Category: Student features

9 evidence-based study tips













Statistical significance explained in plain English

Warren Davies, a positive psychology MSc student at UEL, provides the latest in our ongoing series of guest features for students. Warren has just released a Psychology Study Guide, which covers information on statistics, research methods and study skills for psychology students.

Today I’m delighted to discuss an absolutely fascinating topic in psychology – statistical significance. I know you’re as excited about this as I am!

Why is psychology a science? Why bother with complicated research methods and statistical analyses? The answer is that we want to be as sure as possible that our theories about the mind and behaviour are correct. These theories are important – many decisions in areas like psychotherapy, business and social policy depend on what psychologists say.

Despite the myriad rules and procedures of science, some research findings are pure flukes. Perhaps you’re testing a new drug, and by chance alone, a large number of people spontaneously get better. The better your study is conducted, the lower the chance that your result was a fluke – but still, there is always a certain probability that it was.

In science we’re always testing hypotheses. We never conduct a study to ‘see what happens’, because there’s always at least one way to make any useless set of data look important. We take a risk; we put our idea on the line and expose it to potential refutation. Therefore, all statistical tests in psychology test the probability of obtaining your given set of results (and all those that are even more extreme) if the hypothesis were incorrect – i.e. the null hypothesis were true.

Say I create a loaded die that I believe will always roll a six. I’ve invited you round to my house tonight for a nice cup of tea and a spot of gambling. I plan to hustle you out of lots of money (don’t worry, we’re good friends and always playing tricks like this on each other). Before you arrive I want to test my hypothesis that the die is loaded against my null hypothesis that it isn’t.

I roll the die. A six. Success! But wait… there’s actually a 1:6 chance that I would have gotten this result, even if the null hypothesis was correct. Not good enough. Better roll again. Another six! That’s more like it; there’s a 1:36 chance of getting two sixes, assuming the null hypothesis is correct.

The more sixes I roll, the lower the probability that my results came about by chance, and therefore the more confident I could be in rejecting the null hypothesis.

This is what statistical significance testing tells you – the probability that the result (and all those that are even more extreme) would have come about if the null hypothesis were true (in this case, if the die were truly random and not loaded). It’s given as a value between 0 and 1, and labelled p. So p = .01 means a 1% chance of getting the results if the null hypothesis were true; p = .5 means 50% chance, p = .99 means 99%, and so on.

In psychology we usually look for p values lower than .05, or 5%. That’s what you should look out for when reading journal papers. If there’s less than a 5% chance of getting the result if the null hypothesis were true, a psychologist will be happy with that, and the result is more likely to get published.

Significance testing is not perfect, though. Remember this: ‘Statistical significance is not psychological significance.’ You must look at other things too; the effect size, the power, the theoretical underpinnings. Combined, they tell a story about how important the results are, and with time you’ll get better and better at interpreting this story.

And that, in a nutshell, is what statistical significance is. Enthralling, isn’t it?

Editor’s note (07/09/2010): This post has been edited to correct for the fact that statistical significance pertains to the likelihood of a given set of results (and those even more extreme) being obtained if the null hypothesis were true, not to the probability that the hypothesis is correct, as was erroneously stated before. Sincere apologies for any confusion caused.

Why psychologists study synaesthesia








Five minutes with the authors of two recent influential studies in psychology

In this post we’ve asked the authors of two recent studies a number of questions about their influential work, including what inspired them in the first place. The studies are covered in detail in the new GCSE (an exam taken by 13-16 year-olds in parts of the UK) syllabus run by the OCR exam board in the UK. The researchers’ answers provide a revealing insight into the creativity and meticulousness underlying the design of psychology experiments.

Terry, W.S. (2005). Serial position Effects in Recall of Television Commercials. Journal of General Psychology, 132, 151-63.

Scott Terry: “Although I am a fairly traditional experimental psychologist, I look for research that bridges the laboratory-applied divide. I found some surveys that asked people to recall commercials they had recently seen on television, but I realized that the internal validity of such designs was limited. I believe the strongest scientific conclusions require the combination of both realistic field research and controlled experiments. So I decided to use commercials as the stimulus materials, but otherwise follow the standard laboratory format for a free recall experiment: stimulus duration, retention interval, recall and recognition testing. (Okay, I also thought that a study of serial position in memory for commercials was a cute idea.)

The main challenge faced in these studies was in assembling the lists. We (student John Bello and I) videotaped commercials. Then, using two videotape recorders, we had to copy and paste from tape-to-tape to construct the lists. Multiple lists, multiple sequences, and multiple experiments. If we had waited a few years the Apple software for video files would make the process simpler.

The resulting publication seems to be of some general interest. Textbook writers want to know more, and university students use the idea for projects. However, it seems the memory psychologists note the research is atheoretical (not addressed to any particular theory of serial position). Advertising researchers say it is not realistic enough. So there is still no common ground between the two camps.

I continue to research everyday memory phenomena, such as the difficulty in learning names, and why people forget the locations of objects placed in special locations. As for commercials, I’ve seen enough for now.”

Yuki, M. Maddux, W. W., and Masuda,T. (2007). Are the windows to the soul the same in the East and West? Cultural differences in using their eyes and mouth as cues to recognize emotions in Japan and in the United States. Journal of Experimental Social Psychology, 43, 303-311 . (link is to full-text pdf).

Masaki Yuki (Hokkaido University): “The inspiration for this study was my personal experience. Since my childhood, I have been amazed by how different American smiles were compared to my standard. Their facial expressions were much more intense, while opening their mouths widely, and raising the corners of their mouths up high. Later, when I communicated with my American colleagues by email, I realized that the happy ‘emoticons’ that they used, or :), was different from that of Japanese (^_^). And one day, it dawned on me that these faces actually looked exactly like typical American and Japanese smiles. It was the moment when I came up with the hypothesis that, if that is really the case, Americans and Japanese would look at different parts of the face when they try to infer others’ feelings: the mouth for Americans, the eyes for Japanese.

I started looking for scientific evidence which might support my impression based on these anecdotes. The range of studies that provide us with relevant ideas varies. First, cultural psychologists had pointed out that East Asians generally emphasized interpersonal harmony more than North Americans. Second, emotion researchers maintain that, East Asians are more likely than their Western counterparts to control/suppress their facial expression. Third, much neurophysiological evidence indicates that control of muscle around the mouth is easy, but it is hard to do it with the muscle around the eyes. Thus, if you try to interpret genuine emotion of others who are trying to suppress their facial expression, you had better look at their eyes. We attempted to synthesize these findings by examining cultural differences in interpretation of facial expressions.

To assess the independent effects of shapes of eyes and mouth on emotion perception, we used artificially morphed images in which the eyes and mouth were taken from different emoticons and facial expressions. However, we acknowledge that we could include images of full happy and sad faces (with both the eyes and mouth smiling or crying) in the experimental design, which may allow us to broaden our findings to images of natural facial expressions.

Our findings caught broad attention, both in academics and general public. The paper has been cited by psychological and neuroscientific articles, and the story has been mentioned by major newspapers and radio shows. It is really exciting for me to share the findings with people in a variety of fields.

Our team, Takahiko Masuda at University of Alberta, William W. Maddux at INSEAD, and myself, are now conducting a more sophisticated study so as to replicate the findings. I am hoping that this will provide us with much clearer evidence which further proves our hypothesis. Besides, I am also hoping that the other lines of research of mine, such as cross-cultural differences in group processes, and socio-ecological foundations of cross-cultural differences, will attract more attention, like this paper did 🙂 “

Link to resources post for OCR A-level.

How do psychologists study what we know about ourselves?







How to study

Dr. Nate Kornell of UCLA, with the fifth article in our ongoing series of guest features.

Although as students we have all spent countless hours studying, we receive little guidance in how to study effectively. There are no shortcuts to effective studying, but in general, being actively involved in learning makes studying effective. Some specific points are obvious: pay attention in class, do the reading, don’t procrastinate, while others should be obvious but aren’t: study in a quiet place without distractions, don’t send text messages during class, ask questions if you are confused.

Here are three unintuitive but very effective ways of studying based on findings from psychological research:

Space your study. We humans, and other animals as well, learn more by spacing study sessions out in time (pdf) than we do by massing them together (e.g. by cramming). For example, read a chapter at one time, and review it at another time; if you are studying a set of flashcards, study it every day, instead of intensely all at once. My own research has shown the benefits of spacing in learning about artists’ styles, learning vocabulary words using flashcards, and learning physics concepts, among other topics. If you don’t think spacing will work for you, think again—spacing is virtually always effective, even when it feels counterproductive.

Ask yourself questions. Testing oneself while studying has two advantages: First, it requires retrieving knowledge from memory. Doing so creates powerful memories (pdf) that are not easily forgotten. Second, self-testing allows you to diagnose your learning. If you test yourself before your exams, you can identify and rectify your weaknesses beforehand, instead of regretting them afterwards. A warning though: Self-testing when the information is still fresh in your memory, immediately after studying, doesn’t work. It does not create lasting memories, and it creates overconfidence.

Summarize and integrate. After going to class or reading a chapter, try to summarize the main points, and think about how they relate to the topic at large and to your own experience. This process, known as knowledge integration, creates lasting memories, and has the added benefit of requiring you to recall the information. One way to do so is to “learn by teaching”—that is, tell others about what you have learned, including fellow students or, if you don’t mind being boring, friends and family. Explaining requires integration and summarization, and it is an excellent way to expose the gaps in your own knowledge.

The steps above might seem burdensome, but the long-term benefits far outweigh the costs. A student looking to minimize effort would do well to follow them.

Link to more information.
Link to Nate Kornell’s website.
Link to article from this month’s Psychologist magazine on how to think like a psychologist (open access).

Psychological research in virtual worlds

Nick Yee of Stanford University, with the fourth article in our series of guest features.

Virtual worlds (such as World of Warcraft and Second Life) have received a great deal of media and academic attention recently. While these virtual communities provide us with a new and fascinating area of study, it is also important to understand how these virtual environments provide us with new research tools.

Several lines of research in this area have emphasized the methodological possibilities of this emerging technology. One research paradigm known as Transformed Social Interaction purposefully breaks and alters the rules of social interaction in order to gain insight into communication and interaction processes. In the physical world, two people interacting in the same space necessarily share the same reality. On the other hand, in a virtual environment where users view the shared environment from their own computer terminals or virtual reality goggles, their realities need not be congruent. Thus, for example, I may perceive my avatar (a digital representation of myself) to be short while you perceive my avatar to be tall. These non-congruent reality scenarios open up a range of research questions in stereotype threat, behavioral confirmation, and self-perception theory among other psychological theories.

Virtual environments also allow us to endlessly recreate and customize how we appear. While it is difficult to alter a participant’s height (let alone race or gender) in a lab experiment, virtual environments make it easy to explore what it means to be in a different body. For example, a line of research known as the Proteus Effect has shown that users conform to stereotypes based on their avatar’s appearance. Thus, participants given attractive avatars provided more information about themselves to a confederate stranger than participants given unattractive avatars. In addition to putting participants in someone else’s body, virtual environments also allow participants to watch their avatar (i.e. themselves) do something they never did. The fluidity of our virtual bodies allows us to ask provocative questions related to identity, false memories, and cognitive dissonance.

And finally, virtual environments keep track of a great deal of behavioral data. Everything a user does in an online game can potentially be tracked and accumulated over time with a precision not possible in the physical world. While a great deal of psychology research focuses on individual, dyadic, or small group effects, virtual environments provide the opportunity to study social interaction and communication processes at a community level. For example, could altruism be engineered into a virtual community via non-congruent realities? Furthermore, these virtual environments could also allow experimental manipulations on a scale not previously possible in traditional lab settings.

Further Reading:

Bailenson, J.N., Beall, A.C., Loomis, J., Blascovich, J. & Turk, M. (2004). Transformed Social Interaction: Decoupling Representation from Behavior and Form in Collaborative Virtual Environments. PRESENCE: Teleoperators and Virtual Environments, 13(4), 428-441.

Yee, N. & Bailenson, J.N. (2007, in press). The Proteus Effect: Self Transformations in Virtual Reality. Human Communication Research.

Ducheneaut, N., Yee, N., Nickell, E. & Moore, R.J. (2006). “Alone Together? Exploring the Social Dynamics of Massively Multiplayer Games.” In conference proceedings on human factors in computing systems CHI 2006, pp.407-416. April 22-27, Montreal, PQ, Canada.

The Digest needs you. If you’d like to write about your area of psychology research, please get in touch on: christian at

An introduction to psychophysics

In the third of our ongoing series of guest features for students, Dr. Tom Stafford of the University of Sheffield introduces psychophysics.

How far away can you see a candle at night? Why can’t you see it at the same distance during the day? How much do I have to turn up the volume before something seems twice as loud?

All these questions are about measuring the relation between physical qualities and the psychological impressions they cause. Psychophysics is the part of psychology which involves the systematic and precise investigation of these relationships.



Imagine: you can make an empty bag feel heavier by putting in a book, but a single book won’t make a bag full of bricks feel heavier, even though in both cases you are adding the same amount of weight. Weber’s Law gives you a mathematical way to calculate how much you would need to increase or decrease the physical weight to produce a subjective impression of a change in heaviness. It also allows you to compare sensitivity between the senses – showing, for example that we are more sensitive to brightness than loudness, because the proportional change needed to create a noticeable difference for lights is smaller than that needed for sounds.


Read an excerpt of Fechner, G. (1860). Elements of psychophysics (HE Adler, Trans.). New York: Holt, Rinehart and Winston.

Link to the psychophysics introduction by Webvision.
Check out the other articles in this ongoing series, including “Why psychologists study twins“, “A lyrical guide to using the web” and “Podcasts – a clickable list“. Forthcoming in the series: “Systematic reviews” and “Virtual reality and online games” – stay tuned!

Psychology podcasts: a clickable list

Updated Feb 2017


Hidden Brain


School of Psych

All in the Mind


The Methodology for Psychology Podcast
Interviews with psychology researchers.

You Are Not So Smart

60-Second Mind

The Psychology Podcast

Psycomedia [recently re-started after a hiatus]
A comedy podcast dedicated to the funny side of psychological research.

Very Bad Wizards
A philosopher and a psychologist ponder the nature of human morality.

Secret Psychology of Persuasion
Interview-based podcasts presented by Nathalie Nahai.

Psychology of attractiveness podcast

Royal College of Psychiatrists
Interview-based podcasts, presented by Raj Persaud and others.

Shrink Rap Radio

All in the Mind (from ABC Radio in Australia)


The PsychFiles

The Perception and Action podcast

Who cares? What’s the point?

The Human Zoo [no longer updating]

N of Us [no longer updated]

Group Therapy [no longer updated]

Psychtalk [last updated in 2013]

My Three Shrinks [no longer updating]
a podcast by three psychiatrists, each with a different perspective.

Autism podcast [no longer updating]

This Week in the History of Psychology [no longer updating]


Why psychologists study twins

In the second of our on-going series of guest features for psychology students, Dr. Angelica Ronald of London’s Institute of Psychiatry describes the use of twin studies in psychology.

Psychologists are often trying to control one thing to look at its effect on something else. This results in the plethora of artificial experiments and carefully-matched control groups in psychological studies. The beauty of twin studies is that they provide psychologists with a natural experimental design – there’s no need for any additional control groups.

This natural design comes about because there are two types of twins: those who share all their genes (because they were formed from the same egg which split early on in development), called identical or monozygotic twins, and those who, just like non-twin siblings, share on average half their genes (they are formed from two separate eggs), called fraternal or dizygotic twins.

Twin designs address the nature-nurture question. Behaviour geneticists compare how alike one twin is with the other twin on whatever variable they are interested in; in my case this is autistic behaviours. If genes influence variation in autistic behaviours, identical twin pairs who share all their genes will be highly similar in their degree of autistic behaviours whereas fraternal twins will be much less similar. This is what we have found.

It’s the same for a diagnosis of autism: when one identical twin has autism, in 60 per cent of cases their co-twin also has autism. With fraternal twins there is a different pattern: most of the time when one twin has autism, the other does not have a diagnosis.

Just as much as twin studies have told us about genetics, they have been paramount in revealing the importance of the environment. For example, it is true that about 60 per cent of identical twins have the same autism diagnosis i.e. if one is autistic, the other is too. But in the other 40 per cent or so of identical twins, if one has autism, the other does not. This is sound proof that autism is not completely genetically determined – because if it were, both identical twins in a pair would always show the same degree of autistic problems. Genes play a role in risk but there must be some influence of the environment on the child’s outcome as well.

This example represents just the tip of the iceberg of how twin studies can contribute to psychology and our understanding of the causes of human behaviour. Of course no study design is perfect: like most research designs, the twin design has a number of assumptions, and even though it’s a natural experiment and we don’t have to control any variables, behavioural geneticists have to collect huge samples of twins (usually in the 1000’s) to be able to be certain about their findings.

Further reading:

Plomin, R., DeFries, J.C., McClearn, G.E. & McGuffin P. (2001). Behavioral Genetics (4th edn). New York: Worth Publishers.

Ronald, A., Happé, F., & Plomin, R. (2005). The genetic relationship between individual differences in social and nonsocial behaviours characteristic of autism. Developmental Science, 8, 444-458.

Ronald, A., Happé, F., Bolton, P., Butcher, L. M., Price, T. S., Wheelwright, S., Baron-Cohen, S., & Plomin, R. (2006). Genetic Heterogeneity Between the Three Components of the Autism Spectrum: A Twin Study. Journal of the American Academy of Child & Adolescent Psychiatry, 45, 691-99.

If you’d like to write a mini-feature about your area of research, please get in touch.