Multitasking Flashcards
What is the cocktail party effect? How was this experimentally proven?
An ability to filter out other stimuli whilst focusing on one stimuli.
Cherry conducted an experiment where subjects had to shadow a spoken message from one ear. Subjects were unable to repeat what was said in the other ear but could identify the speaker’s gender.
Moray followed the same design as Cherry but one word was repeated in the subjects unattended ear 35 times without it being noticed.
What experiment raised issues with Broadbent’s early selection model?
Moray - dichotic listening experiment and told to listen to one ear and ignore other ear. When Moray presented subjects name in unattended ear, 1/3 of subjects heard their name.
Gray and Wedderburn - Dear Aunt Jane experiment. Subjects were told to focus on one ear. Message presented was Dear 7 Jane. Unattended ear had 9 Aunt 6. When subjects were asked what they heard they reported that they had heard Dear Aunt Jane.
These experiments show that people processed information from the unattended ear that was relevant to them.
What changes were made to Broadbent’s early selection model?
Messages –> Attenuator –>(full strength attended message; and unattended message) –> Dictionary unit –> message to memory
Triesman proposed that selection of messages occurs in 2 stages - first the attenuator analyses incoming messages in terms of physical characteristics, language and meaning. The attenuator analyses the message to determine the attended message. Both messages pass through with the attended message at full strength and unattended message passing through too.
The message goes through to the dictionary unit which contains words and phrases with different thresholds for being activated.
What experiments led to late-selection models of attention?
Mackay - subjects listened to ambiguous sentences such as “they were throwing stones at the bank” in the attended ear and had to shadow this. They were played words either “money” or river” in the unattended ear. Subjects had to indicate which sentence from a pair was better fitting with the sentence that they had heard previously. Subjects were more likely to pick sentence that reflected the biased word in their unattended ear - even though subjects said they were unaware of word in unattended ear.
This led to late selection model - where information is processed to the level of meaning before the message to be further processed is selected.
What is processing capacity?
Amount of information that people can handle and sets a limit on their ability to process incoming information.
What is Broadbent’s filter model?
Messages —> Sensory memory —> Filter –> Detector ->Memory
Messages enter sensory memory and then pass through to the filter where it is filtered based on certain characteristics of information (i.e. voice type). The detector processes the meaning of the message and then passes this to STM.
It is an early-selection model. It is a bottleneck model (i.e. everything comes in but the filter restricts the flow of information).
What is perceptual load?
Perceptual load is related to the difficulty of the task. i.e. easy or well-practiced tasks have low perceptual load (low-load tasks)
What was Forster and Lavie’s experiments?
Forster and Lavie - subjects saw circle of letters and had to indicate if a target letter (X or N) was present. Found that responses were faster when the distraction letters were all the same (i.e. ooooooN) rather than different letters (i.e. DJKSXLR). Same letters represented low-load task and different letters represented high-load task. Faster response for low-load task.
Forster and Lavie also found that an irrelevant stimulus (i.e. a picture of a dog below the circle of letters) made the response time slower for low-load task in comparison to the high-load task.
They explain the load theory of attention - for tasks that have a low-load and utilise a small amount of processing capacity, there is spare processing capacity that the brain uses capacity on the distraction. In a high-load task, there is limited processing resources available and therefore distraction is ignored.
What is the Stroop effect?
Stroop effect is that task irrelevant stimuli are extremely difficult to ignore.
Stroop - name colour of shape. Then name colour of word that is a colour. Subjects responded slower in the second version. This is because it is difficult to ignore the task irrelevant stimuli (the words that are colours). This is because reading is an automatic, highly practiced processed and our brain naturally reads the words.
What is divided attention?
Divided attention is the ability to divide attention between two or more tasks. Distribution of attention can occur (i.e. playing on a game and listening to a conversation).
Divided attention can be achieved with practice (called automatic processing).
Divided attention becomes more difficult when tasks are harder.
When is divided attention easier? What experimental evidence is there for this?
Divided attention is easier with practice, through automatic processing.
Schneider and Shiffrin required subjects to hold information about target stimulus in memory and pay attention to a series of distractor stimuli and determine if target stimuli is present in distractor stimuli. Shown target stimuli (number). Then rapid presentation of test frames which contained distractors (letters) occurred. Subjects had to indicate if target was present.
On first attempts, performance was low. After many repeated trials (900), performance reached 90%.
Schneider and Shiffrin concluded that automatic processing occurred.
What is automatic processing? What experiment shows this?
Automatic processing is processing that occurs without intention and at little cost to a person’s cognitive resources.
Schneider and Shiffrin experiment - target stimuli and identifying if present in distractor. Results showed task became automatic after around 600 trials.
When is divided attention harder?
Divided attention is more difficult with harder tasks. Schneider and Shiffrin changed experiment so that target and distractor was both letters and numbers. Subjects were unable to use automatic processing even with practice.
What is the 100-car naturalistic driving study?
Video recorders in 100 vehicles recorded what the driver was doing, as well as the view of front and rear of car.
The recordings documented 82 crashes and 771 near crashes.
In 80% of crashes and 67% of near crashes, the driver was inattentive in 3 seconds beforehand. Texting was one of most distracting activities (nearly 22% of crashes).
What results support that distraction whilst driving results in crashes?
100-car naturalistic driving study
Toronto survey - risk of collision was 4 times higher when driver using cell phone or not. No difference for handsfree or hand-held.
Strayer and Johnston - simulated driving test where subjects had to apply the brakes as quickly as possible in response to a red light. Subjects who were talking on a cell phone missed twice as many red lights as those who weren’t and increased time to brake. There was decrease in performance for both handsfree and holding it. Talking on the phone uses cognitive resources required for driving.
What is the modal model of memory?
The modal model of memory was introduced by Atkinson and Shiffrin. It proposes three types of memory: Sensory; Short-term; and Long-term.
What is sensory memory? What is persistence of vision?
The retention, for brief periods of time, of the effects of sensory stimulation.
i.e. sparkler trail of light - movies and projectors - image flashes 24 times per second to give illusion of movement.
Persistence of vision - continued perception of a visual stimulus even after it is no longer present (i.e. gaps between movie frames; rapid movement of sparkler).
What experimental evidence is there for the length of the sensory store?
Sperling - flashed an array of 12 letters for 50 milliseconds and asked subjects to report as many letters as possible (whole report method). Subjects reported on average 4.5 letters of the 12. Subjects said they saw all of the letters but their perception faded faster than they could recall.
Sperling displayed 12 letter array and played a tone immediately after display indicating which row to focus on. Subjects were to report as many of the 4 letters as they possibly could from the line indicated by the tone (partial report method). Subjects were able to report on average 3.3 out of 4 letters.
Sperling did delayed partial report method - tone was played after a delay up to 1 sec after the image was displayed. Subjects were only able to report slightly more than 1 letter per row after 1 sec.
Sperling concluded that information from our visual receptors stored in sensory memory decays within a second.
What is iconic and echoic memory?
Iconic memory is the brief sensory memory for visual stimuli.
Echoic memory is the persistence of sound. Echoic memory lasts for a few seconds after presentation of original stimulus (e.g. someone saying something, you responding what and then you hearing what they actually said before they repeated it).
What is short-term memory?
Short-term memory is the system involved in storing small amounts of information for a brief period of time (15-20 sec)
What is the duration of STM? What evidence is there of this?
STM lasts for about 15-20 seconds.
Peterson and Peterson - recall task - subjects had to remember 3 letters and then count backwards in threes until told to recall the three letters. They found that subjects remembered only about 12% of three-letter groups after 18 secs. Due to delay.
What is proactive interference? Experiment?
What is retroactive interference?
Proactive interference is interference that occurs when information that was previously learned interferes with learning new information.
Keppel and Underwood - looked at Peterson and Peterson recall data and found that on the first trial, performance was high (even above 18-second delay) but performance dropped on the more trials completed.
Retroactive interference is when newly learnt information interferes with remembering old learning (i.e. learning a new language makes it more difficult to remember previously learnt language).
How many items can be held in STM? Evidence?
Magic 7 + or - 2 (Miller)
Digit span tests - average capacity is 5 to 9 items. Digit span is the number of digits that a person can remember.
What evidence contradicts Millers 7 + or - 2 rule for STM capacity?
Luck and Vogel - measured STM capacity by change detection. Subjects saw two pictures flashed one after another and subjects had to determine what had changed between first and second picture. Luck and Vogel used coloured squares. Subjects performance started decreasing at as little of 4 squares.
Miller proposed that chunking helps increase STM capacity. Smaller units are combined into larger units (i.e. phrases, sentences).
- Ericsson - got a runner, S.F. to remember strings of up to 79 digits through creating meaningful chunks that were related to things he already knew.
Alvarez and Cavanagh - used change detection procedure of Luck and Vogel but found that more complex objects (i.e. shaded cubes) reduced STM capacity.
