2.2 Distortions in perception (c9) Flashcards
perceptual distortion involves
an inconsistency, or mismatch, btwn a perceptual experience and physical reality
define visual illusions
he perception of a visual stimulus in a way that conflicts with how it is in physical reality
Müller-Lyer illusion
Ames Room illusion
what is agnosia?
Agnosiais characterised by loss or impairment of the ability to recognise and identify objects, persons, sounds or other sensory stimuli using one or more of the senses despite otherwise normally functioning senses.
can agnosia be explained by a problem with the sense organ itself..?
The deficit cannot be explained by a problem with the sense organ itself, attention, memory, language problems, or unfamiliarity with the stimuli.
is agnosia limited to one sense
yes mostly vision, hearing or touch.
define visual agnosia
Visual agnosiais loss or impairment of the ability to recognise visual stimuli.
do people w visual agnosia have difficulty recognising familiar objects and possibly faces?
yes
how rare is agnosia
less than 1% of people diagnosed with brain damage have agnosia.
does agnosia occur suddenly or gradually?
The disorder can occur suddenly due to a stroke or traumatic brain injury, or gradually due to a brain tumour, overexposure to an environmental toxin (e.g. carbon monoxide poisoning), a developmental disorder, dementia, or another neurological condition.
the type(s) of visual agnosia acquired by the individual and the symptoms primarily depend on the…
specific location of the damage, its extent and severity.
is there a direct cure for agnosia
no
Instead, the underlying cause is treated if found and when possible. For example, if caused by a tumour, surgery and/or radiation may be an option.
how is agnosia treated?
Rehabilitation plays an important role in the treatment of agnosia.
In particular, compensatory strategies involving the use of other senses are taught.
Perceptual sets can cause perceptual distortions when they…
cause us to taste something that isn’t really there, or cause us to taste something more or less intensely than it truly is in our food.
can the appearance of food and its packaging, for example, give us certain expectations and then actually influence the flavours we taste?
yes
the intensity of the colour of the food we eat…
can lead to perceptual distortions in flavour judgement.
the more intense the colour of food,
the more flavour we perceive that we are tasting even when this is not the case.
past experience has predisposed us to expect …
that a brighter colour means something is more ripe or intensely flavoured.
can how a food feels in our mouth, or its ‘texture’, affect our experience and judgement of a food’s flavour?
Yes
In what ways does texture affect our judgement of flavour?
- can change the intensity of the flavour we experience. This is because the texture of food determines how much of it actually is received by our gustatory receptors and how long it stays in the mouth. This is not a perceptual distortion because we are physically able to taste more or less of the food we are consuming depending on its form.
- can also change how much we enjoy the flavour we perceive. Whether we judge food to be tasty is also dependent on its texture. This is often informed by our expectations of how a food should feel and our past experiences with specific food items. If you were given soft crackers, would you still enjoy them? Our enjoyment of flavour according to texture is not necessarily a perceptual distortion either.
synaesthesia is
a perceptual phenomenon experienced by certain individuals that involves cross communication between sensory systems and can distort an individual’s perceptual experiences
Synaesthesia is a phenomenon of perception that occurs when two sensory systems cross over in an abnormal and involuntary way.
More specifically, when one sensory system is activated, another sensory system also involuntarily experiences unusual or unexpected perceptions.
is synaesthesia a mental health disorder?
no
list consistent characteristics of synaesthesia
automatic and cannot be controlled
The perceptual experiences elicited in the secondary sense feel very vivid and real.
synaesthesia is generally experienced one-way: a person who sees the colour green when looking at the number 4 will not see the number 4 when looking at the colour green.
synaesthesia is usually consistent: a person who sees the number 4 as green will usually always see it as green and not some other colour.
the way synaesthesia is experienced is unique to the individual
synaesthesia is relatively common: there are a wide range of estimates regarding its prevalence, and some forms are far more common than others. However, estimates can range from as high as one in 100 people to as low as one in 2000 people
are there different forms of synaesthesia?
yes
list some proposed explanations for synaesthesia
Synaesthetes are highly sensitive to the associations a sensory stimulus triggers. In childhood development, unusually strong networks are formed through learning between a sensory stimulus and its associations.
the brain networks of synaesthetes are structurally unique. The connections and associations between different areas of the brain may be connected in ways such that the activation of one area automatically triggers the activation of another.
the amount of synaptic pruning that would occur for non-synaesthetes may not occur as much for synaesthetes, leaving unpruned connections that can be activated in an unusual way. This does not mean that the brain is unhealthy or not intact.
