PSY1EFP Lecture Notes - Lecture 8: Hemispatial Neglect, Frontal Eye Fields, Attentional Blink
18 Jun 2018
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EFP Lecture 8 Session 1 – Cognition (3)
Emotion captures attention
Perceptions and memories are not all created equal. They are modulated by their emotional significance.
Attention helps us to separate the wheat from the chaff, determining what we will focus on and process further and
what we will ignore
Thus, attention works to prioritise information processing , allocating resources to processes that are biologically or
motivationally important to the organism – emotion captures attention.
Emotion and Cognition
It’s no surprise that your emotions and mood influence your ability to think and process information. e.g., anxiety
reduces working memory capacity and problem-solving ability by distracting you from the task at hand.
People in a good mood tend to have better recall than people in a bad mood. Good moods facilitate the encoding and
retrieval of positive information, whereas bad moods facilitate the encoding and retrieval of negative information.
Emotion and Attention
Emotional content influences the way you deploy attention too
In visual search tasks, angry and happy faces are detected faster than neutral faces, suggesting that emotional faces
direct the allocation of attention
Other emotion-laden stimuli, such as snakes or spiders, are also detected faster than neutral stimuli such as flowers or
mushrooms
In the standard Stroop task, participants have to name the colour of the ink in which a colour word is printed (e.g.,
GREEN). In the emotional Stroop task, participants have to name the colour of the ink in which an emotional or
neutral word is printed (e.g., FAILURE).
Research indicates that the speed of colour naming emotional words is slower than the speed of colour naming
neutral words, indicating interference from the distracting emotional word
Research indicates that the attentional blink is reduced when targets are strongly emotional words or images e.g.,
Anderson (2005) used the attentional blink paradigm to test the recognition of negative emotional words (e.g.,
scream), negative emotionally arousing words (e.g., rape) and neutral words (e.g., apple)
Anderson found that negatively emotional words are less susceptible to the attentional blink than neutral words.
The effects of emotion on attention strongly suggest that we have automatic attentional processes that scan and
analyse the perceptual field, searching for biologically relevant (i.e., threatening) events. Thus, stimulus features
relevant to survival capture attention, including fearful or angry faces, negative emotional stimuli (and positive
emotional stimuli – reward!), and threatening fauna (snakes, spiders)
Attention in the Brain
The brain’s attentional system is anatomically separable from its data processing systems: they interact, but remain
distinct
Attention is not localised in one specific region of the brain, but involves distributed network of regions : regions carry
out different functions
Orienting network -Responsible for shifting attention to various locations (frontal eye fields, parietal lobe, pulvinar,
superior colliculus)
Alerting network -Responsible for waking you from sleep and surveying environment for relevant stimuli (many
subcortical, incl. thalamus)
Executive attention network -Responsible for inhibiting automatic responses to stimulus (prefrontal cortex)
Unilateral Neglect
Damage to different parts of the right hemisphere, esp. damage to the right parietal lobe, results in unilateral neglect
syndrome
Patients ignore the left half of their visual field, have no conscious perception of objects in that part of space, and
ignore inputs coming from the left side of the body
Patients are typically unaware of the problem, and may forget to wash/shave/apply makeup to the left side of their
face, forget to dress the left side of their body (rare, but documented!), or neglect to eat food on the left side of their
plate
Research by Marshall & Halligan (1988) demonstrates that patients may show tacit awareness of stimuli that cannot
be consciously recollected or identified. They presented patient P.S. with two line drawings of a house
In one drawing there was a fire coming out of a left-hand window. P.S. reported that the drawings were identical. But
when asked which house she would like to live in, she reliably chose the house that was not burning!
find more resources at oneclass.com
find more resources at oneclass.com
Unilateral Representation Neglect
Bisiach & Luzzatti (1978) first demonstrated that some patients with unilateral neglect also neglect the left-hand side
in their mental representations of objects and scenes
They asked two neglect patients to imagine being in the Piazza del Duomo in Milan (their home town), and to describe
the buildings and other features around the square
When asked to imagine that they were standing on the steps of the cathedral, nearly all of the features mentioned,
would have been to their right, but when asked to imagine standing at the opposite end of the square, most of the
features mentioned were those on the other side, previously neglected!
Balint’s Syndrome
We normally perceive a visual world that is seamless and richly detailed, However this smooth perception is really an
illusion: our brains combine multiple images which gives us the perception of a seamless surround
Patients with Balint’s syndrome perceive the world differently, and are incapable of joining their perceptions: they
perceive the world as a series of disjointed single objects
Balint’s syndrome is a spatial disorder of attention that typically results following bilateral parietal damage
Objects compete for our attention: patients are unable to see more than one thing at a time (simultanagnosia)
Patients have ‘sticky’ visual fixation and exhibit severe difficulties voluntarily moving fixation (optic apraxia). Patients
are unable to reach toward the correct location of perceived objects (optic ataxia)
Because patients with Balint's syndrome lose spatial information outside their own bodies, meaning that they cannot
locate an item they perceive, nor can they tell when an item is moved towards or away from them, they are
functionally blind except for the perception of one object in the visual scene at a time
Synaesthesia
Synaesthesia is a fascinating phenomenon in which in which stimulation of one sensory modality leads to reports of
“extra” automatic, involuntary experiences in a second modality. e.g., letter Q as crimson with a slight taste of fennel
piano music is light blue and feels smooth Wednesday is indigo blue.
The most common and most often reported forms of synaesthesia involves letters or digits inducing particular colours
(colour graphemic synaesthesia) that appear as a surface feature of the letters and digits
Synaesthesia is reasonably common (1/2000; 6:1 female to male), and a number of well-known people have reported
their experience e.g., David Hockney (music – colour) Vladimir Nabokov (grapheme – colour) Richard Feynman
(grapheme – colour) Jean Sibelius (music – colour) Nikolai Rimsky-Korsakoff (musical keys – colour)
Synaesthesia and Attention
The idiosyncratic binding of colours with letters/numbers in synesthetes is thought to occur in much the fashion
as normal perception : synaesthesia requires attention to bind the perceived form features with the internally
generated colour features
Rouw & Scholte (2007) found that synesthetes have more white matter connections between different parts of
the brain (including inferior temporal, superior parietal and frontal cortices)
Importantly, in grapheme-colour synesthetes, there was greater connectivity between the fusiform gyrus
(grapheme form recognition) and an adjacent area specialized in the perception of colours
Ward et al. (2010) demonstrated the important role of attention in synaesthesia using a shape detection task.
They tested 36 grapheme-colour synesthetes who had different coloured synesthetic perceptions of the numbers 2
and 5, and 36 controls. In the task, they were required to detect a shape made of 2s embedded in a background of 5s
(or a shape made of 5s in a background of 2s)
Ward et al. gave their participants only 1 second to identify the embedded shape
Results showed that synesthetes (41.4%) were able to identify the embedded shape significantly better than
controls (31.5%; chance performance = 25%)
Summary
Emotion captures attention : emotions and mood influence your ability to think and process information, and
similarly, emotional content influences the speed at which you process stimuli
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Efp lecture 8 session 1 cognition (3) Perceptions and memories are not all created equal. Attention helps us to separate the wheat from the chaff, determining what we will focus on and process further and what we will ignore. Thus, attention works to prioritise information processing , allocating resources to processes that are biologically or motivationally important to the organism emotion captures attention. It"s no surprise that your emotions and mood influence your ability to think and process information. e. g. , anxiety reduces working memory capacity and problem-solving ability by distracting you from the task at hand. People in a good mood tend to have better recall than people in a bad mood. Good moods facilitate the encoding and retrieval of positive information, whereas bad moods facilitate the encoding and retrieval of negative information. Emotional content influences the way you deploy attention too.
