Reaction Time
Abstract:
Motion, which is the process by which something moves from one place to
another, is broken down into two categories: scalars and vectors; scalar
measurements given magnitude, but vector measurements given magnitude and
direction. Distance and displacement are similar in that they give a measurement of
the space traveled, but displacement is a vector and therefore has a direction and
measures only all of the space traveled when going from going from “point A” to
“point B” in a given cycle or pathway. Speed and velocity are similar because they
give a measurement of how fast something is traveling, except that velocity is a
vector measurement and gives a direction. Acceleration is a vector measurement
and is defined as a change in velocity. The human body is divided into many systems,
and the system that controls the process of sending, receiving, and processing nerve
impulses is the nervous system. When stimuli, changes in the environment, are
detected, the body produces a response. The time elapsed between processing a
stimulus and giving forth a response is the reaction time. The purpose of the
experiment was to choose a variable and see if and how the variable affects the
control group’s reaction times. The variable selected was wearing prescription
glasses while catching a falling ruler; the hypothesis was that the variable would
slow down the reaction time of the test subject. After all data was recorded and
charted, the data rejected the hypothesis and therefore the reaction times were
quicker when using the variable during the experimental trials.
Introduction:
Motion is defined as the process by which something moves from one place to
another. Motion can be classified three ways: linear, which is motion in a straight line,
rotational, which is motion around an axis, and curvilinear, which is a combination of
both linear and rotational motion. Motion was first kinematically described by Galileo;
Galileo described concepts such as velocity and acceleration. Motion can be described in
two ways: scalar and vector (Lerner/Wilmoth, 2008). Scalar and vector measurements
both are similar in that they describe magnitude (how much or how far an object travels).
Vector measurements are more precise in that they give a direction along with magnitude.
Examples of scalar measurements are length, distance, mass, volume, density,
temperature, pressure, and speed. Examples of vector measurements include
displacement, momentum, acceleration, thrust, velocity, and weight (Benson, 2009).
Distance and displacement are two similar, yet very different concepts that deal
with motion. Distance, when talking about physics, refers to the extent of space that
exists between two points. Distance is a scalar measurement and therefore a direction is
not entailed with distance. Displacement is a vector measurement which refers to the
extent of space that exists directly from “point A” to “point B”. Besides distance being a
scalar measurement and displacement being a vector measurement, distance and
displacement differ in what each measure. Distance measures all of the space traveled
when going from going from “point A” to “point B” in a given cycle or pathway.
Displacement measures the actual distance directly from the beginning to end; if a start
point and an end point are one in the same, the displacement would then be 0. Because of
this relationship, displacement is always less than or equal to the distance (Elert, unk.).
Speed and velocity are like distance and displacement in that they are both very
similar, yet very different. Speed refers to the ratio of distance to the change in time.
Speed is a scalar measurement and therefore does not have a direction. In the common
vernacular, speed refers to how fast an object is traveling. The formula for speed is as
follows: speed = distance / ∆t (change in time). Velocity is similar to speed, but velocity
refers to the ratio of displacement to change in time rather than distance. Velocity is a
vector measurement and therefore has a direction. Like speed, velocity can be referred to
how fast something is going when speaking in the common vernacular. The only
difference is velocity gives a direction and gives the distance from “point A” to “point B”.
The formula for velocity is as follows: velocity = displacement / ∆t (change in time).
Speed and velocity are both usually measured in meters per second or kilometers per
hour (Elert, unk.).
Another concept that involves motion is acceleration. Acceleration in physics
terminology is the rate of change of velocity to the change in time. Acceleration refers to
the increase of velocity over a period of time, and deceleration refers to the decrease of
velocity over a given period of time. In the common vernacular, acceleration is referred
to as speeding up, which is slightly different then its true scientific definition. Because
acceleration is a change in velocity, acceleration occurs when the direction changes
because accleration is also a vector measurement just like velocity. Acceleration can be
calculated using the following formula: acceleration = (final velocity – initial velocity) /
∆t; acceleration is measured in m/s2 (Elert, unk.).
Gravity, which is the force that exists between all masses in the universe, is
known to pull masses down to the ground. For example, when someone jumps, they lift
off the ground but return shortly due to the gravity on Earth. The theory of gravity was
first proposed by Sir Isaac Newton who began hypothesizing after Newton was hit on the
head by a falling apple from a tree above. Gravity makes life possible to be in “real time”
as sometimes gravity is referred to, whereas on other planets where gravity either makes
movement near impossible to lift off the ground or too little gravity to remain on ground
for extended periods of time. This gravity puts forth a uniform gravitational acceleration
that occurs with all masses present on Earth. The acceleration due to gravity on Earth is
equal to Earth’s gravity because objects will gain velocity as the down ward pressure
forces them down ward at a rate of 9.8 m/s2 (Elert, unk.).
The human body consists of many smaller “parts” or “sections” which act
together to regulate normal health and bodily function. These systems of the body work
independently to complete specific tasks that each system was “designed” to complete.
When these systems work in a joint effort, the individual systems join together to
complete tasks and body functions that could not be achieved independently. These
systems include the circulatory system, digestive system, endocrine system, immune
system, excretory system, respiratory system, muscular system, skeletal system,
reproductive system, and the nervous system. The system responsible for sending,
receiving, and processing nerve impulses throughout the body is the nervous system
(Goddard, 2009).
The nervous system consists of three major sections: the central nervous system,
peripheral nervous system, and autonomic nervous system. The central nervous system
can de divided into two major sections, the brain and the spinal cord. The brain contains
over 100 billion neurons, or brain cells, and is divided into three main sections: the
cerebrum, the medulla oblongata, and the cerebellum. The cerebrum is the largest part of
the brain and contains several “lobes” which are small sections of the brain to perform
specific tasks such as audio comprehension, visual comprehension, hormone control, and
logic. These sections are connected by long nerve fibers. The strength of these
connections of nerve fibers are currently known to highly influence an individuals
intelligence. The cerebellum is attached above the top of the spinal cord tip. The
cerebellum is the second largest part of the brain which serves as a “balancer” which
keeps muscle tone and bodily balance in proper function. The medulla oblongata is the
smallest part of the brain, is located directly on the tip of the spinal cord and is
responsible for regulating heartbeat, blood pressure, breathing, and reflex centers for
reflexes such as vomiting, coughing, sneezing, and hiccupping. The spinal cord is
attached to the brain and runs about halfway down the spine of the human body; its
purpose is to connect the brain with the peripheral nervous system (Farr, 2002).
The peripheral nervous system is responsible for the relay of nerve impulses that
are sent, received, and processed by the central nervous system. As with the brain, the
nervous passages are formed from neurons. Sensory input from the body surface, from
joint, tendon, and muscle receptors, and from internal organs passes centrally through the
roots of the spinal cord; this is the primary concept of the peripheral nervous system. The
autonomic nervous system is an offshoot of the peripheral nervous system which
provides the normal processes needed to maintain the proper bodily function of all
muscles, glands, and organs. For example, when the following occurs, the peripheral
nervous system is the main component for the response. When a person touches
something hot, the nerve endings on the finger tips realize that the object being touched is
very hot. These nerves send impulses through the peripheral nervous system to the brain,
which instantaneously sends an impulse back to the nerves on the fingertips, telling the
nerves to flinch and back off of the object. The example given demonstrates the concept
of stimuli and responses (Farr, 2002).
Stimuli, or a stimulus in the singular, are a “detectable change in the environment;
that which influences or causes a temporary increase of physiological activity or response
in the whole organism or in any of its parts,” (Biology-Online, 2009). Stimuli occur
nearly every second of every day, and can sometimes go unnoticed. Stimuli are the
outside “forces” that trigger a reaction from the body. Stimuli are the major concept that
exist in the senses of the body and include such examples as smells, sounds, feelings,
visuals, tastes, etc. Stimuli cause the human body to trigger a response, which is a
response produced by the body-either voluntary or involuntarily- in response to the
stimulus or stimuli. Responses are necessary in order for the human body to operate as
the body is supposed to; reactions protect us from damaging the various sensory organs
of the body, such as the ears, nose, mouth, hands, skin, and eyes. The body will send a
response to the brain, telling a given person whether or not a noise is too loud for the ears,
something is too hot or cold for the skin, too sour or rotten for the mouth/tongue, too
much strain on the eyes, etc. The theory of stimulus-response is vital in understanding the
thought process and reaction time (Farr, 2002).
A reaction, in biological terms, refers to a response in the stimulus-response
theory. Stimuli are transformed into impulses by the sensory nerves, which send different
frequencies of impulses to the brain. These impulses are registered by the brain and the
central nervous system and send back impulses through the peripheral nervous system to
the sensory nerves. These stimuli responses generally occur in less than one second, but
longer responses, such as verbal responses or responses needing logical reasoning and
thought may take longer. The time that spans through this chain reaction is known as the
reaction time. There are four main types of responses: simple, go/no-go, discrimination,
and choice. Simple responses include performing action when one is told, such as hitting
a button when a light flashes. Go/no-go responses include performing an action only
under certain conditions, such as hitting a button when a light flashes green, but
restraining when the light flashes red. Choice responses require the person to take into
consideration both the stimulus and response longer because of different choices of
actions with different conditions. An example would be hitting a circular button when a
light flashes green, hitting a triangular button when a light flashes red, and hitting a
square button when the light flashes yellow. Discrimination responses require an analysis
of a pair of items and include such actions as determining which image of two given
photos is brighter, newer, etc. Simple responses are almost instantaneous whereas go/ nogo, choice, and discrimination responses require more reaction time to process and
choose the correct answer (Kosinski, 2009).
Reaction time itself may vary based on many factors that contribute to the varied
results of reaction time. Variables that affect reaction time include alertness, age, gender,
hormones, hand orientation, direct vs. peripheral vision, practice, exposure to subject
being tested, fatigue, dietary habits, distractions, good/poor vision, good/poor hearing,
alcohol level, breathing cycle, emotions, drugs, exercise, illness, intelligence, and
personality type. Depending on these factors at a given time, reaction times may vary.
This is the primary reason why extensive experiments with many trials and variables
must be performed to gather accurate data about a person’s reaction time (Kosinski,
2009).
The purpose of the initial experiment was to provide a control group for the
experimental trials. The purpose of the experiment was to choose a variable and see if
and how the variable affects the control group’s reaction times. Each group was to drop a
ruler and calculate the time elapsed before catching a falling ruler. The variable selected
was the use of prescription-lens glasses to distract and disorientate the subject of the trials.
With unclear vision, the test subject would probably show a difference in reaction time as
compared to the controlled experiment. Another purpose of the experiment is to see if
there is a direct correlation between the amount of times a person texts daily (survey
question) and the reaction time of the test subjects. The hypothesis for the experiment is
that the application of prescription glasses will disorient the test subject and will therefore
have a longer reaction time. The experiment tests the simple response to a stimulus, with
only one key stimulus and one known response. The reason that the hypothesis given is
suggested is that often people have very different eyesight and prescriptions and therefore,
not many of the test subjects will be able to see the ruler drop as clearly as a few will be
able to. The hypothesis with regards to the survey question is that the more times a
person texts daily, the quicker the reaction time will be, because texting requires a person
to respond to text messages quickly; the hypothesis is that the more texts sent will result
in lower reaction times because of exposure to quick responses.
Materials and Methods:
The materials and formulas needed for the experiment include the following:
 Half-meter stick
 Prescription-lens eye glasses
 Scientific calculator
 {s=(v1)(t) + (1/2)(a)(t2)} where “s” stands for distance, “v1” stands for initial
velocity, “a” stands for acceleration, and “t” stands for time.
 Survey question: How many times do you send texts in an average day?
 Survey response slips
The experiment was divided into three different sections: the control experiment,
the experiment with the variable applied, and the survey questionnaire. The control
experiment was set up first by dividing the class into smaller groups of four. A half-meter
stick was supplied and was held by the person conducting the experiment. Held by the
highest number and the 1-cm mark nearest to the floor and furthest from the conductor of
the experiment, the test subject was told to prepare himself/herself to catch the ruler. The
test subject, using his/her dominant hand, was told by the conductor of the experiment
that he/she would drop the ruler at any moment in the next five seconds. After the ruler
was dropped, the test subject must catch the ruler as quickly as possible. The process was
repeated four times for each group member. The displacement of the ruler was recorded
to be used in the formula, s = (v1)(t) + (1/2)(a)(t2), to calculate the total time elapsed
between dropping and catching the ruler, or the reaction of time of the test subject; the
data was recorded and averaged for later use in data tables.
The second section of the experiment began with the process of finding a variable
that could be applied to the control experiment with the hopes of having an effect on the
reaction time of the test subject. The variable chosen was the application of prescription
eyeglasses while catching the ruler; this variable would influence the ability to see the
ruler dropping. Each of the other groups selected a different variable; during the actual
“variable experimental trials”, each member of each group was to catch the ruler another
three or so times, each with a different variable applied. The data was plugged into the
formula, s = (v1)(t) + (1/2)(a)(t2), to reveal the reaction times of each person’s trials; the
data was recorded and averaged for later use in data tables.
The final section of the experiment was to create a survey question that would be
applied to the experimental data to discover is there is a correlation between the two. The
following question was asked, “How many times a day do you send text messages on
average?” Survey response slips were printed out and distributed to each test subject with
the possibility of answering: 0-25 times a day, 25-50 times a day, 50-75 times a day, and
100+ times a day. After the surveys were filled out, all of the data was compiled and
organized into various separate tables and bar graphs.
Data:
Table 1: Class Data from Controlled Experiment
Name
Gender
Control Reaction Time (s)
Mr. Boylan
Male
0.15
Aishvarya
Female
0.24
Daniela
Female
0.24
Kamil
Male
0.2
Joe
Male
0.37
Marie
Female
0.38
Monique
Female
0.14
Sal
Male
0.08
Kelly
Female
0.17
Tyler
Male
0.22
Alex
Female
0.07
Chris
Male
0.18
Movses
Male
0.2
Catherine
Female
0.29
Adriana
Female
0.42
Mary Grace
Female
0.15
Anna Rose
Female
0.21
Jovan
Male
0.18
Shaminy
Female
0.38
Sabrina
Female
0.22
Kevin
Male
0.21
Johnny
Male
0.18
Brian
Male
0.22
James
Male
0.2
Mike
Male
0.09
Table 2: Class Data for Experimental Variable
Name
Average Reaction Time
Reaction time
while wearing
prescription
glasses (s)
0.24
Ruler
Displacement
while wearing
prescription
glasses (m)
0.12
Aishvarya
Daniela
0.24
0.17
0.17
Sal
0.08
0.05
0.07
Kamil
0.20
0.24
0.22
Joey
0.37
0.22
0.20
Marie
0.38
0.28
0.23
Kelly
0.17
Void*
Void*
Monique
0.14
0.25
0.22
Sabrina
0.22
0.11
0.13
Mike
0.09
0.15
0.17
0.15
Chris
0.18
0.23
0.21
Tyler
0.22
0.26
0.23
Alex
0.07
0.13
0.16
Shaminy
0.38
0.32
0.25
Brian
0.22
0.10
0.13
Catherine
0.29
0.33
0.25
Mary Grace
0.15
0.30
0.23
Anna Rose
0.21
0.26
0.24
Movses
0.20
0.11
0.15
Jovan
0.18
0.12
0.15
James
0.20
0.19
0.18
Johnny
0.18
0.09
0.14
Adriana
0.42
0.36
0.26
Mr. B
0.15
0.17
0.17
Kevin
0.21
0.35
0.27
*unable to participate due to health issues.
Table 3: Survey Responses to Question:
“How Many Times in an Average Day Do You Send Texts?
Name
Gender
Average Control
Reaction Time (s)
Survey Responses
25-50
Mr. B
Male
0.15
Aishvarya
Female
0.24
Daniela
Female
0.24
100+
50-75
0-25
Kamil
Male
0.20
Joe
Male
0.37
Marie
Female
0.38
Monique
Female
0.14
Sal
Male
0.08
Kelly
Female
0.17
Tyler
Male
0.22
Alex
Female
0.07
100+
0-25
0-25
25-50
100+
100+
100+
0-25
Chris
Male
0.18
Movses
Male
0.20
Catherine
Female
0.29
Adriana
Female
0.42
Mary grace
Female
0.15
50-75
0-25
50-75
0-25
0-25
Anna rose
Female
0.21
Jovan
Male
0.18
Shaminy
Female
0.38
Sabrina
Female
0.22
Kevin
Male
0.21
Johnny
Male
0.18
Brian
Male
0.22
James
Male
0.20
Mike
Male
0.09
100+
0-25
100+
25-50
100+
0-25
25-50
50-75
Bar Graph 1: Class Average Reaction Time
Class Average (with Experimental
Variable Applied) (s)
0.16
0.22
Class Control Average (s)
0
0.05
0.1
0.15
0.2
0.25
Class Control Average (s)
Class Average (with
Experimental Variable
0.22
0.16
Average Reaction Time
Bar Graph 2: Average Control Reaction Times
Grouped By Survey Response
0.19
0.24
0.16
0.24
0
0.05
0.1
0.15
(values in seconds)
Discussion:
0.2
0.25
People who
text 100+
times a day
People who
text 50-75
times a day
People who
text 25-50
times a day
People who
text 0-25
times a day
After the data was compiled and the tables, charts, and trends were analyzed, the
data shows that the hypothesis is rejected. The original hypothesis stated that the
application of prescription glasses would make seeing the ruler dropping harder and
would therefore cause the reaction times to be longer than in the control trials. The results
show that the average class reaction time for the experimental trials was 0.16 seconds,
whereas the average reaction time during the control trials was 0.22 seconds. The reason
for this is mostly due to exposure to the test at hand. During the control experiment, the
challenge of catching a falling ruler at a random moment was novelty and challenging.
After many trials of practiced, the test subjects were already accustomed to catching the
ruler in the quickest possible fashion. The manner in which the subjects caught the ruler
and the strategies of the test subjects were in favor of the test subjects based upon the
ruler. The survey responses did not show distinct enough differences to say that there is a
direct correlation between texting and reaction time; for the most part though, those who
text more often seem to have better reaction times than those who don’t text at all.
Although the data seems extremely accurate, there are, in fact, several ways that
the data/experiment could have had error. The most probable reason for error would be
human error with regards to calculations. The calculations for finding the reaction time of
each trial required a decent amount of work, and therefore left a decent amount of room
for error. Another place for error is the actual displacement of the ruler because there is a
high possibility that the displacement of the ruler could have been misread.
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