Cognition Exploring the Science of the Mind
Chapter 1; The Science of the Mind
Amnesia A disruption of memory, often due to brain damage.
Introspection The process through which one looks within, to observe and record
the contents of one’s own mental life.
Behaviorist theory Broad principles concerned with how behavior changes in response to
different configurations of stimuli (including stimuli that are often
called rewards and punishments). In its early days, behaviorist theory
sought to avoid mentalistic terms (terms that referred to
representations or processes inside the mind).
Transcendental method A type of theorizing proposed by the philosopher Immanuel Kant. To
use this method, an investigator first observes the effects or
consequences of a process and then asks; what must the process have
been to bring about these effects?
Working memory The storage system in which information is held while that
information is being worked on. All indications are that working
memory is a system, not a single entity, and that information is held
here via active processes, not via some sort of passive storage.
Formerly called short-term memory.
Working-memory system A system of mental resources used for holding information in an easily
accessible form. The central executive is at the heart of this system,
and the executive then relies on a number of low-level assistants,
including the visuospatial buffer and the articulatory rehearsal loop.
Articulatory rehearsal One of the low-level assistants hypothesized as being part of the
loop working-memory system. This loop draws on subvocalized (covert)
speech, which serves to create a record in the phonological buffer.
Materials in this buffer then fade, but they can be refreshed by
another cycle of covert speech.
Subvocalization Covert speech in which one goes through the motions of speaking, or
perhaps for a detailed motor plan for speech movements, but without
making any sound.
Phonological buffer A passive storage system used for holding a representation
(essentially an internal echo) of recently heard or self-produced
sounds.
Concurrent articulation A requirement that a research participant speak or mime speech
task while doing some other task. In many cases, the person is required to
say “tah-tah-tah” over and over, or “one, two, three, one, two, three”.
These procedures occupy the muscles and control mechanisms
needed for speech, so they prevent the person from using these
resources for subvocalization.
Cognitive neuroscience The effort toward understanding humans’ mental functioning through
close study of the brain and nervous system.
Anarthria An inability to produce overt speech.
H.M. had no issues remembering things before his operation. He seemed completely unable to recall
any event that occurred after his operation.
People who suffer from amnesia (like H.M.) sometimes commented on the fact that in important
ways, he didn’t know who he was. Without a memory, there is no self. Our self-concept depends on
our knowledge (in particular, on our episodic knowledge).
,The cognitive revolution (1950s/1960s) brought a huge shift in the style of research used by most
psychologists. The new style was intended initially for studying problems as memory problems and
decision making.
One idea of the cognitive revolution was that the science of psychology cannot study the mental
world directly. Second idea is that the science of psychology must study the mental world if we are
going to understand behavior.
Wilhelm Wundt and his student Edward Bradford Titchener launched a new research enterprise, and
according to many scholars, it was their work that eventually led to the modern field of experimental
psychology. In their view, psychology needed to focus largely on the study of conscious mental
events (feelings, thoughts, perceptions and recollections). They concluded that there is the only
person who can experience or observe your thoughts is you. They therefore concluded that the only
way to study thoughts is for each of us to use introspection (look within), to observe and record the
content of our own mental lives and the sequence of our own experiences. The investigators were
soon forced to acknowledge that some thoughts are unconscious and this meant that introspection
was inevitably limited as a research tool. Introspection also has problems with the testability.
Behaviorism; ( John b. Watson)
1. Behaviors of organisms are observable
2. You can record how the pattern of behaviors changes with the passage of time and with the
accumulation of experience
In the late 1950s, psychologists were convinced that a lot of our behavior could not be explained in
these terms. The way people act and the ways that they feel, are guided by how they understand or
interpret the situation, and not by the objective situation itself.
Immanuel Kant transcendental method; you begin with the observable facts
and then work backward from these observations. We study mental processes
indirectly, relying on the fact that these processes, themselves, invisible, have
visible consequences.
Working memory holds information in an easily accessible form so that the
information is, so to speak, at your fingertips, instantly available when you need it.
Working memory is hypothesized to have a small capacity.
To launch the rehearsal loop, you rely on the process of subvocalization (silent
speech). In other words, you quietly say the numbers to yourself. This inner voice,
produces a representation of these numbers in the phonological buffer.
- Concurrent articulation is easy, but it blocks use of the articulatory loop
and consistently decreases memory span.
- With concurrent articulation and visual presentation of the items, sound-
alike errors are largely eliminated.
- Testing people’s memory by using complex visual shapes; there should be
no effect of concurrent articulation; if people aren’t using the rehearsal
loop, there should be no cost attached to denying them use of the loop.
- Concurrent articulation blocks use of the loop but has no effect on
someone’s ability to read brief sentences, to do simple logic problems and
so on. Blocking use of the loop does have an effect when you are reading
more complex sentences or doing harder problems; that’s because these
, harder tasks require analysis and the storage of interim steps, and so require the entire
working-memory system (executive and the assistants)
Actual muscle movement aren’t needed for subvocalization because the results are the same without
these movements. It seems likely therefore, that inner speech relies on the brain areas responsible
for planning and controlling the muscle movements of speech and not the movements themselves.
Chapter 3; Visual Perception
Cornea The transparent tissue at the front of each eye that plays an
important role in focusing the incoming light.
Lens The transparent tissue located near the front of each eye that
(together with the cornea) plays an important role in focusing
incoming light. Muscles control the degree of curvature of the lens,
allowing the eye to form a sharp image on the retina.
Retina The light-sensitive tissue that lines the back of the eyeball.
Photoreceptors Cells on the Terina that are sensitive to light and that fire (i.e., send a
signal to adjacent cells) when they are stimulated by light.
Rods Photoreceptors that are sensitive to very low light levels but that are
unable to discriminate hues and that have relatively poor acuity.
Often contrasted with cones.
Cones Photoreceptors that are able to discriminate hues and that have high
acuity. Cones are concentrated in the retina’s fovea and become less
frequent in the visual periphery. Often contrasted with rods.
Acuity The ability to see fine detail.
Fovea The center of the retina and the region on their eye in which acuity is
best; when a person looks at an object, he or she is lining up that
object with the fovea.
Bipolar cells A type of neuron in the eye. Bipolar cells receive their input from the
photoreceptors and transmit their output to the retinal ganglion cells.
Ganglion cells A type of neuron in the eye. The ganglion cells receive their input
from the bipolar cells, and then the axons of the ganglion cells gather
together to form the optic nerve, carrying information back to the
lateral geniculate nucleus.
Optic nerve The bundle of nerve fibers, formed from the retina’s ganglion cells,
that carries information from the eyeball to the brain.
Lateral geniculate nucleus An important way station in the thalamus that is the first destination
(LGN) for visual information sent from the eyeball to the brain.
Akinetopsia; patient L.M. was completely unable to perceive motion- even though
other aspects of her vision seemed normal.
How does vision operate;
- The process begins with light. Some of this light hits the front surface of the
eyeball, passes through the cornea and the lens, and then hits the retina, the
light -sensitive tissue that lines the back of the eyeball.
- The cornea and lens focus the incoming light so that a sharp image is cast
onto the retina. Adjustments in this process can take place because the lens
is surrounded by a band of muscle.
When the muscle tightens, the lens bulges somewhat, creating the
proper shape for focusing the image cast by nearby objects.
, When the muscle relaxes, the lens returns to a flatter shape, allowing the proper focus
for objects farther away.
- On the retina, there are two types of photoreceptors; specialized neural cells that respond
directly to the incoming light.
Rods; are sensitive to very low levels of light on so play an essential role whenever you
are moving around in semi darkness or trying to view a fairly dim stimulus. But the rods
are also color-blind they can distinguish different intensities of light, but they provide no
means of discriminating one hue from another.
Cones; less sensitive than rods and so need more incoming light to operate at all. But
cones are sensitive to color difference. There are three different types of cones, each
having its own pattern of sensitivities to different wavelengths. Your perceive color by
comparing the output form these three cone types.
- Cones have another function; they enable you to discern fine detail. The ability to see fine
detail is referred to as acuity and acuity is much higher for cones than it is for the rods. This
explains why you point your eyes toward a target whenever you want to perceive it in detail.
You are positioning your eyes so that the image of the target falls onto the fovea, the very
center of the retina. Here, there are much more cones than rods, with the result that this is
the region of the retina with the greatest acuity.
In portions of the retina more distant from the fovea, the rods predominate.
- Photoreceptors stimulate bipolar cells, which in turn excite ganglion cells. The ganglion cells
are spread across the entire retina, but all of their axons converge to form the bundle of
nerve fibers that we call the optic nerve. The information is sent first to a way station in the
thalamus called the lateral geniculate nucleus (LGN); from there, information is transmitted
to the primary projection area for vision in the occipital lobe.
Lateral inhibition A patter in which cells, when stimulated, inhibit the activity of
neighboring cells, in the visual system, lateral inhibition in the optic
nerve creates edge enhancement.
Edge enhancement A process created by lateral inhibition in which the neurons in the
visual system give exaggerated responses to edges of surfaces.
Mach bands A type of illusion in which one perceives a region to be slightly darker
if it is adjacent to a dark region. This illusion, created by lateral
inhibition, contributes to edge enhancement.
Single-cell recording A technique for recording the moment-by moment activation level of
an individual neuron within a healthy, normally functioning brain.
Receptive field The portion of the visual field to which a cell within the visual system
responds. If the appropriately shaped stimulus appears in the
appropriate position, the cells; firing rate will change. The firing rate
