Sunday, August 29, 2010

How to improve your cognitive function

In an era of ever increasing lifespan, a recent study estimated that there would be 81.1 million people with dementia by 2040 (Ferri et. al., 2005). The prevalence and incidence of dementia has also been documented to increase with increasing age (Fratiglioni, Ronchi & Ag├╝ero-Torres, 1999).

Abraham Lincoln in his infinite wisdom, once said: “In the end, it's not the years in your life that count. It's the life in your years”. So what can we do to enhance our cognitive functions as we age?

The link between exercising and cognitive health is an area of intense research but some questions remains unanswered. What component of cognitive functioning does exercise improves and how much does the quantity of exercise affect any subsequent increase in cognitive functions? Masley, Roetzheim & Gualtieri (2009) provides some answers.

Participants were classified into 3 conditions for a 10 week intervention programme.
  • Control (0 – 2 days/week of aerobic activity)
  • Moderate (3 – 4 days/week of aerobic activity)
  • Intense (5 – 7 days/week of aerobic activity)
They were administered with a set of computerized battery tests that examined their performance on 5 domains – memory, psychomotor speed, information processing time, attention and cognitive flexibility. After a 10 week exercise programme intervention, they were required to complete the test again and their pre and post treatments scores were compared.


  • After controlling for demographic factors such as age, gender and education, only cognitive flexibility (a measure of executive function) improved significantly.
  • There was a positive relationship between amount of exercise and improvements in cognitive function. The more you exercise, the larger the increase in executive function.

So what are you waiting for? Go get yourself some aerobic exercise (preferably in a natural environment) because interaction with a natural environment as opposed to an urban environment has also been shown to improve cognitive functions. (Berman, Jonides  & Kaplan, 2008)
Masley S, Roetzheim R, & Gualtieri T (2009). Aerobic exercise enhances cognitive flexibility. Journal of clinical psychology in medical settings, 16 (2), 186-93 PMID: 19330430

Berman, M., Jonides, J., & Kaplan, S. (2008). The Cognitive Benefits of Interacting With Nature Psychological Science, 19 (12), 1207-1212 DOI: 10.1111/j.1467-9280.2008.02225.x

Ferri, C., Prince, M., Brayne, C., Brodaty, H., Fratiglioni, L., Ganguli, M., Hall, K., Hasegawa, K., Hendrie, H., & Huang, Y. (2006). Global prevalence of dementia: a Delphi consensus study The Lancet, 366 (9503), 2112-2117 DOI: 10.1016/S0140-6736(05)67889-0

Fratiglioni, L., De Ronchi, D., & Ag??ero Torres, H. (1999). Worldwide Prevalence and Incidence of Dementia Drugs & Aging, 15 (5), 365-375 DOI: 10.2165/00002512-199915050-00004

Tuesday, August 17, 2010

Becoming a Better Person: The Good, the Bad, and the Past

When we think of ourselves as being morally good or morally bad, what goes on in our brains? What moral memories does our mind gather to affirm that we are one or the other, and how are these memories influenced by cognitive biases?

In some ways, we are already aware of some cognitive biases in the way we remember events. For example, we know of an "emotional bias" where emotional memories are remembered more vividly, are typically easier to retrieve and seem more familiar, even when the actual memories are not typically accurate. There also appears to be a"positivity bias" in that positive memories tend to be more vivid then negative ones and are less easily forgotten.

Not much research has been done on moral memories and given that moral memories are often emotional ones (cheating on a partner for instance, or helping someone and receiving their gratitude in turn), similar cognitive biases might exist. In this study, the authors hypothesize that we would remember ourselves doing good deeds more recently, a sort of "temporal bias".

The authors collected 700 autobiographical moral memories and characterized them on 3 categories of good versus bad. They also measured how long ago these events took place and collected data on possible contributing factors like gender, IQ, personality, etc. They then compared the mean age of the morally good memories to the morally bad memories and found that the morally good memories were always more recent.

What could drive these findings? The authors list 3 distinct and fascinating possibilities.

1) People actively reconstruct their memories to render their most recent acts, the acts to which one is most accountable, in a more positive light and relegate bad deeds to the distant past where one can come up with a host of reasons like "I was young" or "I didn't know better". This would be a real "temporal bias".

2) Perhaps bad decisions are more emotionally arousing and hence are remembered better (refer to "emotional bias" above) and their memories, older.

3) There is some real difference in the way people act when they are younger and when they older, so they remember their older self as being more morally good while their younger self as being morally bad. This would be a non-psychological explanation for the phenomena examined above.

While I think the study does indeed have several flaws that makes it hard to disentangle the possibilities, the idea it raises is quite exceptional. The way I interpret it is that, for the most part, we always strive to be better people, but we can never forget the wrongs that we have done. The solution that the brain seems to have evolved, if the authors are correct, is to relegate the ugly deeds to the past, and push the good to the present.

ResearchBlogging.orgEscobedo, J., & Adolphs, R. (2010). Becoming a better person: Temporal remoteness biases autobiographical memories for moral events. Emotion, 10 (4), 511-518 DOI: 10.1037/a0018723

Saturday, August 14, 2010

Cognitive Inferences and Optical Illusions

Ever wondered what allows us to be so perceptive about the world around us that it's almost taken for granted? Or why it is so difficult to create a robot with human-like perception, intelligence and understanding?

The discovery that the brain forms assumptions about the world in order to facilitate our lives has been one of the most illuminating insights from psychology and neuroscience.

Assumptions, or cognitive inferences, are what separates humans from robots. One very salient instance of this is our ability to see a man and his shadow against a wall, and not perceive that there is actually another physical object next to the man. Robots need to be programmed an infinite number of rules to overcome just this problem which our brain easily solves by utilizing assumptions that have been formed based on our experiences and through learning

One very interesting way of teasing out these assumptions is by means of optical illusions. Optical illusions fool us because they violate our assumptions about what we see. A really good one I'd recommend is this illusion by Edward H. Adelson.

What is special about this, you might ask? Well, Tile A and Tile B are objectively the same colour.
Look again. It might be hard to believe at first, but it really is!

And to prove it (I couldn't believe it myself initially), I did the following. I created a brownish-green oval, copied it so that there are exactly two same coloured ovals, and shifted them into the tiles.

Amazingly, the two ovals appear different accordingly.

To shortcut the process above, here's probably what's going on.

The bar in the middle is really a uniformly grey bar.

What's happening is that our mind cannot divorce the effect of shadows from our perception. As long as the picture shows the green cylinder casting a shadow, the 'shadow assumption' module of our brains gets activated and the things in relation to it will be affected. A robot should typically see Tiles A and B to be the same.

Our assumptions fill in the gaps so that our perception of the world becomes seamless and efficient (and it doesn't feel like we're constantly bombarded with stimuli).
Adelson, E. (1993). Perceptual organization and the judgment of brightness Science, 262 (5142), 2042-2044 DOI: 10.1126/science.8266102

Adelson, E. (2001). On seeing stuff: The perception of materials by humans and machinesHuman Vision and Electronic Imaging VI, Bernice E. Rogowitz; Thrasyvoulos N. Pappas, Editors, pp.1-12

Saturday, August 7, 2010

What should you spend on to maximize your happiness?

When it comes to spending our money, we instinctively think that we will derive the most happiness by spending it on ourselves, regardless of whether it is to pay that pesky bill, or buy ourselves a nifty new gadget or that gorgeous handbag that we have been eyeing for ages. But is spending money on ourselves really the best way to boost our happiness, or is there something more to it? Dunn, Aknin & Norton (2008) provide some unexpected insights.

The researchers hypothesized that, compared to spending money on ourselves, spending money on others will actually make us happier. 632 Americans were asked to rate their happiness, indicate their annual income and also estimate how they spend their money in a month, which was subsequently categorized into Personal Spending & Prosocial Spending.


  • Personal Spending (Bills & expenses, Gifts for themselves) was not a significant predictor of happiness.
  • Prosocial Spending (Gifts for others, Donations to charity) was a significant predictor of happiness.
The authors proceeded to extend their study to investigate whether people who received a windfall would be happier if they had spent it on themselves or on others. The windfall here refers to a profit-sharing bonus for 16 employees in a company. They were asked to rate their happiness 1 month before (Time 1) getting the bonus and after 6-8 weeks (Time 2). Participants were then asked to estimate how they spent the bonus, which was also subsequently categorized into Personal Spending & Prosocial Spending.


  • Personal Spending (Bills & expenses, Rent or mortgage, Buying something for themselves) was not a significant predictor of happiness at Time 2.
  • Prosocial Spending (Buying something for someone else, Donating to charity, Other) was a significant predictor of happiness at Time 2.
  • They also found that how the participants spend the bonus was more important than the size of the bonus.
In order to establish a causal relation using an experimental methodology, the researchers gave participants either $5 or $20 and were instructed to either spend it on themselves (Personal Spending) or to spend it on others (Prosocial Spending).


  • Participants who were in the Prosocial Spending condition reported greater happiness than participants who were in the Personal Spending condition.
  • The size of the money ($5 or $20) did not have a significant effect on happiness.
So how can we make use of these findings to maximize our happiness by deciding on what we should spend on?

In sum:

  • Allocate some of our spending on others (Gifts, donations etc.).
  • The sum does not have to be big, even an amount of $5 when spent in a prosocial manner can result in significantly higher happiness levels.
  • We can make ourselves happier than a person with a bigger bonus by simply tweaking how we spend our cash.
Dunn, E., Aknin, L., & Norton, M. (2008). Spending Money on Others Promotes Happiness Science, 319 (5870), 1687-1688 DOI: 10.1126/science.1150952