Volition

Volition: the act or instance of making a conscious choice/decision. The concept of volition is intimately related to notions of free will.

Which brain systems allow us to purposefully interact with the world?

• Primary motor cortex is the end-point of the motor system. It is somatotoptically organised. Parietal inputs to the motor cortex give sensory guidance

We have consciousness that allows us to make voluntary actions. It begins with intentions/goals, then action, then the outcome.

Determinism: the universe runs by deterministic laws; everything that happens must be inevitable. All events, including moral choices are completely determined by previously existing causes.This theory provides no room for free will - it precludes it as humans cannot act otherwise than they do.

Wegner & Wheatley's (1999) study on priming showed that humans can be fooled into thinking they've done something they haven't, and our experience of conscious free will is fallible.

Libet's (1983) study found that conscious intentions do not always cause action - awareness of intention to press a button occurred between 300 - 1000ms after readiness potential. Soon et al (2008) supports this; brain activity occurred up to 10s prior to the movement predicted response. Participants were only aware of the decision to make a specific response about 1s prior to the movement.

These 2 experiments suggest that conscious intention/will to act may be dependent on earlier brain activity

The suggestion that free will is an illusion has implications for legal and moral responsibility.

• can we hold people responsible for their actions?
• are people worthy of praise or blame for their actions?
• should people be labelled as criminals and possibly imprisoned if they have no control over their actions?

Vohs & Schooler (2008): 2 conditions, anti free will condition: read passage claiming that rational, high-minded people, including most scientists, now recognise that actual free will is an illusion. Control condition read a passage from a chapter on consciousness, which didn't discuss free will. The anti free will condition group cheated more on a maths task.

Maybe believing in free will has an important social function - regulating our behaviour

Optic ataxia

• Problems using visual information to guide movement - some or all of visual guidance over reaching with the hand and arm are lost. In reaching for an object, a person with severe optic ataxia may seem to ***** in the dark, extending a flattened hand hesitantly until chance contact allows the object to be retrieved by touch. Optic ataxia is associated with damage to the parietal input pathway to the motor cortex

Parkinson's disease

• Long-term degenerative disorder of the central nervous system that mainly affects the motor system. Most obvious symptoms are shaking ,rigidity, slowness of movement, and difficulty with walking. Associated with damage to the subcortical pathway

Anosognosia is a deficit of self-awareness, a condition in which a person with a certain disability seems unaware of its existence. It results from physiological damage to brain structures, typically in the parietal lobe, or lesions on the fronto-temporal-parietal area in the right hemisphere.

Asognosia for hemianaesthesia: sensory loss

Asognosia for cerebral achromatopsia: loss of colour vision

Anosognosia for hemiplegia (AHP): patient is unable to move a particular body part, but the patient is unaware of this deficit. It is associated with lesions to right perisylvian regions. Berti et al (2008) described a patient with AHP: presented with severe and persistent anosognosia for her left hemiplegia. Even though she could not raise the arm or touch things with it; she never reported any motor problems and when asked, claimed it could move without any problem.

Fotopoulou et al (2009): patients with AHP show a preserved experience of being able to move despite paralysis

Some patients appear to have unusual experiences of controlling their own movements. These patients feel as though they are being controlled. Frith (1992): "The force moved my lips. I began to speak. The words were made for me". Mellor (1970): "When i reach my hand for the comb it is my hand and arm which move, and my finger that pick up the pen, but I don't control them".

Thought insertion as a symptom of schizophrenia: the feeling that one's thoughts are not their own, rather they belong to someone else and have been inserted into one's mind.

There is evidence schizophrenic patients can't predict the future sensory consquences of their own movements - they can tickle themselves. Perceived intensity of sensory consequences of voluntary action should be attenuated; this is because we can predict these sensory consequences. This is why we can't tickle ourselves. However, patients with schizophrenia can.