revision list Flashcards
broadbent’s filter model
Broadbent developed the filter theory: information is held in a preattentive temporary store,.and only sensory events that have some physical feature in common are selected to pass into the limited capacity processing system.
early selection models of attention
Broadbent developed the filter theory: information is held in a preattentive temporary store,.and only sensory events that have some physical feature in common are selected to pass into the limited capacity processing system.
Treisman changed this into the filter-attenuation theory which says that early selection by filtering precedes stimulus identification, but the filter attenuates the information only on unattended channels. These are both early-selection theories.
The early-selection view by Broadbent: the human information processing system is like an information channel with limited capacity. He thought that attention works to select information at an early level based on attributes like the location or pitch. His filter theory says that there is a filter that protects the information-processing model from being overloaded. It assumes that information from the senses first enters a buffer where it can be held for a short time. Information that fits the filter is then passed along to the limited capacity channel, where it can be identified. The results of this analysis are then sent to a response system and may be used to update expectations about what is likely to occur in the given situation. However, sometimes potentially relevant information gets past the selective filter, like hearing your name.
This is why Treisman proposed the filter attenuation theory: the selective filter does not completely block out unwanted information, but only attenuates or reduces the strength of unattended stimuli.
late selection models of attention
Deutsch and Deutsch proposed the late-selection theory, in which unattended stimuli are always identified and that the bottleneck occurs in later processing.
EEG
reflects all neural processing occurring within a given time interval and therefore is not very informative as to what specific processes are occurring.
- ERP: event-related potentials. Computed by averaging together many EEG’s of a particular event to eliminate noise. Advantage: it is measured throughout the time intervening between the presentation of the stimulus and the making of a response, allowing precise measurement of the time course of attentional processes.
fMRI
fMRI: functional magnetic resonance imaging. Depends on the blood oxygen level- dependent (BOLD) response. The increase in blood oxygen is measured using the specific magnetic properties of blood and the surrounding tissue. It doesn’t require invasive measures and it’s getting quite accurate.
task-switching
Task-set switching: efficient, coordinated performance of complex tasks often depends on the ability to switch from one task or task component to another. Advance reconfiguration can help with this: they’re like processes that facilitate this transition. Switching costs are increases in RT and error rates on the task after the switch and reflect the time needed to adopt the appropriate task set. Task-set switching depends on two components: a top-down, control component and a bottom-up component in which the stimulus triggers the appropriate set. It does not seem to be the case that task-set switching is always all-or-none, and repeating the same task has benefits over task switching regardless of foreknowledge.
Task-set switching and executive control: it may be that executive control is responsible for determining which task will be performed, but that readiness (and RT) to perform the task depends on more automatic processes of inhibition and activation from preceding trials. Also, there might be a general need to reinstate the stimulus- response mapping (aka retrieve it from memory), so switching seems to contain restart costs and may also reflect negative transfer.
De Jong: model of residual switching costs based on limitations in the ability to fully prepare for a new task before the presentation of the first stimulus and on the failure to take advantage of opportunities for advance preparation. He proposes that residual switch costs rest largely on a “failure to engage” in advance preparation for an upcoming task. If this is true, residual switch costs should be observed only on trials for which performers fail to prepare for the new task.
sources of switch costs
Switching costs are increases in RT and error rates on the task after the switch and reflect the time needed to adopt the appropriate task set. Task-set switching depends on two components: a top-down, control component and a bottom-up component in which the stimulus triggers the appropriate set. It does not seem to be the case that task-set switching is always all-or-none, and repeating the same task has benefits over task switching regardless of foreknowledge.
Donder’s subtraction logic
The personal equation was a correction to equate different astronomers’ readings. Wundt saw this as the time it takes to switch attention voluntarily from one stimulus to another.
Donders measured this using the subtractive method, in which the time for a particular process could be estimated by adding that process to a task and taking the difference in RT. There are three types of reactions: a (simple reaction), b (choice reaction), and c (go or no- go reaction; respond to one stimulus but not another). The difference between c and a was presumed to reflect the time for stimulus identification, and the difference between the b and c was considered to be the time for expression of the will. Wundt criticised this and proposed d, which is like a but the subjects are instructed not to respond until they have identified the stimulus.
CODELAB EXPERIMENT
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Cognitive load theory
Cognitive load and instructional learning: when a display does not provide a learner with sufficient information, the learner must integrate instructional or textual information with the displayed information to achieve this understanding. This worsens performance because of split attention. Cognitive load theory: performance decreases when there is split attention because cognitive workload increases. You can reduce this by using auditory presentation for the textual material that needs to be integrated with the information in a diagram. It’s even better if the pieces of information to be integrated are located in close physical proximity, presented in distinct modalities, or colour-coded.
psychological refractory period (PRP paradigm)
stimulation of neurons was followed by a refractory phase during which the neurons were less sensitive to stimulation. Responses are slower when a stimulus follows the preceding one by a short interval.
dual-task performance may suffer because both stimuli cannot be fixated at the same time, and to avoid this, the stimuli for the two tasks are often presented in different sensory modalities and the responses are made with different effectors. An important finding is that the RT to the second stimulus is slowed relative to when that stimulus is presented alone, and this is called the psychological refractory period (PRP) effect. This shows that at least some processes may be carried out for only one task at a time.1
Attentional Blink.
performance shows a half-second dip after only one word has been identified. It seems to stem from interference of the processing requirements of the target. The second target may be processed to a certain extent but the resulting representation requires further processing in order to be stored in memory. If a previous item is still receiving stage 2 processing, selection of a new item has to wait because stage 2 processing is limited. Reporting an item briefly presented in a sequence requires that the item be identified, selected, and consolidated.
Flanker compatability effect
Flanker-compatibility effect: responses are relatively slow and inaccurate when the target is flanked by incongruent letters, intermediate when the flankers are neutral letters, and faster when the flanker letters require the same response as the target. The flanker letters are perceptually processed even though instructions are to focus on only the central letter, but also information is often processed to the point of producing a lateralized readiness potential, which is indicative of motor preparation. Flankers assigned to an incompatible response produce more interference than flankers not assigned to any response, which suggests that the interference arises because of conflicting response information.This is an example of the failure of early selection in that people are not able to filter out flanker information. The flanker-validity effect is that people can learn a probabilistic relation between the target and the flanker, even when instructed to ignore the flankers.
- Reducing the flanker effect can only be done with spatial separation. Research has suggested that making the task easier actually makes selection more difficult, because there is spare capacity.
- Summary: flanker effects reflect difficulty in suppressing irrelevant information.
Simon effect
the finding that responses are faster when the stimulus appears on the same side as the assigned response than when it does not. It shows that it is not necessary that the relevant and irrelevant dimensions of the stimuli be related (like colours and their names) in order for interference effects to occur. The Simon effect is the result of conflicting spatial codes. Hommel: the spatial code associated with stimulus position forms rapidly when the stimulus is presented and then decays automatically, without the application of voluntary inhibitory strategies.
Stroop effect
an important property is that it is asymmetric, meaning that incongruent
colour words slow colour naming, but incongruent ink colours do not slow colour- word reading. Some scientists argue that the stroop effect does not imply a pure form of automatic processing in which words can never be ignored. For example, if only one letter of a word is coloured, colour-naming responses are less influenced by the presence of incongruent colour words. This shows that the requirement to focus attention on just one letter of a word stops the automatic reading of the entire word. Stroop effects can also be affected by changing the proportion of congruent and incongruent stimuli.
