Sensory Adaptation Experiment

1Sensory Adaptation Experiment

Running Head: SENSORY ADAPTATION EXPERIMENT

Biological Influences

Carla J. McCoy

Unit 2 Discussion Board – Aspects of Psychology

American InterContinental University

January 18th, 2009

Page 1


Abstract

Three experiments have been conducted and recorded in this Article in order to experience

Sensory Adaptation. You will be able to identify with the process and results of each experiment

as well as learn what Adaptation is. Adaptation is evident in each of the experiment results

described and the Sensory Systems that are involved in these experiments will be described from

the receptors all the way into and including the brain. Theories were used that surround one of

the Sensory Systems in regards to how we smell, touch, taste, see, and hear. This article will also

show how adaptation is important from an evolutionary perspective. The Thesis for this Article

is “Intoxicated with Sensory Pleasures, we all are unguarded”

Page 2


Introduction

Sensory Adaptation will give individuals the experience of learning a change in

perception of what messages are sent to the brain and how the brain deals with them. Everyone

has Senses, but not everyone exercises those senses allowing the brain to process the experience.

This paper will discuss the Sensory Adaptation of rubbing my index fingers over a piece of

coarse sandpaper a few times, rating it’s coarseness on a scale from 1 (very soft) to 7 (very

coarse), not once, but twice in order to gain an opinion of whether or not my perception of

coarseness changed. I will also take one cup with sugar water and one with fresh water, first

taking a sip of the sugar water and swishing it around in my mouth for a few seconds before

spitting it out, then tasting the fresh water to see what perception I receive. Three medium sized

bowls will be placed in front of me in order for me to submerse my hands into. One bowl of

water will be a mixture of very hot and very cold water, another bowl will contain very cold tap

water, and the last bowl will contain very hot tap water. I will submit my right hand into the cold

water while my left hand will be submersed at the same time into the hot water for

approximately 3 minutes. Once the three minutes are up, I will then transfer both of my hands to

the lukewarm water filled bowl and explain what I sensed. (McCoy, C., 2009)

Page 3


Process and Results of Each Experiment

Sensory Adaptation of Sandpaper – After obtaining a very coarse piece of sandpaper, I

proceeded to rub my index fingers gently on top of it a few times. I would rate it’s coarseness on

a scale of 7 which is very coarse. This experiment gave me chill-bumps and was also irritating.

After a minute or two of resting my index fingers, then going back and rubbing the same fingers

over the paper I found that it isn’t as coarse the second time as it was the first time. I would rate

it’s coarseness at 4 which lead me to believe that my senses adapted to the coarseness.

Sensory Adaptation of both Sugar and Fresh water – After obtaining the Ingredients

which consist of Sugar, two cups, and Fresh tap water, I took one cup and put Sugar in with

Fresh Tap water and stirred it together. In the second cup I only put Fresh tap water. I proceeded

to taste the cup with Sugar water, held it in my mouth and swished it around for several seconds

without swallowing it. I noticed that my taste buds became over stimulated and less sensitive to

the sweetness the longer it was in my mouth. But when I tasted the Fresh tap water and did the

same thing, I noticed it tasted salty which surprised me because I didn’t add any salt so the fresh

tap water had a more prominent affect or result.

Sensory Adaptation of Hot, Cold, and Lukewarm water – I placed three bowls in front of

me on the counter. In one bowl I added very hot tap water. In another bowl I added very cold tap

water, and in the third bowl I added lukewarm water. I placed the cold bowl of water in front of

my right hand and the hot water in front of my left hand, and left the lukewarm water in the

middle. Once I submersed my left hand in the hot water and my right hand in the cold water my

reaction wasn’t what I thought it would be. I honestly thought I would end up needing to go to

the restroom due to the hand that was submersed in hot water, but after holding my hands in the

separate bowls of water for about a minute, then submersing them into the lukewarm water, what

Page 4


happened was that it appeared that the roles of the water switched somehow. It turns out that

once my left hand was in hot water and my right one in cold that the minute they there

submersed in the lukewarm water that their roles reversed. My left hand that was in the hot water

actually felt cold in the lukewarm water where my right hand that was in the cold water felt hot

in the lukewarm water. This explains something to me from my past that I’m sure everyone can

relate to. When I was growing up and went swimming a lot when I’d get out of the cool water in

the pool, stand in line for a few minutes then jump off the diving board only to find the pool was

much warmer once I got back in.

Adaptation

Adaptation can be best explained in the experiments I’m performing and presenting here

in this article. A presentation such as this one of the same stimulus in a continued manner has

caused receptors to become less sensitive to the stimulus, where in other areas of the presentation

a much stronger stimulus will activate receptors. This process is known as Adaptation and can

occur very quickly where odors and tastes are involved. (Prentice Hall, 2007). A good example

to show what Adaptation is would be to take a simple Jalapeño and squeeze the juices from it

over the top of your enchilada. The enchilada will be hot at first in the areas the juice Jalapeño

juice was applied, which has caused the receptors to become less sensitive due to repeated

tastings. However, problems can occur if you take the same Jalapeño and you cut it in slices and

lay the slices on top of the enchilada which would be adding more fire to the taste and would

activate your receptors, especially in people who have not adapted their taste buds to this

particular way of eating and will find the enchilada very hot!

Page 5


How Adaptation is Evident in each Experiment

A. Sensory Adaptation is Evident using Sandpaper – Sensory Adaptation is Evident using

Sandpaper because the coarseness was not as high the second time when rubbing the

sandpaper. I believe what happened here is that the senses were over stimulated the first

time the sandpaper was rubbed, and had adjusted in my brain to that sense, so when the

sandpaper was rubbed the second time around it was less sensitive, less irritating and felt

less coarse.

B. Sensory Adaptation is Evident using Sugar and Fresh water – Sensory Adaptation was

Evident using Sugar and Fresh water as well because when the Sugar was placed in my

mouth, and swished around and then spit out, it was the Salt water that over stimulated

my senses and became more prominent.

C. Sensory Adaptation is Evident using Hot, Cold and lukewarm water – Adaptation is

Evident in this Experiment because the results reversed roles and were shocking. This

was Evident in the lukewarm water where both hands that were previously placed in cold

and hot water, One in hot and the other in Cold, Once removed placed in lukewarm

water this is where Sensory Adaptation is Evident because the hand that had previously

been submersed in hot water now felt cold, yet the hand that was previously submersed

in cold water, now felt hot in the lukewarm water.

Sensory Systems in each Experiment

A. Sensory Systems using Sandpaper – When explaining the Sensory System in this

experiment from the receptors down into and including the brain the Tactile (touch) sense

was used. A tactile sensory receptor is the peripheral ending of a sensory neuron along

with its accessory structures which can be part of the nerve cell or epithelial or connective

Page 6


tissue. There is information that is carried from each skin receptor to several neuronal

axons which is a strip on top of the brain surface called the somatosensory cortex which is

basically the “rind” and is about sex millimeters or one-quarter inch, thick. The

Somatosensory Cortex is packed with cell bodies of CNS neurons that receive “skin

input” from all parts of the human body. Sensory input pours into the CNS neurons.

Messages about Sensory input are sent to other brain areas from the somatosensory cortex.

Tactile sensory maps in the cerebral cortex do not reflect correct proportions of skin areas.

A person’s fingertips contain about 100 times more receptors per square centimeter rather

than the skin on the back. More CNS neurons are devoted to receiving fingertip sensations

which results in the cortical area receiving input which is huge in comparison to the

human back that receives input. (Murray, M., Ph.D.; 2009)

B. Sensory Systems using Sugar and Fresh water – Taste cells are epithelial cells that

function as sensory receptors. There are approximately 50-60 taste cells that are located in

taste buds that are pear shaped. Taste cells are located through microvilli project into a

taste pore. Non-Receptor basal cells do not project into the pore; these are located on the

basement membrane and are different through various morphological steps into a mature

taste cell. Taste cells are replaced every 10 days. When saliva is transporting the dissolved

polar molecules that are sweet or bitter such as sugar or caffeine to the taste pore there is

Transduction of chemical stimuli into nerve impulses. Polar molecules bind to receptors

on the microvilli within the taste pore which are coupled to a G-protein called gustaducin

which is followed by the activation of a second messenger. A receptor potential generates

that allows a voltage dependent Ca++ channel to open and allow discharge of

neurotransmitters into the synapse which results in an action potential to generate in the

Page 7


afferent nerve ending. Electrolytes interact with receptors on the taste membrane which

open the ion-gated channel protein and increase the flux of Na+ and K+. Stimulation of

hundreds of taste buds on the tongue will generate a neural code which can be detected by

humans and identified because specific taste quality due to the neural code for each type

of stimuli being decoded by the central nervous system. (Hutchins, M., Dr. 2009)

C. Sensory Systems using Hot, Cold and Lukewarm water – This would apply as a

Temperature Receptor which lay directly under the skin. Temperature is stimulated by hot

and cold receptors, although there are more cold receptors than there are heat receptors the

degree of stimulation will always depend on the number of receptors that are stimulated.

There are various receptors in the skin when using hot an cold substances that work

together in combination as a complementary system that enables sensation of different

temperatures such as lukewarm water in this experiment. In this particular experiment

Paradoxical heat occurred because both hot and cold receptors were simultaneously

stimulated. (Nicholas, L., 2009)

Theories Surrounding one Sensory System

Some theories I will be describing in detail using the “taste” sensory system will explain

just how exactly we taste. First of all we need to realize there are two different sorts of papillae

on the tongue which are flat ones and slender ones. If you look at your tongue you will see there

are round, bright red ones in color. You will also notice there are paler colored ones which are

the slender type which would basically be the tip and sides of your tongue that are shiny. All

humans have approximately 10,000 taste buds on our tongues that can detect five tastes although

it had been thought that there were only four tastes for a very long time. Our tongues play an

important role in every day life because without our tongues we would not be able to taste, talk,

Page 8


swallow, or chew. (EmbarrassingProblems.com, 2009) Taste or Tasting has two very important

jobs: One is that it warns us about bad foods, and it also attracts us to good foods. (Moss, M.,

2004) Most people do not realize there are actually 5 tastes. When we think of taste we think of

salty, bitter, sweet, and sour, but thanks to Auguste Escoffier who actually invented veal stock.

The fifth taste is called “umami” which also means “delicious” or “yummy” in Japanese but

called L-glutamate in English. (Krulwich, R., 2007)

We also need to take a look at Olfaction which is where taste and trigeminal receptors

both contribute to flavor together. What Olfaction does is amplify the sense of taste and can be

proven by doing experiments such as taking Cantaloupe and Honey Dew Melon and slicing them

up and placing them each in their own bowls. If you hold your nostrils completely closed while

sampling one piece from one bowl, then the taste between the two are indistinguishable. Smell

and Taste work together to form results. (NationMaster.com, 2003-2005) One more thing I’d like

to include is that there are Scientists that have discovered taste receptors in the tongue that sense

fat. (DietsInReview, 2009) According to Professor Nada Abumrad of Washington University

School of Medicine in St. Louis, Missouri, “There is evidence that obesity may be associated

with an abnormal brain response to the sensory perception of a meal” (Abumrad, N., 2009)

Importance of Adaptation from an Evolutionary Perspective

Human Adaptations make up Human Nature in a systematic interaction between

phenotypic output and environmental input. Adaptation is basically the ancestral environment

from which it evolved and does not have to necessarily be connected to current conditions.

Adaptations solve reproductive problems and have functions. Human Adaptation is beneficial in

surviving and reproducing which can be passed on to our offspring. (Schaffner, S., 2008)

Page 9


Conclusion

Intoxicated with Sensory Pleasures, we all are unguarded when it comes to Biological

Influences such as our Sensory System, Neurotransmitters, Neurons, and Receptors. Using these

experiments provided here in this Article you can see how different each experiment is by the

different results each one produced and how Adaptation is Evident in each of these experiments.

Our Sensory Systems play an important role in combination with one another in how we live our

lives and the experiences we experience on a daily basis. As shocking as these experiments were

that I did for this Article, I must say I now have a want to try even more experiments such as

these at home. These experiences are etched in my own brain, never to be forgotten and It is my

hope that every reader who reads this Article will invent and create new Experiments to try and

share their stories about the process and results of their own experiments. (McCoy, C., 2009)

Page 10


Citations

Psychology, Fifth Edition, by Stephen F. Davis and Joseph J. Paladino. Published by

Prentice Hall, Copyright © 2007 by Pearson Education, Inc.

Health Press Ltd, Embarrassingproblems.com, (2009) Tongue problems at

http://www.embarrassingproblems.co.uk/tongue.htm

Moss, M., (2004) how Do We Taste, CBS Interactive Inc. (2009) at

http://findarticles.com/p/articles/mi_qa4128/is_200411/ai_n9464943

Krulwich., R., (2007) Sweet, Sour, Salty, Bitter … and Umami NPR, (2009) at

http://www.npr.org/templates/story/story.php?storyId=15819485

NationMaster.com, (2003-2005) Encyclopedia: Olfaction at

http://www.nationmaster.com/encyclopedia/Olfaction

Wellsphere, (2009) Your ‘Mystery’ Taste Receptor at http://www.wellsphere.com/weight-

loss-article/your-mystery-taste-receptor/422561

Abumrad., N., (2009) Washington University School of Medicine in St. Louis, Missouri

Murray, M., Ph.D.; (2009) Neuroscience for Kids Staff Writer Our Sense of Touch at

http://faculty.washington.edu/chudler/twopt.html

Hutchins, M., Dr.; Integrative Oral Sciences 1507 Chemical Sensory System Functions

(continued) The University of Texas Health Science Center at Houston

Nicholas., L., (2009) Introduction to Psychology, second edition p.91 at

http://books.google.com/books?

Page 11

http://books.google.com/books?id=MP5X2SK2DCgC&pg=PA91&lpg=PA91&dq=Sensory+System+using+hot+and+cold&source=web&ots=WbnLg0SWJZ&sig=p42bVer8rERgh3jM5wPbZmYuo2Q&hl=en&sa=X&oi=book_result&resnum=2&ct=result


http://www.wellsphere.com/weight-loss-article/your-mystery-taste-receptor/422561







id=MP5X2SK2DCgC&pg=PA91&lpg=PA91&dq=Sensory+System+using+hot+and+col

d&source=web&ots=WbnLg0SWJZ&sig=p42bVer8rERgh3jM5wPbZmYuo2Q&hl=en&

sa=X&oi=book_result&resnum=2&ct=result

Schaffner, S. & Sabeti, P. Evolutionary adaptation in the human lineage. Nature

Education 1(1), (2008)

McCoy, C., (2009) American InterContinental University Individual Project. Biological

Influences

Page 12




References

Electronic Resource: https://mycampus.aiu-online.com

Electronic Resource: http://www.embarrassingproblems.co.uk/tongue.htm

Electronic Resource: http://findarticles.com/p/articles/mi_qa4128/is_200411/ai_n9464943

Electronic Resource: http://www.npr.org/templates/story/story.php?storyId=15819485

Electronic Resource: http://www.nationmaster.com/encyclopedia/Olfaction

Electronic Resource: http://www.wellsphere.com/weight-loss-article/your-mystery-taste-

receptor/422561

Electronic Resource: http://faculty.washington.edu/chudler/twopt.html

Electronic Resource: http://www.uth.tmc.edu/courses/dental/smell-taste/taste.html

Electronic Resource: http://books.google.com/books?

id=MP5X2SK2DCgC&pg=PA91&lpg=PA91&dq=Sensory+System+using+hot+and+cold&sour

ce=web&ots=WbnLg0SWJZ&sig=p42bVer8rERgh3jM5wPbZmYuo2Q&hl=en&sa=X&oi=boo

k_result&resnum=2&ct=result

Electronic Resource: http://www.nature.com/scitable/topicpage/Evolutionary-Adaptation-in-the-

Human-Lineage-12397

Page 13

http://www.nature.com/scitable/topicpage/Evolutionary-Adaptation-in-the-Human-Lineage-12397

http://www.nature.com/scitable/topicpage/Evolutionary-Adaptation-in-the-Human-Lineage-12397




http://www.uth.tmc.edu/courses/dental/smell-taste/taste.html








https://mycampus.aiu-online.com/

Business

Sensory Adaptation Experiment