FRANCISCUS ages 15-40 (the control group), then conduct the

FRANCISCUS DONDERS’ SUBTRACTION METHOD

Finding the area of the brain that
degenerates the most due to aging

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Introduction

This investigation aims to find what area
of the brain degenerates the most due to aging, using Franciscus Donders’
subtraction method. If you have heard of Franciscus Donders, you probably know
him as the man who studied the anatomy of eyes. If you read the article “Frans
Cornelius Donders” by Encyclopaedia Britannica, you will discover that he was
one of the most influential psychologists alive. Similarly, if you read any of
the four books written by Franciscus Donders you will learn that he was the
first person to measure reaction time. To me, Franciscus Donders holds the
answer to my curiosity about how a person’s cognitive state relates to their
reaction time. I have read several articles about Donders and his experiments,
all of which intensified my desire to seek understanding of people’s reaction
time. The spark of my curiosity came from the senior home where I currently
volunteer. Looking into Donders’ experiments made me wonder what area of the
typical senior brain degenerates the most since their teenage years. The number
of seniors in the world has been rising over the years, doubling in the past 30
years; currently 8.5% of the world’s population consists of people age 65 and
over. This topic is extremely significant as it could allow for a new innovation
in science and technology to better accommodate the needs of the
aging population.

 

Plan of
Action

          To find the area of the brain that seniors are the most underdeveloped
in, I will need to conduct Donders’ three experiments on people ages 15-40 (the
control group), then conduct the same experiments on seniors ages 65 and over,
to find their reaction times (RT). I will then use two bar charts to graph
their reaction times separately and break them down into their most elementary
sections (simple, choice and selection reaction times). If my experiments go
according to plan, the results should replicate those of Donders.

 

Belief of
Psychology in the 1800s

Science has changed drastically through
time; Two thousand years ago, people believed that the Earth was flat and were
proven wrong. Similarly, two hundred years ago, the belief that the mind was
impossible to study spread throughout the world. However, not all scientists
believed this, one of whom was Franciscus Donders. He proved that it was
possible to break down a person’s reaction times into its different components
(Simple, choice and selection reaction times; explained below).

 

“This procedure of estimating the time it
takes to perform various cognitive operations is called the subtractive method.
However, the method soon came under attack from psychologists who relied on
introspection as a method of gathering data” (Goldstein 6)

 

After reading various articles on what
psychologists believed in the 1800s, I realized that there was a main group of
people called observers who believed that mental processes used for responding
to a stimulus happens instantaneously. This belief became popular until
scientists realized that they often arrived at different conclusions. Due to
this, Donders’ subtraction method was accredited again and is currently used as
a method to measure one’s reaction time.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Donders’
Three Experiments

            In 1868, Franciscus
Donders conducted three experiments used to measure people’s reaction time. The
first experiment (Donders A) was conducted to measure people’s simple reaction
time (the time it takes someone to respond to the presence of a stimulus). The
second experiment (Donders B) tested people’s choice reaction time (the time it
takes someone to respond a certain way according to the stimulus that shows
up). Lastly, the third experiment (Donders C) measured people’s recognition/selection
reaction time (the time it takes a person to respond to one stimulus and not to
a different stimulus).

 

 

Figure 1

Diagram to show stimulus and
response(s)

in Donders’ three experiments

S1 represents Stimulus
1.

S2 represents Stimulus
2.

R1 represents Response
1.

R2 represents Response
2.

 

 

 

 

 

 

 

 

Donders’
Experiments Explained

Donders A:

Donders asked his test subjects to push a
button as quickly as they possibly can when they saw a light (S1)
turn on. This is an example of simple reaction time.

 

Donders B:

In his second experiment, Donders asked
his subjects to push the left button (R1) when the left light (S1)
turned on and push the right button (R2) when the right light (S2)
turned on. This is an example of choice reaction time.

 

Donders C:

Donders’ third experiment also consists
of two stimuli; if a blue light (S1) appears then press the button
(R1), however, if a red light (S2) appears then do not
press the button. This is an example of selection reaction time.

 

 

 

 

 

 

 

 

 

My Three
Experiments

I went through numerous archives to try
to find data that Donders might have left behind, but to my disappointment I
could not find any useful information or data from his experiments. Since there
is not much data regarding Donders’ experiment results, this makes my endeavor
even more intriguing as it is striking new ground.

Due to the lack of data from Donders’
experiments, I will gather the reaction times first-hand by conducting a
similar variation of his experiments on people ages 15-40 and compare those
results to the results I get from seniors ages 65+. At the end of this
investigation, I will use this data to recreate Donders’ segmented bar chart. An imitation of Donders’ segmented bar chart
is shown below because I couldn’t find the original chart that Donders made
from his experimental results in 1868.

 

 

 

Figure
2      

Imitation of Donders’
segmented

bar chart to show different stages

of reaction time

 

 

 

 

 

 

 

 

 

 

 

 

Simple
reaction time

Selection reaction time

Choice reaction time

 

 

The chart above could be
simplified down into three equations:

1)     Simple RT = required for the simple task

2)     Selection RT = (The time required for the
selection task) – (The time required for the simple task)

3)     Choice RT = (The time required for the
choice task) – (The time required for the selection task)

 

Figure 2 could be summed up with one of
the most important founding principles in psychology: “The time it takes to
perform a task depends on the number and types of mental stages involved”
(Ardi); By finding the mental stage (be it simple, selection or choice reaction
time) that seniors require the most time on in comparison to those from the
control group (ages 15-40), I can easily identify which part of the brain
seniors require the most time to process information. After that step, it would
be quite straightforward for me to complete my aim of finding what area of the
brain seniors lack the most development in.  

Experiment 1 (Simple Task):

a)     
My
variation on Donders A will be a classic ruler drop test (as shown in Figure 3).
In this experiment I will ask my volunteer to hold out their index finger and
thumb on either side of the vertical ruler. Their thumb will be at the 0 cm
mark, the 50 cm long ruler drops without notice, and it is their duty to catch
the ruler at the instant it is released; this is my method of testing one’s
simple reaction time.

 

Figure 3

Diagram to show

The Ruler Drop Test

 

 

 

 

 

 

 

Experiment 2 (Choice Task):

b)      My variation on Donders B will be very
similar to The Ruler Drop Test, but instead of only using one
ruler, I will be using two. I will ask the participant to hold out both their
hands, just like how they did in the first experiment. If the ruler on the left
drops (S1), then catch it with the left hand (R1). If the
ruler on the right drops (S2), then catch it with the right hand (R2).
This choice task will measure one’s Choice RT + the time required for the
selection task

(This equation was previously
mentioned under Figure 2).

 

Experiment 3 (Selection Task):

c)      My variation on Donders C will consist of
two different coloured papers: a yellow and a pink coloured paper. If the
yellow paper is revealed (S1), then press the button (R1).
If the pink paper is revealed (S2), then do not press the button.
The button will connect to a stopwatch that will show the Selection
RT + the time required for the simple task.

Data
Collected

            I conducted my three
experiments on people ages 15-40 and ages 65+ and gathered the data. The table
below shows the data collected:

 

Person

Measurements
Collected From Experiments on Ages (15-40)

 

Experiment
1
(cm)

Experiment
2
(cm)

Experiment
3
(seconds)

1

13.5

12.3

0.286

2

16.3

15.1

0.311

3

13.8

19.2

0.275

4

11.3

12.4

0.327

5

8.9

12.5

0.289

 

Person

Measurements Collected From Experiments on Ages (65+)

 

Experiment
1
(cm)

Experiment
2
(cm)

Experiment
3
(seconds)

6

27.3

22.5

0.394

7

24.6

21.8

0.387

8

27.8

28.2

0.595

9

23.5

20.3

0.396

10

21.5

22.7

0.462

 

 

 

 

Problems
Encountered

            When I
conducted my experiments on my first participant I already knew the process was flawed
because I saw that their
reaction time (RT) in experiment 1 was surprisingly longer than in experiment
2. This did not make any sense, because according to Donders, experiment 2
should have taken the longest time as it required simple RT, selection RT and choice
RT; but experiment 1 only tested one’s simple RT, hence the RT for experiment 1
should have been much faster than experiment 2. This boggled my mind for an
extremely long time so I resorted to doing extensive research on the verifications
of Donders’ subtraction method as I began to doubt whether or not his method
had flaws in it. However, I learnt that people have proven the subtraction
method like in this article I read “Verification of Donders’ Subtraction
Method” by Robert Gottsdanker.

I then began to wonder whether or not my
experiments were flawed, then I came to the conclusion that there was no way
the design of my experiments could have caused such a big impact on the
results. After more investigation, I stumbled upon the book which answered this
conundrum “Experimental Psychology” by B. Kantowitz, H. Roediger, and D. Elmes.
The book states “If negative transfer is not anticipated, within-subject
designs where each participant, experiences all three Donders reactions, are more
efficient.” (Experimental Psychology, 236) It basically means that if a
participant goes through all three of the experiments, they are more efficient
compared to someone who only got exposed to one experiment.

This made a lot more sense to me because all
my test subjects were exposed to all three experiments; and since experiment 2
was so similar to experiment 1, they were already prepared for what’s to come
which defeated the purpose of these experiments. This meant that I need to
conduct the same experiments, but this time I will only conduct one experiment
per person. For example, I will conduct experiment 1 on participant 1,
experiment 2 on participant 2, and so on.

I will now conduct the same experiments but on a new batch of test
subjects.

These are the data from my second attempt:                         

 

Measurements Collected From Experiments on Ages (15-40)

Experiment 1
(cm)

Experiment 2
(cm)

Experiment 3
(seconds)

14.7

25.3

0.183

15.4

23.6

0.202

15.8

24.1

0.198

14.3

26.2

0.221

16.9

25.9

0.192

 

Measurements Collected From Experiments on Ages (65+)

Experiment 1
(cm)

Experiment 2
(cm)

Experiment 3
(seconds)

27.3

42.4

0.236

24.6

47.7

0.301

24.8

42.9

0.271

23.5

39.1

0.248

27.5

46.7

0.298

 

 

 

 

 

After looking at my second batch of data,
I can tell that it should fit Donders’ results perfectly as all the RT in
experiment 2 took a longer time than in experiment 1; but just to be sure, I
still need to convert my results from experiments 1 and 2 into seconds so I can
compare the results from all three experiments. To do this, I will use one of
the kinematics equations that I learnt in physics class. Here is the formula:

Let “d” represent the distance (in metres).

Let “vi” represent the initial velocity (in
m/s).

Let “a” represent the acceleration (in m/s2).

Let “t” represent the reaction time (in seconds).

Since the acceleration of any object (in
this case, the ruler) on Earth due to gravity is approximately 9.81m/s2,
I can substitute a=9.81m/s2 into the function. Furthermore, since
the initial velocity of the ruler is 0m/s. Therefore, I can also substitute vi=0m/s
into the function. By
doing so, I would simplify the formula down into a simple exponential function,
as shown below.

Here is the simplified form of the
function after substituting in a=9.81m/s2
and vi=0m/s:

 

To
isolate for reaction time (t):

   ,  

For example, to find what “t” is, given
that the participant caught the ruler at the 15cm mark, I first need to convert
15cm into metres. So d=0.15m and

After I put my data from experiment 1 and 2 into the
function to solve for reaction time, I get this:

                              

Measurements Collected From Experiments on Ages (15-40)

Experiment
1
(seconds)

Experiment
2
(seconds)

Experiment
3
(seconds)

0.173

0.227

0.183

0.177

0.219

0.202

0.179

0.222

0.198

0.171

0.231

0.221

0.186

0.230

0.192

 

Measurements Collected From Experiments on Ages (65+)

Experiment
1
(seconds)

Experiment
2
(seconds)

Experiment
3
(seconds)

0.236

0.294

0.236

0.224

0.312

0.301

0.225

0.296

0.271

0.219

0.282

0.248

0.237

0.309

0.298

 

 

Before I continue, I
need to find the expected value/mean for each experiment. So I put all the data
from each experiment into this formula:

Let  represent the mean.

Let  represent the sum
of all the values.

Let “n” represent the number of data.

 

Expected
Value of Reaction Times

Ages (15-40)

Ages (65+)

Experiment
1
(seconds)

Experiment
2
(seconds)

Experiment
3
(seconds)

Experiment
1
(seconds)

Experiment
2
(seconds)

Experiment
3
(seconds)

0.177

0.226

0.199

0.228

0.299

0.271

 

 

 

 

Time
for Each Mental Stage to Occur

Ages (15-40)

Ages (65+)

 

Simple
RT
=
RT from Experiment 1
 177 ms
 
Selection
RT
=
RT from Experiment 3 – Simple RT
 199 ms – 0.177 ms
 22 ms
 
Choice
RT
= RT from Experiment 2 –
Selection RT – Simple RT
 226 ms – 22ms – 177 ms
 27 ms

Simple
RT
=
RT from Experiment 1
 228 ms
 
Selection
RT
=
RT from Experiment 3 – Simple RT
 271 ms – 228 ms
 43 ms
 
Choice
RT
= RT from Experiment 2 –
Selection RT – Simple RT
 299 ms – 43 ms – 228 ms
 28 ms

Now it is time for me
to recreate Donders’ segmented bar graph using the data above. And the bar
graphs came out like this   

Now I need to find the mental stage
(simple, selection or choice) that has the largest percentage of change between
people ages 15-45 and ages 65+. This would determine the mental stage which
degenerates the most due to aging. To calculate the percentage of change
between each mental stage, I will use this formula:

 

Let  represent the percentage change
in each mental stage.

Let V1 represent the mean RT
of seniors (in ms).

Let V0 represent the mean RT
of people ages 15-40 (in ms).

Mental Stages: Percentage of Change

Simple RT

Selection RT

Choice RT

 

 

 

 

From this, I can deduce that the mental
stage that degenerates the most in seniors’ due to aging is the part of the
brain that deals with cognitive selective attention. Since “Selective auditory
and visual attention activates mostly distinct prefrontal areas” (Emma Salo),
this means that the area of the brain seniors lack the most development lies
within the ‘prefrontal areas’. I was curious which specific part of the
‘prefrontal areas’ in the brain is most prominently used in the process of selective
attention. Then I read the book “Elsevier” which said that the “Division of
attention activates the

left-middle frontal gyrus” (Salo). After a bit of further investigation,
I discovered that the left-middle frontal gyrus is the subsection inside the
prefrontal cortex which is most active during the process of selective
attention; it is also the part of the brain which degenerates the most due to
aging. 

 

 

 

 

Conclusion

            When I started doing research on Donders’
RT experiments I was amazed to discover that there is a strong relationship
between one’s RT and their cognitive functions. By the end of the
investigation, I have discovered that a typical senior’s left-middle gyrus is
the area of the brain that degenerates the most due to aging. This is crucial
as the gyrus not only controls selective attention, which I’ve established, but
also long-term memory in seniors. As a result, to prevent the deterioration of
the gyrus one can improve their long-term memory by doing daily physical
exercises, mastering a new skill, and mediating. This research exploration has
identified a significant and relevant global problem dealing with the mental
health of seniors. It has been a fascinating adventure to really dig deep into
the understanding of the human mind and pinpoint the critical area of the brain
where the brain degenerates the most over time.       

            However, the biggest
lesson I have learnt from this investigation is that there are always errors in
every experiment you conduct. Donders’ experiments were not inerrant, he tested
people’s RT by asking them to press the button as soon the light turned on.
However, the person’s physical health could have contributed also to their RT.
In my case, when I conducted experiments on seniors, I noticed that some of
them have arthritis and others are near-sighted. All of these factors
contribute to their RT and consequently, their RT does not entirely reflect
their mental state.

            I have been left with a
desire to know more about the human mind. Through researching about Donders’
subtraction method, I’ve stumbled along another method that also uses reaction
time to identify different mental stages called the ‘additive factors method.’
Also, if I ever get the opportunity to re-create this investigation, I would do
a couple of things differently. Firstly, I would avoid the same mistakes that I
made during this investigation as clearly outlined above. Secondly, I would use
the ‘additive factors method’ instead of Donders’ subtractive method, to see if
my results would have been different. 
Lastly, I would focus more on trying to reduce the sources of error in
my experiments. I would accomplish this by conducting all my experiments in the
same room and conditions to eliminate any external factors that may flaw the
results.      

 

 

References/Bibliography

1.)    “Biography F.C. Donders.” Donders Institute, www.ru.nl/donders/agenda/donders-lectures/biography-donders/.

2.)    “Cognitive Psychology: Connecting Mind, Research and Everyday
Experience.” Google Books,
books.google.ca/books?hl=en&lr=&id=vTtvCgAAQBAJ&oi=fnd&pg=PT5&dq=Goldstein%2C%2BE.%2B%282011%29.%2BCognitive%2Bpsychology%3A%2BConnecting%2Bmind%2C%2Bresearch%2C%2Band%2Beveryday%2Bexperience%2B%283rd%2Bed.%29.%2BAustralia%3A%2BWadsworth%2BCengage%2BLearning.&ots=xdTuDsYURS&sig=4MG2pCVKuB0zwOH2ESw8Ac7OTlo#v=onepage&q&f=false.

3.)    “Brain Activity Associated with Selective Attention,
Divided Attention and Distraction.” Brain Research, Elsevier, 28
Mar. 2017, www.sciencedirect.com/science/article/pii/S0006899317301361.The Editors of Encyclopædia Britannica. “Frans Cornelis
Donders.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 29 May
2015, www.britannica.com/biography/Frans-Cornelis-Donders.

4.)    “Experimental Psychology.” Google Books,
books.google.ca/books?id=by1vCgAAQBAJ&pg=PA236&lpg=PA236&dq=donders%27%2Bexperiment%2Bdata&source=bl&ots=zLrK_UEUyV&sig=qR6Lmp03woQ62SPhu_Nersw96pk&hl=en&sa=X&ved=0ahUKEwiMnv7s_srXAhVH-2MKHRkeBDAQ6AEIKzAB#v=onepage&q=donders’%20experiment%20data&f=false.

5.)    “Franciscus Donders.” Wikipedia, Wikimedia
Foundation, 25 Nov. 2017, en.wikipedia.org/wiki/Franciscus_Donders.

6.)     “Mental Chronometry.” Wikipedia,
Wikimedia Foundation, 29 Nov. 2017, en.wikipedia.org/wiki/Mental_chronometry.

7.)     “Psych
256: Cognitive Psychology FA 15.” Powered by Sites at Penn State –
WordPress,
sites.psu.edu/psych256fa15/2015/09/06/blog-post-1-franciscus-donders-and-reaction-time/.

8.)    Goldstein, E. (2011). Cognitive
psychology: Connecting mind, research, and everyday experience (3rd ed.).
Australia: Wadsworth Cengage Learning.

 

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