Introduction to attention and working memory research Flashcards
Describe the difference between bottom-up and top-down selection
In top-down selection, stimuli are actively prioritised based on their relevance. This process involves conscious control. Bottom-up selection would be prioritising stimuli reflexively like a flashing light.
Give examples of limitations in sensory processing capacity
Attentional limitations occur in all sensory modules, because the brain filters information through attentional priorities.
Visual Limitation example
- Inattentional Blindness: failure to notice a fully visible & salient stimulus when attention is focused on another task or stimulus
- Change Blindness: difficulty in detecting changes in visual scenes when the changes occur gradually or during interruptions such as blinks, saccades, or other visual disruptions
Auditory Limitation example
- Cocktail Party Effect: In noisy environments, individuals may have difficulty attending to and processing specific auditory stimuli while filtering out background noise. But if we hear our name somewhere our attention shifts immediately (=name effect)
Describe the difference between focused, divided, and sustained attention
Focused attention is the same as selective attention, such as in Posner’s spotlight model and can be researched using the visual search task.
Divided attention is distributed attention on the whole visual display, and can be measured using the whole report paradigm.
Sustained attention is attention that requires constant focus. It can be measured using the SART (sustained attention to response task), in which participants are presented with a series of digits. They are instructed to respond as quickly as possible to each digit, except for a designated target digit to which they must withhold their response for a prolonged time period.
Describe the Posner cueing task and what it measures
Posner’s cueing task is a way of measuring selective attention. Researchers use both endogenous cuing, in which the participants attention to the cue is voluntary (indicative arrow in the center of the screen), and exogenous cueing, in which the participant’s attention is automatically captured because it is reflexive (like a flashing light). Both valid, invalid and neutral cues are used to measure the participant’s reaction time. Researchers concluded that a mental spotlight describes that the brain attends to spatial locations and that stimuli that appear in that locations are processed faster.
Describe the visual search task and what it measures
In a visual search task, selective attention is measured by pop-out (red X in environment of black O) versus conjunction search (black X in environment of black O). Pre-attentively, pop-out features can be analysed in parallel, whereas conjunction search takes place in a sequential, aka serial manner. When using serial attention, one links different information about the items on display to recognise and identify the correct target, which is also referred to as the feature integration theory of attention.
Describe the whole and partial report tasks and what they measure
Whole report is used to study divided attention, and capacity and duration of sensory memory. The participants are presented with a visual display, typically a grid of letters, for a very short duration and are immediately afterwards, asked to recall as many items from the display as possible.
Partial report measures focussed attention, in the same fashion as the whole report, but now using attentional cues only a part of the report is requested afterwards.
Describe the feature integration theory.
Conjunction search takes place in a sequential, or serial manner. When using serial attention, one links different information about the items on display to recognise and identify the correct target, which is also referred to as the feature integration theory of attention.
Explain the distinctions between early vs. late, and parallel vs. serial attentional selection
In a visual search task, pop-out versus conjunction search is researched in which the latter takes more time. Pre-attentively, pop-out features can be analysed in parallel, whereas conjunction search takes place in a sequential, or serial manner.
In early selections models, the idea is proposed that a stimulus is tossed out as irrelevant before perceptual analysis of the stimulus is complete. In contrast, late selection models describe that all inputs are processed equally, after which selection takes place at higher stages of information processing.
Describe Bundesen’s TVA model of attention
Bundesen’s theory of visual attention posits that visual attention acts as a selective mechanism, which allocates limited processing resources to relevant stimuli while ignoring irrelevant stimuli. Attention viewed as a parallel race instead of a serial processing
Model parameters in TVA
Capacity related
- K: visual short-term memory span (elements)
- C: visual processing speed (elements/s)
- T0: threshold for conscious visual perception
Parameters for attention weights
- W index: spatial attention weights (left vs. right)
- α: Distractedness (relative weight of distractor vs target)
Describe Baddeley’s model of working memory
Baddeley’s model of working memory consists out of a Executive Center that manages temorary storages over three domains:
(1) the phonological loop: retain infromation by repeating it in your head using language
(2) the visualspatial sketchpad: retain information by sketching it in your head using vision
(3) the episodic buffer: temporary workspace that acts as bridge between working memory and long-term memory.
Explain the concept of alertness and how it can be measured
Alertness is a general term for the response readiness, and specifically refers to the subjective perception of being awake and attentive. Tests to measure alertness are usually test that initially require sustained attention because they tend to be sensitive to alertness, like SART. Another way to measure alertness is pupil dilation.
Explain the concept of arousal and how it can be measured
Arousal is a physiological and psychological state of alertness, wakefulness & readiness.
According to the Yerkes-Dodson law, follows cognitive performance an inverted U-shaped function of arousal.
Arousal can be measured using EEG wavelengths that vary through sleep stages, heart rate variability, skin conductance, respiratory rate and pupil size.
Describe main aspects of the neural basis of arousal
The neural pathways that modulate arousal is the Ascending Reticular Activating System (ARAS). Upon sensory input it releases neurotransmitters through two patways.
(1) The dorsal pathway courses through the intralaminar nucleus of the thalamus to the cortex.
(2)The ventral pathway passes through the hypothalamus and the basal forebrain and on to the cortex.
Involved neurotransmitters are noradrenaline released from locus coeruleus, promoting wakefulness. Serotonine released from raphe nuclei, involved in emotional arousal.
Discuss the relation between levels of arousal and consciousness
Arousal is a prerequisite for consciousness: Without a sufficient level of wakefulness and alertness, consciousness cannot emerge. At lower arousal levels (deep sleep) consciousness is absent or greatly diminished, but when arousal levels increase, consciousness emerges ranging from basic sensory awareness to higher-order cognitive processes such as self-awareness.
(1) The dorsal pathway (ARAS) courses through the intralaminar nucleus of the thalamus to the cortex. People with lesions of the thalamus are usually awake but unresponsive. (2) The ventral pathway passes through the hypothalamus and the basal forebrain and on to the cortex. People with an injury to the ventral pathway find it difficult to stay awake and tend to sleep more than the usual amount.
Describe the interplay between bottom-up and top-down driven attention
Top-down control is about goal-driven attention such as prioritising studying over scrolling on the phone for a good grade, whereas bottom-up control is stimulus-driven such as a loud noise that requires attention even though one’s studying. Another definition that describes top-down control is voluntary attention, or endogenous attention. Bottom-up control is also referred to by reflexive attention or exogenous attention.
Describe other anatomical structures implicated in attentional control
top-down neuronal projections from attentional control system (dorsal + ventral attention control system) contact neurons in sensory cortical areas to alter their excitability -> response of sensory areas to a stimulus is enhanced if the stimulus is given high priority by the dorsal/ventral attention control networks
Describe effects of attention in the brain’s perceptual systems, as measured by ERP
Event Related Potentials (ERPs) can be used to measure neural mechanisms of visuospatial attention by means of EEG. The first positive ERP wave is called P1, and typically is measured in the occipital cortex contralateral to the visual hemifield of the stimulus. The P1 is greater in amplitude when the visual stimulus appears at a location to which a participant is attending
Describe effects of attention in the brain’s perceptual systems, as measured by fMRI
In fMRI studies with human participants, it was shown that attention to one visual hemifield activated multiple regions of visual cortex in the contralateral hemisphere. In other words, visuospatial attention van influence stimulus processing at many stages of processing, ranging from V1 to IT cortex.
Describe effects of attention in the brain’s perceptual systems, as measured by single-cell studies
The P1 is greater in amplitude when the visual stimulus appears at a location to which a participant is attending. In monkey studies using single cell recording, it was showed that selective spatial attention affects the firing rates of V4 neurons which supports the finding.
Describe the general anatomy of cognitive control, especially with regard to the prefrontal cortex
Executive function is another word for cognitive control, describing the set of psychological processes that enable us to perform goal-oriented behaviour. The prefrontal cortex houses the brain areas that are necessary for executive functions, such as the lateral prefrontal cortex, medial frontal cortex, frontal pole and orbitofrontal cortex.
Describe physiological correlates of working memory
An important anatomical structure for working memory is the lateral prefrontal cortex (LPFC), or executive centre. There seems to be a lateral-medial gradient that respectively processes more environmental versus personal history and emotional information. Another interesting gradient of the prefrontal cortex is the anterior-posterior gradient that reflects abstract versus palpable information.
Discuss the relation between working memory and cognitive control
Working memory = temporary storage + manipulation of information necessary for cognitive tasks. It allows individuals to hold information in mind while performing cognitive operations
Working memory provides resources for executive functions
Describe the main psychological features and brain lesions of the neglect syndrome
Unilateral spatial neglect is a disease in which patient’s brain’s attention network is damage in one hemisphere, causing complete neglect of the contralateral visual field. It is caused by damage to right posterior parietal lobe and temporo-parietal junction. Often, drawing tests like sketch a clock or make + from -, are used to research or diagnose. It is important to note that these patients are not blind in one visual field, rather extinction of stimulus in the affected visual field takes place when it is overwritten by other stimuli in the unaffected visual field. In that sense, it is better to talk about biases.
Describe other conditions where attention or cognitive control is disturbed after brain damage
A Bálient’s patient has problems with perceiving the visual field as a whole scene (simultainagnosia), guiding use movements voluntarily (ocular apraxia) and reaching to grab objects (optic ataxia). This is also an attentional disorder, in which bilateral occipitoparietal lesions occurred. These patients have trouble to perceive multiple objects in space.
