~ Sensation & Perception ~
|
This rather disturbing looking fella to your left is known as the sensory homunculus. Homunculus is Latin for "little man", and this nightmare of a figure is a representation of how your brain sees you. The areas that are grossly enlarged correspond to those areas of the brain that are the most important parts of the body for the processing of information, and are therefore related to our senses.
Our senses then, are what take in information about our environment, without which, we might as well dwell in a sensory deprivation tank. And if we are to believe the 1980 movie Altered States (among my all time favorite films) concerning the consequence of what happens when you spend too much time in a |
completely sensation-deprived state, floating in water, in complete blackness, with no sound of any kind, no stimuli coming in through your senses, we somehow break through the space-time continuum, are hurled through evolution of the ages, and then further, becoming a bionic version of The Hulk all the while wrecking havoc with your cellular composition, that conversation belongs to science fiction. But not entirely. In sum, sensation is how we are able to negotiate our environment.
If sensation can be defined as the information that we take in from our five senses (taste, touch, smell, hearing, and seeing), perception is what the brain does with that information and the mind's interpretation of it. Sensation occurs when he hear music, but it is our perception of that music that distinguishes Handel from Hip-Hop, and Beethoven from Bob Dylan, or any of it from nothing more than noise. When our senses perform as they should, all of us interpret water as wet, boiling water as scalding, champaign as bubbly, and honey as sweet. However, whether or not you actually like or can tolerate the taste of champaign or honey, is a matter for our perceptions, and perceptions vary widely. Our perceptions are guided by culture, heredity, accommodation and adaptation, all of which becomes a part of what we call our personal preferences.
Perhaps nowhere is the connection between the worlds of philosophy and neuroscience more apparent than with the early understanding of sensation and perception, and its relevance to the brain and mind, body, and soul. It was the philosopher Immanuel Kant (1724-1804) who caused the shift in our knowledge about how we take in and perceive the world, that up until his theory, was the way in which the mechanisms of our brain was understood since the 6th century Hellenistic period. The prevailing theory prior to Kant and held by Rene Descartes (1596-1650), and a modified version from Socrates (470 BC), was the Aristotelian doctrine concerning the soul and Descartes subsequent interactive dualism. We were getting closer to the all-important understanding of physiology and neurology as separate from soul.
Beginning with the Copernican Revolution in the mid 1500's with his On the Revolutions of Heavenly Spheres published in 1543, this is generally credited with having ushered in the scientific revolution at the forefront of the Age of Enlightenment. Rapidly came the scientific theories and inventions by Sir Isaac Newton, Francis Bacon, and of course Galileo. That said, the philosophies of Kant were formed in no small measure by David Hume's (1711-1776) theory of causality, which in turn reaped the philosophical benefits from historical giants such as Pierre Flourens (1794-1867), whose experimentation concerning the localization of brain function and Paul Broca (1825-1880) whose brilliant work with the language centers of the brain ushered in and solidified the mapping of the brain into its cytoarchitectural and functional component. Which brings us to sensation and perception.
In order to understand the functions of sensation and perception, it was necessary to first find them structurally. In other words, was there an area of the brain where our senses reside, as in an actual place? During this period of time, there was considerable interest from experimentalists predominantly in Germany, France, and the United States, on what is now referred to as localization of function. After some early fits and starts, a 'language center' of the brain was discovered by a young Paul Broca (c.f. language) which solidified the discovery that our neocortex indeed had specific areas that corresponded to specific functions. It was the Scotsman David Ferrier (1843-1928) that discovered there were sensory areas, located just behind experimentalists Fritsch and Hitzig's newly discovered motor strip. Just behind the motor strip area, located within the occipital cortex, is the region we now know is responsible for vision. Next came the discovery of auditory centers located within the temporal lobe. Thus began the mapping of the brain and the localization of function as we know it today.
In the 1996 movie Mulholland Falls, Nick Nolte plays a gangster member of the LA hat squad who, while investigating the death of a young woman, finds himself seated across from John Malkovich who plays ret. General Timms, head of the Atomic Energy Commission, who is schooling Nolte on basic physics. Malkovich tells him the following:
Did you know the atom is itself mostly empty space? Almost completely empty but with tiny fragments of matter.
And since this entire universe is made up of atoms, everything we see and touch, in fact the very floor beneath us
is made up of almost completely empty space. The only reason we don't fall through it, is because these tiny particles
of matter are just whirling about at such speed, that they give us the illusion of solidity. But actually, the floor is
spinning right underneath our feet. And these tiny particles of matter, which are so small, no on has ever sen them,
never, contain enough energy to blow up this hour and an entire city, and every person on earth.
What the Malkovich character is referring to is a phenomenon called change blindness and transsaccadic memory. Change blindness is a phenomenon whereby our perceptual ability is rather poor in being able to detect change, especially as it relates to motion. Psychologist William James discussed this in his 1890 Principles of Psychology. Change blindness is related to the neural process that, in part because of change blindness, enables us to perceive things as one smooth picture instead of multiple still images. A good example of this is stroboscopic movement popularly known as the phi phenomenon. The phi phenomenon is a perceptual illusion that causes us to perceive motion where there is none. A modern example is that of a gif, a computer file otherwise known as a graphic interchange format Gifs use the process whereby light and motion is seemingly produced where there is none. Obviously there is no actual motion involved in the pictures below, the Dalmatian is not running and the famous faces are not not turning their heads, but we perceive it as such...
If sensation can be defined as the information that we take in from our five senses (taste, touch, smell, hearing, and seeing), perception is what the brain does with that information and the mind's interpretation of it. Sensation occurs when he hear music, but it is our perception of that music that distinguishes Handel from Hip-Hop, and Beethoven from Bob Dylan, or any of it from nothing more than noise. When our senses perform as they should, all of us interpret water as wet, boiling water as scalding, champaign as bubbly, and honey as sweet. However, whether or not you actually like or can tolerate the taste of champaign or honey, is a matter for our perceptions, and perceptions vary widely. Our perceptions are guided by culture, heredity, accommodation and adaptation, all of which becomes a part of what we call our personal preferences.
Perhaps nowhere is the connection between the worlds of philosophy and neuroscience more apparent than with the early understanding of sensation and perception, and its relevance to the brain and mind, body, and soul. It was the philosopher Immanuel Kant (1724-1804) who caused the shift in our knowledge about how we take in and perceive the world, that up until his theory, was the way in which the mechanisms of our brain was understood since the 6th century Hellenistic period. The prevailing theory prior to Kant and held by Rene Descartes (1596-1650), and a modified version from Socrates (470 BC), was the Aristotelian doctrine concerning the soul and Descartes subsequent interactive dualism. We were getting closer to the all-important understanding of physiology and neurology as separate from soul.
Beginning with the Copernican Revolution in the mid 1500's with his On the Revolutions of Heavenly Spheres published in 1543, this is generally credited with having ushered in the scientific revolution at the forefront of the Age of Enlightenment. Rapidly came the scientific theories and inventions by Sir Isaac Newton, Francis Bacon, and of course Galileo. That said, the philosophies of Kant were formed in no small measure by David Hume's (1711-1776) theory of causality, which in turn reaped the philosophical benefits from historical giants such as Pierre Flourens (1794-1867), whose experimentation concerning the localization of brain function and Paul Broca (1825-1880) whose brilliant work with the language centers of the brain ushered in and solidified the mapping of the brain into its cytoarchitectural and functional component. Which brings us to sensation and perception.
In order to understand the functions of sensation and perception, it was necessary to first find them structurally. In other words, was there an area of the brain where our senses reside, as in an actual place? During this period of time, there was considerable interest from experimentalists predominantly in Germany, France, and the United States, on what is now referred to as localization of function. After some early fits and starts, a 'language center' of the brain was discovered by a young Paul Broca (c.f. language) which solidified the discovery that our neocortex indeed had specific areas that corresponded to specific functions. It was the Scotsman David Ferrier (1843-1928) that discovered there were sensory areas, located just behind experimentalists Fritsch and Hitzig's newly discovered motor strip. Just behind the motor strip area, located within the occipital cortex, is the region we now know is responsible for vision. Next came the discovery of auditory centers located within the temporal lobe. Thus began the mapping of the brain and the localization of function as we know it today.
In the 1996 movie Mulholland Falls, Nick Nolte plays a gangster member of the LA hat squad who, while investigating the death of a young woman, finds himself seated across from John Malkovich who plays ret. General Timms, head of the Atomic Energy Commission, who is schooling Nolte on basic physics. Malkovich tells him the following:
Did you know the atom is itself mostly empty space? Almost completely empty but with tiny fragments of matter.
And since this entire universe is made up of atoms, everything we see and touch, in fact the very floor beneath us
is made up of almost completely empty space. The only reason we don't fall through it, is because these tiny particles
of matter are just whirling about at such speed, that they give us the illusion of solidity. But actually, the floor is
spinning right underneath our feet. And these tiny particles of matter, which are so small, no on has ever sen them,
never, contain enough energy to blow up this hour and an entire city, and every person on earth.
What the Malkovich character is referring to is a phenomenon called change blindness and transsaccadic memory. Change blindness is a phenomenon whereby our perceptual ability is rather poor in being able to detect change, especially as it relates to motion. Psychologist William James discussed this in his 1890 Principles of Psychology. Change blindness is related to the neural process that, in part because of change blindness, enables us to perceive things as one smooth picture instead of multiple still images. A good example of this is stroboscopic movement popularly known as the phi phenomenon. The phi phenomenon is a perceptual illusion that causes us to perceive motion where there is none. A modern example is that of a gif, a computer file otherwise known as a graphic interchange format Gifs use the process whereby light and motion is seemingly produced where there is none. Obviously there is no actual motion involved in the pictures below, the Dalmatian is not running and the famous faces are not not turning their heads, but we perceive it as such...
|
|
These perceptual experiences are well known examples of the Gestaltist perspective, and you can see more of them here. |