Free Will Flashcards
Summarise how the PFC governs our immediate and later behaviour (information from conscious control lecture)
The PFC allows for more flexibility of responses by adding the possibility to delay responses (WM), inhibit responses, or add value to the response options. These values are obtained via associative learning or conditioning. Finally, the learned responses are incorporated into lower levels and become ‘routine’.
How else could you refer to the higher stages of the sensory-motor hierarchy then?
Inhibition, social norms, long term goals, working memory: Cognition
What evidence is there against the notion that the PFC is responsible for our perception of ‘I’? (2)
Classic frontal lobe cases like Phineas Gage: huge personality changes, but no loss of consciousness, of sense of agency, of ‘I’
1950’s frontol lobotomies / leukotomies: outrage over personality changes mostly by family and relativesof patients, not by patients themselves
What did Lhermitte (guy who coined utilisation behaviour) observe in his patients regarding their sense of “I” and agency?
Lhermitte summarised utilisation and imitation behaviour under the term ‘Environmental Dependency’: behaviour is more strongly driven by external inputs than by internal goals, working memory, or social norms.
But patients never lose the sense of ‘agency’. When asked whether it was ‘they’ who did it, they will say ‘I did it’. When asked why, they will answer ‘Why not, these things just lie there.’
Instead what was missing from these frontal patients?
Damage to any part of the brain alters parts of your personality, your functionality, of ‘you’. The prefrontal cortex influences behaviour by adding ‘the point of view’ of goals and rewards, working memory, prospective memory, social norms and other contexts.
When this is damaged, the balance between external and more internal drives is shifted. The ‘I’ has changed, but is not lost
Explain the behaviour which is observed in the analogy of the major life decisions of a frog
A frog will slap at ‘worms’ within ~10 cm, or jump at them when further away (automatic feeding behaviour). When a frog is between frog and worm, it will avoid the barrier.
Describe the neural mechanisms behind the behaviour described in the major life decisions of a frog
The frog’s eye projects retinotopically to the tectum (Equivalent to SC). Electrical stimulation shows that each location in the tectum produces either a snap, jump or turn.
Hence there is a fixed relation between a stimulus in the visual field, and the behaviour produced. Anything small that moves within the visual field will be snapped at.
The ‘avoid the barrier’ machinery of the frog in the pretectum. Electrical stimulation of the pretectum elicits avoidance.
How does the frog select between catching the fly and avoiding the barrier?
A simple winner-take-all mechanisms does the job: no need for added ‘control’ mechanisms. The two systems (tectum and pretectum) are tuned for different sizes. Optimal acquisition size is a spot 6 deg in diameter, optimal avoidance size is 45 deg diameter.
How was this frog behaviour manipulated in an experimental setting?
- Lesions of tectum cause frogs to not catch flies anymore. They still avoid barriers or escape from enclosings
- Cuts of the pretectum cause uninhibited snaps and jumps at all preys, regardless of barriers
How is this frog analogy then applied to humans?
What system is ‘in control’, the tectum or pretectum?Is the frog taking ‘free’ choices?
Humans are ‘frogs’ with just more complex tectum and pretectum. Mutual inhibition between different modules, levels, drives is what makes a decision happen
Describe the results of a study which examine this behavioural inhibition. (3)
Brain activity is measured when a people were carrying out an activity (hitting a baseball?) and their stop signal reaction time (SSRT) was measured.
IFG (inferior frontal gyrus) (involved in inhibitory control) activity is high in both successful and failed stop signal stops but not ‘go’ trials. Motor activity is high in go and failed stop trials, low in successful stop trials. STN (part of basal ganglia connected with IFG) shows similar activity as IFG.
What conclusions could be drawn on this neural research on inhibitory control?
Successful stopping depends more on anticipatory activity of motor cortex than on ‘strength’ of IFG. ‘Control’ center doesn’t decide!
A similar study regarding a ‘battle’ was done with food. Describe this study
Hungry subjects rated items on taste and healthiness. Subjects then select between healthy (e.g. apples, broccoli) and unhealthy foods(candy bars, chips), that they later really have to eat. Subjects were split into self-control and no-self control groups based on their amount of healthy choices.
Describe the neural activity observed in this study on self control
VMPFC (ventro-medial prefrontal cortex) activity correlated with ratings of tastiness. Self control was correlated with DLPFC (dorso-lateral prefrontal cortex) activity.
Yet another inner conflict was researched, this time with fear. Describe this study.
A participant was places in a scanner (fMRI) . A live snake (or toy Teddie bear as a control) was placed at the end of the scanner on a conveyer belt. Participants could control the distance from them and the object at the end of the trolley.
Thank fuck I never had to do that experiment.
What behaviour was noted in the study and what neural activity was noted?
For the bear they would just bring in straight to them. For the snake they were encouraged to be brave and they would bring it a bit closer, push back, bit closer, back etc etc.
Some regions (right insula, right Dorsal ACC) win when you retreat, others (Subgenual ACC, Right temporal pole) win when you advance.
How do these results then Frame the concept of choice?
Choices are the result of a ‘battle’ between subcortical (basic) and cortical (higher level, cognitive) approach and avoidance systems
How is our continuous search for reward often framed in different ways and what does V dawg call it?
More, bigger, higher, better, tastier, more exciting, more beautiful, more fun
Ambition, drive, passion, addiction
GREED
Aside from this dopamine reward and greed drive being taken advantage of in advertising?
Fear (of missing out) F.O.M.O
Sales, lotto etc
What is the third drive mentioned and what neural mechanisms are particularly relevant to it?
Herd (contagious behaviour)
Mirror neurons which are only found in social animals
Describe 2 experiments which demonstrates social compliance and their behavioural results (3)
Asch: Which of the lines A, B, and C is equally tall as the line on the left? Subject alone: 99% correct. Subject in a room with six people, five of whom say ‘B’: 32% of subjects say ‘B’.
Learner(actor, ‘cardiac patient’) has to learn words, sits in other room. Teacher (subject) has to apply electrical shocks when wrong answers are given. Experimenter watches and gives instructions. 65% of subjects apply the maximal voltage of 450 Volts, even when the learner screams, bangs on the wall, or becomes silent. Replications: puppys, police call, etc
24 students, randomly assigned as Guard (uniform) or Prisoner (gown). Experiment had to be ended after 6 days due to extreme mental and physical cruelty of guards towards prisoners. Forced push-ups, hosing with water, bag on head, humiliation, undressing, etc. An outsider was the first to notice the cruelty
Also elevator compliance
What do subjects blame this inaccuracy on later in the Asch study? What is this an example of?
themselves: ‘I don’t see that well today’: Post-hoc rationalisation
What were the results of an fMRI variant of Asch’s experiment? (2)
fMRI variant (complex mental rotation task- bit harder): 41% follow the crowd. Followers show changed activity in visual cortex. Non-conformists show increased activity in Amygdala: fear of social rejection?
What name is given to this type of contagious/compliant behaviour?
Herd behaviour
Describe a famous study which initially sought to study free will and the results
Theres a wheel of numbers and a pointing arrow rotating. Person decided when to stop by pressing a button and notes which number it was at when they decided to stop. Study shows that the motor action recorded by EEG is prepared two thousand ms at least before they acknowledged that they recorded deciding when to push it (readiness potential).
Subjects press a button at t = 0. The actual movement is preceded by the subjective intent to actwith ~250 ms. But this subjective intent to act is itself precededby ~500 –1000 ms of neural activity of the motor cortex (Cz)
What are the conclusions and implications of this readiness potential study?
Conclusions and implications: Our conscious intent to act is in fact the result of an unconscious process.
Free will is an illusion
What critiques have there been on the Libet experiments? (7; 2,3,2)
Clock issues
- Perceived time of W can be influenced by events (like a sound) after the button press
- Getting awareness of urge takes time itself
RP issues
- Is RP just attention to clock
- RP also present when no movement is executed
- Average causes smearing out of ERP that may occur simultaneously with W (what is distribution of W’s)
Interpretation
- Free will still possible (but wouldn’t that require a free will RP in itself?)
- Too simple behaviour, unnatural
How has the clock issue of perceived time not being recorded right been solved? Describe the results of a study
in an fMRI study where the participant has to pick left or right, Predicting LEFT or RIGHT button press from brain activity 8 seconds before decision is consciously made or felt. This is a much bigger difference than a couple hundred ms
How has the distribution of W’s issue of perceived time not being recorded right been solved? Describe the results of a study
Fried et al (2011) recorded from implanted electrodes in medial frontal cortex of human subjects. Just like in the Libet paradigm they had subjects press a button at ‘free will’, while recording moment in time subjects felt the urge to press (W), and when they actually pressed (P). Notice W occurs 2-15 seconds after start, and that P-W is maximally 300ms.
What else did they find when attempting to show that this observation was not the effect of smeared averages?
They found two types of neurons that either consistently increase their activity before W, or that consistently decrease activity before W
This happens up to 1.5 seconds before W
From this discovery of the two neurons which changed their activity before a button is pressed what did the researchers then do?
They built a classifier (SVM, 70% training data, 30% test data), to determine from a set of neurons whether activity had departed from baseline, and hence whether W was imminent. The classifier could predict the imminence of W about 1 second before actual W.
How did neurons in the different areas differ in their predictive abilities? Which type of neuron was a better predictor? (3)
Performance was best in medial frontal cortex (B), did not depend on whether increasing or decreasing neurons were used (F), and was earliest in the SMA(C).
How has the critique of the simplistic pressing of a button been answered? Describe this study
20 subjects, Californian residents, viewed statements about the benefits of sunscreen use while in an fMRI scanner.
Before and after the scan, subjects were asked about their intentions to use sunscreen in the following weeks, and their attitude towards sunscreen use.
they were given sunscreen in a ‘thank you bag.’ After one week they received a surprise survey about actual sunscreen use.
What were the results of this sunscreen experiment?
50% more sunscreen was used. But this correlated very weakly and non-significantly with reported intentions (r = 0.17), and not with reported attitude (r = -0.08). What people say they will do says nothing about what they will actually do
Neural activity during the scan was a much better predictor of behaviour change, even when controlled for self reported attitude and intentions.
What brain activity predicted the behaviour better than the reported attitudes and beliefs?
Activity in the a priori MPFC ROI during the presentation of persuasive messages, compared with rest, was reliably associated with behaviour changes in sunscreen use from pre-to postscan (p= 0.030). After controlling for self-reported attitude and intention changes, activity in the MPFC ROI was still reliably associated with behaviour change from pre-to postscan (p= 0.041).
Whole brain searchlight analysis of regions that were positively correlated with behavior change: strongest correlations found in the mPFC(r = 0.64) and precuneus(r = 0.71). i.e the valuation system
How have the results of this sunscreen study been replicated? (3)
- Neural activity in smokers watching anti smoking ads vs their intentions and quitting behaviour. Also this study then predicted the success rate of the anti smoking campaigns better their opinion or an expert opinion regarding likelihood
- fMRI activation of reward centers in 27 teenager subjects predicted USA wide sales of newly released popsongs. Their opinion did not!
- fMRI response of 18 subjects to chocolate advertisements predicts increase in sales of chocolate bars at point of sales, Questionnaires did not
What field of research/ business do these predictive fMRI studies touch on?
Neuromarketing
What can be observed when showing black and white faces and recording fMRI?
In each of us, also in people without conscious racist feelings, the amygdala is more strongly activated by black faces than white faces. (also with fat, old people)
This activation correlates not with conscious racist attitudes but, but with unconscious, implicit bias (IAT)
Where is a positive IAT towards black people compared to white people found?
Nowhere
Does this implicit racism come with age? If so what age?
Starts very early (like 2) and gets worse with age
How is it thought that these biases come about?
Fear conditioning
Explain fear conditioning using a study
Rat is put in a box with a light, speaker and floor which conducts electricity. A light alone will elicit no response (CS), a foot shock (US1) or a loud noise (US2) will elicit a normal startle on their own. During training a foot shock and light at the same time will illicit a normal startle (UR), after that training a light alone will elicit a normal startle (CR). A light and sound but no foot shock will elicit a potentiated startle (potentiated CR).
This demonstrates the power of fear conditioning of learning to associate the fear response to an unconditioned stimulus (primary fear/ threat) with a conditioned fear response to a conditioned stimulus (secondary fear/ threat).
What brain activity is involved in this fear conditioning? How do we know this?
Fear conditioning is absent after a lesion to the amygdala. (conscious knowledge of link between blue square and shock but no startle or skin conductance in reaction)
What early 1920 experiment demonstrated fear conditioning in humans
Little Albert and his rabbits
How could fear conditioning apply to racism
Negative valuations are probably caused by the constant exposure to the association between African Americans and negative issues in popular media, such as TV, film, newspapers, etc
But do these IAT scores have any effect on behaviour?
Yes, Unconscious (IAT) race preference has effects on social behaviour.
Give three examples of how this difference in behaviour has been shown to correlate with IAT scores
Interracial/Social Behaviour: White college students whose IAT measures revealed stronger White racial preference had more negative social interactions with a Black than a White experimenter.
Interracial/Employment: An IAT measure of race preference predicted discrimination in a simulated hiring study when the climate of the work situation suggested that management endorsed White race preference.
Interracial/medical: Emergency and GIM resident physicians’ IAT-measured Black–White race preference predicted fewer recommendations for desirable thrombolysis treatment for Black than White myocardial infarction patients. Doctors with High IAT (implicit negative bias towards black) were less likely to treat the black patient with thrombolysis and more likely to treat the white patient with thrombolytic, than doctors with Low IAT
What do these IAT scores demonstrate about our unconscious opinions?
Conscious opinions can be independent of unconscious biases, while the latter still drive behaviour; while we consciously think black people are ok, the negative associations with black people can still be built and influence our actions.
A study asked people to choose between different pairs of stockings? What did this study demonstrate and what were the findings?
Select between 4 identical pairs of stockings. Choices were driven by recency effects (right one chosen 4 x more often). However choices were described with irrelevant features ( e.g feels better).
This demonstrate post-hoc realisations.
What is choice blindness and describe a study which demonstrates it
Subjects choose between females according to personal attraction. Choice is switched via sleight of hand. 76% of trials the switch is not noticed!
Subjects give motivations for ‘their’ choice(which was not their original choice) that vary from confabulation to motivations that pertain to the forced choice instead of the original one: Post-Hoc Rationalization
What does this choice blindness study attempt to demonstrate?
Motivations do not lead our choices: Choice blindness
How does this phenomenon find more evidence in experiments involving brain lesion patients? Describe two of these studies
Gazzaniga’s split-brain experiments. The Brain Interpreter:
The left hemisphere puts all information together into a final narrative, a story about the motivations and goals of our actions and thoughts.
Patient sees only the chicken leg and not the snow scene in his left hemisphere. Yet he selects both the shovel and the chicken as relevant to the images. His explanation for selecting the shovel: You need it for cleaning out the chicken shed. The true reason for selecting the shovel: the unconscious picture of the snow scene
Patient can also be shown a command like “laugh” in the left hemisphere and start laughing. When asked about this the patient will say something like “oh you said something funny.”
What, therefore, is the primary role for “I” your behaviour?
Many brain processes that determine our behaviour escape conscious awareness. These brain processes ‘decide’ before the ‘I’ decides what to do.
The primary role the ‘I’ plays seems to be to ‘explain’ what we are doing. This happens after the fact: post-hoc rationalisation. This function is executed by the left hemisphere ‘brain interpreter.’ This is similar like when explaining why another person or animal is doing something, probably evolved through evolution to predict behaviour as somehow we started doing it to ourselves.
Describe an experiment that further examines how we may post-hoc rationalise our own behaviour
A subject has their hands replaced by those of another person behind them. The subject is hearing instructions (wave, point, etc) that are then executed by the hands. After a while the subject gets the feeling that they are his own hands.
What conclusions are drawn about the false hands and commands study?
The feeling of agency is a mere ‘construction.’ Therefore conscious actions interpret the actions that we perform.
There are illusions very similar to this false hands study, what are these illusions? (2)
The Rubber Hand Illusion:
Own hand is out of sight, rubber hand lies in front of subject. Subjects’ hand is rubbed in sync with rubber hand on table. After a while, rubber hand is felt as belonging to own body
‘Whole body’ Rubber Hand illusion:
Subjects (PS) sees himself (VF) in VR goggles. He is stroked on the back in sync with the dummy that is filmed (PF). After a while, he feels an ‘out of body experience’ towards the VF copy. This does not happen when stroking is out of sync, or with non-corporeal objects
Name two pathological conditions in which the sense of body ownership is lost
- Alien Hand Syndrome
- (He)Autoscopy, OOBE
How does the popular concept of free will influence society?
FREE WILL IN SOCIETY: In the law, it is assumed that human behavior is (uniquely) governed by rational thinking and conscious free will. If not, you are not responsible for your actions. From these, constructs like ‘Limited mental responsibility’, ‘premeditation’ have been incorporated in the law. We are raised with these concepts from an early age: ‘Mommy, I didn’t do it on purpose….’ Is that justified given our current knowledge?
