Chapter 3 - Attention & Consciousness Flashcards
What is attention?
The ability to selectively concentrate on one aspect of the environment while ignoring other things.
What are the 4 types of attention?
Active vs passive attention.
- Active: controlled in a top-down way by the individual’s goals or expectation.
- Passive: controlled in a bottom-up way by external stimuli.
Focused vs divided attention
- Focused: try to attend to only one source of information while ignoring other stimuli.
- Divided: performing 2 tasks simultaneously
Why does active and passive attention exist?
attention is a limited resource. cannot afford to do active attention on everything.
Describe the shadowing task used by Cherry to study selective auditory attention.
He played different auditory messages in both ears, listeners have to attend to only one. Very little seems to be extracted from the non-attended message, initially suggesting that the meaning of the non-attended message is not processed at all.
Eg: I play PM Lee’s voice and Mr Brown’s voice -> I chose to pay attention to Mr Brown -> cannot say what PM Lee was talking about.
When the message was spoken in a foreign language or was played backwards, did the results change?
no.
If physical changes were made, were they easily detected? Eg: a pure tone
yes
What are the 3 theories that attempt to explain why we have limited abilities in extracting information from 2 sources that are presented simultaneously?
bottleneck concept
1) Broadbent’s theory
2) Treisman’s Attenuation Theory
3) Deutsch & Deutsch Theory
What did Broadbent propose about the location of the bottleneck?
Argued that there is a filter/bottleneck early in processing that allows information from one input or message through it on the basis of its physical characteristics. The other input remains briefly in a sensory buffer and is rejected unless attended to rapidly.
Describe the extraction of auditory messages using Broadbent’s theory.
1) 2 stimuli presented simultaneously are processed by the sensory register (low-level perceptual analysis)
2) However, only the attended input is allowed through the filter and undergoes semantic analysis.
3) You can select the input you wish to pay attention to using physical characteristics (eg gender of speaker, ear of input). The other input remains briefly in a sensory buffer and is rejected unless attended to rapidly. If not, you won’t get any semantic information from this rejected input.
What are some of the limitations associated with Broadbent’s theory?
too inflexible to say that you will not process any meaning from your unattended messages.
how do you explain a scenario whereby you are able to hear someone mentioning your name, even though you were not attending to that conversation?
What did Treisman propose about the location of the bottleneck?
The location of the bottleneck is more flexible than what Broadbent suggested.
Proposed that listeners start with processing based on physical cues, syllable pattern, and specific words and move on to processes based on grammatical structure and meaning. If there is insufficient processing capacity to permit full stimulus analysis, later processes are omitted.
With regard to Treisman’s theory, are later processes COMPLETELY omitted?
No.
Filter only attenuates/reduces the effect of unattended information. Might explain subjects’ awareness of unattended information.
Helps to explain why you can hear things personally relevant to you even though you are not attending to it. Eg when someone calls your name from afar.
What did Deutsch and Deutsch propose about the location of the bottleneck?
Argued that all stimuli are analyzed, but response is influenced by the most important/relevant stimulus. Bottleneck in processing becomes much nearer to the response end of the processing system than what Broadbent proposed in his theory.
What results did Deutsch and Deutsch obtain from the shadowing paradigm?
What they expected: There is complete perceptual analysis of all stimuli, and hence there should be no difference in detection rates .
What actually happened: However, much more target words were detected on the shadow message, hence Deutsch and Deutsch’s view is not consistent with empirical data.
When Coch et al asked listeners to attend to one of 2 auditory messages and detect targets presented on the attended or unattended message, what was found?
ERPs were recorded to provide a measure of processing activity.
ERPs 100ms after target presentation were greater when the probe was presented on the attended message than on the unattended one. Suggests that there was more processing of attended than of unattended targets.
If you were to carry out a dichotic listening task, with 3 digits being presented to each ear, would 3 digits be said or 6?
- Most recalled the digits ear by ear rather than pair by pair.
EG: 498 to one ear, 852 to the other. Recall would be 498, 852 and not 489582 –> not so intuitive as u can see.
What does the dichotic listening task suggest about auditory attention?
Suggests that the digits on one ear were stored briefly while those on the other ear were processed. Consistent with the notion that listeners select auditory stimuli for processing on the basis of their physical features (ie. ear of arrival).
Also consistent with the notion that listeners select auditory stimuli for processing on the basis of their physical feature, and can exhibit more flexibility.
How is there less evidence of a bottleneck when 2 channels are in different modalities?
If one message is auditory, while the other is visual, results can be different.
Listeners heard words over the telephone while doing a visual object-tracking task. The shadowing task didn’t interfere with the object-tracking task. Indicates that 2 dissimilar inputs of different modalities can be processed more fully than assumed by Broadbent.
How do top-down processes and bottom-up processes help one to pay attention to auditory stimuli?
Top-down:
Helps to inhibit brain activity elicited by irrelevant auditory stimuli, hence allowing listeners to focus more on the attended information.
bottom-up: directly by auditory input.
Explain the “winner-takes-all” mechanism.
Processing of one sound (winner) suppresses the brain activity of all other sounds (loser)
Inhibitory processes reduce brain activity associated with voices we want to ignore. Inhibitory processes are more effective when there are clear-cut physical differences between the attended input and the ignored input.
What can visual attention be likened to?
zoom lens, donut, spotlight
How is visual attention like a spotlight?
By Posner. Think of Mike Posner I TOOK A PILL IN IBIZA
Illuminates a relatively small area, little can be seen outside the beam of light. However, this beam of light can be redirected flexibly to focus on any given object.
How is visual attention like a zoom lens?
Eriksen and St James (Think Sony Ericsson and St James power station)
We can volitionally increase or decrease the region of focal attention (can be done at will), just as a zoom lesn can be moved in or out to alter the visual area it covers.
Eg: When driving a car, it is mostly desirable to attend to as much of the visual field as possible to anticipate danger. However, when we spot a potential hazard, we zoom in/focus on it to avoid an accident
What did Muller do that lent support to the zoom lens analogy?
Participants initially saw 4 squares. They were then cued to focus their attention on either 1 square, 2 square or 4 squares.
Four objects were then presented, one in each square. Observers then had to decide whether a target object (eg a white circle) was present in one of the cued squares.
What results did Muller obtain?
During target detection, targets are detected fastest when the attended region was smallest (one square).
The cueing phase forced them to zoom their attention in and out. Also, during the target detection phase, it was evident that those who were asked to focus on more squares took longer to pick out the target.
TRADE OFF BETWEEN REGION SIZE AND PROCESSING EFFICIENCY
Is there evidence to show that attention is not consistent with the zoom lens theory?
We can use visual attention more flexibly than assumed by the theory.
Study – Present two digits a short distance apart in two locations. On some trials, one digit was presented in the space between the two cued locations.
According to zoom lens theory, the area of maximal attention should include the two cued locations and the space in between. Hence, detection of the digit presented in the middle should have been very good.
Findings – detection of digit presented in the middle was poor. Not consistent with zoom lens theory, but rather show split attention.
How is visual attention like a doughnut?
Suggests that attention can be split. Attention can be directed to 2 regions of space not adjacent to each other -> attention can be more flexibly deployed than suggested by zoom lens metaphor, and can perhaps have multiple spotlights.
Is there evidence to support the doughnut analogy>
Presented participants with stimuli at 5 different locations at the same time. Looks smth like this.
x x
x
x x
When observers were told to attend to the upper-left and bottom-right locations only, there were peaks of brain activation in brain areas corresponding to these locations.
However, there was much less brain activation in areas between the locations, including the centre of the visual field. Can be shaped like a donut, nothing in the middle.
What is neglect and what causes it?
A disorder of visual attention in which stimuli or parts of stimuli presented to the side opposite the brain damage are undetected and not responded to; the condition resembles extinction but is more severe.
Damage to the right hemisphere.
What symptoms do neglect patients exhibit?
When they copy a drawing, they typically leave out most of the details from the left side of it.
- Failure to attend to stimuli presented to the left side of the visual field and have no conscious awareness of them.
Stimuli presented to the left side of the visual field are not processed. True or false?
False. The stimuli still receive some processing.
After getting patient to report pictures, the patients had to identify degraded pictures. Performed better on old picture that had been presented to the left visual field than on new pictures. Thus, the old pictures had received some processing during the first phase of the experiment.
List some factors that determine if one would be easily distracted or not.
Anxiety
Salience of distractors
Demands of current task (perceptual load theory)
Proximity of task-irrelevant stimuli to task-relevant stimuli
What does the perceptual load theory propose and assume?
Assumes that attentional capacity is limited.
Attentional capacity is primarily allocated to the attended information. Residual capacity can then be allocated to unattended stimuli.
For demanding tasks, perceptual load is high, and hence less residual capacity for unattended stimuli.
Is there evidence that supports the perceptual load theory?
Had subjects search for a letter in a circle (eg X or N)
IV1: Low-load vs high-load (high load had other non-target characters placed randomly in the circle)
IV2: Distractor vs no distractor.
Found that the cartoon character was only distracting in the low-load condition. Shows that when perceptual load is low, little attentional capacity is required to attend to the information present (letter to be identified). Hence, it leaves one with a large amount of residual capacity, which can then be used to attend to unattended stimuli, the cartoon character in this case.
Answer these questions:
Performance of high-anxious participants was impaired by distraction whereas there was no such effect in low-anxious participants. True/False?
Distractors that are task-irrelevant are more disruptive than distractors that are task-relevant. T/F?
Task-irrelevant stimuli close in space to task stimuli are more distracting than those further away. T/F?
True.
False. Task-relevant distractors prove to be more disruptive than task-irrelevant distractors.
True.
What is cross-modal attention, and what misconception does this correct?
The coordination of attention across 2 or more sense modalities.
Shows that attentional processes in each sensory modality DOES NOT operate independently of those in another modality and that such processes are not modality specific.
Name 2 types of illusions associated with cross-modal attention and define them.
Ventriloquist illusion: The mistaken perception that sounds are coming from their apparent visual source. Think about how you used to think that car music came from the front, but actually the music source is the speaker located at the back of the car.
Rubber hand illusion: The misconception that a rubber’s hand is one’s own, it occurs when the visible rubber hand is touched at the same time as the individual’s own hidden hand.
What conditions must be satisfied before the ventriloquist illusion takes place?
Recall: What does SET stand for?
1) Visual and auditory stimuli must occur close together in time.
2) Sources of visual and auditory stimuli must be close together in space.
3) Sounds must match expectations raised by the visual stimulus. (you see the car front whatever it’s called lol -> expect music to be played -> if music is played, good. if something else comes out, run. jk but if something else comes out it doesnt qualify to be a ventriloquist illusion.
When does vision capture sound and when does sound capture vision?
Vision captures sound when the visual modality provides more precise information about spatial location, and this is usually the case.
However, sound does capture vision when the visual modality is severely blurred or poorly localized.
Thus, we combine visual and auditory information effectively by attaching more weight to the more informative sense modality.
What is the body swap illusion?
The participant and experimenter squeeze each other’s hands repeatedly. The participant wears a special helmet equipped with two CCTV cameras so that he/she sees the experimenter’s POV.
Participants perceive that the stimulation caused by squeezing hands originates in the experimenter’s hand rather than their own!
Researchers then moved a knife either close to the participant’s or the experimenter’s hand. The participants showed a greater emotional response when the knife was close to the experimenter’s hand than when it was close to their own hand
Why does the body swap illusion occur?
we place special emphasis on vision as a reliable source of information, especially vision from the first-person POV. Hence, we can even experience ourselves in someone else’s body when viewing the world from their viewpoint.
What is the body size effect an extension of?
Body swap illusion
What is the body size effect?
The size of the body mistakenly perceived to be one’s own influences the perceived size of objects in the environment.
Why does the body size effect occur?
depends in large measure on our lifelong experience of seeing everything from the perspective of our own body combined with our general reliance on the visual modality.
How does the body size effect work?
Next, participants saw the POV of a doll. When participant’s body and the doll’s body were touched simultaneously, the participant experienced the doll’s body as his/her own. The size of the doll was changed in different conditions.
Small doll → other objects were perceived as larger and further away
Large doll → other objects were perceived as smaller, and nearer
Similar mechanism as body swap illusion (reliance on visual modality). Note that touch information has to match the visual information appropriately.
What is the “face-in-the-crowd” effect?
The finding that threatening (angry) faces can be detected more rapidly among other faces than faces with other expressions. Possibly because we detect angry expressions in an automatic way not requiring attention.
Effect has been replicated using naturalistic crowd scenes.
This effect is amplified more in anxious individuals.
What conditions must be satisfied before the ventriloquist illusion takes place?
Recall: What does SET stand for?
1) Visual and auditory stimuli must occur close together in time.
2) Sources of visual and auditory stimuli must be close together in space.
3) Sounds must match expectations raised by the visual stimulus. (you see the car front whatever it’s called lol -> expect music to be played -> if music is played, good. if something else comes out, run. jk but if something else comes out it doesnt qualify to be a ventriloquist illusion.
When does vision capture sound and when does sound capture vision?
Vision captures sound when the visual modality provides more precise information about spatial location, and this is usually the case.
However, sound does capture vision when the visual modality is severely blurred or poorly localized.
Thus, we combine visual and auditory information effectively by attaching more weight to the more informative sense modality.
What is the body swap illusion?
The participant and experimenter squeeze each other’s hands repeatedly. The participant wears a special helmet equipped with two CCTV cameras so that he/she sees the experimenter’s POV.
Participants perceive that the stimulation caused by squeezing hands originates in the experimenter’s hand rather than their own!
Researchers then moved a knife either close to the participant’s or the experimenter’s hand. The participants showed a greater emotional response when the knife was close to the experimenter’s hand than when it was close to their own hand
Why is it difficult for airport security scanners to detect dangerous items?
Need to search for a wide range of different objects
Eg. knives, guns, and improvised explosive devices.
Compared performance on single-target search (either metal threats or improvised explosive devices) vs dual-target search (both categories of objects). Ability to detect target objects was significantly worse with dual-target search than single-target search.
Problem with dual-target search was that the two target categories didn’t share any obvious features (eg. colour; shape)
Illegal & dangerous items are present in only a minute fraction of luggage
Rarity of targets make it hard for detection
When targets appeared on 50% of trials, 80% were detected. When targets appeared on 2% of trials, only 54% were detected.
Not due to lack of attention, but due to excessive caution about reporting a target because each target was so unexpected.
What is the body size effect an extension of?
Body swap illusion
What is the body size effect?
The size of the body mistakenly perceived to be one’s own influences the perceived size of objects in the environment.
Why does the body size effect occur?
depends in large measure on our lifelong experience of seeing everything from the perspective of our own body combined with our general reliance on the visual modality.
How does the body size effect work?
Next, participants saw the POV of a doll. When participant’s body and the doll’s body were touched simultaneously, the participant experienced the doll’s body as his/her own. The size of the doll was changed in different conditions.
Small doll → other objects were perceived as larger and further away
Large doll → other objects were perceived as smaller, and nearer
Similar mechanism as body swap illusion (reliance on visual modality). Note that touch information has to match the visual information appropriately.
What is the “face-in-the-crowd” effect?
The finding that threatening (angry) faces can be detected more rapidly among other faces than faces with other expressions. Possibly because we detect angry expressions in an automatic way not requiring attention.
Effect has been replicated using naturalistic crowd scenes.
This effect is amplified more in anxious individuals.
The faster detection of angry faces than happy ones is amplified in what kind of individuals?
Anxious.
Are emotional faces detected faster than non-emotional ones?
Yes.
Eg: happy faces detected quicker because it shows teeth.
What model arose from an extension of the feature integration theory?
Guided search theory - activation map.
How to improve the performance of security screeners.?
Sophisticated training schemes
Computer-based training system (X-Ray Tutor). Starts with easy views of threat items, and moves on progressively to threat items with harder views (ie. obscure shape). Provide performance feedback on each trial.
Results – substantial improvement in performance, especially with improvised explosive devices which are less familiar and have more variable shapes, compared to knives & guns. Training improves the ability to recognize targets but does not reduce number of eye movements before target fixation.
Each inspector can specialise in searching for each category of threat items
Limitations – need 2 or more screeners for each bag, which would increase costs
Artificially increase number of threat targets
Include some “test bags” containing target items
How do we tell if visual search involves parallel or serial processing?
Assume all stimuli are targets.
Serial processing (one item at a time) → first item will always be a target, so detection times should not depend on the number of items on display.
Applied to complex visual tasks involving detecting a specific direction of rotation (eg. pinwheels rotating clockwise)
Parallel processing (simultaneous) → more targets means more information available, hence detection times should decrease as number of targets increase. Applied to tasks where target & distractors only differed along a single feature dimension (eg. colour, size, orientation)
Some visual search tasks involve parallel search while others involve serial search.
But parallel processing account for most findings on visual search as opposed to serial processing (72% vs 28%)
Tasks involving serial processing tend to be complex and had long average detection times.
Why is it easier to search for a target in the single-feature search? use the feature integration theory to explain.
Targets defined by a single feature “pop out” effortlessly regardless of the number of distractors
can use parallel processing (processing several stimuli at once)
Why is it harder to search for a target in the conjunctive search condition?
slower performance as there were many distractors + it will take much longer to decide that a target wasnt present than that it was present.
In contrast to single feature search, we need to process targets defined by a combination of features one by one using time-consuming serial processing.g
What does the feature integration theory say about visual search?
Feature integration theory shows that processes involved in visual search depends on nature and complexity of the target.
What are some limitations of the feature integration theory?
Speed of visual search does not depend only on target characteristics. Other factors include:
Similarity among distractors
Search is faster when distractors are very similar to each other
Similarity between target and distractors
For single-feature targets, the number of highly similar distractors has a large effect on speed detection.
For multiple-feature targets, only distractors that share at least one feature with the target, are important. (ie. If distractor does not share any feature with the target, we will ignore it)
What did Wolfe propose about the guided search theory?
Initial processing of basic features produce an activation map, with every item in the visual display having its own level of activation. Attention is directed towards items on the basis of their level of activation, starting with the most activated.
This assumption explains why search times are longer when some distractors share one or more features with targets. This model shows how visual search can be made more efficient by ignoring stimuli not sharing any features with the target.
Is visual search a top-down process. Illustrate how this works.
Hint: When looking at a picture, do you go straight to a part where something is likely to appear or do you scan every section of the picture?
Yes.
In real life, visual search is often selective and not random. This involves top-down processes based on our knowledge of where the specific object is most likely to be found.
Eg. searching for a person in real-life outdoor scenes
Observers typically fixate on relevant regions (eg. sidewalks) and ignored irrelevant regions (eg. sky; trees)
Observers also fixate on locations that are very different from neighbouring regions, as well as areas containing visual features characteristic of a human figure.
Why do experts exhibit better visual search performance when searching for something related to their expertise?
experts scan a larger region of visual space during each eye fixation when searching for expert-relevant targets
Why do high multitaskers perform poorer than low multitaskers?
High multitaskers develop “breadth-based cognitive control.”
Associated with being not selective or discriminating in their allocation of attention
Hence hard for them to avoid being distracted and switch attention efficiently.
Low multitaskers, on the other hand, are more likely to have top-down attentional control, but they might be so focused on the immediate task that they ignore other potentially useful information.
What potential danger might arise if a driver used his phone while driving?
Reaction times to events (eg. activation of brake lights on front car) increased by 250 ms compared to no-phone control conditions.
250 ms translate to extra 5.5m stopping distance for motorist going at 80kph.
Findings were consistent regardless of whether drivers used handheld or hands-free phones, or if drivers were talking or listening.
Also found that drivers had little awareness of the negative impact of using cell phones.
Didn’t slow down or keep a greater distance
Drivers using hands-free cell phones were less likely to attend closely to brake lights of front car, or to pedestrians or advertisements.
How do you improve your ability to mulittask, and explain this using a study.
PRACTICE. Occurs because processing changes from being a controlled process to an automatic one.
Study – two students received 5h training a week for 3 months. They were tasked to read short stories for comprehension while writing down words to dictation. Initially, they found it hard to combine these tasks. Their reading speed and handwriting suffered severely. After 6 weeks of training, both could read as rapidly and with as much comprehension as doing only that task. Quality of handwriting also improved. Performance improved further with extra training.
Distinguish between controlled processes and automatic processes.
Controlled:
- are of limited capacity
- require attention
- can be used flexibly in changing circumstances
- involves serial processing
Automatic
- suffer no capacity limitations
- do not require attention
- cannot be used flexibly in changing circumstances; once you learn it is very difficult to modify it.
- involves parallel processing
You use ______ processing for varied mapping and parallel/automatic processing for ________ mapping.
controlled/serial
consistent
Distinguish between varied mapping and consistent mapping.
Varied mapping: targets and distractors were letters. hence more difficult to find target because you have to compare each item in the memory set with every item in the visual one at a time until a match is found. took longer. requires controlled processes of limited capacity and requires attention.
Consistent mapping: target is always a number and distractors are always letters.
However, even if sensitive techniques are used, would we still be prone to interference effects? Provide evidence.
Yes. Evidence – Performance slowed down as number of items increased. Because if performance were truly automatic, response speed should be unaffected by number of items in the memory set and visual display.
Argued that we will always find evidence of interference in dual-task performance if sensitive techniques are used.
What is the psychological refractory period effect?
The slowing or response to the 2nd of 2 stimuli when they are presented close together in time.
Are there any exceptions where we don’t exhibit PRP? Will PRP be eradicated after numerous rounds of practice?
Yes. For very simple tasks that require little attentional processing.
no, prp still present.
List 4 features related to automaticity:
1) unconscious
2) fast
3) efficient
4) goal-unrelated.
note that they exist on a spectrum.
Use the concepts of automatic and controlled processing to explain the Stroop effect.
2 pathways involved: word reading pathway and color reading pathway. what you are supposed to do is to name the colour, but the colour of the word and the word contradict. eg: i show you the word “green” but it’s type in blue.
so word reading: automatic, color naming: controlled.
need to exert more attentional control to name the colour correctly.
Define consciousness.
Consciousness is defined as the normal mental condition of the waking state of humans, characterised by the experience of perceptions, thoughts, feelings, awareness of the external world, and self-awareness (for humans).
What are 3 key features of consciousness?
Sentience: Our subjective experience of awareness, which is only available to us as we are experiencing the experience.
Access to information: Relates to our ability to report the content of our subjective experience without being able to report on the processes producing experience.
So it’s like you can explain what you went through but you cannot explain WHY you went through that.
Self-knowledge: Our ability to have conscious awareness of ourselves.
Can there be consciousness in the absence of attention? Why and how so?
Yes.
Limited capacity of attention means that we can only attend to 3-4 items at a time. However, it was found that people could maintain approximately 7 visually presented in conscious awareness for almost 1 second –> can be consciously aware of more information than currently being attended to .
How are attention and consciousness not closely linked?
Observers were shown gratings and given the task of reporting the duration of their afterimage. –> so what you do is you let them see this pattern of gratings, then when they look up they’ll see this “invisible” gratings.
Amount of attention available to process the gratings was manipulated, as was the visibility of the gratings.
- IV1: Amount of attention available.
- IV2: Visibility (clear or blurred)
Consciously seeing the grating increased afterimage duration, whereas attention to the grating decreased afterimage duration
- cognitive processes associated with attention and consciousness can differ substantially.
What we are consciously aware of is generally determined by focused attention but it is possible for one to exist without the other.
How does attention influence behaviour in the absence of consciousness?
Jiang et al demonstrated that in spite of an absence of conscious awareness, straight males attended to invisible female nudes while straight females attended to invisible male nudes.
Gay males -> gay male nudes, lesbian women -> in between male and female nudes.
Explain the illusion of free will, and what causes us to believe we have much free will?
causes: 3 principles. (PCE) –> sounds like an expressway right.
Free will: The notion that we voluntarily choose what to do from a number of possibilities. This notion has been challenged by those who claim that nonconscious processes determine our actions.
Priority principle: We regard our thoughts as causing our actions when they occur just beforehand.
Consistency principle: thoughts consistent with the actions that follow, more likely to be regarded as being causally responsible than inconsistent ones.
Exclusivity Principle: Thought not accompanied by obvious alternative causes of action are more likely to be perceived as causing those actions.
What did Libet do to illustrate the illusion of free will?
If he ask about Libet rmb it’s about illusion of free will (libet -> liberty -> free)
Participants were asked to bend their wrist and fingers at a time of their choosing. The time at which they were consciously aware of the intention to perform the movement and the moment at which the hand muscles were activated were recorded.
What did Libet obtain from his experiment?
On some trials, participants were told to veto the action they had decided to make. Libet claimed that the decision to veto an action was based on a conscious intention in contrast to the position with performed actions.
Time at which they were consciously aware of the intention to perform the movement: readiness potential
- 350 ms before they reported conscious awareness to actually bend their fingers and wrist.
- 550 ms before they actually performed the action.
Conscious awareness to bend their fingers preceded the actual hand movement by 200 ms.
This shows that some preparation of a forthcoming action occurs before the individual is consciously aware of what he/she is going to do.
Since Libel’s experiment actually did not consider the exact timing that participants have conscious awareness of their intention, what can be done? Give an example of a study.
Soon et al: Focused on activation in brain areas - prefrontal cortrex - associated with decision processes. Participants had to decide whether to make response with left or right index finger. This is concerned with prediction using BRAIN AREAS (prefrontal cortex)
Found that decision that participants were going to make could be predicted from brain activity in parts of the prefrontal and parietal cortex up to 7 seconds before they were consciously aware of their decision
Activity in the motor areas: 5 seconds before conscious awareness of participants’ decisions predicted the timing of their responses.
What possibility about consciousness does the issue of split-brain patients bring up?
Do such patients have 2 consciousness? One in each hemisphere.
Which part of the brain is cut in split-brain patients?
hint: what brain part links the 2 hemispheres together
corpus callosum
Which brain area is often associated with decision making processes?
prefrontal cortex.
Are there any issues with saying that “Your decisions are strongly prepared by brain activity. By the time consciousness kicks in, most of the work has already been done.”?
Conclusion is based on the misleading assumption that an individual’s personal identity and his/her brain are completely separate
Research focuses on performance of trivial actions, which may have little relevance for real-life situations where action is more significant
We probably make most use of our sense of personal responsibility when making whether decisions. The whether decision was probably preceded by conscious intention even if the what and when decisions were not.
How do split brain patients ensure the environmental info reaches both hemispheres?
moving their eyes around.
Is there any evidence to show that split-brain patients only have one consciousness?
Face recognition
Patient NG recognised her own face equally well regardless of whether it was presented to left or right hemisphere. Her self-recognition performance was only slightly worse than healthy individuals, suggesting the existence of basic self-awareness in both hemispheres.
If split-brain patients only have one consciousness, where is it located at? What is the other hemisphere in charge of then?
System is based in the left-hemisphere known as the interpreter.
It seeks explanations for internal & external events to produce appropriate response behaviours. It provides coherent interpretations of events.
Left hemisphere more likely to be dominant because language abilities are often centered there
Probably plays the dominant role in consciousness
Right-hemisphere – “low level processing activities” (eg. basic self-awareness)
Limited ability to process language. Hence it is hard to know whether it possesses its own consciousness.
It probably lacks its own consciousness. Could be very disruptive if each hemisphere had its own consciousness because of potential conflicts between them.
Is there evidence to show that split-brain patients can have 2 consciousness?
Patient Paul S
He has reasonably good right-hemisphere language abilities
Right hemisphere controls left hand. Could spell his own name using left hand.
Presented a chicken claw in left hemisphere and a snow scene in right hemisphere
Chose a picture of chicken with RIGHT hand (LH)
Chose a shovel with LEFT hand (RH)
Suggest that Paul S had a separate consciousness in each hemisphere
BUT his explanation of his choices were strange: “The chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed”.
Shows that his left hemisphere was interpreting behaviour initiated by the right hemisphere with no clear evidence that the right hemisphere was contributing much to the interpretation.
List 3 assumptions made when using the Global Workspace Theory.
1) The early stages of information processing involve many special-purpose processors carrying out specialized functions in relative isolation from each other. These processors are located in numerous brain areas and are generally not associated with conscious awareness.
2) Consciousness is associated with integrating information from several special-purpose processors.
3) Even though consciousness can be associated with activation in numerous brain areas, 2 areas are most likely to be activated: parts of the prefrontal cortex and anterior cingulate.
Is there any support for the assumption that the early stages of information processing involve many special-purpose processors carrying out specialized functions in relative isolation from each other?
When words were consciously perceived, there was widespread activation in visual, parietal, and prefrontal cortex.
When words were not consciously perceived (masking), activation was largely confined to the visual cortex and there was no detectable activation of parietal or prefrontal areas
Is there any support for the assumption that consciousness is associated with integrating information from several special-purpose processors?
Study – asked participants to indicate location of a target stimulus and report their subjective awareness of its presence. Used event-related potentials (ERPs) to compare brain activities on trials when there was vs wasn’t conscious awareness of target stimulus.
Findings – amplitude of early ERP components were unaffected by presence of conscious awareness. However conscious awareness was associated with a late wave of activation between 400-600 ms after stimulus onset spread widely across the brain. Issue of causality – did brain activity precede and influence conscious awareness? Or did it occur as a result of conscious awareness?
Is there any support for the assumption that parts of the prefrontal cortex and the anterior cingulate are most likely to be activated during consciousness?
Study – presented participants with auditory stimuli (sounds) and visual stimuli (pictures of objects) under masked conditions (hard to consciously perceive). Compared brain activation on trials where stimulus was identified (conscious perception) vs stimulus unidentified (lack conscious perception)
Finding – activation in the lateral prefrontal cortex and anterior cingulate was associated with both auditory and visual conscious awareness.
Damage to prefrontal cortex makes it harder to achieve conscious perception.
Which part of the brain, when damaged, makes it harder to achieve conscious perception?
Prefrontal cortex.
