📍
CIPD NOTES
Lecture 7
Notes:
Form perception is the ability to distinguish an object from its general background.
Contours play a crucial role in form perception by separating forms from the general
ground.
Contours are formed whenever a marked difference occurs in the brightness or
color of the background.
Contours give shape to objects and mark one object off from another or from the
general ground.
Subjective contours can be perceived without any energy difference on the two
sides of the contour.
Organization in form perception explains our perception of complex patterns as
unitary forms or objects.
Gestalt psychologists proposed that the whole is more than the sum of its parts.
The law of proximity states that items close together in space or time tend to be
perceived as belonging together.
The law of good figures says that there is a tendency to organize things to make a
balanced or symmetrical figure that includes all the parts.
Continuation is the tendency to perceive a line that starts in one way as continuing
in the same way.
Law of Closure:
CIPD NOTES
1
Refers to perceptual processes that fill in gaps in stimulation to create a whole form
rather than disjointed parts
Applies to all senses, not just vision
Monocular cues for depth perception:
Cues that operate when only one eye is looking
Includes clearness, interposition, shadows, gradients of texture, and movement
Binocular cue for depth perception:
The fact that the two eyes receive slightly different views of the world, known as
retinal disparity
The greater the disparity between the images, the closer the object appears
Most important binocular cue for depth perception
Geometry of Retinal Disparity:
The image of an object is not the same in both eyes due to the distance between
them (about 65mm)
The correspondence between distance and the amount of disparity is why retinal
disparity is used as a depth cue
Lecture 8
Decision-making involves choosing one option among several possibilities.
Making a decision is equivalent to making up one's mind.
Problem-solving is different from decision-making because individuals must
generate their own solutions.
Decision quality is assessed in terms of consequences.
Judgement is an important initial part of the decision-making process.
Most decisions are risky because we cannot be sure of the outcome.
People make decisions that will maximize their subjectively expected utility.
CIPD NOTES
2
Heuristics are strategies that simplify cognitive tasks by ignoring some information,
with the goal of making decisions more quickly, frugally, and/or accurately.
Tversky and Kahneman (1974) argued that most people use heuristics when
making judgments.
The heuristic of representativeness involves judging the similarity of the current
situation to a previous one, which can lead to biases based on surface similarities
and the representativeness of the original situation.
The heuristic of availability involves judging the likelihood of events based on how
easily they can be remembered or imagined, which can lead to biases based on the
frequency of events and the ease of remembering them.
The adjustment heuristic involves starting with a certain subjective probability and
raising or lowering it based on the circumstances, which can lead to biases based
on the initial level of the estimate (anchoring effect).
When making a decision, you can make a list of the things that are important to you
and give each one a weight based on how important it is. Then, you can rate each
option based on how well it meets each of these criteria. You can multiply the rating
by the weight to give it a score, and then add up all the scores to get an overall
score for each option. This can help you make a more informed decision by taking
into account what's most important to you.
Prospect theory is a way to understand how people make decisions. It suggests that
people are more worried about losing something than gaining something. So, they
are willing to take risks to avoid losing what they already have. This theory has been
supported by studies on things like how people react to the way choices are
presented to them, or how they feel about past investments. However, the theory
has some limitations, like the idea that people have a "reference point" that may not
be very clear. Additionally, when people have more personal experience with a
situation, the theory may not hold up as well. Finally, according to the theory, people
should be more careful with gains, but some people are still careful even when it
comes to losses, and others take risks in both cases.
When making decisions, people often start by getting rid of options they don't like,
and then they compare the remaining options in detail to make a choice. However,
experts sometimes just focus on one option and make quick decisions, even when
they're under time pressure. But sometimes, making a decision can cause people to
CIPD NOTES
3
forget important information that could have helped them make a better choice.
Finally, sometimes the best way to make a decision is to first think about it
consciously, and then let your subconscious mind process the information and help
you reach a conclusion.
Lecture 9
Notes for "What is Stress?"
Definition of Stress:
Stress is the body and mind's reaction to a perceived or real threat, change or event
These threats, changes or events are called stressors
Stressors can be internal (such as thoughts, beliefs or attitudes) or external (such
as loss, tragedy or change)
Stress:
Involves threats and challenges to individuals
Involves responses to situations
Is a process by which we appraise and cope with environmental threats and
challenges
Has both positive and negative effects on individuals
Positive effects include motivation to conquer problems
Negative effects include threatening our resources
Eustress:
Eustress is positive stress
Occurs when stress is high enough to motivate individuals to take action and
accomplish tasks
Distress:
Distress is negative stress
CIPD NOTES
4
Occurs when stress levels are either too high or too low
The body and/or mind responds negatively to stressors
Stress response system:
Involves stress hormones such as epinephrine (adrenaline) and norepinephrine
Fight or flight response prepares the body for action
General adaptation syndrome (GAS) is the body's adaptive response to stress
GAS is very general and responds no matter what the stressor is
Stressful life events can have significant health consequences and are of three types:
Catastrophes: unpredictable, large-scale events like war or earthquake
Life Changes: events like death, marriage, divorce, or loss of job that make a
person more vulnerable to disease
Daily Hassles: annoying events in everyday life like rush hour traffic or
roommates that have a cumulative effect on health
Social and cultural sources of stress are:
Social conditions that promote stress, such as poverty, racism, or crime
Low SES tends to have the highest levels of stress
Culture clashes lead to stress, like a company owned by a different culture, and
refugees and immigrants suffer too
Perceived control can decrease stress, anxiety, and depression, but perceptions of
control must be realistic to be adaptive
Explanatory style can affect health outcomes:
Optimism predicts better health outcomes and uses external, unstable, and
specific explanations for negative events
Pessimism predicts worse health outcomes and uses internal, stable, and global
explanations for negative events
Stress, personality, and heart disease:
Coronary heart disease is North America's leading cause of death
CIPD NOTES
5
Habitually grouchy people tend to have poorer health outcomes
Stress and resistance to disease:
Indirect effects of stress on health promote jeopardizing behaviors like smoking
or drinking
Psychophysiological illnesses result from the physiological effects of
psychological states, such as hypertension or headaches.
Lecture 10
Electroencephalogram (EEG) is a method of recording the electrical activity of the brain.
Here are some detailed notes on EEG:
1. Sensory systems relay impulses from receptors to specific sites in the cerebral
cortex responsible for perception and localization of individual sensations. The
awake brain processes these impulses to be perceived.
2. The behavioral state is correlated with a discrete pattern of brain electrical activity.
Feedback oscillations within the cerebral cortex and between the thalamus and the
cortex produce this activity and are determinants of the behavioral state.
3. Arousal can be produced by sensory stimulation and by impulses ascending from
the brainstem to the thalamus and then to the cortex.
4. Nociceptive unmyelinated nerve terminals in the skin have receptors that can be
activated by nociceptive stimuli such as heat.
5. Changes in membrane potential and relative membrane permeability to Na+ and K+
during an action potential.
6. Ascending tracts carry sensory information from peripheral receptors to the cerebral
cortex. The dorsal column pathway mediates touch, vibratory sense, and
proprioception while the ventrolateral spinothalamic tract mediates pain and
temperature.
CIPD NOTES
6
7. The structure of the cerebral cortex is composed of cortical layers, and the Golgi
stain shows neuronal cell bodies and dendrites, Nissl stain shows cell bodies, and
Weigert myelin sheath stain shows myelinated nerve fibers.
8. Neocortical pyramidal cells receive nonspecific afferents from the brainstem and the
thalamus, recurrent collaterals of pyramidal cell axons, commissural fibers from
mirror image sites in the contralateral hemisphere, and specific afferents from
thalamic sensory relay nuclei.
9. Evoked cortical potentials occur when the electrical events that occur in the cortex
after stimulation of a sensory receptor are monitored with a recording electrode. If
the electrode is over the primary receiving area for a particular sense, a surfacepositive wave appears with a latency of 5–12 ms. This is followed by a small
negative wave, and then a larger, more prolonged positive deflection frequently
occurs with a latency of 20–80 ms. The first positive-negative wave sequence is the
primary evoked potential, and the second is the diffuse secondary response.
Notes on Ascending Arousal System:
1. The ascending arousal system is a complex polysynaptic pathway that includes
monoaminergic, cholinergic, and histaminergic neurons.
2. These neurons project to the intralaminar and reticular nuclei of the thalamus, which
then project diffusely to wide regions of the cortex including the frontal, parietal,
temporal, and occipital cortices.
3. The EEG recorded from the scalp is a measure of the summation of dendritic
postsynaptic potentials rather than action potentials.
4. Propagated potentials can be generated in dendrites, and recurrent axon collaterals
end on dendrites in the superficial layers.
5. The cell body-dendrite relationship is that of a constantly shifting dipole, and current
flow in the dipole produces wavelike potential fluctuations in a volume conductor.
6. When the sum of the dendritic activity is negative relative to the cell body, the
neuron is depolarized and hyperexcitable; when it is positive, the neuron is
hyperpolarized and less excitable.
Notes on Sleep Stages: Non-REM & REM Sleep:
CIPD NOTES
7
1. Non-REM sleep is divided into four stages, with stage 1 being the transition from
wakefulness to sleep and the EEG showing a low-voltage, mixed frequency pattern.
2. Stage 2 of non-REM sleep is marked by the appearance of sinusoidal waves called
sleep spindles and occasional high voltage biphasic waves called K complexes.
3. Stage 3 of non-REM sleep is characterized by the appearance of a high-amplitude
delta rhythm in the EEG, reflecting a further reduction in arousal and muscle tone.
4. Maximum slowing with large waves is seen in stage 4 of non-REM sleep, and the
characteristic of deep sleep is a pattern of rhythmic slow waves, indicative of
marked synchronization of cortical and thalamic activity.
5. REM sleep gets its name from the characteristic rapid, roving eye movements that
occur during this stage of sleep and are recorded as an electrooculogram (EOG).
6. Except for eye movement, there is almost a complete loss of skeletal muscle tone in
REM sleep, and the threshold for arousal from sleep by sensory stimuli is elevated
during this time.
7. Dreaming occurs in both REM and non-REM sleep stages, but their characteristics
differ.
Lecture 2-6
Human-Machine System
A human-machine system is a combination of human and machine resources working
together to achieve a common goal. To understand how this system works, it is
important to consider perception and how humans receive and interpret information.
Perception
Perception involves becoming aware of objects, relationships, and events through our
senses. There are different levels of perception, depending on the stimulus and task at
hand, ranging from simple detection to identification and recognition.
CIPD NOTES
8
Visual perception involves color, form, depth, and product size. Auditory perception
includes loudness, pitch, and localization. Haptic/tactile perception is concerned with
texture, while smell perception deals with odors. The eye has two basic receptors: rods
and cones, with rods being more sensitive to light in low illumination conditions,
whereas cones function at high levels of illumination.
Light is radiant energy that can excite the retina of the eye and produce a visual
sensation. The visible spectrum ranges from about 380 to 780 nanometers, with color
perception varying depending on the wavelength. The Purkinje effect refers to the shift
in sensitivity from photopic to scotopic vision as illumination levels decrease.
Sound is a sensation of acoustic waves, and unpleasant or disturbing sound is generally
treated as noise. Cutaneous receptors include mechanoreceptors, thermoreceptors,
and nociceptors, and serve as touch, pressure, vibration, temperature, and nociception
(pain).
Smell and taste are visceral senses that are closely associated with gastrointestinal
function. They evolved as protective mechanisms to avoid the intake of potentially
harmful substances. Smell and taste receptors are chemoreceptors that are stimulated
by chemical molecules in solution in mucus in the nose and saliva in the mouth.
Attention
Attention is the perceptual process that selects certain inputs for inclusion in our
conscious experience or awareness at any given time. Our sense organs receive a
multitude of stimuli, but we only perceive a few of them clearly. Attention divides our
field of experience into a focus and a margin, with events that we perceive clearly being
at the focus of experience and other items perceived dimly at the margin of attention.
Attention is constantly shifting, and what is at the focus one moment may be in the
margin the next, and vice versa.
Types of Attention
There are four types of situations or tasks involving the direction of attention:
1. Selective Attention: Involves monitoring several channels of information to focus on
a particular channel or stimulus while ignoring others.
2. Sustained Attention: Involves maintaining focus on a task over an extended period
of time.
CIPD NOTES
9
3. Divided Attention: Involves multitasking or attending to multiple tasks
simultaneously.
4. Alternating Attention: Involves switching focus between tasks that have different
requirements.
Introduction
Information processing involves acquiring, storing, retrieving, and utilizing
information
Cognitive architecture includes memory stores, cognitive processes, and
metacognition
Learning is the process by which changes in behavior arise as a result of
experiences interacting with the environment
Multiple-Resource Theories of Divided Attention
Proposes that there are several independent resource pools
Wickens (1984) suggests four dimensions for resource allocation: stages, input
modalities, processing codes, and responses
Design successful divided-attention tasks by minimizing potential sources of
information, providing information about relative task priorities, minimizing task
difficulty, making tasks dissimilar in terms of demands, and considering the learning
level of manual tasks
Sustained Attention or Vigilance
Ability to remain alert to stimuli over prolonged periods
Vigilance decrement occurs over the first 20 to 35 minutes of the task, characterized
by a decline in speed and accuracy of detection
To design successful sustained-attention tasks, provide appropriate work-rest
schedules and task variation, increase the conspicuity of the signal, reduce
uncertainty as to when or where the signal will occur, inject artificial signals, provide
feedback on detection performance, adequately train observers to identify signals,
emphasize the importance of the task being performed to improve motivation,
CIPD NOTES
10
reduce the rate at which stimuli are presented if it is high, and maintain optimal
environmental factors such as noise, temperature, and illumination
Age and Information Processing
Age has a significant impact on our information processing abilities
To design successful information processing tasks for the elderly, strengthen
displayed signals, reduce time-sharing demands, maintain a high level of
compatibility, provide time between execution of a response and signal for the next
response, allow the person to set the pace of the task where possible, and allow
more time and practice for initial learning of material
Learning and Memory
Key principles of early theories on learning include dependence on sampled data
and building associations using contiguity, frequency, similarity, and contrast
Repeated exposure to stimuli can lead to habituation, a decrease in
strength/occurrence of a behavior, or sensitization, a temporary increase in the
strength of responses to other stimuli
Memory aids seamless exchange of information across different stages of
processing/stores to serve everyday task demands
Memory is broadly organized into sensory memory, working memory, short-term
memory, and long-term memory
The Atkinson and Shiffrin model proposes that memory consists of a sensory
register, a short-term memory store, and a long-term memory store
Conclusion
Effective design of tasks requires an understanding of the cognitive processes
involved
By taking into account multiple-resource theories of divided attention, sustained
attention or vigilance, age-related changes in information processing, and principles
of learning and memory, designers can create tasks that are more efficient and
effective.
CIPD NOTES
11