Juliette Siegfried, MPH – Brain Blogger http://brainblogger.com Health and Science Blog Covering Brain Topics Mon, 09 Apr 2018 12:00:43 +0000 en-US hourly 1 https://wordpress.org/?v=4.9.5 The Brain’s Stopwatch – Emotions and Time Perception http://brainblogger.com/2013/04/04/the-brains-stopwatch-emotions-and-time-perception/ http://brainblogger.com/2013/04/04/the-brains-stopwatch-emotions-and-time-perception/#comments Thu, 04 Apr 2013 11:00:35 +0000 http://brainblogger.com/?p=14396 Albert Einstein, when asked to explain his theories in layman’s terms, once famously said, “When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute and it’s longer than any hour. That’s relativity.”

That’s also how our brains work to “tell time,” according to research conducted by Sylvie Droit-Volet from Blaise Pascal University and Sandrine Gil from Poitiers University, France. These neurophysiologists point out that although we have five senses with which to measure the universe around us, our brains have no specific receptors with which to measure time. Most of the time we manage anyway, have a pretty good idea of whether things happen “on time” or “not on time,” and after the age of six we can make fairly accurate assessments of time duration — how long it takes for common actions to happen.

After the age of eight we also begin to develop remarkably sophisticated abilities to “count time,” meaning to accurately tell how many seconds or minutes have passed between an initial “Start now” stimulus and a final “Stop now” stimulus. Brain researchers in the early 60s theorized that this sense of “subjective time” was due to a mechanism in our brains similar to a stopwatch, which operates similar to the ticking of a clock. When we pay attention to it, this internal clock allows us to develop a pretty good sense of objective time.

But does this “brain stopwatch” always “tick” at the same rate?

Have you ever, for example, been in a dangerous situation like an automobile accident and had your perception of time “slow down,” as if objective time itself were passing more slowly? Have you ever had a conversation with a beautiful person, à la Einstein’s quote above, and felt time pass more quickly? How does that happen if we’ve got an internal stopwatch in our brains constantly ticking away?

To find out, Droit-Volet and Gil conducted a number of experiments in which subjects were shown excerpts from three different types of potentially emotion-provoking films and then asked to subjectively estimate the duration of a visual stimulus. One group of films was designed to provoke fear (Scream, The Blair Witch Project), another group to provoke sadness (Philadephia, City Of Angels), and a third group to provoke neutral reactions.

After watching the fear-provoking films, the subjects consistently perceived the stimulus as lasting longer than it really did; the emotion of fear seemed to trigger a “slowing down” of time. There were no such time distortions after watching the other two groups of films. Speculating about the possible causes of this, the researchers suggested that the phenomenon might be partly physiological — the emotion of fear causes a state of physical arousal that may also speed up our “internal clocks.” When you are afraid, your heart speeds up, your blood pressure increases, your pupils dilate, and your body unconsciously goes into “fight or flight” mode, preparing to either defend itself or run away. The sad or neutral films may not have affected the subjects’ sense of time as much because there was no corresponding change in physiological functions.

Gil and Droit-Volet also found this time dilation effect when subjects merely looked at the face of someone close to them expressing an emotion such as shame. Previous studies have indicated that when we see shame in others, we instinctively try to mimic the other person’s emotional state. As Droit-Volet explains,

This reflective activity distracts attention from time-processing, so that estimated time seems shorter than it really is.

She also points out that these changes in our perception of time are not the result of a malfunction of our internal clocks, but a shifting of our attention in response to events:

There is no single, uniform time, but rather multiple times which we experience. Our temporal distortions are a direct translation of the way in which our brain and body adapt to these multiple times, the times of life.

More research must be conducted to understand exactly how our perceptions of time change, but one thing is certain — they change. Time really is relative.

References

Buhusi CV, & Meck WH (2005). What makes us tick? Functional and neural mechanisms of interval timing. Nature reviews. Neuroscience, 6 (10), 755-65 PMID: 16163383

Droit-Volet S, Fayolle SL, & Gil S (2011). Emotion and time perception: effects of film-induced mood. Frontiers in integrative neuroscience, 5 PMID: 21886610

Image via Jim Barber / Shutterstock.

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Bilingualism May Be Neuroprotective http://brainblogger.com/2013/03/29/bilingualism-may-be-neuroprotective/ http://brainblogger.com/2013/03/29/bilingualism-may-be-neuroprotective/#comments Fri, 29 Mar 2013 11:00:42 +0000 http://brainblogger.com/?p=14297 The ability to communicate in multiple languages not only provides doorways to new cultural and social experiences but also apparently promotes brain growth and staves off the onset of dementia and Alzheimer’s disease.

Researchers at the University of Kentucky and Kyungpook National University in South Korea studied 110 participants (who were either bilingual or monolingual) while undergoing functional magnetic resonance imaging (fMRI). The results of the experiments showed that older adult bilinguals “showed better perceptual switching performance than their monolingual peers” and that older adult bilinguals required less blood flow to the frontal cortex and cingulate cortex in order to complete certain mental tasks.

The study suggests that “lifelong bilingualism offsets age-related declines in the neural efficiency for cognitive control processes.” In other words, as the brain ages, it inevitably becomes less able to conduct the thought processes involved in everyday life.  According to the study, being bilingual throughout life helps delay this slowdown.

Other studies, such as the one conducted at the University of Toronto, have shown that bilingualism significantly improves white matter integrity and thickening of the cerebral cortex. White matter relays communications between various parts of the brain, and its deterioration results in decreased cognitive speed and acuity. The cerebral cortex is the layer covering the outer part of the cerebrum and is often referred to as gray matter. It is here where most information processing takes place in the brain.

Bilingualism has been regarded by some as a hindrance to a child’s intellectual development. Although there is plenty of data to show that bilingual brains keep both language systems active even when speaking or reading in just one, this is less of a drawback than was once believed. In fact, it conditions the brain to resolve the internal conflict between the languages, thereby strengthening its cognitive abilities.

A 2004 study on monolingual and bilingual (French and English) children found that the bilingual children were quicker at performing mental tasks such as sorting objects on a computer screen by color and shape. Other studies have reinforced the collective evidence that bilingualism improves the brain’s ability to plan, solve problems and perform mentally challenging tasks. It also improves the ability to ignore distractions, hold information in mind, and switch attention from one important task to the other.

In essence, a bilingual brain “exercises” the abilities that help keep it young: concentration, memorization, rapid purposeful switching, and flexibility. Although the benefits are greatest for those with lifelong experience in multiple languages, it is never too late to start learning a new way of talking and thinking.

References

Gold BT, Kim C, Johnson NF, Kryscio RJ, & Smith CD (2013). Lifelong bilingualism maintains neural efficiency for cognitive control in aging. The Journal of neuroscience : the official journal of the Society for Neuroscience, 33 (2), 387-96 PMID: 23303919

Luk G, Bialystok E, Craik FI, & Grady CL (2011). Lifelong bilingualism maintains white matter integrity in older adults. The Journal of neuroscience : the official journal of the Society for Neuroscience, 31 (46), 16808-13 PMID: 22090506

Bialystok E, & Martin MM (2004). Attention and inhibition in bilingual children: evidence from the dimensional change card sort task. Developmental science, 7 (3), 325-39 PMID: 15595373

Image via Raywoo / Shutterstock.

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