuff, the physical world, is full of distortions and imperfections. Divine truths

are discovered by reason, by the mind, by contemplation. Observation of matter yields

something much less.

The founders of Christianity trusted in Plato's dualism and for a thousand years

almost the whole of Europe embraced it or at least a variation of it. In those Middle Ages

between the Ancients and the Modern Era the natural world and all its contents was, for the

most part, debased and maligned. Matter was considered flawed, distorted; only shadows

of real truths which reside in a transcendental world. The objects of this world were

thought to misdirect our efforts away from the divine. Believers will be saved and

nonbelievers will suffer for all eternity. Truth lies in heaven, in scripture and in the

authority of the Church. The physical world has little to offer.

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THE DAWN OF SCIENCE

Not until the Enlightenment and the Renaissance did the physical world regain prominence.

Stephen Greenblatt tells us that we owe it all to a monk named Poggio Bracciolini. In theearly 1300s Poggio found an ancient manuscript buried in a German monastery.

Lucretius's On the Nature of Things (50 BCE) glorified the natural world and poked fun

at superstitions about the gods and their supernatural power. According to Greenblatt,

Poggios re-introduction of Lucretius's naturalism began the modern world.

Other events also helped to usher in a new era. Martin Luthers challenge to the Catholic

Church weakened its hold, Guttenbergs invention of the printing press allowed alternative

views to be known, and explorations to the New World elevated the importance of goods,

riches and earthly matters. But perhaps the most important force of the new age came from

the birth of science.

Although Aristotle might correctly be identified as the founder of science it was not until

the early astronomers and physicists of the modern era that science took hold. Copernicus

(circa 1500 ) rejected the religious view that the earth was the center of the universe and

claimed that it revolved around the sun. Galileo (circa 1600 ) supported that idea and got

excommunicated for it. Isaac Newton (circa 1675) set down the laws that govern the

physical world and provided a handbook that guides our lives even today.

Essential to the Newtonian world view was the importance of observation. No longer

should we accept religious authority without proof. No longer is Platos reason and

contemplation enough. Yes, it is good to think and to hypothesize and to speculate about

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the way things work but ideas must be supported in the material world. Experiments and

controlled observation are required. The actions of the physical world have the final say.

And, those actions can be known only by observation: seeing, touching, and hearing. We

can measure and quantify the properties of the world and thereby increase our

understanding and our control. Aristotle thought that heavier things would fall faster than

lighter things but after Galileo dropped weights off the Tower of Pisa his views replaced

those of Aristotle. He observed the moons of Jupiter through a crude telescope and

concluded that Copernicus was right. Observation of the physical world, not the ancient

philosophers and not religious dogma, has the final say.

Most of us accept the methods and principles of science unhesitatingly. Reality, truth,

facts, exist and we are able to observe and measure them. We can see, touch and hear them

but even if we cant they are still there. Reality does not depend on us. Reality is what it

is. We are bystanders in the natural world, it would continue just fine without us. Maybe!

We are, in a sense, outside the physical world but have access to it through the senses. We

do both science and life the same way. Truth comes through observation: We come to

know and understand by perceiving the world. From the scientific point of view the senses

are the windows to reality and truth.

PERCEPTION AND THE WORLD

Having spent much of my adult life studying and teaching the psychology of perception I

have had some second thoughts about this view. The relationship between the physical

world and our experience of it is not as straight forward as some might like. Maybe truth

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can be found through observation but there have been many doubters along the way.

Soon after the onset of the Renaissance and birth of science John Locke ( 1690)

recognized that some qualities of the physical world are given in sensory stimulation butothersecondary qualities, as he called them, are not. There is nothing physically in the

apple resembling its sweetness or its redness. These aresecondary qualities; they are

ideas which emanate from the physical properties of the apple but have no resemblance to

those physical properties. Secondary qualities are partially physical because they emanate

from physical properties but they are also psychological. The apple reflects light which

produces the experience (idea for Locke) of redness, but light waves are not red; they

have no color. The sweetness of the apple is produced by particles in its flesh but our

experience is nothing like those particles. In other words, we experience qualities which are

not really in the world but rather in us and come into being when worldly things come

together with our sense organs.

George Berkeley (1709) followed Locke. As a Bishop in The Church, Berkeley wasoffended by the growing interest in materialism and science which seemed to be

replacing religion as the way to truth. Berkeley wrote about the perception of size and

distance and showed how even these primary qualitiesare ideas just like Lockes

secondary qualities. There is no referent in visual stimulation for the perception of

distance, it is just space. The perception of size can not be based on the size of a retinal

image which varies with the distance of the viewed object. Berkeley questioned the

veracity of perception as a window to the physical world. He went so far at to suggest that

existence depends on ideas or perceptions: to be is to be perceived as he put it.

Perception is not necessarily a copy of reality but rather a psychological phenomenon.

The relationship between the material world and its perception is less than clear.

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David Hume (1748) pointed out that a central idea of the blossoming Newtonian science,

causality, was also not given in physical stimulation. You can see one billiard ball strike

another but you can not see that the first caused the movement of the second. Causation is

not given in stimulation but is rather an idea like Lockes secondary qualities. You can

see sequence, ball A hits ball B, but you can not see the causation between them.

Causation is imposed by the mind when events happen in quick sequence. Although

causality is a core idea of science, it is not observable.

Emanuel Kant (1781) attributed the experience of causality to what he called an a prioricategory. That is, Kant tells us that we humans are constructed to experience concepts like

time, space and causality under certain conditions. These ideas or perceptions result from

the brains operations on certain configurations of sensory stimulation. They are not given

in sensory stimulation itself but result from the minds operation on sensory stimulation.

THEORETICAL APPROACHES TO PERCEPTION

In the modern era there have been two fundamental approaches to the study of sensory

perception. The more traditional approach is grounded in the ideas of the philosophers

noted above. It maintains that sensory stimulation is not sufficient to account for

perception but rather must be enriched with cognitive content like memory. Our past

experience joins the processing of sensory stimulation to create a meaningful perception.

Irwin Rock called this view the indirect theory of perception and described the perceptual

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process as akin to thought, inference, cognition and reasoning.. In the 1950's James

Gibson suggested that there is actually enough information in sensory stimulation to

account for our perceptual experience. For example the perception of distance is explained

by gradients of texture found in retinal stimulation. Looking down the hallway produces a

retinal image of the tile floor. The images of these tiles on the retina get smaller with

increasing distance. Like the retinal space between railroad tracks decreases with

increasing distance, the size of floor tiles on the retina also decreases. An observer doesn't

have to enrich his visual stimulation with knowledge to see distance, he just has to attend

to the gradient of texture contained in the retinal stimulation. Detection of the gradient

is sufficient to produce the perception of distance. As a graduate student and for most of

my professional life I was a faithful Gibsonian, wholeheartedly embracing the direct

theory of perception. However, as the psychology of perception became more and more

influenced by research in neurophysiology it was hard not to recognize the

contribution of cognitive influences.

VISUAL PERCEPTION OF THE WORLD

I would like now to review some contemporary thinking in the neurophysiology of visual

perception. Visual perception is very different from the operation of a camera which simply

focuses an image on a light sensitive surface like film. Seeing involves a highly complex

series of neurological processes which we will briefly describe here.

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Sunlight bounces off objects and is reflected to our eyes. The reflected light waves travel

through the pupil and are focused by the lens to form a clear picture on the retina. The

retina contains millions of light sensitive cells called rods and cones and these cells

transduce or transform light energy into electro-chemical energy. They take in light and

send out nervous impulses that travel through the optic nerve up to the brain.

As messages from the retina enter the brain they go first to a place called the lateral

geniculate nucleus or LGN. The LGN is kind of a transfer station for incoming sensory

information and is organized like the rods and cones of the retina. That it, it isretinotopically organized as many of the visual areas of the brain. The LGN sends

information to the primary visual cortex at the back of the brain. We used to think that the

primary visual cortex was the center for seeing but we know better now. Actually, it is just

a gathering place for primitive pieces of visual information. Groups of receptors in the

retina, i.e. groups of rods and cones, work together and are able to detect certain small

pieces of a visual scene. Cells in the visual cortex receive this grouped information, via

the LGN, as lines, angles, and curves. We may think we have a picture in our mind but all

that the primary visual cortex has are these elementary bits and pieces that eventually get

put together to form a meaningful perception.

The lines, angles and curves that are briefly stored in the visual cortex soon leave there and

head for still further processing. They move forward via two general routes or pathways.

The what pathway carries information about color, shape and size as it travels into the

temporal lobe of the cortex and heads toward still higher centers of the brain. The where

pathway(now also referred to as the how pathway) carries information that enables us to

see movement, location and spatial relationships. It follows a different route moving

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upward in the brain into the parietal lobe. An article in the Proceedings of the National

Academy of Science 1 states The monkey cortex [similar to ours] contains at least 30

separate visual areas, occupying about one half of the total cortex. We now know that

there is no single visual center in the brain but rather different regions and locations which

progressively combine and integrate information that eventually becomes a meaningful

perceptual experience. Sereno and Allman (1998) 2 note that percentage of cortical areas

beyond the primary visual cortex that are implicated in vision varies between species. In

turtles and hedgehogs there appear to be only two cortical visual areas. This contrasts

strongly with primates, for example, which have more than twenty visual areas. They note

Total visual cortex ...occupies 45-55% of the total neocortex in most mammals that have

been examined but it is probably larger than 75% in apes and humans.

The what and where ('how' to respond ) pathways beginning in the visual cortex wind

their way forward to the prefrontal lobes behind the forehead. The frontal lobes are the

most recent part of the brain and are most developed in the humanoids but we humans have

larger prefrontal areas than our distant cousins. The prefrontal lobes may well be the seat

of our humanness. Their complex bidirectional connections to other areas of the brain

including the emotional centers, cognitive areas, sensory pathways from more basic visual,

auditory and other sensory centers, permit the integration of inputs into meaningful

conscious experiences. We believe it is here that conscious perceptions are formed. It is

here that executive decisions seem to be made. It is here that perceptions are briefly stored

so that meaningful actions can take place. That is why the where pathway is also called

the how pathway: it decides how to act on the percept.

PERCEPTUAL ORGANIZATION

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The lines, angles and curves that form our perceptions can be organized in different ways

as so many optical illusions demonstrate. In the two illusory figures above it is easy to

experience alternative organizations. If you stare at the Necker Cube for a minute or so

you will probably notice that it flips directions or changes orientation. In the vase/face

figure you can focus on the center of the figure and see the vase or you can attend to the

outside white areas and see two faces looking at each other. The same bits and pieces can

be experienced differently. More than the bits and pieces are at play here. What you know

counts too. Past experience plays a role in organizing the bits and pieces.

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http://www.nmr.mgh.harvard.edu/mkozhevnlab/?tag=individual-differences Modified

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HUMAN AND ANIMAL BRAINS

Our prefrontal lobes have access to huge amounts of information stored in different

regions of the brain. And, the connections are usually bi-directional so that signals can

flow in both directions. There is more at play here than the external stimulus. Perceptions

are unlike photos; they are extremely complex integrations of stimulus representations,

cognitive processes and even emotions.

We have seen the complexity of the human visual system which includes many areas of the

cortex, including the occipital lobes, the parietal lobes, the temporal lobes, the frontal and

prefrontal lobes. While we share these brain regions with the higher primates; the apes,

gorillas, chimpanzees, and even some other animals lower on the evolutionary ladder, there

are some important differences.

Human and other primate brains are structurally similar but our human brains are much

larger and heavier. They are also qualitatively different. It appears that there has been a

disproportionate development of the prefrontal areas in humans. The surface of the human

prefrontal areas is characterized by much greater gyrification. These gyrations or folds

permit the size of the prefrontal cortex to increase without increasing its area. In other

words, our prefrontal lobes are indeed larger than other primates but more importantly they

contain much greater surface area. There is much greater neural density in the human

prefrontal areas. This density seems to permit increased interconnectivity which may be

behind our distinct cognitive advantages. Rilling (2006) 3 suggests that humans are a

positive outlier among the primates.

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..natural selection uniquely modified the human brain to deviate from the rules of

brain design that obtain among other primates. A unique evolutionary modification in

the human prefrontal cortex is intriguing because this brain region is involved in

many cognitive operations that are especially well-developed in humans, such as

symbolic thinking, knowledge of appropriate behavior, decision making, planning

cognitive control, and working memory.

Cognitive psychologist David Premack (2007) 4 has suggested that the 'basic uniformity'

among mammalian brains, assumed since Darwin, prevailed until the 1980's. More

recently neuroscientists have discovered significant dissimilarities between the brains of our

nearest cousins and ourselves. One difference lies in the organization of the visual cortex

which is much more complex in humans that in apes. Recently Schoenemann and

colleagues (2005) 5 have discovered a large difference in the white matter of the prefrontal

areas in humans and other primates. Whilst gray matter is primarily associated with

processing and cognition, white matter modulates the distribution of action potentials,

acting as a relay and coordinating communication between different brain regions. This

observation lends further support to the increased ability of the human prefrontal areas to

function as integration centers for many areas of the brain.

Premack points out that for many years we have focused on the ability of other primates to

perform actions like using tools, language, human like social behavior, etc. We have

focused on the similarities between us. However, we should also point out the

dissimilarities. As charming as we find the other primates we should note that they have

not yet built libraries and universities. They have not yet mastered the art of neurosurgery

or created cell phones or computers. They have not yet discovered other galaxies or how to

make a motion picture. We are different. We are 'outliers.'

It seems safe to conclude that while the human brain has similarities to other mammals and

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primates there are also important differences. Because our brains differ both quantitatively

and qualitatively our perceptions are also very likely to differ. Our human visual input

undergoes extremely complex processing and integration with several areas of the brain.

Our perceptual experience does not have a point for point correspondence with either

sensory stimulation or with the physical world. As Locke, Berkeley, Irwin Rock and many

others have claimed, our perceptions are complex cognitive events.

If we are to survive and prosper our sensory experience must reasonably represent the world

in which we live. However, we don't need access to everything in the world. We have no

personal access nor need of much of the electromagnetic spectrum. Energies flow aroundus without notice. Radio waves and ultraviolet waves, X rays and microwaves surround us

all the time but we have no personal sensory detectors to experience them. We have no

sensory apparatus to detect sounds below or above a certain frequency. We have no

immediate visual access to atoms or molecules although they surround us at all times. We

see the flower blossom but we do not see the microscopic particles that comprise it. We

are told that the universe consists of items such as atoms, electrons, protons, quarks, and

now waves of particles; none of which is observable except maybe to physicists in very

specialized laboratories. It appears that we really don't know 'reality' at its most basic

levels.

As other species, we need to find water, food, shelter, and mates. Our sensory systems

were designed to detect these necessities. And the same is true for the birds and the bees

and the bugs and the beasts. However, we all need different forms of food, shelter, and

mates. We are built to accommodate our needs and our distant and not so distant cousins

are blessed with the equipment and programs to fulfill theirs. I suspect that the bluebird in

the tree experiences a very different tree than we do. He may see nesting possibilities or a

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source of food. We detect delicate leaves, blossoms, and graceful branches. Their tree is

not our tree but we both are seeing correctly. Yes, there is overlap in our visual worlds. We

also see the small branch the bird alights on and the berry his selects for dinner. The tree

exists. The material world is not an illusion. But it most likely exists differently for each

of us. Different species live in different worlds, all real, all co-existing, all equally valid.

As the path of the electron takes many forms, so may our experience of the world.

CONCLUSION

Twenty five hundred years ago Plato claimed that to know and understand everlasting truths

we must forsake the shadows of the material world and exercise our unique human ability

to think and reason. Aristotle's syllogisms demonstrate our human capacity for reasoning.

All men are mortal, Socrates is a man, therefore Socrates is mortal Some things are self

evident.

I like the Greek idea of reason and find much to recommend it. The Greeks thought of

reason as our defining human characteristic, our special gift, the quality that makes us

different from other species. But we all know that reason can sometimes fail us. Reason

must be used correctly and that does not always happen.

The Church of the middle ages embraced the ancient Greek commitment to reason but

modified it to fit the times. They called it 'revelation', God's direct influence upon ones

thinking. Of course, Church dogma and authority were considered imbued with reason

and must be so regarded by all. A thousand years of reliance on 'revelation', dogma and

authority proved very painful for millions.

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In our time scientific methods seem to be the preferred path to knowledge, facts, and

truthfulness. Observation and measurement, not reason, not dogma, not authority, are

trustworthy guides to reality. We have suggested however, that human observation and

perception may also be problematic. Our perceptions are not only subject to error, our very

humanness may limit the capacity to know. Perception is a cognitive process, grounded in

neurophysiology. Since the brains of species differ their cognitive processes are likely to

differ too. Surely we humans see the lake differently than the fish who live there. Are we

right and they wrong? Is there a right? Could it be that we are all right? Are there many

worlds?

Now that we have come to doubt the primary methods of knowing where do we stand? Is

truth a dying concept? Quantum theory is inconsistent with our most fundamental

assumptions about the world. It is almost impossible to comprehend; even Einstein couldn't

endure it. How do we navigate a probabilistic universe without facts and without

certainty, without truth? Are we on our way to a new paradigm for knowing and living?

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NOTES

1. Ungerleider, L. G., Courtney, S. M., and Haxby, J.V. (1998) A Neural System for

Human Visual Working Memory. Proceeding of the National Academy of Sciences,

Vol. 95, pp 883-890.

2. Sereno, M. I. and Allman, J.M. (1991). Cortical Visual Areas in Mammals. In A.

G. Leventhal (ed) The Neural Basis of Visual Function. London: Macmillan, pp160-

172.

3. Rilling, J. K. (2006) Human and NonHuman Primate Brains: Are they Allometrically

Scaled Versions of the Same Design? Evolutionary Anthropology 15, pp.66-77.

4. Premack, David (2007) Human and Animal Cognition: Continuity and Discontinuity.

Proceedings of the National Academy of Sciences, Vol. 104, no. 35, pp.13861-13867.

5. Schoenemann, P. T. , Sheehan, M. J. and Glotzer, L. D. (2005)Nature Neuroscience,

Vol 8, pp242-252.

6. Please see Forrester, Rochelle, (2002) Sense Perception and Reality for a similar

view as suggested here but she has cast it primarily in the context of modern physics.Her paper can be viewed at http://homepages.paradise.net.nz/rochelle.f/Sense-Perception-

and-Reality.html

I was able to find only a very scant literature on the visual pathways of animals. I think

this issue might benefit greatly from further exploration of the literature and research on

animal neurophysiology regarding perception.

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http://io9.com/5890414/the-4-biggest-myths-about-the-human-brain

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