Biological Influences and Sensory Adaptation
Conduct three of the following experiments and record your
reactions. Be specific for each experiment.
1. Rub your index fingers gently over a piece of very coarse
sandpaper a few times and rate its coarseness on a scale from 1 (very soft) to
7 (very coarse). After a minute or two, rub the same finger over the paper and
again rate its coarseness. Did your perception of the coarseness change? How?
2. Distribute one cup with sugar water and one with fresh
water. Take a sip of the sugar water and swish it around in your mouth for
several seconds without swallowing it; gradually, it should taste less sweet.
After swallowing it (or spitting it back into the cup), taste from the cup
containing fresh water. Did the taste of the fresh water surprise you? How?
3. Take about 15 index cards and a flashlight that is opaque
on all sides (so that light shines only through the front) into a very dark
room. After placing all 15 cards over the beam of light, slowly remove the
cards one at a time until you can barely detect the light, and then count the
number of cards that remain over the light. After a few minutes, the light
should begin to look brighter. When this is the case, add a card and see if you
can still see the light. Repeat this process of gradually adding cards over a
15-minute period. Were you able to detect an increasingly dim light the longer
you spent in the dark?
4. Fill 3 medium-sized bowls with (a) very hot (but not
painfully so) tap water, (b) very cold tap water, and (c) a mixture of the very
hot and very cold water. Arrange them, so your right hand is in front of the
cold water, your left hand is in front of the hot water, and the lukewarm water
is in the middle. Submerse your hands into the water (right into cold, left
into hot) for about 3 minutes. After 3 minutes, quickly transfer both hands to
the lukewarm (middle) bowl. What did you sense?
In all four experiments, you will experience Sensory
adaptation. Fully describe the process and results of each experiment.
What is adaptation? Explain adaptation not as just a general
dictionary definition. Explain how adaptation is evident in each of your
experimental results. Comprehensively describe the sensory systems involved in
these experiments, from the receptors all the way into and including the brain.
Describe in detail the theories surrounding one of the sensory systems in
regards to how we smell, touch, taste, see, etc. Include a discussion on how
adaptation is important from an evolutionary perspective.
