Glass Half Full or Faulty Frontal Lobe?

Researchers recently reported that optimism may not be as rosy as once thought. In fact, optimism may actually be due to a brain malfunction. How is that for a glass-half-empty view of the world?

Scientists at the Wellcome Trust Center for Neuroimaging at University College London enrolled 14 volunteers to evaluate optimism in the face of bad news. While undergoing functional magnetic resonance image scans, the volunteers were presented with 80 negative scenarios, including being divorced, developing chronic diseases, and being a victim of crime. Each volunteer was asked to estimate the probability that these events would happen to him or her. While still in the scanner, the volunteers were presented with the actual probabilities of each event occurring. After the scans, volunteers were again asked to estimate the probability of each negative event. They also completed questionnaires that assessed optimism.

Essentially, the study found that in eternally optimistic people, the brain rejected bad news. If the estimated probability of a negative event was better than a participant expected, activity in the frontal lobe increased and the participant updated his or her own estimate in accordance with the true estimate. All participants in the study showed increased frontal lobe activity in this scenario.

Alternatively, if the estimates were worse, optimistic people displayed less frontal lobe activity and did not significantly update their own estimates. Optimists effectively ignored bad news, even when substantiated by facts.

The authors assert that this blind optimism is due to a malfunction in the prefrontal cortex that is supposed to update neural coding of undesirable information regarding the future likelihood of negative events. The brain is supposed to update personal risk factors when presented with negative information.

While optimism does have health benefits — lower anxiety, decreased stress, and improved health — unrealistic optimism can be detrimental to our well-being. People who are unrealistic about their risk of negative events are more likely to engage in risky behavior such as unsafe sexual practices, consumption of drugs or alcohol, or investing in less-than-secure financial situations.  In fact, a related study reported that optimism predicts the occurrence of alcohol-related negative events; higher levels of optimism predicted more negative events, despite facts and past experience supporting the risky nature of the activities. A little pessimism, or even skepticism or realism, likely helps the fittest survive.

The study was quite small, and optimism is a highly subjective trait that varies across cultures, genders, and age groups. The authors are not telling people not to have a positive outlook — optimism surely has its place — but they do insist that optimistic brains are not functioning properly.

I would be remiss if I left out Monty Python’s rose-colored life lesson in a story about optimism: “Always look on the bright side of life.” But, in this case, we should be more appropriately reminded that “nobody expects the Spanish inquisition.” At least, optimists don’t.


Dillard AJ, Midboe AM, Klein WM. The dark side of optimism: unrealistic optimism about problems with alcohol predicts subsequent negative event experiences. Pers Soc Psychol Bull. 2009;35(11):1540-50. PMID: 19721102

Sharot T, Korn CW, Dolan RJ. How unrealistic optimism is maintained in the face of reality. Nat Neurosci. 2011 Oct 9. PMID: 21983684

Rose JP, Endo Y, Windschitl PD, Suls J. Cultural differences in unrealistic optimism and pessimism: the role of egocentrism and direct versus indirect comparison measures. Pers Soc Psychol Bull. 2008;34(9):1236-48. PMID: 18587057

Image via Mandrakephoto / Shutterstock.

Jennifer Gibson, PharmD

Jennifer Gibson, PharmD, is a practicing clinical pharmacist and medical writer/editor with experience in researching and preparing scientific publications, developing public relations materials, creating educational resources and presentations, and editing technical manuscripts. She is the owner of Excalibur Scientific, LLC.
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