COGS101 Lecture Notes - Lecture 12: Neurophysiology, Comparator, Extreme Measures
2 Jun 2018
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Week 12 – Disorders of the Self
What are disorders of the self?
• We all inherently have an idea what self means, but it is difficult question to
answer specifically
o Philosophers have argued for millennia how to best understand this
• Self as an entity that is distinct from everything else in environment
• Two key aspects:
o Experience of influencing the world (sense of agency)
o Experience of having a distinct physical body (sense of body
ownership)
• Our sense of self depends on the representations of our actions and our bodies
• Our sense of self can be disturbed in many cognitive disorders:
o Schizophrenia
o Alien hand syndrome
o Somatoparaphrenia
o Phantom limbs
o Anorexia nervosa
o Out of body experiences
• Disorders of the self → experimental paradigms = cognitive models about the
self
• This topic is about disorders of self and experimental paradigms
• Two important questions:
o What signals are used by our cognitive system to form distinct
representations of our actions and our bodies?
o How can we measure changes in the sense of self?
Sense of agency:
• The feeling of causing an event to occur is what we call our sense of agency
e.g. lifting up your arm
• We mainly notice our sense of agency when it is disturbed
• Waking up early is an example of sense of agency being disturbed
o When the alarm goes off; but if you sleep in, what causes that to
happen? If you get up, what causes that to happen?
• Driving without agency
o When you have no recollection of how you got to your location
• Causes of flow:
o For flow to occur, the demands of a situation must just exceed an
individual’s skill
o If someone’s skill level is much higher than needed for a task, they
will experience boredom or relaxation but not FLOW (and vice versa
may experience anxiety/arousal)
• Characteristics of flow:
o Common in expertise across domains
o Complex, well trained actions are experienced as subjectively
effortless
o Strong feelings of intention for outcomes, absent intention for specific
actions
• Ritual – agency change
find more resources at oneclass.com
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o Some religious rituals involve states of trance and possession
o Triggered by range of stimuli → music, chanting, dancing, fasting,
psychotropic substances
o Subjective experience of control by an external entity
o No agency over behaviours that they perform (e.g. Voodoo in Haiti)
• Hypnosis – agency change
o High hypnotizable participants frequently describe their actions as
occurring without conscious intention
▪ Classic suggestion effect – “It was my arm that moved, but I
did not feel like I made it happen”
o Hypnosis leads to change in self monitoring so that self-generated
actions are experienced as if they were externally caused
• Clinical disorders of agency:
o Anarchic Hand Syndrome
▪ Neurological condition where a patient’s arm makes
coordinated, seemingly purposeful actions without conscious
intentions
▪ Very rare (only approx. 40 reported cases)
▪ Results from neurological damage to supplementary motor area
▪ Motor movements triggered by external stimuli without
inhibition
o Delusions of control
▪ Feeling that actions, thoughts or emotions are caused by an
external entity
• Thought insertion – someone feels thoughts of another
person have been placed inside their head
• Thought broadcast – thoughts can be heard by others
• Thought withdrawal – thoughts can be removed by
another entity
• Made emotions – feels that emotions have been
altered/replaced by someone else
• Made movements – body actions controlled by external
entity
▪ Relatively common in schizophrenia, can also occur in mood or
dissociative disorders
• Other clinical conditions involving disorders of agency:
o Negative symptoms in schizophrenia
o OCD
o Depression
o Addiction
• Typically agency disruptions are not considered to be core features of these
disorders above
Cognitive models of agency:
• The comparator model (Wolpert, 1997)
o Based on neurophysiology of actions
o We first have an intention to move – this sets of two motor signals;
the first triggers our muscles which leads to an action occurring, the
second motor commands generate motor prediction of what intended
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Participant generates tickling motion with right hand: 2. Computer selects the delay condition: zero self produced, 100ms delay, 200ms delay, 300ms delay or externally produced: 3. Robot makes tickling motion on left hand after appropriate delay: 4. Participant rates tickliness: tickliness was inversely correlated with participants" level of control. Impaired predictions evidence that this occurs in schizophrenia and delusion of control. Impaired sensory feedback also leads to mismatch and disruption in agency. If the thought is consistent with the event. Body self-perception: what can cause disorders of body self-perception, brain injury due to a stroke, changes to body self-perception are most common after damage in certain areas in particular of the right side of the brain, e. g. It does not seem to matter that the hand does not look exactly like one"s own hand and that the hands are in different locations: the rubber hand illusion is reduced when presenting, asynchronous touch, non-body objects.
