Saturday, July 21, 2012

Cheezy poofs only taste good when all is right

In our early years, we are taught about the five senses: hearing, sight, taste, touch and smell. These senses (supposedly) make up our own personal toolbox for perceiving the world around us, and we are initially taught that our senses give us an accurate representation of what we perceive: cookies always smell like cookies, cheezy poofs always taste oh-so-good.

This idea that our brain perceives the world exactly as it is starts to break down when we are exposed to optical illusions: images that differ from what we think is real. One of my favorite ones is on the right: the A square and the B square are actually the same shade of grey, even though we perceive them to be different. As it turns out, neuroscientists are increasingly finding out that most of our senses, not just vision, are far from perfect when it comes to representing the world accurately. How we feel, what we are doing, what we just did, pretty much anything can influence our perception.

In a recent study about perception, researchers investigated the relationship between morality and taste. They started by having participants read a short story. Not everybody got the same story to read: a third of the participants read a story in which something morally bad happens (shoplifting, or a politician accepting a bribe), a third read a story in which something morally good happens (a gift to a homeless family, or a good Samaritan stopping a mugging), and a third read a story in which something boring happens (a student choosing a major, or waiters chit chatting). The participants were then asked to rate the morality of the story, and not surprisingly, they rated the stories exactly as you would expect – the shoplifting and bribe-accepting as being morally bad, and so on.

The researchers then pretended that the study was over, and that they were now starting a new study that had to do with product-testing. The participants were asked to drink a teaspoon of a mysterious drink (in reality, diluted blue Gatorade), and then rate the taste of the drink on a scale from very disgusting to very delicious. Can you see where this is going?

As you might have guessed, the participants that had read a “morally bad” story rated the drink as more disgusting, and the participants that had read a “morally good” story rated it as more delicious (the ones who got the boring story rated it somewhere in the middle). That is to say, the participant’s experience of a moral judgment significantly influenced their perception of taste. Seems like we can’t trust any of our senses!

The researchers discussed the results of this study in the context of how we process morality and so on, but I think it’s even more interesting to think of this as a prime example of just how much our brain puts a personal slant on everything we experience. I also see implications for issues like overeating and emotional eating.

Can you think of a time when food tasted different because of emotional reasons? Share in the comments!

Reference: The bitter truth about morality - virtue, not vice, makes a bland beverage taste nice. (2012) Eskine KJ et al. PLoS One 7(7): e41159.

Monday, July 16, 2012

Sitting ducks die... Maybe.

I think it’s pretty safe for me to assume that you’re sitting down right now. Some of you might be so lucky to have a treadmill desk (on my long list of wants) or you might be reading this on your mobile device while waiting in line at the grocery store, but chances are most of you are sitting. Many people around the world do what I call “sitting for a living”, meaning working at a desk for the larger portion of the day. A recent study reported that Taiwan, Norway, Saudi Arabia and Japan are the “most seated” countries with people sitting over 6 hours per day. It’s a no-brainer that sitting all day is bad for your health – it’s been associated with health issues like Type 2 diabetes and cardiovascular disease. Conversely, it’s also known that exercise is good for you and helps prevent health issues like – you guessed it – Type 2 diabetes and cardiovascular disease. Based on these findings, the government has established guidelines suggesting adults get at least 150 minutes of moderate to vigorous exercise per week to benefit from physical activity.

Long work hours combined with all this evidence about the health benefits of exercise has led to a new label: what I call the “active couch potato”, one who is both sedentary and physically active. These people, like me, work 8- to 10-hour days at a desk, but also exercise – for example, they cycle to work, or jog regularly. So the question becomes: is regular exercise sufficient to offset sitting all day on most days?

A recent study tries to shed light on the relationship between sitting and life expectancy, regardless of exercise. After seeing a number of dubious headlines about this study such as “Sitting less can boost your life expectancy” and “Sitting ourselves to death” (gasp!), I thought I’d take a look at the original research and report back.

The researchers carried out a “meta-analysis”, which essentially means an “analysis of analyses”. They looked through previously published scientific articles on the topics of sitting and life expectancy, pooled the results together, and crunched the numbers to get a “big picture”. To make their results easier to understand, they divided sitting habits in three levels: level 1 means sitting less than a quarter of the time in a normal day, level 2 means sitting about half the time, and level three means sitting three quarters of the time or more. What their results show is that going from level 2 or 3 to level 1 (meaning sitting less) can mean a gain of 2 years in life expectancy.

So what? Do we really conclude that sitting is a silent killer?

Not so fast. We have many reasons to believe that sitting is bad for our health, but this article isn’t necessarily one of them. For one thing, the researchers themselves point out that their results don’t mean that someone who sits less can expect to live longer. Life expectancy is a measure that can only apply to populations, not to individuals, so while the study is relevant in a “big picture” kind of way, it means little for your own personal habits and life expectancy.

The authors also make one big assumption in their model: that sitting more causes a shortened life expectancy. However, the study results don’t tell us whether there is a direct cause-and-effect relationship. I talked about confounders in previous posts, and this is a perfect place to continue this discussion. For my new readers, confounders are variables that the researcher didn’t take into consideration, which could explain his results in a different way. For example, in this instance, the researchers find that sitting more shortens life expectancy. However, the real explanation could be that people who sit more end up eating more spicy Cheetos, and it’s the chemicals in the spicy Cheetos that actually shortens their life expectancy. See what I mean? Of course this is a silly example, but you get the idea (and of course I will never give up spicy Cheetos).

Can you think of possible (silly or not!) confounders in this study? Share in the comments!

You can count on more articles about sitting in the future. Since this one didn’t really answer whether sitting and exercising cancel out, I’ll keep looking.  

Reference: Sedentary behaviour and life expectancy in the USA: a cause-deleted life table analysis. (2012) Katzmaryk PT, Lee I-M. BMJ Open 2:e000828.

Sunday, July 8, 2012

Hurray for Higgs

There has been a lot of discussion in the news recently about the discovery of the Higgs boson particle at the Large Hadron Collider in Geneva.

I'm sure some of you would like to know more about this, and I would have loved to write a good post about the discovery and its implications. Sadly, my knowledge of subatomic particle physics is somewhat limited (and by limited I mean nonexistent).

So instead, I recommend the following video for an introduction to the Higgs boson:

What is the Higgs Boson?

And since this wouldn't be a proper Scientific Chick article without a good measure of hype debunking, here's a more critical take on the news:

Cross-Check Blog


Friday, July 6, 2012

Healthy aging: As easy as do-re-mi ♪ ?

We’re all growing old – for all the recent advances in science and all the predictions of science fiction, this is still an inescapable fact. By 2050, there will be roughly 89 million older adults in the US, twice as many as there are now. While old age chases most of us down if we’re lucky, that doesn’t mean we’re entirely powerless in the process.

Previous entries in my blog looked at various ways to promote healthy aging: walking and lifting weights, eating less, learning languages. Some of these lifestyle changes, like exercise, are easy to incorporate later in life, while others, like bilingualism, may depend on the environment you grew up in. Today’s new finding about healthy aging fits in the latter category. It's a bit like a lottery: were you one of the lucky ones who benefited from an anti-aging activity in your youth?

Researchers were interested in how the brain responds to sound. We already know that brain structures that lie at the base of your brain, called subcortical structures (sub > beneath, cortical > the outer layer of your brain) are important for detecting fast-changing sounds like the ones we make when we talk. The precise timing of your brain reacting to sounds degrades as you get older, and scientists believe this is why grandma sometimes doesn’t really follow what you’re saying.

In this study, the researchers measured the precision of this timing by putting electrodes on participants’ heads (the outside only!) and recording the signals their brains generated when they heard the syllable “da”. As expected, the older participants didn’t have as precise a timing as younger ones. More interestingly, however, was that this age-related decline wasn’t nearly as bad in participants who were musicians.

So the take-home message is that lifelong musical experience can help make your brain better equipped to deal with aging. No doubt it also comes with other benefits - my grandma, in her eighties, had forgotten much of her adult years but still delighted fellow residents of her care home with her flawless rendition of the "Sweet bye and bye". Now of course while this is an interesting article, the results don't come as a huge surprise – by now you probably have figured out that the whole “use if or lose it” saying has a lot of truth to it.

Conveniently, I just bought a piano. Now if only I could reap all the benefits just by looking at it…

Reference: Musical experience offsets age-related delays in neural timing (2012) Parbery-Clark A, Anderson S, Hittner E, Kraus N. Neurobiology of Aging 33:1483.e1-1483.e4.

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