CHAPTER-4
DESIGN AND METHODOLOGY
The main purpose of the present experiment was to investigate the state
dependent effect of temperature on memory.
Various hypotheses were
formulated regarding this effect. The present chapter gives an outline of the
design and methodology used to test various hypotheses.
Design
The present experiment was conducted to investigate the state dependent
effect of high temperature on memory. For this purpose, a 4x2 factorial
design was used. In this experiment, four different levels of temperature
Exposure both
before learning
and retention
No exposure
Before
retention
2SVC
Level of temperature
4T'C
38 C
v
SouC
n= 10
n= 10
n= 10
n= 10
n= 10
n= 10
n= 10
n= 10
N=80
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Sample
A sample of total 80 subjects having an age-group of 17-23 years, belonging
to either sex was randomly selected from the student population studying in
various pose-graduate courses in M. D. University, Rohtak.
They were
further randomly allocated to eight groups and were randomly assigned to
various treatments as per the factorial design on previous page.
Material Used
Temperature Chamber
A very small room ( 10' x 4' x 10' ) was used as the temperature chamber
for conducting the experiment. It was equipped with both the room heaters
and air conditioner. Room heaters were used to raise the temperature to
higher levels in comparison to the existing room temperature and the fans
were kept off and air conditioner was used to cool the room to lower degrees
from the existing room temperature as per requirement.
Room - temperature thermometer
The thermometer which is used to know the temperature of a room or
atmosphere is called room temperature thermometer or atmospheric
thermometer. The instrument consists of two components, a glass body
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having bulb at the lower end containing mercury and circular knob at the top
for hanging the thermometer of Kwality brand name company. The body of
thermometer has the markings from - lOoC to 57°C.
List of nonsense syllables:
For the present experiment, a list of 15 nonsense syllables (cvc of30 to 40%
association value) was prepared.
These items were selected from a
#
standardised list of non-sense syllables by Glaze's list.
Memory Drum:
A memory drum was used to present the list of nonsense syllables to the
subjects. This device consisted of a drum mounted behind a screen. A strip
of paper having equally spaced non-sense syllables was fastened around the
drum. The drum is driven by a constant speed motor and exposes each
syllable through a window in the screen. This memory drum could be set at
a speed of I, 2, 4 and 8 seconds.
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Temperature
The degree of hotness of a body is called its temperature.
Feelings of
warmth and coolness are relatively not absolute (except at the extremes).
There is temperature level that for particular region of skin, will produce a
sensation of temperature neutrality neither warmth nor coolness.
This
neutral point is not an absolute value but depends on the prior history of the
thennal stimulation of that area. If the temperature of a region of skin is
raised by few degrees, the initial feeling of warmth is replaced by one of
neutrality. If the skin temperature is lowered to its initial value, it now feels
cool. Thus increase in temperature lower the sensitivity of cold receptors.
Temperature surrounding the body in a specific environment is known as
room temperature.
Memory
,-
Remembering
IS
the process that makes available to the individual
something he has learned earlier. Remembering can be considered as the
present knowledge of some event or fact that have occurred before. The
learnt material retained by the individual is referred to as his memory. Short
tenn memory is the storage and retrieval of infonnation that is remembered
for a very short period of time. Long tenn memory may last for days,
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months, years or even a life time. Remembering is a word which includes
several mental activities like recall, recognition and retention. Just as every
mental activity, memory has a physiological foundation.
Briefly,
remembering is a psycho-physiological activity.
Method
The main purpose of the present experiment was to investigate the state
dependant effect of high temperature on memory. A sample of SO subjects
.
was randomly selected from the students population studying in various
postgraduate courses in M.D.V. Rohtak. These students were randomly
assigned to eight groups which were exposed to 4 different levels of
temperature (2SoC, 3SoC, 42°C and SO°C). For each temperature level, 10
subjects were taken in two groups to be exposed to the required degree of
temperature only once i.e. before acquisition and 10 to be exposed twice i.e.
both before acquisition and retention.
Before bringing the subjects into the laboratory,
temperature was set in. For this purpose, a small room was taken and fitted
with two heaters and air conditioner.
The heater or air conditioner
(according to the condition) were put on and the room temperature
thermometer was set in the laboratory so as to take the continuous reading of
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the temperature. The required temperature was maintained by putting off
and on these rods as required.
Now, when the laboratory was set for the experiment, the
subject was brought in the room having a temperature set at level of 25°C
(with the help of air conditioner) and made to sit comfortably.
Simultaneously, time of the subject's entry in the chamber was noted. After
that, the subject was constantly seated for 20 minutes in the chamber at this
temperature level of 25°C.
The purpose of seating the subjects for 20
minutes was to activate the physiological and phychological effect of the
temperature on the subjects. Therefore, after 20 minutes, the instructions
pertaining to the experiment were given in the following manner:
" This is a simple learning experiment.
A senes of
nonsense syllables will be presented to you through the window of a
memory drum. Each syllable will be exposed for 2 seconds. A nonsense
syllable is a combination of 3 letters without any meaning. These syllables
will come one by one at a regular rate. You have to look at these syllables
carefully. After the list has been presented once, the syllables will be shown
once again, this time you have to anticipate each syllable. It means you have
to spell out each syllable before it appears on the window. When the symbol
marking the beginning of list (-), appears, you are to spell out the first
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syllable. When the first syllable appears, you are to spell out the second, and
so on through the entire list. Remember, your task is to spell each syllable
before it appears on the window. This procedure will be continued until you
have spelled out each syllable correctly on two consecutive trials.
If
something is not clear, you can ask. "
After having confirmed that the procedure was clear to
the subject, the subject was made to take the sitting posture. They were
made to sit on
a stool in front of the memory drum at an eye level with the
window of memory drum. Now the memory drum was started. Nonsense
syllables were presented at the 2 second interval. The subject was asked to
read them aloud.
From the next trial onwards, subjects attempted to
anticipate the syllables in a serial order. The correct syllable was presented
whether or not the subjects anticipated it. Thus, each presentation of the
series was both a learning trial and a test retention. The subject's response
was noted down on each trial and for each syllable. Correct anticipations
were indicated by a tick mark (,f) and incorrect ones by a cross (X). This
procedure was continued tiII the criterion of two errorless anticipations. In
this manner, a complete record of attempts was obtained.
All the subjects were given an uninformed retention test
after 24 hours.
The subjects of experimental group were seated for 20
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minutes in the chamber in the same temperature conditions as during
learning. The purpose of seating was to put the subject in the same state in
which the subject had learnt the list. It was done to investigate the state
dependent effect of different temperatures on memory. But the subjects of
control group were not given any exposure of the temperature level before
retention test. During retention, each subject was told to recall the nonsense
syllables which were learnt a day before. During retention, the free recall
method of retention was followed. Subjects attempted to recall them and
responses were noted down. Each correctly recalled syllable was given one
score. Thus, total retention scores obtained were recorded for each subject.
The data obtained in this way was finally tabulated for
further analysis.