03 November 2007

What happens in my brain when I imagine that people actually read my blog?

Lady Macbeth [to Macbeth]: Great Glamis! worthy Cawdor!
Greater than both, by the all-hail hereafter!
Thy letters have transported me beyond
This ignorant present, and I feel now
The future in the instant.
--Macbeth, Act I, Scene V. (The Oxford Shakespeare)

Obsessions with self-preservation
Faded when I threw my fear away
It's not a thing you can imagine
You either lose your fear
Or spend your life with one foot in the grave
Is God the last romantic?
--"Spark" by Over The Rhine (Drunkard's Prayer, 2005)
Optimism or delusions of grandeur? Bullish or blinkered? Looking on the bright side, or gazing through rose-colored glasses? Am I a romantic, or am I just in denial?

ResearchBlogging.orgI do consider myself a romantic, and this blog is a testament to a particular form of optimism that I just can't shake off: I'm ever hopeful that people (like me) can learn new things and change their minds. But sometimes I worry: is my optimism (on this subject, and hundreds of others) unreasonable? Or worse...is my optimism unreasonable but also adaptive, a pitiful delusion without which I can't otherwise get by?

[Waits for jeers of skeptics to die down] Actually, being (overly) optimistic is apparently a universally human trait. I may be a romantic, but...I'm not the only one. (Imagine!)

Consider these opening sentences in a research article ("Neural mechanisms mediating optimism bias," Sharot et al., Nature 450:102-105) published in Nature this week:
Humans expect positive events in the future even when there is no evidence to support such expectations. For example, people expect to live longer and be healthier than average, they underestimate their likelihood of getting a divorce, and overestimate their prospects for success on the job market.
Lord, what fools these mortals be! Yes indeed; but how does this happen? The study by Sharot et al. set out to identify mechanisms in the brain that might account for what they call "pervasive optimism bias." First the authors note that this "optimism bias" is considered to be a mark of good mental health, and exhibits apparent adaptive value; excessive pessimism correlates with symptoms of depression, and of course excessive optimism can lead to recklessness. A "normal" dose of optimism, they note, "can motivate adaptive behaviour in the present towards a future goal." Nevertheless, the authors describe this normal (wild-type?) human stance as "a moderate optimistic illusion." Yikes! We're all deluded.

Okay, so how does this work? Previous work has shown that, when imagining the future, people use the same brain systems that they employ when recalling the past, suggesting that the construction of an imagined future involves the rearrangement of pictures and stories from the remembered past. So we might expect to see these systems somehow involved in the expression of optimism.

The authors used functional MRI (fMRI) to look at brain activity while subjects were thinking about events in their lives that centered on a "life episode" like "winning an award" or "the end of a romantic relationship." They correlated the brain imaging with the participants' ratings of their experience of these episodes, which were either past or future events (i.e., recollections or imagined scenarios). And they used a psychological test (the Life Orientation Test-Revised, or LOT-R) to measure "trait optimism" and thereby estimate the relative optimism or pessimism of individual experimental subjects.

The behavioral data alone reveal some interesting things about people and their optimism. Amazingly, future positive episodes were judged to be more positive than past positive events, and were felt to be closer in time than any other experience, past or future. And there's more:
Negative future events were experienced with a weaker subjective sense of pre-experiencing, and were more likely to be imagined from an outsider viewing in, than positive future events and all past events (Fig. 1b). The more optimistic participants were, as indicated by the LOT-R scores, the more likely they were to expect positive events to happen closer in the future than negative events, and to experience them with a greater sense of pre-experiencing (Fig. 1c, d).
So, humans in general seem to think (or feel) that the future looks better than the past, and optimistic people seem to be able to better connect with the positive illusion of the future that they create.

Combining the various techniques enabled the authors to identify some brain regions of interest (ROIs) with regard to optimism. Some of these areas are The Usual Suspects: the rostral anterior cingulate cortex (rACC), the posterior cingulate cortex, and the dorsal medial prefrontal cortex, all areas that were previously implicated in autobiographical memory recall and in the construction of imagined future scenarios. Activation of these regions accompanies optimism, presumably because optimism requires a vision of the future. That's all interesting and informative, but it's not what makes this paper so intriguing. I think the paper's real impact arises from the fact that the imaging analysis implicated a fourth brain area in optimism bias: the amygdala. This region of the limbic system is famously involved in emotional processing, and the authors suggest that the amygdala's role in optimism is to add emotional impact to the imagined future events. They demonstrate "strong functional connectivity" between the amygdala and the rACC during the process of imagining future positive events, and not while imagining negative scenarios. And, importantly, they document a correlation between the strength of activation of the rACC and the overall optimism of the person, as measured by the LOT-R. I find this graph compelling:
Two aspects of their discussion are worth noting. First, not surprisingly, the authors highlight the relevance of their findings to the understanding of depression. Perhaps depression causes -- or arises from -- malfunctioning of the systems that Sharot et al. have implicated in optimism. Second, the authors make an important distinction between remembering and imagining in the interpretation of their results. Namely, there are two potentially relevant differences between remembering and imagining: the temporal difference (past versus future) and the reality difference (real versus imaginary). The authors speculate that the optimism bias functions when constructing imaginary scenarios, and that the past versus future distinction is only relevant because the past is real and the future is imaginary.

In any case, the article provides another glimpse into the workings of the hunk of meat in our skulls, a messy wet organ that somehow creates memories and imagination, and in the process conjures various carrots, hanging out there in front of us, urging us to ignore our (reasonable) fears and plunge into an unknown future, eyes on an illusion concocted by...functional crosstalk between the amygdala and the rostral anterior cingulate cortex.

That last part didn't sound quite right. But I think that's the way it is. And I think Christians should get used to learning how various aspects of humanness are explainable on the basis of the workings of the brain.

Now I'll imagine a future where my blog article, on the brain systems that fill us with optimism, is being read by scores of people, all picturing their own private versions of the grail beacon.

Article(s) discussed in this post:

  • Sharot, T., Riccardi, A.M., Raio, C.M. and Phelps, E.A. (2007) Neural mechanisms mediating optimism bias. Nature 450:102-105.

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