characteristics of ADHD
inattention characteristics
- often has difficulty sustaining attention in tasks or play activities’
- Is often easily distracted by extraneous stimuli
- Often does not seem to listen when spoken to directly
hyperactivity characteristics
- Often fidgets with hands or feet or squirms in seat
- Is often on the go as if driven by a motor
- Often blurts out answers before questions have been completed
- Impairment in multiple settings
Broadbent’s filter model of attention
1) sensory memory: holds all of the incoming information for a fraction of a second and then transfers all of it to the filter.
2) The filter identifies the message that is being attended to based on its physical characteristics—speaker’s tone of voice, pitch, speed of talking, and accent—and lets only this attended message pass through to the detector in the next stage. All of the other messages are filtered out.
3) The detector processes the information from the attended message to determine higher-level characteristics of the message (meaning).
4) STM: The output of the detector is sent to short-term memory, which holds information for 10–15 seconds and also transfers information into long-term memory, which can hold information indefinitely.
the bottle neck model (broadbents)
- bottleneck restricts information flow
- doesn’t just slow down the flow but keeps large portion of the information from getting through.
- lets information through based on specific physical characteristics (rate of speaking, pitch of the speaker’s voice)
challenging broadbents model
- we should not be conscious of information in the unattended messages.
- Neville Moray (1959) did a dichotic listening experiment; subjects were instructed to shadow the message presented to one ear and to ignore the message presented to the other ear
- ## Moray presented the listener’s name to the unattended ear, 1/3 subjects detected it
dear aunt jane
- information presented to the unattended ear is processed enough to provide the listener with some awareness of its meaning.
- subjects were told to shadow the message presented to one ear.
- (shadowed) ear –> “Dear 7 Jane,”
- unattended ear –> “9 Aunt 6.”
- subjects reported “Dear Aunt Jane.”
- Switching to the unattended channel to say “Aunt” –> subject’s attention had jumped from one ear to the other and then back again. (taking the meaning of the words into account)
Treismans attentuation of memory
- selection occurs in two stages, and uses an attenuator
The attenuator analysed the incoming message in terms of it’s physical characteristics, language and the meaning. Both attended and unattended stimuli pass through, attended messages pass through with more strength. The message is then analysed in the dictionary unit assigning meaning to words.
-If voices are similar, then it might be necessary to use meaning to separate the two messages.
- attended message at full strength and the unattended messages still present, but weaker
- “leaky filter” model.
message is analysed by the dictionary unit.
early selection model
proposes a filter that operates at an early stage in the flow of information.
- broadbent
- treismans
A LATE SELECTION MODEL
- messages can be selected at a later stage of processing, based primarily on their meaning.
- But as research in selective attention progressed, researchers realised that there is - no one answer to what has been called the “early–late” controversy
Early selection can be demonstrated under some conditions and later selection under others, depending on the observer’s task and the type of stimuli presented.
Nilli Lavie processing capacity and perceptual load
people can ignore distracting stimuli depending on their processing capacity and perceptual load
processing capacity
the amount of information people can handle and sets a limit on their ability to process incoming information;
perceptual load
difficulty of the task
Sophie Forster and Lavie (2008) the role of processing capacity and perceptual load
- The subjects’ task was to respond as quickly as possible when they identified a target, either X or N.
- Subjects pressed one key if they saw the X and another key if they saw the N. This task is easy for displays where the target is surrounded by just one type of letter, like the small o’s.
- the task becomes harder when the target is surrounded by different letters
- This difference is reflected in the reaction times, with the hard task resulting in longer reaction times than the easy task.
- However, when a task-irrelevant stimulus—like the unrelated cartoon character is flashed next to the display, responding slows for the easy task more than for the hard task.
- which the circle represents the person’s processing capacity and the shading represents the portion that is used up by a task.
- with the low-load task, there is still processing capacity left resources are available to process the task-irrelevant stimulus, and even though the person was told not to pay attention to the task-irrelevant stimulus, it gets processed and slows down responding.
the stroop effect
by J. R. Stroop in 1935.
- name, as quickly as possible, the colour of ink used to print each of the shapes.
- repeat the same task specifying the colour of the ink, not the colour name that is spelled out.
- This effect occurs because the names of the words cause a competing response and therefore slow responding to the target
- the task- irrelevant stimuli are extremely powerful, because reading words is highly practiced and has become so automatic that it is difficult not to read them
stimulis salience
stimulus salience—the physical properties of the stimulus, such as colour, contrast, or movement.
- capturing attention by stimulus salience is a bottom-up process because it depends solely on the pattern of light and dark, colour and contrast in a stimulus.
- However Scanning can still be based on cognitive factors (characteristics that have meaning to you)
attentional capture
When attention due to stimulus salience causes an involuntary shift of attention
*important if it serves as a warning of something dangerous
scene schemas
- top-down processing is also associated with - scene schemas—an observer’s knowledge about what is contained in typical scenes
- people look longer at things that seem out of place in a scene= means that attention is being affected by their knowledge of what is usually found in the scene.
scanning based on task demands
- the timing of when people look at specific places is determined by the sequence of actions involved in the task.
- person’s eye movements were determined primarily by the task.
- The person fixated on few objects that were irrelevant to the task, and eye movements and fixations were closely linked to the action the person was about to take.
- Furthermore, the eye movement usually preceded a motor action by a fraction of a second
just in time strategy
eye movements occur just before we need the information they will provide
precueing
- determine whether presenting a cue indicating where a test stimulus will appear, enhances the processing of the target stimulus.
- subjects reacted to the square more rapidly when their attention was focused on the location where the signal was to appear.
- Posner interpreted this result as showing that information processing is more effective at the place where attention is directed.
same object advantage
- attention can enhance our response to objects
- when attention is directed to one place on an object, the enhancing effect of that attention spreads to other places on the object.
attention
the ability to focus on specific stimuli or locations
selective attention
attending to one thing while ignoring others.
letters with a small letter flanked with another (competing stimuli)
- apparently isn’t as bad in ADHD as sustained attention shows to be (hard to pick up in ADHD)
distraction
one stimulus interfering with the processing of another stimulus.
divided attention
paying attention to more than one thing at a time.
