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Think Aloud Activity – IB / Modern Psychology
I. Justification for Think Aloud
As part of my launch unit, I knew that I needed to introduce them to the textbook. However, the
introductory chapter in psychology textbooks is both easy and very difficult. The language is often not
difficult and the concepts seem simple, but often times the chapter overviews thousands of years of
history leading up the science of psychology and a broad range of topics that do not seem connected. In
other words, the students can read it, but have difficulty fully grasping and remembering it.
I wanted to start going through the three foundational ideas of psychology. Because Descartes’s ideas
are difficult to grasp in their entirety, I decided to do this as a think aloud. Below is a typed version of
their textbook where I have filled in what I said to the students as I was thinking aloud. The next stage
will be to put them into mixed ability groups and have them doing a think aloud.
II. Text and Teacher Thinking
Text is from: Grey, P. (2011). Psychology (6th Ed). New York: Worth Publishers.
Descartes Version of Dualism: Focus on the Body
2. What was Descartes’s version of dualism? How did it help pave the way for a science of psychology?
Prior to Descartes, most dualists assigned all the interesting qualities of the human being to the soul.
The soul was deemed responsible for the body’s heat, for its ability to move, for life itself. In Trieste of
Man (1637/1972), and even more explicitly in The Passions of the Soul (1649/1985), Descartes
challenged this view. He had performed dissections of animals and human cadavers, was familiar with
research on the flow of blood, and began to regard the body as intricate, complex machine…
When I read this, I think about my experiences actually dissecting animals in biology and diagrams I’ve
seen of the human body. I can picture the cardiovascular system of a human and I know that inside of
various animals the systems are similar.
that generates its own heat and is capable of moving even without the influence of the soul.
This might sound funny but right now I am thinking about how if you take wires with electricity and
touch them to the muscles of the body, they will contract even though the person might not will it to
happen. I remember when I was in high school there were infomercials for electrodes you could attach to
your abdominals that would work them out for you while you watched TV. I got to try one (my friend had
it) it felt so strange because the muscles were working on their own.
Although little was known about the nervous system in his time, Descartes’s conception of the
mechanical control of movement resembles our modern understanding of reflexes, which are
involuntary responses to stimuli (see Figure 1.1).
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At this point I can’t help but look over at the picture. When I first looked at the page I was intrigued by it
since it looks so strange. The caption reads “Descartes believed that reflexes occur through purely
mechanical means. In describing this figure, Descartes (1637/1972) suggested that the fire causes
movement in the nearby particles of the skin, pulling on a ‘thread’… going to the brain, which in turn,
causes a pore to open in the brain, allowing fluid to flow through a ‘small conduit’ to the muscles that
withdraw the food…’ Alright, as I read this I think of our DI club and David because their group made a
hand-like device that uses air/water to open and shut the ‘hand’. There are lots of hydraulic devices I
have seen that use water pressure to control the movements. It sounds like Descartes thought that the
body moved by threads and water pressure. I can’t help but think of tarantulas. I know that they don’t
have muscles like we do and their movement really does work by fluid pressures in their bodies. However,
I also know that the human body does not work this way, but that it does have reflexes that use electro
chemical signals and muscles.
Descartes believed that even quite complex behaviors can occur through purely mechanical means,
without involvement of the soul. Consistent with church doctrine, he contended that nonhuman animals
do not have souls, and he pointed out a logical implication of this contention: Any activity performed by
humans that is qualitatively not different from the behavior of nonhuman animal can, in theory, occur
without the soul.
Alright this makes me think of my dog Sunny. According to church doctrine, Sunny is soulless whereas I
am not. So I have this soulless animal in my house. Yet Sunny can do some pretty amazing things. She
has learned some human speak: she responds to the names of my family and learned several tricks. If
you say her name she will turn around and look you in the face. She can walk, run, bark, eat, poop, etc.
She even seems to be happy or sad in the behaviors I see from her. I totally see why Descartes would
come to this conclusion. If Sunny can do it, and she doesn’t have a soul, it must be a physical process of
the body.
If my dog…
Hey look, Peter Grey, the author, thought about his dog too.
(who can do some wondrous things) is just a machine, then a good deal of what I do – such as eating,
drinking, sleeping, running, panting, and occasionally going in circles – might occur purely mechanically
as well.
In Descartes’s view, the one essential ability that I have but my dog does not is thought, which Descartes
defined as conscious deliberation and judgment. Whereas previous philosophers ascribed many
functions to the soul, Descartes ascribed just one – thought.
This makes me think about Sunny the dog. She’s pretty smart, and appears to be able to think. So how
does this work with Descartes dualism and the soul?
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But even in his discussion of thought, Descartes tended to focus on the body’s machinery. To be useful,
thought must be responsible to the sensory input channeled into the body through the eyes, ears, and
other sense organs, and it must be capable of directing the body’s movements by acting on the muscles.
I get this – if I was suddenly blinded, deafened, and someone took away my ability to feel/touch… I would
be in almost total darkness… I would not have any information by which to make any decisions. I would
not be able to do anything.
How can the thinking soul interact with the physical machine – the sense organs, muscles, and other
parts of the body? Descartes suggested that the soul, though not physical, acts on the body at a
particular physical location. Its place of action is a small organ (now know as the pineal body) buried
between the two hemispheres (halves) of the brain (see Figure 1.2).
I know this structure in the brain. It is small. I also know from my biology background that it creates
hormones that deal with sleep. Hmmm… but humans are not the only animal to have this structure. This
means I know that Descartes must not have been wholly correct. This also makes me think of the song
Soul Meets Body by Deathcab for Cutie. Descartes must have been trying to figure out where the soul
and body communicate. The soul can’t make any decisions without getting information from the senses,
but the body can’t move and perform actions without instructions from the soul…
Threadlike structures, which we now call nerves, bring sensory information by physical means into the
brain, where the soul receives the information and, by non-physical means, thinks about it. On the basis
of those thoughts, the soul then wills movements to occur and executes its will by triggering the physical
actions in the nerves that, in turn, act on muscles. Descartes’s dualism, with its heavy emphasis on the
body, certainly helped open the door for a science of psychology.
This makes sense… he used logical, theological arguments to open up the study of the human body to
science.
3. Why was Descartes theory, despite its intuitive appeal, unsuitable for a complete psychology?
Descartes’s theory is popular among non-scientists even today, because it acknowledges the roles of
sense organs, nerves, and muscles in behavior without violating people’s religious beliefs or intuitive
feelings that conscious thought occurs on a non-physical plane. But it has serious limitations, both as a
philosophy and as a foundation for a science of psychology. As philosophy, it stumbles on the question
of how a non-material entity (the soul) can have a material effect (movement of the body), or how the
body can follow natural law and yet be moved by a soul that does not (Campbell, 1970).
Yeah… this is a pretty serious problem. If the immaterial and material are two totally different states that
do not interact, how do they communicate with each other?
As a foundation for psychology, the theory sets strict limits, which few psychologists would accept today,
on what can and cannot be understood scientifically. The whole realm of thought and all the behaviors
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cannot be understood scientifically. The whole realm of thought, and all behaviors that are guided by
thought, are out of bounds for scientific analysis if they are the products of a willful soul.
This is definitely a problem. If the definition of psychology is the “scientific study of behavior and mind”
and everything in mind is not observable at all… everything dealing with thinking is not available for
study. This obviously cannot be the case based on our definition.
III. Evaluation
Students will work on practicing this activity with the other sections of the text on the three
foundational ideas of psychology. As a group they will have the chance to discuss, process and record
materials into their notes.