Cog + behaviour: Volition Flashcards
What are the 2 broad positions regarding determinism and free will?
- Metaplysical libertarianism
- -> claim determinism is false and hence free will ESIXT
- Hard determinism
- -> claim determinism is true and hence free will DOESN’T exist
What do both metaphysical libertarianism and hard determinism assume is the relevant factor in free will?
Determinism
Rather than looking at free will with determinism as the relevant factor, what alternative argument can you take up?
- Incompatibilism VS compatibilist
What does an imcompatibisit believe about free will?
- -> CAUSAL determinism is the crucial factor in free will
- -> (true for both meta + hard determinism)
- -> If your conscious choice is determined by something other than itself, then you are not free
What does an compatibilist believe about free will?
- -> denies determinism is relevant + maintain that alternative constraints are key
- -> eg free from coercion
- -> just come sort of contribution in the decision rather than sole determination still = Free will
What did Libet et al in 1983 do resulting in them suggesting the unconscious brain processes precede conscious decision to act?
- asked to watch a rotating clock face and press a button at any random time
- but report when they feel like they are going to press the button
- Electrodes on PF motor areas recorded readiness potential (RP)
= negative shift in electrical potential before action occurred! - evidence against free will??
What are some criticisms of Libet et al’s study in 1983 (clock)?
- action = trivial
- time of ‘will’ subjectively reported = may vary depending on the devision of attention
- makes assumptions about the nature of RP = that it reflects a preconscious decision process…?
- EEG = limited spatial resolution so only limited insight into the specific brain regions involved
What are some challenges faced by using RP as a reflection of preconscious decisions process?
- long assumed RP reflects some form of planning/ preparing for movement
- BUT Schurger et al showed similar pattern if decision to move were based on placing a threshold on the accumulation of random fluctuations in neural activity (bg noise)
What did Soon et al in 2008 find suggesting RPs must also have antecedent causes?
- ppt watched stream of letters
- in their own time, need to choose right or left button
- need to tell which letter was present when they decided to press a button
= Pattern classification algorithm predicted which hand 7 seconds before decision - areas identified known to be involved in prospective memory
What is prospective memory?
memory associated with doing something in the future
What are some methodological limitations of Soon et al’s study in 2008 (RPs + antecedents)?
- EEG = limited spatial resolution vs temporal
- fMRI = good spatial resolution vs temporal (blood flow)
- WHAT we really need are electrodes in our brains!!!
What did Fried et al in 2011 find when they tested the Libet paradigm w/ single neuron recordings - 12 epileptic patients w/ inter-cranial electrons in medial frontal areas?
- the pattern with the RP (surge in negativity) was observed in both the pre-SMA + SMA (supplementary motor area)
- -> time of conscious intention could be predicted by small subpopulations of these
What did Fried et al find about pre-SMA and SMA and the feeling of intention?
- SMA, not pre-SMA contained more active neurons before the feeling of intention
- suggests the feeling of intention may correspond to the moment when an unconscious plant is enacted = volition
What is volition?
intention in action
What evidence are there suggesting the suppression of action and its voluntary initiation are closely linked?
- sub populations of neurons decreased in activity in the pre-SMA providing evidence for an inhibitory component
- these changes in activities are invisible to fMRI
Is the ‘urge to move’ epiphenomenal - a simple correlate of action?
NO: urge can exist independently of action
- Fried et al 1991; stimulating PFC reported xp the ‘urge to move’ without movement being made
- same found when parietal areas stimulated
What are the 2 different pathways actions can happen?
- Voluntary
= flexible intelligent interaction w/ current + historical context - Stimulus driven action
= guides object orientated actions such as grasping
What is the pathway for voluntary action?
- loop through basal ganglia - integrate range of cortical signal to drive appropriate actions
- Dopaminergic inputs from substantial nigra to straitum provide modulation based on reward
What is the pathway for stimulus driven action?
- Info from sensory cortex is replayed to intermediate-level representations in the parietal cortex
- Then relayed to the lateral part of the pre-motor cortes –> motor cortex
What disorder derives from some fault in volition?
- Anarchic hand; Dr Stangelove syndrome (german salut)
- -> person reports their had has a will of its own
What is the difference between anarchic hand and alien hand?
Alien hand = person dissociate themselves from it
vs
Anarchic hand = know their hand is their own
What was the initial explanation for the Anarchic hand?
- initially thought to be due to disconnection of the hemispheres
- since patients who had corpus callosotomy = symptoms
–> FAILS as it could need to result from a separation between the right hemisphere motor cortex + left hemisphere areas for planning + execution
= but anarchic not always found in left hand
What is a more current explanation for anarchic hand?
- damage to the SMA collaterally impairs voluntary circuit leaving action guided primarily by external stimulus cues on that side
= So action not result of ‘will’ but stimulus driven = cannot be inhibited
What would you expect to happen if you have damage to SMA bilaterally
Utilisation behaviour
- patients show urge to use objects that are in sight
- also observed in dementia
- often not aware behaviour is inappropriate
