Tuesday, December 28, 2010

Detecting facial emotions: Women vs Men

Do women really recognize facial emotion better than men? Existing literature on the subject remains contradictory with some studies showing a female advantage (albeit with small effect sizes) and others failing to find any gender differences. Hoffman and colleagues (2010) suggest that expression intensity is an important factor mediating gender differences in recognizing emotions and that while women do recognize facial emotions better than men, this advantage only exists for subtle emotional facial expressions.

Using a facial expression morphing tool (FEMT), they manipulated the intensity of the emotional facial expression for their stimuli. Looking at the 40% intensity, I must say that it is in fact pretty hard for me to identify.

click to enlarge

Conforming to their hypothesis, they found that women indeed only recognize subtle emotional expression better than men but not when full-blown emotions are displayed. Decreased emotional intensity negatively affected the judgments of male participants more than that of female participants.  

But of course accurately detecting facial emotions is just the first part of the equation, whether you deal with it adequately is another thing altogether - especially when they are subtle. 


Hoffmann H, Kessler H, Eppel T, Rukavina S, & Traue HC (2010). Expression intensity, gender and facial emotion recognition: Women recognize only subtle facial emotions better than men. Acta psychologica, 135 (3), 278-83 PMID: 20728864

Thursday, December 2, 2010

Early Life Experience and Neurodegeneration

Although some studies have found that early life environmental factors can affect our vulnerability to neurodegenerative diseases such as Alzheimer’s disease in later life, the underlying neuronal mechanisms of such vulnerability are not well understood. By looking at post mortem rhesus monkey brains, Merrill et al. (2011) finds an association between early life experience and subsequent risk of exhibiting neurodegeneration in later life.

In the study, β-amyloid plaque density and synaptophysin immunoreactivity in the brains of the rhesus monkeys that had lived in standard sized cages VS small cages (29% smaller than standard cages) for the first 15 years were compared. Young monkeys were also used as a basis for comparison.

β-amyloid plaque density

β-amyloid deposition has been established as the central cause of Alzheimer’s disease (Hardy & Allsop, 1991). The researchers found that monkeys that were housed in small cages had higher β-amyloid plaque density and amyloid load in the superior temporal gyrus compared to monkeys that were housed in standard sized cages. Young monkeys had no detectable amyloid deposition and were not graphed.
click to enlarge

However, I think the β-amyloid density results should be taken with a pinch of salt. Although the authors did mention that there is considerable individual variation - which parallels data in human studies, the effects seemed to be heavily driven by the monkey which had almost 140 plaques per mm square. Also, there were only 5 monkeys in the small cage condition and 3 of them appear to have comparable β-amyloid density levels. The authors also did not include individual data for the superior temporal gyrus amyloid load graph but the large error bar again suggests significant individual variations.

Synaptophysin Immunoreactivity

Monkeys reared in small cages also showed a reduction in synaptophysin immunoreactivity - a presynaptic marker, in the superior temporal gyrus. This indicates a decrease in synaptic density and activity which has been linked with cognitive impairment in Alzheimer's disease.
All said, the value of the study lies in their finding “early life experience is associated with degenerative change in the non-diseased aged brain” (emphasis theirs). Therefore, even in normal aging, our early life experiences can affect the rate of neural degeneration. Remind me to get a bigger crib for my child in the future.

Merrill DA, Masliah E, Roberts JA, McKay H, Kordower JH, Mufson EJ, & Tuszynski MH (2011). Association of early experience with neurodegeneration in aged primates. Neurobiology of aging, 32 (1), 151-6 PMID: 19321231

Wednesday, November 17, 2010

Effects of sleep on Remembering to Remember

Prospective memory is a class of memory that is unique in that it involves the future rather than the present or the past. Various examples of prospective memory include remembering to buy a pet monkey, or remembering to break up with your girlfriend or remembering to do that blasted thesis that you have been putting off for the umpteenth time. Hence, some researchers have called it the act of "remembering to remember" (Winograd, 1988). Although prospective memory is quite important for daily functioning and goal fulfilment, research on it has been quite sparse in comparison to other forms of memory. One big question remains: how do we remember to remember? Do we devote some resources to maintain this intention? Or is it maintained without anything being devoted to it?

You know you want it.

One theory of prospective memory suggests that prospective memory can be both effortful and automatic. One way in which prospective memory can be automatic is when cues in our environment alert us to something we have to do. Kvavilashvili and Fisher (2007) has found that individuals often encounter cues related to a goal (eg, seeing a monkey in the magazine, receiving a text message from the girlfriend) and these cues spontaneously remind participants of their goal. Another way in which prospective memory is maintained is through conscious retrieval. Other researchers have also found that prospective memory surprisingly is better after 15 minutes than 3 minutes, one interpretation being that participants consciously retrieve and rehearse the goal prior to and up to the point when they are going to execute it (Hicks, Marsh & Cook, 2005).

One question that arises from these findings is that, what happens when we sleep on something? During sleep it appears that both automatic and effortful mechanisms are absent; we don't consciously retrieve and rehearse goals, and we aren't exposed to cues from the external environment. In such a case we might expect that prospective memory would weaken. However, given that a huge amount of literature has also shown that sleep improves memory, we might expect that sleep would improve prospective memory. These contradictory hypotheses form the basis for Scullin and McDaniel's study, "Remembering to execute a Goal: Sleep on it!" (2010)

The researchers had participants do a series of tasks (too lengthy to cover), while remembering to do a particular action at a particular time ("press the Q key when you see the word table or horse"). In one set of participants, this target came after a short delay (20 minutes) while in the long delay condition, participants were told to come back after 12 hours for another series of experiments and the target came there. The other crucial manipulation was time of day, the experiment for one set of participants was started in the morning, and the other set at night. The study was between groups, so participants were spread out across 4 conditions.

1. Short Morning Delay

2. Short Evening Delay

3. Wake Delay (from morning to night, during which time the participant was awake)

4. Sleep Delay (from night to morning, during which time the participant was sleeping)

What the researchers found was that sleeping improved the ability to remember to do something, as compared to being awake. In some of the tests, the performance was almost as good as if one was tested after 20 minutes. One important possible confound in this experiment was that the sleep and awake conditions also differed not just in amount of sleep but also when the experiment was conducted. The authors eliminated this confound by comparing performance for prospective memory during the day and night after a short delay and found that time of day had little effect.

So the results are inconsistent with the idea that sleep might undermine prospective memory by preventing conscious retrieval or exposure to environmental stimuli. It seems like prospective memory might not rely heavily on these 2 processes, as suggested by some proponents of the theory above. The implication being that if you need to remember to do something, you might as well sleep on it.

But how does sleep improve prospective memory? The authors suggest that sleep increases associative binding and that it amplifies weak goals or links. In this case, it seems like prospective memory might not be very much different from other types of memory. However the authors find that sleep improves prospective memory for only certain types of tasks, thus raising new avenues for research into different kinds of prospective memory and how they are affected by different variables.

One problem which I found in this paper was that the participants were engaging in quite an unnatural prospective memory task, in which case environmental cues present during the awake phase would not help the participant in remembering to do the task. On the other hand, in the real world, such environmental cues would be present and abundant (like seeing your thesis supervisor). So in that sense, the authors can't make the claim that sleeping improves prospective memory more than staying awake and being exposed to constant pictures of monkeys.

Another interesting idea that this paper raises is the implication of sleep on prospective memory in old people. It has been found that prospective memory is one memory that is especially impaired and gets worse with old age (they keep forgetting to get the groceries for instance). Old people also get less sleep, especially sleep of the slow wave kind. Coincidence? :)

This post was chosen as an Editor's Selection for ResearchBlogging.org
Scullin MK, & McDaniel MA (2010). Remembering to execute a goal: sleep on it! Psychological science : a journal of the American Psychological Society / APS, 21 (7), 1028-35 PMID: 20519489

Saturday, November 13, 2010

Jealousy, Turning Saints into the Sea?

"Not so long ago jealousy was considered a pointless, archaic institution in need of reform. But like other denials of human nature from the 1960s, this bromide has not aged well. ... The rock musician who wrote 'If you love somebody set them free' also wrote 'Every breath you take, I'll be watching you.'"

- Steven Pinker, on David Buss's The Dangerous Passion

Have you ever felt threatened in the presence of others you perceive to be superior to you? I recall one time when I was a teaching assistant in an introductory psychology course and, in the middle of a discussion about how jealousy is experienced when your partner interacts with someone else who appears to have higher mate value than you, an eager student asked, “Professor, but how do you know if that person has a higher mate value than you?” To which the professor smiled and cheekily said, “Oh, you just know.”

To humour the bemused student, the professor gave some scenarios. If you’re a guy, just imagine this. Some other socially dominant male is talking to your girlfriend or wife, and he’s trying to make her laugh. Worse, she actually laughs along and looks like she’s having a very comfortable and enjoyable time. If you’re a lady, imagine the reverse – your boyfriend or husband has met a younger and physically attractive woman, and now he’s the one trying to make her laugh, and she’s playing along and being very reciprocative. That creeping feeling of alarm bells and jealousy becomes just a tad more resonant.

In the dating and mating game, what exactly are those social cues that get us to be on our guard, to experience inferiority and to feel threatened? Gutierres, Kenrick and Partch (1999), researchers looking at the issue through an evolutionary perspective, explored the oft-cited mating preferences of men for physical attractiveness and women for status and social dominance, and elucidated interesting sex differences in contrast effects.

The researchers gathered data from 91 undergraduate females and 99 undergraduate males and primed the men with either physically attractive men or socially dominant men while, on the other hand, priming the women with either physically attractive women or socially dominant women. Exposure to physically attractive men or women was done by showing participants photographs of people, while exposure to socially dominant men or women was done by getting participants to read a descriptive profile of a person with high dominance.

Interestingly, their study found that men’s self-assessments of desirability were adversely affected by exposure to highly socially dominant men and were relatively unaffected by exposure to physically attractive men. Conversely, women’s self-reports of their mate value were more affected by the physical attractiveness than by the social dominance of the women to whom they were exposed. This demonstrated that humans are sensitive to the selective mate preferences of the opposite gender. If we consistently fail to match up to the quality of our rivals, this can have an effect on how we perceive our own desirability!

More recently, another set of experiments conducted by Maner, Gailliot, Rouby and Miller (2007) also looked at how our state of mind affects the level of attention we give to stimulus objects in our environment.

A total of three studies were done on undergraduate students to explore how this interacts in the scene of human mating. It was found that when participants were primed with feelings of romantic and sexual arousal, a ‘mate-search’ psychological mechanism was activated which resulted in greater attentional adhesion* towards attractive members of the opposite sex. On the contrary, when participants were evoked with feelings of jealousy (imagining a scenario that perhaps closely resembles the one that the professor had painted), a ‘mate-guard’ state of mind was primed which led to greater attentional adhesion to attractive same-sex targets.

So is jealousy simply a manifestation of insecurity? Perhaps the answer is both yes and no. Yes, because it does seem apparent that the mind is designed to experience jealousy when the environment provides feedback on where you stand. If there are many people of the same sex as you in the room who are far more attractive, that’s good reason to feel insecure especially when being evaluated by members of the opposite sex. But jealousy isn’t only just a manifestation of insecurity because it serves an important adaptive function – to alert us to the potential dangers of losing your mate, telling us to be aware of snakes and wolves in the environment, and getting us to turn on our A-game where necessary. As David Buss writes in The Dangerous Passion, jealousy is as necessary as love and sex.

* Attentional adhesion refers to how readily a person tends to a particular stimulus. In most documented cases, this is determined by measuring participants' reaction time taken to respond to stimulus.

Maner JK, Gailliot MT, Rouby DA, & Miller SL (2007). Can't take my eyes off you: Attentional adhesion to mates and rivals. Journal of personality and social psychology, 93 (3), 389-401 PMID: 17723055

Gutierres, S., Kenrick, D., & Partch, J. (1999). Beauty, Dominance, and the Mating Game: Contrast Effects in Self-Assessment Reflect Gender Differences in Mate Selection Personality and Social Psychology Bulletin, 25 (9), 1126-1134 DOI: 10.1177/01461672992512006

Buss, D. M. (2000). The Dangerous Passion: Why Jealousy Is As Necessary As Love and Sex. New York: Free Press.

Monday, October 25, 2010

Racial Differences in the Concept of Beauty

Are average composite faces the most attractive faces or are highly attractive faces markedly different from average faces? Rhee & Lee (2010) agrees with Perrett & Yoshikawa (1994) that the most attractive face is actually the average of attractive faces and that an average face; while attractive, is not the most attractive.

They also argue that previous concepts of beauty such as the divine proportion (golden ratio) are not a good measure of beauty across different races and should not be used as an overarching universal indicator of beauty. Between different races, there appears to be different characteristics that are deemed beautiful. They merged some of the most attractive female faces of African, Caucasian, Chinese and Japanese people respectively, to create the images below.

They also mentioned some of the defining characteristics of beauty for the different races.
  • African: Narrow nose, smaller and more acute eyes, smaller upper lip, slender chin compared to the average African face.
  • Caucasian: Somewhat masculine, narrow palpebral (eyelids) height, angulated and squared mandible (lower jaw), protruding cheek and fuller lips compared to the average Caucasian face.
  • Chinese: Narrow cheek, slim and thin face, lantern jaw.
  • Japanese: relatively longer face, slightly slanted eyes, sharp chin and chubby cheeks.

Unfortunately, they did not conduct any experimental study to compare attractiveness ratings of such faces versus other faces that are considered beautiful based on traditional morphometrics. It would also have been interesting to look at how the male composite faces would look like. 

Rhee SC, & Lee SH (2010). Attractive Composite Faces of Different Races. Aesthetic plastic surgery PMID: 20953953
Perrett DI, May KA, & Yoshikawa S (1994). Facial shape and judgements of female attractiveness. Nature, 368 (6468), 239-42 PMID: 8145822

Thursday, October 14, 2010

The link between coffee and acute ischemic stroke onset

Do you drink coffee on a regular basis? I do. And what does drinking coffee have to do with acute ischemic stroke (caused by disruption of blood supply to part of the brain)? In a study published in Neurology, Mostofsky and colleagues investigated the relationship between drinking caffeinated coffee and the risk of acute ischemic stroke in the next hour.

Using a case-crossover design, each subject served as his/her own control. All the subjects were patients with a confirmed diagnosis of ischemic stroke. Coffee consumption information one hour before the onset of stroke symptoms was compared with their frequency of coffee consumption in the previous year.

They found that drinking coffee doubles your risk of ischemic stroke onset in the next hour compared to drinking other caffeinated drinks such as tea or cola; which may be due to lower concentrations of caffeine in those drinks.

When they looked at the frequency of caffeinated coffee intake in the previous week, they found that only people who were drinking ≤1 cup of coffee per day had increased risk for ischemic stroke in the following hour.

The take-home message?

  • Drinking coffee temporarily increases one’s risk of ischemic stroke – especially so for infrequent drinkers (≤1 cup of coffee per day).

Well, I don’t think I’m willing to forsake my coffee just yet so I’m going to have 2 cups a day instead of my usual 1 a day.

Mostofsky E, Schlaug G, Mukamal KJ, Rosamond WD, & Mittleman MA (2010). Coffee and acute ischemic stroke onset: The Stroke Onset Study. Neurology PMID: 20881275

Tuesday, October 5, 2010

What the Presence of Attractive Young Women can do to Men

Much has been said about the female preference for resources and the male preference for physical attractiveness, but at the time of James R. Roney's (2003) writing little had been done to tease out cognitive mechanisms that underlie this adaptive preference.

Roney thus set out to ascertain the ability of ecological cues to prime and activate psychological constructs related to mate attraction and establish linkages between human mating and social cognition.

In his first study, participants - young students from the 10th and 12th grades of a Midwestern high school - were made to answer three large booklets of surveys. However, the manipulation of the environment within which the surveys were answered was as follows: in the first condition, all participants were male; in the second condition, all participants were female; in the last condition, males and females were present during the study. Without knowing what the experimenter was up to, participants answered questions in the surveys, and nested in those surveys were questions related to one's attitudes towards wealth and resources.

The results fascinatingly appear to support evolutionary theories about human mating. Male students in the mixed-sex environment reported higher valuations of material wealth than did male students in the same-sex environment.

The young men in the mixed-sex condition also reported higher ratings of having an active dating life. These findings suggest that the presence of females may have primed implicit mate attraction goals and, subsequently, the activation of cognitive attitudes associated with mating objectives (detailed manipulation checks were conducted via cleverly placed questions on items such as current relationship status and mate preferences, reducing the possibility of confounding variables).

Now that the first experiment appears to be consistent with evolutionary theory predictions, Roney sought to find out if other mating goal-related attributes in men can be primed. In his second study, male participants were exposed to advertisements featuring either younger female models or older female models, after which they filled out a questionnaire.

The results again confirm evolutionary theory hypotheses - men in the younger models condition reported higher valuations of wealth (replicating the findings of the first study), had a greater desire to display/showcase talent and, interestingly, listed self-descriptive traits that increase men's odds of attracting women (this was confirmed through separate ratings of the male participants' self-descriptive traits by women), such as ambitiousness and aggressiveness.

Roney's study thus brings evolutionary psychology one step further by utilizing ecologically realistic stimuli, in the process demonstrating powerful but previously unknown psychological effects. Specific to this study, visual exposure to young women caused significant changes in the attitudes and personality trait descriptions of the young male participants. In particular, young men who were exposed to young women reported far more favourable attitudes towards material wealth than did men exposed to either other men or older women.

This makes sense because if securing a mate was an important task in ensuring the survival of one's lineage (without which those of us alive today wouldn't be here), then there should be psychological mechanisms present to facilitate the achievement of such goals, and men should thus be sensitive to cues that relate to both potential mates and resources. Using an adaptive basis for understanding psychology can also prove useful, because without this evolutionary context of mating, such stable behavioural changes demonstrated in Roney's study can, at best, only appear random and lead to invalid conclusions.

Roney, J. (2003). Effects of Visual Exposure to the Opposite Sex: Cognitive Aspects of Mate Attraction in Human Males Personality and Social Psychology Bulletin, 29 (3), 393-404 DOI: 10.1177/0146167202250221

Saturday, September 25, 2010

Is eating 6 meals a day instead of 3 a better weight loss strategy?

I’ve come across a significant number of non-peer reviewed articles on the internet about weight loss, body building etc. that advocates eating 6 meals a day (just Google "3 meals or 6 meals" to see what I mean). Reasons given for doing so includes less fluctuation in blood glucose and lower fat storage among others. But is eating 6 meals instead of 3 a day really beneficial for someone trying to cut some flab? Some researchers think not.

In an article published in Obesity, Leidy and colleagues (2010) investigated how differing amount of dietary protein and eating frequency influences our perceived appetite and satiety levels during weight loss. 

In a 12 week experiment, 27 obese men were randomized into either the high protein or normal protein group and were required to engaged in a weight-loss diet that is 750kcal/day lower than their daily needs. Beginning on the 7th week, all participants alternated between 3 meals a day or 6 meals a day, each lasting for 3 days. Information on their perception of daily hunger, desire to eat and thinking about food were recorded and compared.

  • The high protein group felt fuller, had lower desire to snack at night and thought less about food than the normal protein group.
  • Eating 3 or 6 meals a day did not have any effect on hunger, fullness, desire to eat nor preoccupation with thoughts of food.

The take-home message? Getting on a high protein diet appears to be a viable weight loss strategy because it gives you better control over your appetite and satiety but switching to a 6 meals a day strategy appears not to be helpful in these areas.

Furthermore, some previous studies have found a relationship between higher meal frequency and higher colon cancer risk (eg. Shoff et al, 2000 (for women), Wei et al. 2004(for men)). So I were you, I'll think twice about adopting that 6 meals a day plan too readily. 

Leidy HJ, Tang M, Armstrong CL, Martin CB, & Campbell WW (2010). The Effects of Consuming Frequent, Higher Protein Meals on Appetite and Satiety During Weight Loss in Overweight/Obese Men. Obesity (Silver Spring, Md.) PMID: 20847729
Wei, J., Connelly, A., Satia, J., Martin, C., & Sandler, R. (2004). Eating Frequency and Colon Cancer Risk Nutrition and Cancer, 50 (1), 16-22 DOI: 10.1207/s15327914nc5001_3
Shoff, S., Newcomb, P., & Longnecker, M. (1997). Frequency of eating and risk of colorectal cancer in women Nutrition and Cancer, 27 (1), 22-25 DOI: 10.1080/01635589709514496

Saturday, September 18, 2010

Spicy food and collectivism: How the brain shapes culture

We are used to thinking of culture as a social factor and not a biological factor. We attribute dispositions such as being individualistic or being collectivist to the country that one was brought up in, but no one has really looked into why certain cultures tend to be that way. An emerging field of research called cultural neuroscience says that cultural values can be shaped by the brain and genes.

For example, in one striking example I read about quite recently, one hypothesis put forth for the reason why Asian people like spicy food was because spices conferred natural bacteria killing properties that was especially important in a humid climate where food went bad. Over time, the hypothesis goes, people who liked spicy food more and ate more spicy food were less prone to stomach diseases that killed the others, thus passing on their genes for the next generation. A similar finding was found when examining lactose intolerance. Lactose intolerance is far more prevalent in certain regions of Asia where the rearing of lifestock for milk is less common. In Europe however, up to 95% are able to digest lactose, and this is reflected in their preference for milk products like cream and cheese.

In this review by Way and Lieberman, they sought to answer the question as to why certain cultures tend towards individualism and collectivism. They reason that because of evolution, genes that change brain function and influence the cultural norms we adopt and we institute are selected for between people born in different regions. For people brought up in one region that was say marked by famine, grouping together and helping one another might have brought about greater survival for the people, hence the genes that promote this thinking get passed on. In a separate part of the world, marked by conflict perhaps, survival would favor people who think for themselves and for their immediate family members. Over time, those different selective pressures would have promoted different social behaviors in different regions.

What mechanisms might have promoted these behaviors? They reviewed work from scientists studying the distribution of several genetic alleles. Previous work has shown that variation in the serotonin transporter gene, a very important neurotransmitter associated with emotion and reward, was associated with individual differences in social sensitivity. People with the short version show greater reaction to social events such as death or birth of children, regardless of whether it was positive or negative. When these scientists studied the distribution of these alleles in different cultures, surprise surprise! They found that the short version of this allele was much more prevalent in collectivist cultures than individualist cultures.

*higher score on individualism collectivism scale indicates higher individualism.

The authors hypothesize that since this allele makes people more sensitive to being socially excluded, it promotes individuals to tend and befriend, leading to a cultural trend of being more collectivist. There's more to read about other such alleles in the review, but seeing as to how this post is quite wordy already, I'll stop here :)

ResearchBlogging.orgSherman, P., & Billing, J. (1999). Darwinian Gastronomy: Why We Use Spices BioScience, 49 (6) DOI: 10.2307/1313553

Way, B., & Lieberman, M. (2010). Is there a genetic contribution to cultural differences? ... SCAN, 5 (2-3), 203-211 DOI: 10.1093/scan/nsq059

Wednesday, September 8, 2010

Why does Time Slow to a Crawl when we Engage in Laborous Tasks?

"Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute."

- Albert Einstein, on Relativity.

Kathleen Vohs and Brandon Schmeichel, particularly fascinated with Einstein's first observation, sought to establish whether regulating the self can elongate the 'felt' duration of time. "Because people who are self-regulating tend to monitor their behaviour, they are likely to be attuned to the passage of time," explain the authors, "these monitoring responses and resultant attention to time are not found among people who are not regulating."

In simpler terms, 'self-regulation' is likely to be linked with the attention to time. In earlier studies on duration judgment, when participants were asked after watching a TV episode to estimate the length of the episode, they gave shorter time estimates than participants who were told that they had to guess the duration of the episode prior to watching it. It appears that conscious deliberation, as opposed to the non-regulated state of automatic processing, might lead one to be more aware of time passing.

Thus, hypothesizing that deliberate, conscious and effortful self-regulation would lead one to feeling like time has passed slowly, Vohs and Schmeichel conducted four illuminating studies that lent scientific support to the claim.

In Study 1, the authors made participants watch a clip from the film Terms of Endearment, which shows a dying mother saying good-bye to her children, husband and mother. Participants were made to either naturally respond to what they saw, or suppress their emotions or exaggerate their emotions while watching the show. This manipulation had been found in earlier studies to be effective in causing participants to consciously regulate their emotions which led to diminished self-control capacity.

Participants were instructed to estimate the length of the video clip after the 11 min 23 sec clip ended.

It was found that participants who exaggerated or suppressed their emotions perceived that the film clip had lasted longer than participants who were natural during the film.

In Study 2, a similar experimental set up was used, although the film was changed from Terms of Endearment to Mondo Cane (depicting the death of wildlife). To determine that longer judgments of time were due to self-regulation specifically and not generic information processing, a new condition called 'reappraisal' was introduced. Participants in the reappraisal group were instructed to view the affectively-charged scenes in a detached manner. The authors explain: "Prior studies have shown that effects associated with emotion control (e.g. memory decrements because of emotion suppression) are absent when participants are given a reappraisal framework within which to view an emotional scene."

Participants were, again, then asked to judge how long the clip lasted.

The results support the idea that the Natural and Reappraisal conditions, which did not require self-monitoring, did not prompt the attention to time that was present in the Suppress condition.

In Study 3, participants were told to read aloud pages of text that corresponded to various types of professions. In the behavioural control group, participants were instructed to 'act out' the profession as depicted by the text, and thus they had to do their best to "act happy, smile and 'get into it'" as expected of the profession. Participants in the no condition group weren't given any such instructions.

After 4 minutes and 23 seconds had passed, participants were interrupted with a questionnaire asking them how long they thought the experiment had lasted. After that, participants were told that they could continue up to a cap of 15 minutes and stop at anytime in between.

Once again, the findings of the first two studies were replicated in the results of Study 3 as participants in the behavioural control group felt that they spent a longer time doing the task than participants in the no condition group. Continuance of the task was also affected by the manipulation, as "the longer participants believed they had been doing the read-aloud task, the shorter they continued with it after the 4:23 mark."

From this, the authors built a model that linked the experimental conditions and subsequent regulatory ability.

The results of this model were supportive of the hypothesis that time perception is a mediator. This model was further supported by a final study.

Thus, across four experiments, the authors found that people's perceptions of the duration of an activity were significantly affected by self-regulatory resource depletion. Whenever some form of cognitive regulation is involved, for instance, emotion regulation or self regulation, people can believe that the task involved lasted much longer. "A taxing self-regulatory activity is remembered as being overly long."

Where Einstein's latter observation is concerned, it might thus be likely that sitting with an attractive member of the opposite sex constitutes a very enjoyable process that requires less self regulation, which makes us less conscious of the passage of time. So, where does this place those who experience anxiety approaching attractive members of the opposite sex?

This post was chosen as an Editor's Selection for ResearchBlogging.org
Vohs, K., & Schmeichel, B. (2003). Self-regulation and extended now: Controlling the self alters the subjective experience of time. Journal of Personality and Social Psychology, 85 (2), 217-230 DOI: 10.1037/0022-3514.85.2.217

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 & Agüero-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

Saturday, July 24, 2010

How to maxmize your happiness from a vacation.

I am sure that most, if not all of us would agree that going on a vacation makes us happy. But are we really happier than people who are not going for a holiday? And if we are indeed happier, how long do these effects persist and how does the length of our vacation and amount of holiday stress impact our happiness levels? These are some of the questions that Nawijn, Marchand, Veenhoven & Vingerhoets (2010) attempt to answer.

Their main findings are listed below.
  1. Pre-trip happiness: Vacationers (n=974) displayed significantly higher degrees of happiness than non-vacationers (n-556)
  2. Post-trip happiness: Vacationers were generally not significantly happier than non-vacationers. Only vacationers who rated their holidays as very relaxed (as opposed to relaxed, neutral, stressful or very stressful) had significantly higher degrees of happiness for the first 2 weeks after the vacation.
  3. Length of vacation was not associated with post-trip happiness.
*Note: The vacation began between week 27 and week 35.

So what do these findings tell us about how we should plan our vacations?

For starters, the planning and anticipation of the upcoming vacation makes us much happier folks than those who are not looking forward to a vacation.

The second finding, in line with the set point theory of happiness, indicates that once we are back from a vacation, our happiness returns rapidly back to baseline levels. Only the 'very relaxed' vacationers get an additional 2 weeks boost of happiness. So if you want that extended endorphins kick, make sure that you are really relaxed during the vacation.

The last finding, together with the first two findings, suggests that in order to derive the most happiness out of your vacation, it would be better to take multiple short trips rather than a long trip. Since the length of the vacation is not associated with happiness, you'll get the most bang for your buck by enjoying the pre-trip happiness generated from planning and anticipating multiple trips.

In sum:
  1. Enjoy the planning process
  2. Do your best to make your trip very relaxing (a trip that is just 'relaxed' doesn't quite cut it)
  3. Multiple short trips are better than one long trip
Nawijn, J., Marchand, M., Veenhoven, R., & Vingerhoets, A. (2010). Vacationers Happier, but Most not Happier After a Holiday Applied Research in Quality of Life, 5 (1), 35-47 DOI: 10.1007/s11482-009-9091-9

Friday, July 16, 2010

Boost your Guitar Hero skills 101 - SLEEP! Really?

We have been told that feeling well-rested while studying and reviewing your work just before bedtime enhances your memory for what you have studied. But when it comes to the role of sleep in motor memory, the answer is less clear. A recent research abstract presented at the 24th annual meeting of the Associated Professional Sleep Societies LLC by Dr Kevin Peters from Trent University suggests that sleep enhances our performance in complex motor learning tasks, as measured by an larger increase in accuracy levels obtained in playing guitar hero in the sleep condition compared to the wake condition.

However, an earlier paper by Cai & Rickard (2009) suggests that after controlling for circadian (time of day) and homeostatic (time since sleep) confounds, participants in the sleep conditions did not display any benefits in a motor sequence task.

The participants in their research were categorized into 3 conditions - a wake group, a 1 night sleep post-training group and a 2 night sleep post-training group. Participants were tasked to tap a number sequence, 4-1-3-2-4 repeatedly and reaction times (RTs) were measured. All participants trained at about 9.30am and were tested on 5.30pm on the day itself or on Day 2 and Day 3 depending on which conditions they were in.

Comparing difference scores of their RTs for the 3 different groups revealed no significant differences between them. If sleeping does indeed improve motor memory, we would expect a significant reduction in RTs for the sleep groups compared to the wake group. Therefore, it appears that after controlling for circadian and homeostatic factors, sleeping after training does not improve motor sequence performance.

Unfortunately, I do not have access to the exact methodology and results of Peter's study to verify if the concerns about the relevant confounds raised by Cai & Rickard (2009) are adequately addressed. Therefore, as far as I'm concerned, the jury is still out on the specific benefits (if any) conferred to motor memory by sleep. But I must say that Peter's design holds much promise (he certainly won't have any trouble finding willing and good subjects).

Well, regardless of whether sleeping helps you perfect that golf swing or ramp up your skill level on guitar hero, it’s still a good idea to get a good night's rest to ward off the negative effects associated with sleep deprivation in other domains of our lives. Afterall, according to a study by Falleti, Maruff, Collie, Darby & McStephen (2003), driving after being awake for 24hrs is like driving with a blood alcohol concentration of 0.05%. Not quite enough to get you arrested but probably more than enough to make you think twice about pulling that all-nighter.

Cai, D., & Rickard, T. (2009). Reconsidering the role of sleep for motor memory. Behavioral Neuroscience, 123 (6), 1153-1157 DOI: 10.1037/a0017672

Falleti MG, Maruff P, Collie A, Darby DG, & McStephen M (2003). Qualitative similarities in cognitive impairment associated with 24 h of sustained wakefulness and a blood alcohol concentration of 0.05%. Journal of sleep research, 12 (4), 265-74 PMID: 14633237

Wednesday, July 7, 2010

Is Money the Arbitrator of the Fine Line Between Self-Interest and Community Spirit?

Does money serve as a great incentive and motivator or does it serve to undermine relationships? At the heart of the debate for society, this is akin to the perennial capitalism vis-à-vis communism conflict. And perhaps the truth is that they are both right.

Vohs, Mead & Goode's (2006) nine experimental studies, which culminated into an illuminating piece of work titled The Psychological Consequences of Money, found that both characteristics of money - a great incentive or an underminer of relationships - emerge from the same underlying process: money makes people feel self-sufficient and therefore behave accordingly.

In Experiment 1, participants were assigned randomly to three conditions. In two conditions, participants were reminded of money (Play Money and Money Prime) while in the control condition, participants were not reminded of money. In each condition, participants were instructed to unscramble jumbled up words to form sensible sentences, and therein lay the prime. In the Money Prime condition, the scrambled text contained concepts of money. In the Play Money and Control conditions, the scrambled texts were neutral, but participants in the Play Money condition were exposed to Monopoly money in their peripheral visual field.

Next, participants were given a challenging but solvable problem to work on. As the experimenter left the room, he offered that he was able to provide assistance if the participant wanted. How long the participants persisted before asking for help became the dependent variable to be measured.

It was observed that participants who were reminded of money (both Play Money and Money Prime) worked on the problem longer than control participants before requesting for help. The difference between the two money conditions (Play Money vs Money Prime) was insignificant.

Experiment 2 was a modification of Experiment 1 such that the constructs being measured were an abundance of money (High Money) against restricted amount of money (Low Money). Participants then had to read aloud an essay in front of a video camera. The video camera was used in place of an experimenter so as to remove the potential confound that might result from status differences between the experimenter and the student.

Participants in the High Money condition read about growing up with abundant financial resources, while participants in the Low Money condition read about growing up with meagre financial resources. Participants were then, like in Experiment 1, unknowingly tested on how long they would take to solve an unsolvable puzzle before requesting help.

Once more, participants in the High Money condition worked significantly longer than participants in the Low Money condition before asking for help. This experiment also confirmed that the effects of money did not depend on relative status differences between the participant and the experimenter/helper.

Given the findings thus far and the overall hypothesis, the authors predicted that people who value self-sufficiency would be less helpful than others because they will tend to expect others to be self-sufficient as well. The authors do not elaborate on this aspect, but a few reasons why this is a reasonable stipulation include:

  • the tendency for people to project their own personalities onto others in order to form more efficient judgments and anticipate behaviours of others,

  • the fact that schemas associated with ourselves are more accessible and thus more easily activated, and

  • the possibility that we have evolved psychological mechanisms to assume that when we are rich, the environment allows for it because we are in a resource-rich area, and we are more likely to be dealing with other rich people residing in our local environment.

Thus, in Experiments 3, 4 and 6 (all involving different sets of randomly selected subjects), the authors sought to test whether participants primed with money would be less helpful relative to control participants.

Using the word descrambling methodology from Experiment 1 to manipulate the priming for both money and neutral conditions, the DV - willingness to provide assistance - was then measured. Experiment 3 tested participants on their tendency to help out in a future task (willingness to help code the data sheets of the current experiment), while Experiment 4 tested their helpfulness on an immediate helping situation (willingness to help a fellow 'latecomer' participant, who was really a confederate, figure out the experiment's instructions). Experiment 6 assessed how willing participants were in donating their participation payment to a university student fund.

It was found that participants in the money condition volunteered to help code fewer data sheets (Experiment 3), spent half as much time providing help to the latecomer on the instructions (Experiment 4) and donated less money (Experiment 6) than participants in the control condition.

In Experiment 5, participants were made to play Monopoly with a confederate. After a few rounds, the game was cleared except for differing amounts of play money. Participants in the High Money condition were left with $4000 (participants will be aware that this is a large sum of Monopoly money having been sensitized to the game), while participants in the Low Money condition were left with $200. Control condition participants were left with no money. For High Money and Low Money participants, the money was kept in conscious sight for the second step of the experiment. At this step, High Money participants were asked to imagine a wealthy future while Low Money participants were asked to imagine a financially insecure future. Control participants were asked to imagine their plans for the next day.

This was followed by a staged accident where a new confederate, who was both blind to the condition the participants were in and carrying a lot of things, walks across the laboratory and drops his pencils (27 in total) in front of the participant. The number of pencils picked up by the participant became the measure of helpfulness.

Participants in the High Money condition helped gather significantly fewer pencils than participants in the Low Money and Control conditions. Helpfulness did not differ between the Low Money group and the Control group.

To ascertain self-sufficiency as the construct that is really being tested, the final three experiments tested the effects of money on social intimacy, desire to engage in leisure activities alone and preference to work alone.

In Experiment 7 involving screensavers, participants were randomly assigned to either the Money condition, Fish condition or No Screensaver condition. All participants were made to fill in questionnaires while sitting in front of an idle computer screen. After a few minutes, one of three screensaver types would appear - one depicting various denominations of currency floating underwater, one with fishes swimming underwater, and one with just a blank screen.

After some degree of exposure to the screensaver, participants were told they would get acquainted with another participant in the same experiment, but the experimenter would require some assistance to arrange the chairs for the session. Participants primed with the Money screensaver placed the two chairs for him or herself and the potential acquaintant farther apart compared to participants in both the Fish group and the No Screensaver group.

Participants primed with money appeared to place more social distance between themselves and others.

Experiment 8 tested whether money-primed participants would prefer being alone even when choosing leisure activities that are potentially of a social nature. The priming manipulation was similar to Experiment 7, except that instead of screensavers being used, participants were now facing posters. The Money condition participants faced a poster showing various denominations of currency, while the two control groups faced a poster showing either a seascape or a flower garden.

Participants were next given a nine-item questionnaire that asked them to choose between two leisure activities per question. Within each item, one option was an experience only one person could enjoy while the other option was for two or more people. Money-primed participants chose more individually-focused leisure activities than participants from the control groups.

Money primes thus appear to lead people to become less social.

Experiment 9 provided a more rigorous test of the self-sufficiency hypothesis by directly assessing social preferences. Participants were put through the screensaver primes from Experiment 7 before being asked whether they preferred to work alone or with others. Once more, participants desired to work less with a peer when exposed to money primes.

The nine experiments provide support for the proposed argument that money activates psychological mechanisms that bring about a state of self-sufficiency. It might even appear somewhat surprising that such minor tweaks in environmental and social conditions towards a heightened sensation of financial resources might induce a person to be more independent and socially insensitive.

As the authors sum up well, "The self-sufficient pattern helps explain why people view money as both the greatest good and evil. As countries and cultures developed, money may have allowed people to acquire goods and services that enabled the pursuit of cherished goals, which in turn diminished reliance on friends and family. In this way, money enhanced individualism but diminished communal motivations, an effect that is still apparent in people’s responses to money today."

So ultimately, perhaps whether you believe money is inherently good or evil might begin with what inclinations you have towards social dynamics and morals to begin with.

Vohs, K., Mead, N., & Goode, M. (2006). The Psychological Consequences of Money Science, 314 (5802), 1154-1156 DOI: 10.1126/science.1132491