The self II: Optimism and the human brain Flashcards
what do we know so far?
The above average effect/superiority illusion
Most people rate themselves above average
Logically impossible!
Most people cannot be better than most people!
We can be blind to our own illusions
the OB
The difference between a person’s expectation and the outcome that follows. If expectations are better than reality, the bias is optimistic
“The optimism bias stands guard. It’s in charge of keeping our minds at ease and our bodies healthy. It moves us forward, rather than to the nearest high-rise rooftop.” (Sharot, 2012)
what can social cog neuroscience tell us about why our optimism persists?
Tali Sharot is one of the leading researchers in this field (and has written a very good book)
Wear rose tinted glasses no matter our age
answers hoping to find
How the brain may play a part in mediating OB
Why we continue to show UO (unrealistic optimism) even when reality tells us we are mad to do so!
Possible role of dopamine in enhancing OB
Sharot et al (2007) - motiv behind studies
Can brain studies shed light on how we think about future positive and negative events?
- Initially looked at how are recollections of memories may not be accurate
- Look at how people imagine the future
- Are the past and future linked in our heads?
- Think about a past one that may be similar or has something in common
- Bind past info with what you perceive future to be like and this creates a concrete situation
- Same neural system used to remember the past
Do optimists and pessimists show different patterns of brain activity when imagining such events?
If so, what does this actually mean?!
Sharot et al. (2007) - method
fMRI data collected whilst participants thought of autobiographical events from past or future
Can be constrained – limited in terms of what you can do – not a very naturalistic env
15 young adults had to think of sig life events or a future event that might happen
Press a button when an event began to take shape in their minds and again when it was fully formed in their heads
Also measured emotional arousal and valence
Then rated memories and projections on 6 factors linked to subjective experience (e.g., arousal, vividness – how strongly they felt, time)
They also completed Life Orientation Test-Revised (LOT-R) – measures trait optimism…
Sharot et al. (2007) - prelim findings
Future positive events rated as more positive than future negative ones
And were imagined to be in closer temporal proximity than future negative ones
Negative future events less strongly experienced than positive future events
The more optimistic participants were (LOT-R score), more likely they were to expect positive stuff to happen to them sooner than negative events, and to experience them more strongly
Sharot et al. (2007) - fMRI findings
Can never assume causality
Several regions of interest (ROIs) were identified
These were: rostral anterior cingulate cortex (rACC), ventral medial prefrontal cortex, posterior cingulate cortex, dorsal medial prefrontal cortex – important bit…these play key role in retrieval of autobiographical memory and imagining future events and…
Amygdala (important for emotion’s role in autobiographical memory)
what did the researchers do next?
Do changes in any of these areas correlate with LOT-R scores? (do more optimistic people’s brains show different patterns of activation?)
Some evidence of a relationship between LOT-R scores and rACC (but not others)
Correlation between rACC and amygdala activity when imagining future positive events (weaker for negative events)
There is a relationship
what might this mean?
We can’t do much about the past, but there is some flexibility in how we interpret the future
Specifically, evidence that we can distance ourselves from negative events and move closer towards positive ones
Especially so for those higher in trait optimism
possible mechanism underlying OB?
“Reduced BOLD (blood oxygen level dependent) signal was observed in the amygdala and rACC during imagination of negative future events related to positive future events…suggesting that the optimism bias may be related to a reduction in negative future thought.”
Experiencing the negative events less strongly in the future
interesting speculations
rACC activity when we think about future events is suggestive of self-regulatory focus that underpins bias in attention and vigilance towards positive events and away from negative ones
Possible link with mechanisms underlying depression (do depressed persons imagine future differently? Does brain activity show this?)
Sharot et al. (2011)
But UO is not always adaptive!
UO persists even when reality provides us with info that challenges such beliefs
Surely when we find out we are wrong to be so optimistic, we should adjust in response?
Influential learning theories suggest we might.
data suggest we don’t
Providing evidence that disconfirms our positive outlook doesn’t always make us change our minds!
Even experts show OB – financial analysts expect improbably high profits, family law attorneys underestimate the negative consequences of divorce
How is OB maintained?
Sharot et al. (2011) - method
Combined learning procedure with fMRI
fMRI data obtained while Ps estimated likelihood of experiencing adverse life events
After each trial told average probability of individual experiencing that event – should recalibrate a bit
Allowed researchers to see how much participants adjusted beliefs following new info
examples of adverse life events
alzheimers
robbery
cancer
PD
Sharot et al. (2011) - results
Selective updating: Ps learned to greater extent from info offering a chance to adopt more optimistic expectations than from info that challenged their rosy outlook
In a nutshell, more likely to update beliefs when average probability of experiencing negative event was lower than their own probability (hey, the future is even rosier than I thought!)
Found in 79% of Ps
Sharot et al. (2011) - but
Was it down to weighting desirable info more strongly in memory? (no – equal memory for both positive and negative items)
- Showed similar memory with positive and negative memories
Was it down to differences in emotional arousal (no)
Was it down to differences in underlying base rates of events (no)
where we are so far
“These behavioural findings suggest a likely computational principle that mediates UO…Specifically, they point to estimation errors as providing a learning signal whose impact depends on whether new information calls for an update in an optimistic or pessimistic direction.” (Sharot et al., 2011)
what about the brain?
They looked at brain activity when desirable (probability less likely than you thought) vs. undesirable (probability more likely than thought) updates were provided
Brain activity (see paper) was greater when probability was more desirable than estimates
This was even more so for those scoring high on LOT-R
summary
“Our findings offer a mechanistic account of how unrealistic optimism persists in the face of challenging information. We found that optimism was related to diminished coding of undesirable information about the future in a region of the frontal cortex…that has been identified as being sensitive to negative estimation errors. Participants with high scores on trait optimism were worse at tracking undesirable errors in this region than those with low scores.” (Sharot et al., 2011)
Sharot et al. (2012) - good news/bad news effect - Lefebrve et al. (2017)
What we know – In Parkinson’s disease, drugs enhancing dopaminergic function (L-DOPA) influence learning of positive and negative outcomes differently (enhance former, impair latter); also impacts on working memory, episodic memory, reversal learning
Sharot et al. (2012) - hyp
“Enhancing dopamine function will influence how healthy individuals incorporate information about probabilities of future life events in an asymmetric manner, increasing an OB.”
Sharot et al. (2012) - method
Double-blind placebo-controlled intervention study
Tested on 2 days, one week apart; in one Ps got L-DOPA, in the other placebo
Similar life events task each time
And then told average probability of experiencing them
Then assessed if they used this info to update estimates; memory test
Also tested another neuromodulator used to treat depression (Citalopram; SSRI) to see if it worked in same way
Sharot et al. (2012) - results
Enhancing Ps dopamine function increased prediction bias in optimistic direction
No such effects for Citalopram
Also found differential behavioural updating for dopamine Ps (L-DOPA impaired updating in response to undesirable info about future)
“We show that a tendency to incorporate undesirable information into one’s forecasts of the future is impaired when dopamine levels are enhanced. This leads to an underestimation of the likelihood of negative events, a fundamental characteristic of UO.”
Implication for treatment of depressed individuals?*
