Monday, November 23, 2015

How Does Disgust Affect Memory?

Emotional experiences clearly affect memory.  At the 50th anniversary of the assassination of John F. Kennedy many people shared their memories of where they were when they heard the news that he had been shot.  This event was shocking, and many people reported having vivid memories of that day, even a half-century later.  People who lived through the explosion of the space shuttle Challenger and the events of September 11, 2001 also have significant emotional memories from these dates.  Although these memories may not be 100% accurate, it is clear that people are influenced by the emotional experience at the time.
It is hard to disentangle all of the factors that influence memory in these stressful situations.  They events are surprising.  They are arousing emotional experiences.  They are negative.  They involve a combination of anger, fear, and sadness. 
Because emotional experiences have an influence on memory, controlled laboratory studies have begun to tease apart the elements of emotion that affect what you remember later.
A fascinating set of studies in the November, 2013 issue of the Journal of Experimental Psychology: General by Hanah Chapman, Kristen Johannes, Jordan Poppenk, Morris Moscovitch, and Adam Anderson looked at the way fear and disgust affect memory. 
In one study, the researchers gathered a series of pictures that were disgusting, scary, or neutral.  Disgusting pictures showed things like a cockroach or a picture of a gruesome disease.  Scary pictures showed things like threatening animals or riots.  The neutral pictures were items like coat hangers or coffee makers.  Ratings obtained before the study found that the scary pictures were slightly more arousing overall than the disgusting pictures. 
Each picture was shown for 2 seconds.  When the picture was presented, a line appeared above it or below it.  Participants had to indicate where the line was relative to the picture by pressing a button.  Then, after a delay of either 10 minutes or 45 minutes, participants were asked to recall as many of the pictures as they could.  This memory test was a surprise.  They had not been told that they had to remember the pictures.
Overall, people remembered more of the arousing pictures (both scary and disgusting) than the neutral pictures.  So, pictures that created a negative emotion were more memorable than those that did not.  The disgusting pictures were better remembered than the scary ones.  This difference was particularly strong after a 45-minute delay.  Finally, participants took longer to respond to the location of the line when the pictures were disgusting than when they were scary or neutral.  This finding suggests that people’s attention was more strongly drawn to disgusting pictures than to scary or neutral ones.
Another study in this series found that this effect was also strong even when there was a one-week delay between the initial exposure to the pictures and the test.
Why does this happen? 
Memory for specific items and specific situations is often not important.  When you encounter a coat hanger, you need to know what it is for, so you need to recognize that it is a hanger.  However, it probably does not matter which hanger it is or when you may have seen that particular hanger before.  As a result, we do not really differentiate our experiences of common objects that do not engage our emotions.
When you experience a frightening situation, though, you probably do want to remember it, because you want to be able to avoid that situation in the future.  With disgusting items, there is even more reason to want to remember them. The things we find disgusting are often items that could make us sick.  So, if we encounter them again, we want to know to avoid them.  In this way, memory acts to help keep us safe.

Wednesday, November 11, 2015

Students Don’t Spread Out Their Study Time Enough

I have been around schools my whole life—first as a student and grad student, and for the last 20+ years as a professor.  My own experience as a student was that I tended to ramp up my studying for exams as the test approached.  I might look over some information a week before the exam, but I was mostly likely to wait until a day or two before the exam to really study in earnest.  My observation of students I teach (and my own kids) is that this pattern hasn’t changed much since I was in school.

But, that pattern of study is not really ideal for good long-term learning.  One of the cornerstones of memory research is the distinction between massed and distributed practice.  Massed practice is when you study all of the information in one burst.  Distributed practice is when you spread your study out over time.  Keeping the total amount of study time constant, massed practice can help for an exam, but it leads to poor long-term recall of the information.  Distributed practice is much better for remembering information over the long-term.

There are several reasons why students might choose to mass their studying right before the exam rather than distributing it over time.  They might just not know that distributed studying is better.  However, they might also just be busy.  Schools often load students up with work, and so it is hard to allocate enough study time in advance of a test, because there is a lot of work to be done.  

An interesting paper by Michael Cohen, Veronica Yan, Vered Halamish, and Robert Bjork in the November, 2013 issue of the Journal of Experimental Psychology: Learning, Memory, and Cognition examined how students allocate study time to items to see if they are sensitive to the benefits of distributing their practice.  

In one study, college students learned word pairs (like truth-justice).  At test, they were going to see the first word and have to produce the second.  Participants first saw all of the pairs on the list one at a time.  They could study them and then were told that the pair would be worth either one point or five points if they remembered it correctly.  Participants were asked to maximize the number of points they got.  After seeing the word pair once and studying it, they were given the option to study it again after a short delay or after a longer one.  When participants chose the short delay, the word pair was shown again after the initial list was seen completely.  Then, a test was given on the items shown after the short delay.  Next, there was a brief distractor period, and then the items with the long delay were shown and a test on those items was given.  

Overall, students tended to prefer to assign the high-value items to the short delay and the low-value items to the long delay.  Despite this preference, they were actually better able to remember the items that they studied with a long delay compared to those with a short delay.  So, people were selecting a method to study that actually made their performance worse.  The researchers replicated this finding in several studies.

In another study, students were able to allocate study time to a hypothetical test they were going to take in the future.  There was a strong tendency to plan for the most study time close to the exam rather than studying more evenly over a long period of time.

Putting all of this together, then, even without any time constraints, students tend to prefer to mass their practice near an exam (cramming) rather than distributing their study time more evenly.  As a result, even when students have the opportunity to learn in a more ideal way, they tend to study in ways that will ultimately lead to more forgetting later.  That means that educators need to do a better job of helping students to develop habits that get them to even out their study time.  It isn’t a matter of studying harder, just studying smarter.

Monday, November 2, 2015

The Emotions Underlying Moral Outrage

Cable TV news is filled with examples of moral outrage.  Hosts of news programs display high levels of anger at some situation going on in the world.  They describe a violation of a deeply-held belief and then their emotion bubbles to the surface.  And, chances are, you have experienced this emotion yourself when a situation crosses one of your moral boundaries. 
But, what kind of an emotion is moral outrage?

This question was explored in a paper in the October, 2013 issue of Psychological Science by Jessica Salerno and Liana Peter-Hagene.  

They explored the influence of anger and disgust on feelings of moral outrage.  The word outrage suggests that anger is a big part of this moral feeling.  And when you are experiencing moral outrage, it certainly feels like intense anger.

These researchers suggest that what separates moral outrage from anger, though, is disgust.  They argue that people need the combination of disgust and anger to get real moral outrage.
In one study, participants viewed testimony and lawyers’ arguments from a murder case.  The testimony included pictures and descriptions of stab wounds from the victim’s throat.  Afterward, participants stated whether they thought the defendant was guilty.  They rated their degree of anger and disgust as well as their sense of moral outrage at the defendant.  

People’s judgments of moral outrage were predicted by a combination of anger and disgust. In particular, anger alone and disgust alone do not create moral outrage.  Instead, it was important to have the combination of the two to experience moral outrage.  The degree of moral outrage then influenced people’s sense of the guilt of the defendant and their confidence in that verdict.  

The researchers also replicated the relationship between anger, disgust and moral outrage using scenarios involving a church group picketing a soldier’s funeral and a description of a sexual assault.  Once again, the combination of anger and disgust led to feelings of moral outrage.  

This research fits with a growing body of work exploring the role of disgust in moral judgments.  Clearly, we experience disgust when there is some situation or food that is dirty.  We extend that disgust to situations that violate our moral beliefs.  So, things that are disgusting have the prospect to engage our moral sense.   When we combine that disgust with anger, then we can slip into the white-hot rage that is common for moral situations.   

Monday, October 26, 2015

Girls and Boys and Math Anxiety

When you wander around college campuses, you see the effects of strong gender differences in preferences for majors.  At many schools, there are far more women than men majoring in psychology and biology, but far more men than women majoring in math and engineering.   

This observation has led researchers to explore reasons why men and women differ in the fields they choose.  One of the factors that has been explored is math anxiety—the amount of anxiety that people anticipate or experience when thinking about or doing math.  A common observation across many studies is that when women are asked about their anxiety about math in general they exhibit a higher level of math anxiety than men.

An interesting study by Thomas Goetz, Madeleine Bieg, Oliver Ludtke, Reinhard Pekrun, and Nathan Hall in the October, 2013 issue of Psychological Science examined three questions. First, they wanted to replicate the finding that women exhibit higher levels of math anxiety then men.  Then, they asked whether women who are currently taking a math class or a math exam are actually experiencing more anxiety than men.  Finally, they explored reasons for the differences in math anxiety.

Across two studies, they got measurements from about 700 German students in grades 5-11.  In one study, students were asked for their general level of math anxiety and then were asked to assess their anxiety twice while taking a math exam.  In the other study, students were asked about their general math anxiety and also their specific anxiety in the middle of a math class.  Students were also asked questions about how good they thought they were at math and information was gathered about their math grades.

Both studies found that the girls were more anxious about math in general than the boys.  Interestingly, when the questions were asked during an exam or during a class, the girls and boys were equal in their level of anxiety (and both boys and girls had very little anxiety in the moment).  

What is going on here?

It isn’t math performance.  The girls and boys in both studies were doing equally well in their math classes.

Instead, it seems to be related to differences between boys and girls in how good they think they are at math.  The boys’ ratings of their competence at math were consistently higher than those of the girls.  Statistical tests show these differences in ratings were related to differences in general math anxiety.

These findings suggest that it would be valuable to help all children get better calibrated about how well they are doing in math classes.  Knowing their level of performance could help them to reduce their anxiety about math in general.  In addition, it might be useful to take children who have general math anxiety and to help them to realize that they do not experience that much anxiety when they are actually doing math.  

Clearly, math anxiety is not the only factor that leads to differences in the majors that people pursue in college and the careers that they establish.  But, anything we can do to reduce the influence of general anxiety on career choices is a good thing.

Monday, October 12, 2015

Fables May Fail to Help Children

Stories are a central way that we pass information to people.  The beauty of stories is that they embed real cultural wisdom in a specific context.  They are easy to remember.  They capture people’s attention.  For all of these reasons, we often use stories to help people learn new strategies for dealing with life.

When we tell stories to young children, though, we often make them even more interesting by introducing fantasy elements.  Aesop’s fables were about animals rather than people.  Picture books are filled with stories of fairies, witches, unicorns, and princesses from faraway lands. 

There are lots of goals for telling stories to children, but there is often at least some attempt to teach kids something about life.  When we hope to educate, does it matter whether the stories are about the real world or about fantasy?

This question was explored in a series of studies published in 2009 in the Journal of Cognition and Development by Alison Shawber, Ruth Hoffman, and Marjorie Taylor.  In these studies, children were told stories about people or fantasy characters who had to solve a problem.  For example, a character might carry a number of apples by wrapping them up in a blanket.  Later, the children would be exposed to a problem like having to carry a lot of marbles.  They were given many objects to solve this problem including a towel.  The correct answer was to wrap the marbles up in the towel, just as the character in the story wrapped up the apples.

In one study, younger children (about 4-years old) and older children (about 5-years old) were told one story about a real child and a second story about a fairy that solved a different problem.  The solutions associated with the real child and the fairy were varied across children, so that the influence of the character was not related to the specific solution presented in the story. 

After hearing the stories, children were given a chance to solve a problem similar to the one described in the story.  If they could not solve it on their own, they were given a hint to use the story.  At the end of the experiment, the children were asked which story they would like to hear again as a measure of whether they preferred the story about the child or the story about the fairy.

Overall, children were more likely to solve the problem when it was told about a real child than when it was told about a fantasy character.  About 75% of the children in the study solved the problem with or without a hint when it was about a real child, but only about 50% solved it with or without a hint when it was about a fairy.

Another interesting result was that the younger children who preferred the story about the fairy to the story about the child had much more difficulty solving the problem than the older children who preferred the story about the fairy.  So, there seems to be a trend where children gradually learn to extract the solution from fantasy setting.

Putting all of this together, it suggests that young children find may find fantasy characters interesting, but they have a hard time learning the point of the story when it is embedded in a fantasy situation.  They find it easier to understand the point of the story when it is about real people.  The older children who liked fantasy stories tended to get better at solving the problem, but even they were much worse overall than the ones who heard the story about the real child. 

This work suggests that when stories are being told to teach children rather than just to entertain them, it might be best to focus those stories on realistic settings rather than fantastic ones. 

Tuesday, September 29, 2015

What Does Nostalgia Do?

When people get nostalgic, they are living in the past.  In those moments, the past seems rosy, and often as more positive than the present.  Nostalgia can be induced by thinking about past events, by going to places you have experienced before, or even by hearing a song that brings back memories of things that happened.  

Is nostalgia a good thing or a bad thing for people?  It clearly seems to make people feel better in the moment. Any time you focus on a positive memory, you tend to get a boost of positive feeling.  But, are there any other positive benefits of nostalgia?

This issue was explored in a paper in the November, 2013 issue of Personality and Social Psychology Bulletin by Wing-Yee Cheung, Tim Wildschut, Constantine Sedikides, Erica Hepper, Jamie Arndt, and Ad Vingerhoets.  They suggested that nostalgia may actually make people more optimistic about the future.

In one study, the researchers simply had college students write a short essay about a past event that made them feel nostalgic or a past event that seemed ordinary.  Ratings suggested that making people write about a nostalgic event made people feel more nostalgic and also slightly more positive than writing about an ordinary event.  Using a program called the Linguistic Inquiry and Word Count (LIWC) software developed by my colleague Jamie Pennebaker and his colleagues, the researchers analyzed the words used in the essays.  LIWC counts different kinds of words that appear in text including words relating to optimism.  People writing about nostalgic events contained more words relating to optimism than people writing about ordinary events.  

In another study, participants instructed to think about a past event that made them feel nostalgic rated themselves as feeling more optimistic than those instructed to think about an ordinary event.  Optimism increased above and beyond any influence that thinking about a nostalgic event had on people’s positive feelings in general.

The remaining studies in this paper examined why nostalgia makes people feel more optimistic.  These studies used internet surveys in order to have a broader age range of participants.  They induced nostalgia in some participants by having them listen to songs or read song lyrics that were associated with nostalgic feelings (for those participants).  

As in the other studies, participants who were induced to feel nostalgic also expressed more optimism of the future.  This optimism is related to two other factors.  First, nostalgia makes people feel more socially connected to others.  This social connection boosts people’s positive feelings about themselves.  That increase in self-esteem then increases feelings of optimism. 
This set of studies suggests that nostalgia can play a beneficial role in people’s lives.  When times are tough, it may seem as though things may never get better.  By focusing on positive times from the past, though, people may help themselves to be more connected to others, which can give them the resources to be more optimistic about the future.

A limitation of this study is that these effects were all statistically reliable, but they were rather small overall.  People got more optimistic, but not by a lot.  It remains to be seen how much of a practical impact nostalgia may have on people’s day-to-day behavior.

Tuesday, September 22, 2015

Some Odd Numbers are Odder Than Others

The ability to classify objects is crucial to thinking. When you place an object into a category, you are able to predict things about it.  When you see a small furry four-legged animal in someone’s back yard, and you categorize it as a dog, then you can predict that it will probably bark and might want to chase a ball or gnaw on a stick.  In this way, your categories allow you to use your past knowledge to help you understand new situations.  

Often, an object is placed into a category because it is similar to other members of the same category.  So, you decide that the furry four-legged animal is a dog, because it looks like other dogs you have seen in the past.  You categorize the tall, woody plants in the yard near the dog as trees, because they are similar to other trees you have seen.

Sometimes, of course, an object belongs in a category because the category has a strict definition that determines who is and who is not a part of it.  In math, an odd number is any number whose final digit is not divisible by 2.  A triangle is any three-sided closed figure. 
An interesting observation over the years is that even when people are faced with categories that have strict definitions, they treat them in a similar way to categories whose membership seems more based on similarity.  In 1983, Sharon Armstrong, Lila Gleitman and Henry Gleitman found that people believed that some members of categories like even and odd numbers are better than others.  So, a number like 400 is judged to be a better example of an even number than a number like 798, even though—technically speaking—both are perfectly good even numbers.

A 2013 paper in the journal Cognition by Gary Lupyan looked at this effect more carefully.  In one study, he gave people one second to classify numbers as odd or even.  The numbers had between 1 and 4 digits.  He manipulated how many of the other digits in the number were of the same parity as the judgment to be made or of opposite parity.  That is, if a four-digit number to be classified was even (because its right-most digit was even), then on some trials all of the other digits were even, on some trials one, two, or three of the other digits were odd.

Unsurprisingly, people were highly accurate at this task.  However, the more of the digits of a number that were the opposite parity to the judgment to be made, the slower and less accurate people got.  In another study, participants were shown numbers and given as much time as they wanted to make judgments, and they made more errors when the numbers had some digits that were opposite to the parity of the correct response.  This effect was also observed when the numbers were spelled out (Three hundred and fifty two) rather than written as Arabic numerals (352).  

Other studies in this paper found a similar effect for triangles.  People got slower and less accurate to classify triangles as they differed more from a typical equilateral triangle.  A third set of studies demonstrated a similar effect for grandmothers.  A woman is a grandmother if her offspring has a child of his or her own.  Yet, the typical grandmother is also older and retired.  The less that particular women resembled a typical grandmother (despite being grandmothers), the less chance that participants judged they had to win a contest in which every grandmother entered had an equal chance to win.  

What does all of this mean?

The human mind is ill-suited to carry out rules.  We need to be able to recognize new items quickly and to figure out what they are likely to do in order to understand how to interact with them.  

It is rare in nature that there is a specific rule that defines a category that does not come along with lots of other features that help to identify the item.  A dog may be an animal that has dog DNA, but dogs also have lots of characteristic features that help us to understand what they are.  (Trees are another matter entirely, though, many things we classify as trees are less related to each other than they are to other plants that we could consider bushes or flowers.)

So, the human mind evolved to focus on classifying items based on their observable properties.  Humans have invented lots of rule-based categories like even numbers, triangles, and even bachelors and grandmothers.  But, we do not have mechanisms that allow us to simply use rules.

You might think that is a problem.  It would be great to adapt to rule-based categories so that we would not make mistakes classifying them.

However, even many categories that seem rule-based are not.  Consider what seems to be a simple concept like murder.  It should seem obvious that killing another person is a crime.  But, what about someone who kills another person in self-defense?  How about an elderly man assisting the suicide of his long-suffering wife to spare her additional years of pain?  It is hard to determine whether these examples are actually murder.  Our ability to use other factors besides rules to classify items allows us to figure out how rule-based categories apply in the real world.