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Samenvatting Cognition and Attention (colleges + boek)
Samenvatting van het vak 'Cognition and Attention'. In de samenvatting zijn zowel de colleges, als het bijbehorende boek verwerkt.
[Meer zien]Voorbeeld 8 van de 57 pagina's
Voorbeeld 8 van de 57 pagina's
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Voorbeeld van de inhoud
Cognition and AttentionCHAPTER 1 – HISTORICAL O VERVIEW OF RESEARCH ON ATTENTION
The philosophical period -> The views of different philosophers on attention:
Vives (1492–1540) -> The more closely one attends to stimuli, the better they will be
retained. Learning consists of the formation of associations. Retrieval occurs through
automatic activation of associated ideas or through intentional, effortful search.
Information storage in STM requires attention -> Example: Change blindness.
Malebranche (1638–1715) -> We have access to ideas, or mental representations of the
external world, but not direct access to the world itself. Attention is needed to prevent ideas
from becoming confused and imperfect.
Leibniz (1646–1716) -> Events can be perceived unconsciously, conscious awareness requires
an act of attention (apperception). Attention can be reflexive (automatically shifted to events
or ideas that demand it, e.g. more salient features) or voluntary.
Herbart (1776–1841) -> Agreed with Leibniz that an event had to be apperceived to enter
conscious awareness. However, he hypothesized that all new perceptual experience occurs
in relation to prior perceptions (by relating the old and new experiences).
A popular view in the 19th century -> People are incapable of attending to more than one
thing at a time -> Hamilton (1788–1856) -> Thought the attention span was more than one
object -> Measured by throwing marbles one the floor and determining how many could be
apprehended -> Followed up by Jevons (1871), who estimated it to be four items.
The development of psychophysics:
Wundt -> Investigated the astronomer’s personal equation -> The time it takes to switch
attention voluntarily from one stimulus to another.
He held that attention is an inner activity that causes ideas to be present to differing
degrees in consciousness.
o Perception -> The entry into the field of attention -> Passive and automatic.
o Apperception -> The entry into the inner focus (becoming aware of a
perceptual event) -> Active and voluntary.
Donders -> Developed the subtractive method -> Estimation of the time for a particular
process by adding that process to a task and taking the difference in RT between the two
tasks. Three types of reactions:
A (simple reaction) -> React as quickly as possible when you see a red or green
square.
B (go or no-go reaction) -> React to red, do not react to green.
C (choice reaction) -> Press “A” for red and “B” for green square.
B – A = Time needed for stimulus identification.
C – B = Time needed for response selection (expression of the will).
Helmholtz (1866) -> By a voluntary kind of intention, even without eye movements or
accommodation, one can concentrate attention on the sensation from a particular part of
our peripheral nervous system and at the same time exclude attention from all other parts.
Attention can be directed to a particular region of a page, in advance of stimulus
presentation, even though the eyes were kept fixed at a central point.
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, Attention is limited -> The letters in by far the largest part of the visual field, even in
the vicinity of the fixation point, are not automatically perceived.
Pillsbury’s (1908) -> The conditions of an act of attention are to be found both in the environment
and in the past experience of the individual.
Task set -> Refers to the readiness to carry out an instructed action in response to a given
stimulus -> Preparation facilitates perception.
Clearness is achieved by inhibiting sensations that were not attended to?
William James (1890) -> Attention is: The taking possession by the mind, in clear and vivid form, of
one of what seem several simultaneously possible objects or trains of thought. Focalization,
concentration, of consciousness are of its essence. It implies withdrawal from some things in order to
deal effectively with others.
Alfred Binet (1890) -> Attention can be understood in terms of interference -> If one task requires
attention, it will interfere with another task that also requires attention.
Dual-task interference -> Mental addition interfered with a task of rhythmically squeezing a
rubber ball a specified number of times -> Did not occur when the timing and number of
squeezes did not have to be monitored.
Behavioursm (1910-1949) -> John B. Watson:
Tabula rasa -> Experience is all that matters, focus on conditioning of behaviour.
Observable, quantifiable behaviour is the proper topic of psychology. Instead of
unobservable (and therefore, unscientific) mental aspects such as attention and
consciousness.
Less research on attention, yet important discoveries were made:
Mental set and shift -> Task-switching (Jersild, 1927) -> Switching between tasks
usually results in more time needed to complete the task (switch cost).
o Subjects had to complete a set of simple, yet engaging interleaving
operations that must be performed in an alternating or repeating sequence
-> A-A-A etc. or A-B-A-B etc.
o Subjects who had to complete a list of two alternating tasks were slower
than subjects who had to perform a single task (mixed lists vs. pure lists).
Psychological refractory period effect (Telford, 1931) -> Stimulation of a neuron is
followed by a refractory period during which the neurons are less sensitive to
stimulation.
Stroop effect (Stroop, 1935) -> A demonstration of interference in the reaction
time of a task. When the print color is not congruent with the name of the color, RT
is higher and more errors are made.
From 1950-1975 -> Cognitive revolution -> Dissatisfaction with behaviourism.
Vigilance (state of being watchful) decrement -> Sustained attention (Mackworth, 1950).
Dichotic listening -> Listening to two messages at the same time -> Repeating only one, this
was easy. From the other message they could only remember physical attributes (e.g.
gender) (Cherry, 1953).
Early selection theories:
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, Filter theory (Broadbent, 1953) -> The attended input (that has some physical
feature in common with the attentional filter) is identified and privileged from the
start, so that the unattended input receives little analysis.
Filter attenuation theory (Treisman, 1960) -> The early selective filter does not block
out unwanted information, but only attenuates or reduces the strength. Usually,
attenuated information will not reach consciousness, but when the information is
familiar or fits the context of the attended information, it may be identified (e.g. your
name).
Late selection theory -> Deutsch and Deutsch (1963) -> Proposed that unattended stimuli are
always identified, the bottleneck occurs in later processing.
Unitary-resource theory (Kahneman, 1973) -> Attention is a single resource that can be
divided among different tasks in different amounts -> Available supply varies as a function of
arousal and task demands. And voluntary allocation strategies determine the tasks and
processes to which the resource should be devoted when the demand exceeds the supply.
EEG and event-related potentials (ERP) -> Electrical brain activity that occurs in response to
(and is measured with respect to) an external stimulus -> Measured by placing electrodes on
the scalp -> Can provide evidence about the nature of the mechanisms underlying the
processing of specific stimuli.
1975 – present -> 854620 scientific articles about “attention”:
Increasingly finegrained analysis of attentional functions.
Increasing knowledge about neural mechanisms.
Development of computation models that use neurobiologically plausible algorithms of
information processing.
Wickens’ multiple-resource model -> Each task has a resource profile -> Tasks with similar resource
profiles are difficult to combine, whereas tasks with very different profiles can be combined quite
easily.
Negative priming -> Explains longer reaction times to a target when it has previously appeared as a
distractor -> E.g. when the word ‘dog’ was a distractor in the first trial, and the target of the second
trial is a picture of a dog.
Feature integration theory (Treisman) -> Space-based approach -> Attention must be allocated to
stimulus locations in order to integrate the features of the stimulus presented at that location.
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, Assumes that basic features of stimuli are encoded into feature maps in parallel across the
visual field at a preattentive stage.
Search for a target distinguished from distractors by a single feature can be based on
processing occurring during this preattentive stage.
The second stage involves coding attentions on a specific location and combining features
that occupy the location into objects.
By directing attention to the location of an object, the various features of that object are
effectively bound into an integrated percept. In this theory, spatial attention serves as a
perceptual glue.
David Marr’s Tri-Level Hypothesis -> Information processing: Perception, attention, memory,
learning, reasoning, deciding, responding -> Must all be understood at different, though inter-related
levels.
CHAPTER 2 – INFORMATION PROCESSING AND THE STUDY OF ATTENTION
Information processing approach -> Focuses on how the information we receive from our
environment is processed by the mind -> Focus on elementary tasks requiring the processing of
sensory information (e.g. at a traffic light, brake/gas pedal).
Defining information -> Bits (binary digits):
A basic unit of information in computing and digital communication.
Can have only one of two values: 0 or 1 -> The two values can be interpreted as logical values
(true/false, yes/no), algebraic signs (+/−), activation states (on/off), or any other two-valued
attribute.
Microchips -> Physical implementation of bits.
One bit is defined as the uncertainty of a binary random variable that is 0 or 1 with equal
probability.
One bit of information is gained when the value of such a variable becomes known.
Number of bits in a stimuli is computed as log2(N) -> N is the number of alternatives.
E.g. in a coin flip, heads or tails are equally likely -> Thus, when the coin lands, one bit of
information [log2(2)] is conveyed.
For two coin flips, there are more outcomes (HH, HT, TH, TT) -> Thus, two bits of information
[log2(4)] are conveyed when the outcome is made known.
4
,The mind as an information processing channel -> Bits in, bits out -> Binary: In = red or green traffic
light, out = gas or brake.
In the 1950s and 1960s -> Many experiments conducted to characterize information
processing efficiency, in terms of the rate of information transmission expressed in bits per
second.
Hick-Hyman Law -> RT linearly related to amount of information transmitted -> Given equally likely
stimuli and perfect performance, RT will increase by a constant amount each time the number of
possible outcomes is doubled -> RT = a + b(bits) = a + b(log2[n]).
A more difficult task, results in slower information transfer, with a steeper increase in RT
across bits -> E.g. say ‘John’ when the stimulus is 6 (as opposed to saying ‘six’ for an easier
task).
The same task for people with different rates of information processing would also be
expected to show differences in slope (i.e., steepness) of the RT-bit function -> Low IQ has
the steepest slope.
The stages of information processing:
Stimulus Response
It is assumed that stages occur sequentially, with one stage delivering input to the next after it has
been completed.
Mental chronometry -> The use of response time in perceptual-motor tasks to infer the content,
duration, and temporal sequencing of cognitive operations.
Subtractive method -> Method of determining the time required to perform a particular process, by
measuring the time to perform a task which includes that process and subtracting from it the time to
perform a task which does not include the process but which is otherwise identical.
Task 1: React to a light (“simple reaction time task”) -> Perception – motor.
Task 2: React to green light, but not to red (“go – no go”) -> Perception – discrimination –
motor.
Choice RT task (“right” if “red”; “left” if “green”) -> Perception – discrimination – response
selection – response.
Go NoGo RT – Simple task RT = Stimulus identification.
Choice RT – Go NoGo RT = Response selection.
Critics on the subtractive method:
Independent stages? Is it really the case that a stage needs to finish before sending its
results on to the next stage (discrete vs. continuous stage models)?
“Pure” insertion? Can a process be inserted into a sequence set of processes without
affecting the functioning of the rest? Reasonably valid for Donders-type tasks, but
interactions do occur.
Assumption of pure insertion -> Insertion of an additional process does not alter the
basic task structure.
5
, Additive vs. interactive effects -> A more powerful and general method for assessing stage
structure (processing modules and their independence) and which stages (stage durations)
are affected by which factors.
Determining which stages are involved in a particular information processing task.
Several factors (i.e., independent variables) are manipulated, and the effects of these
manipulations on time to perform the task are examined.
Additive factors method:
The effect of one factor does not depend on the level of another
factor.
The factors are assumed to affect different stages of processing.
Example: Memory set = 9473 -> Is 5 present in set?
Set size is the amount of letters presented (e.g. 9473 or 645 =
factor A).
Degraded = With tiles behind the 5 (higher level of factor B).
Set size and legibility (=leesbaarheid) affect different processes:
Example: Ttoal = Tbike + Tbus + Ttrain -> Flat tire and train delay have additive effects because the
flat tire only affects Tbike and the train delay only affects Ttrain. Total delay is ∆Tbike + ∆Ttrain.
Inference of stage structure based on AFM has been fairly successful and has produced quite
consistent results.
Interactive factors method:
The effect of one factor is dependent on the level of the other.
The factors are assumed to affect the same stage of processing.
Example: Memory set = 9473 + remember ATBM -> Is 5 present?
Example: Wind and being tired have interactive effects. Only wind
would slow Tbike with 10 min, and being tired would do so with 2
min. But both combined would slow it 20 min (not 12).
Some complications arise when a factor affects multiple stages.
A and B + A and C have interactive effects, logically you
could assume that B and C have interactive effects.
But what if they turn out to have additive effects? Then you could assume B effects
one stage, C affects another and A affects both.
That inference can be tested because it predicts that factor A should also show
interactive effects with any other factor known to show interactive effects with
either factor B or C.
If that predictions fails, again a more complex stage structure should be assumed and
tested.
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,Stage robustness -> If a number of experiments produce data consistent with proposed stages. And if
when two factors show additive effects, the addition of a third factor does not result in a higher
order interaction.
Mental resources -> Energetic demands of processing -> Efficiency of information processing
depends on the amount of mental resources that is required and available for a certain process
(unitary resource model).
Yerkes-Dodsen law -> Relationship between arousal and
performance -> Generally states that performance is an inverted U-
shaped function of arousal, with the optimal arousal level (i.e., the
level at which the inverted U peaks) being lower the more difficult
the task.
Arousal level -> General state of one’s level of stimulation or
readiness to act.
Example: Mouse had to learn to choose the lighter box
(electric shocks were used when entering the darker one). With higher contrast, they learned
faster with a more intensive shock. But with lower contrast this was not the case -> Arousal
overload.
Cue-utilization theory (Easterbrook) -> Arousal affects performance by determining the number of
sources of information (cues) that the organism can effectively monitor.
High arousal -> Favours high selectivity -> E.g. focusing attention on one source of input,
especially while ignoring other distracting cues -> Beneficial when few cues have to be
monitored.
Low arousal -> Favours low selectivity, or dividing attention across many sources of input ->
Distractible (ADHD treated with Ritalin, an amphetamine that reduces impulsivity and
distractibility).
Vigilance -> A state of readiness to detect and respond to infrequent, randomly occurring events.
Cortical arousal and vigilance -> Both terms are often used to refer to a general state of
wakefulness. And factors that increase or decrease arousal level, are associated with
corresponding increases or decreases in vigilance task performance.
Vigilance decrement -> Vigilance performance typically decreases after a short period (20-30
min) of vigilance task performance. This cannot be explained by the arousal levels.
Serial reaction time task -> In which subjects respond to whichever of the five lights comes on by
pressing a corresponding response key.
Performance under conditions of noise and sleep loss:
Noise and normal sleep -> Decrease.
Noise and sleep loss -> Increase, because noise compensates for the arousal reducing
effect of sleep loss.
Performance incentives -> Increases detrimental effects of noise, by further
increasing the already excessive amount of arousal.
Lower arousal -> Equated with the notion of cortical arousal and was hypothesized to be affected by
state variables such as noise and sleep loss.
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, Upper arousal -> Assumed to facilitate controlled, strategic operations that correct sub- or super-
optimal levels of lower arousal, and corresponds to the concept of “effort” (e.g. also performance
incentives).
Broadbent -> Hypothesized that upper arousal becomes depleted as time on task increases,
thus reducing the ability of the subject to compensate for deficient lower arousal.
The three energetical mechanisms (Sanders) -> Arousal, activation, and effort:
Evaluation mechanism monitors arousal and activation and can increase effort -> Which then
increases the potential arousal and activation.
Stimuli themselves can increase arousal at the early stages of stimulus processing, and this
arousal will facilitate later stages of stimulus processing.
Effort (i.e. conscious processing), directly influences the efficiency of response selection, and
activation affects response processing.
This conception of activation at the response stage (i.e. preparation to respond) can be
interpreted as general alertness.
Behavioural measures:
Reaction time -> Evidence accumulation and criteria:
Speed – accuracy trade-off -> Either speed or accuracy can be emphasized to the detriment
of the other.
RT and accuracy are inversely related such that increases
in response speed are generally accompanied by reduced
accuracy of performance.
When RTs are relatively fast, any decreases in RT are
accompanied by large costs in accuracy.
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