Samenvatting Brain and Cognition
Chapter 1 Introduction to cognitive psychology
Cognitive psychology is the branch of psychology concerned with the scientific study of the
mind. Mind, like many other concepts, such as intelligence, can be thought of in a number of
different ways. The mind creates and controls mental function such as perception, attention,
memory, emotions, language, deciding, thinking, and reasoning. Another definition, which
focuses on how the mind operates, is: the mind is a system that creates representations of the
world so that we can act within it to achieve our goals. The first one indicates different types
of cognition (the mental processes). The second definition indicates something about how the
mind operates (it creates representations) and its function (it enables us to act and to achieve
goals). It is no coincidence that all the cognitions in the first definition play important roles in
acting to achieve goals.
In the 1800s, ideas about the mind were dominated by the belief that it is not possible to study
the mind. In 1868: Donders’ pioneering experiment – how long does it take to make a
decision? He determined this by measuring reaction time (= how long it takes to respond to
the presentation of a stimulus). First, he measured simple reaction time by asking his
participants to push a button as rapidly as possible when they saw a light go on. In addition,
he measured choice reaction time by using two light and asking his participants to push the
left button when they saw the left light go on, and the right button when they saw the light go
on.
Stimulus > mental response > behavioral response
Mental responses cannot be measured directly but must inferred from behavior.
1879: Wundt’s psychology laboratory – structuralism and analytic introspection
According to structuralism, our overall experience is determined by combining basic elements
of experience which were called sensations. Wundt thought he could achieve this scientific
description of the components of experience by using analytic introspection, a technique in
which trained participants described their sensations, feelings, and thought processes in
response to stimuli. Wundt is seen by many as leading the shift in the study of the mind from
the rationalist approach to the empiricist approach, emphasizing the pivotal role of
experiments in gaining knowledge about the human mind.
1885: Ebbinghaus’ memory experiment – What is the time course of forgetting?
Rather than using introspection, Ebbinghaus used a quantitative method for measuring
memory.
1890: William James’ Principles of Psychology
No experiments: reported observations of his own experience. Description of a wide range of
experience.
1913: Watson founds Behaviorism
Watson became dissatisfied with the method of analytic introspection because it produced
extremely variable results from person to person, and these results were difficult to verify.
Watson proposed a new approach called behaviorism: Watson wanted to restrict psychology
to observable behavioral data and rejected the idea of going beyond ideas.
,1938: Skinners’ operant conditioning
Focused on how behavior is strengthened by the presentation of positive reinforcers. Like
Watson, Skinner was not interested in what was happening in the mind, but focused solely on
determining how behavior was controlled by stimuli. One general critique was that a simple
stimulus-response theory cannot explain that people often respond to different aspects of the
same stimulus event, and which aspect that is, is not known until the response is made.
Although behaviorism dominated psychology, some researchers were not toeing the strict
behaviorist line.
1948: Tolman’s cognitive map
The use of the term cognitive was difficult to accept because it violated the behaviorists’ idea
that internal processes, such as thinking or maps in the head, were not acceptable topics to
study.
1959: Chomsky’s critical review of Skinner’s language development theory
Skinner argued that children learn language through operant conditioning. Chomsky pointed
out that children say many sentences that have never been rewarded by parents, and that
during the normal course of language development, they go through a stage in which they use
incorrect grammar -> inborn biological programme that holds across cultures. They began to
realize that to understand complex cognitive behaviors, it is necessary no only to measure
observable behavior but also to consider what this behavior tells us about how the mind
works.
1950s = beginning of the cognitive revolution – a shift in psychology from the behaviorist’ s
stimulus-response relationships to an approach whose main thrust was to understand the
operation of the mind.
Flow diagrams for the mind – information processing stages
Input > information processing > output
Cognitive psychology thus accepts the existence of unobserved processes that can be
scientifically studied via the creation and evaluation of mental models.
Models are representations of structures or processes that help use visualize or explain the
structure or process. One purpose of models is to simplify. Two kinds of models:
1. Structural models = which represent structures in the brain that are involved in
specific functions.
2. Process models = which illustrate how a process operates.
Resource models are closely related to the process models mentioned above but focus on the
mental effort or the resources that these processes require. When a process uses a lot of effort
or can only obtain this effort from a limited resource, a capacity problem can arise leading to
ineffective functioning of the process. Another idea that plays a role in these models is that
processes often share resources and therefore have to compete for them.
, Chapter 5 vision
5.1 – Visual Coding
You see an object when it emits or reflects light that stimulates receptors that transmit
information to your brain. The brain codes information largely in terms of which neurons are
active, and how active they are at any moment. Impulses in certain neurons indicate light,
whereas impulses in others indicate sound, touch, or other sensations. In 1838, Johannes
Müller described this insight as the law of specific nerve energies. Müller held that whatever
excites a particular nerve establishes a special kind of energy unique to that nerve.
Light enters the eye through an opening in the center of the iris called the pupil. It is focus by
the lens (adjustable) and cornea (not adjustable) and projected onto the retina, which is lines
with visual receptors. Light from the left side of the world strikes the right half of the retina,
and vice versa. Light from above strikes the bottom half of the retina, and light from below
strikes the top half. The inversion of the images poses no problem for the nervous system.
Messages go from the receptors at the back of the eye to bipolar cells, located closer to the
center of the eye. The bipolar cells send their messages to ganglion cells, located still closer to
the center of the eye. The ganglion cells’ axons join together and travel back to the brain.
Additional cells get information from bipolar cells and send it to other bipolar, amacrine, and
ganglion cells. Amacrine cells refine the input to ganglion cells, enabling certain ones to
respond mainly to particular shapes, directions of movement, changes in lightning, color, and
visual features.
One consequence of this anatomy is that light passes through the ganglion, amacrine, and
bipolar cells en route to the receptors. However, these cells are transparent, and light passes
through them without distortion. A more important consequence is the blind spot. The
ganglion cell axons join to form the optic nerve that exits through the back of the eye. The
point at which it leaves is a blind spot because it has no receptors. In everyday life, you never
notice the blind spot. Anything in the blind spot of one eye is visible to the other eye.
When you look at details, you fixate them on the central portion of your retina, especially the
fovea, a tiny area specialized for acute, detailed vision. Because blood vessels and ganglion
cell axons are almost absent near the fovea, it has nearly unimpeded vision. The tight packing
of receptors aids perception of detail. More importantly for perceiving detail, each receptor in
the fovea connects to a single bipolar cell, which in turn connects to a single ganglion cell that
has an axon to the brain. The ganglion cells in the fovea are called midget ganglion cells
because each is small and responds to just a single cone. That is, each cone in the fovea has a
direct route to the brain. Toward the periphery of the retina, more and more receptors
converge onto bipolar and ganglion cells. As a result, the brain cannot detect the exact
location or shape of a peripheral light source. However, the summation enables perception of
fainter lights in the periphery. In short, foveal vision has better acuity (= sensitivity to detail),
and peripheral vision has better sensitivity to dim light.
The retina contains two types of receptors: rods and cones. The rods, abundant in the
periphery of the human retina, respond to faint light but are not useful in daylight because
bright light bleaches them. Cones, abundant in and near the fovea, are less active in dim light,
more useful in bright light, and essential for color vision.
Although rods outnumber cones, cones provide about 90 percent of the brain’s input.
In the fovea each cone has its own line to the brain. In the periphery, each receptor shares a
line with tens or hundreds of others.
