Confirmation Bias

Hi everyone, this week’s post is an expansion of a brain teaser that I wrote a few months ago about whether we are innately logical – to read that and see how you get on in a test of logic check here. In this, I explained that we tend to fail at classic logic tests because we look for information that supports what we already know, rather than taking all available information into consideration to make our judgments – this is called confirmation bias. It operates in 2 ways: by selective searching for information, and biased interpretation of information.

Once you think about it, it’s surprisingly common in everyday situations. People have superstitions because they notice a link between a certain action and a result, so every they will continue to carry out that action. They do this even if it doesn’t always work – these instances are ignored, but every time the superstition ‘works’ it sticks in their memory and reinforces their actions.

Although this is a relatively simple example, the way we use reasoning has important implications, for example in the criminal justice system. Members of the jury must consider all the information presented to them in order to come up with the correct decision. However, several psychological studies have shown that people’s judgments are easily affected by prejudice and personal expectations, or by a piece of evidence which seems to fit.

For example, Ask & Granhag (2005) asked both criminal investigators and students to read facts about a murder case, but manipulated information so that half of the participants had background information suggesting that a prime suspect had a motive, while the other half were told there might be someone else involved. They found that the students thought it was more likely to be the prime suspect, but only when they had a motive. The investigators showed a similar effect and were less likely to consider problems with the evidence when a prime suspect was identified, rather than if there was someone else – but importantly only if they had a ‘need for cognitive closure’ (basically time pressure and emotional investment in the decision). This shows the imprecise nature of our decision making and how our emotions and initial thoughts can easily cloud our judgments.

In order to avoid confirmation bias, it is important to take into account any information which goes against what you originally thought. In science, people need to actively look for information to go against their theory, because when you’ve disproved alternatives you can be sure that your theory is correct. So it might be worth keeping this in mind..

confirmation bias


Being left handed

As a left handed person and psychology graduate, this is a post I’ve wanted to write for a while because there’s actually a lot I don’t know about how being left handed affects the brain. Me and my dad are both left handed, but at opposite ends of the spectrum – he writes with his left hand (but that’s about it) whereas for me, even picking up something with my right hand feels weird and requires conscious effort. So if being left handed is genetic, why this difference?

Another reason I wanted to find out more information is that I actually quite like being left handed, despite the obvious irritation of everything from scissors to tin openers to computer keyboards being biased to the right-hander (and don’t even get me started on trying to write in anything other than biro). And there might even be some benefits to being a leftie, with theories that it’s linked to creativity, sports, or being good at playing an instrument. Here’s what we know:

About 10% of the population are left handed, although as you can see from the comparison between me and my dad, the degree of left handedness can vary. Men are also more likely to be left handed than women (e.g. Papadatou-Pastou et al, 2008). Scientists still aren’t sure of the exact cause of being left handed, although they are sure there is some genetic component – studies have shown that you are more likely to be left handed if one of your parents is (e.g. McManus & Brydon, 1991b).

Handedness has also been thought to relate closely to language functions in the brain. As you may remember if you read this post, in most people, language functions are lateralised to the left hemisphere (see below). As each hemisphere controls the opposite side of the body, there is thought to be a relationship between hand dominance and language, with right- handers having right side preference due to language functions located in the dominant left hemisphere.


However, in left-handers this relationship is not so clean cut – only about 30% are thought to have their language dominance in their right hemisphere. I actually participated in an fMRI experiment at uni which tested my handedness and language location in the brain, which found that even though I’m left handed, my language functions are normally lateralised in the left hemisphere. So opposite language lateralisation in the brain can’t be the only reason people are left handed, the process is way more complex, and still not something science fully understands.

Several studies have identified a link between being left handed and creativity. For example, Newland (1981) asked almost 100 right handed, and 100 left handed people to complete a test on creative thinking. The results showed that left handed participants scored more highly on all 4 sub-tests, suggesting they have greater creativity. Another study by Coren (1995) found that left-handers have better divergent thinking skills than right-handers – in other words, they are better at exploratory thinking to find solutions and create ideas. Being better at divergent thinking could explain why left handed people are more creative, and thought to be better at logic.

There is a lot of anecdotal evidence which suggests left-handers are smarter, or better at politics e.g. Mensa reported that 20% of its members are left handed (which is double what you’d expect, at 10% of the population). However, unfortunately, I can’t seem to find any actual experiments comparing IQ that back this up! Studies have shown however that professional orchestras have a higher proportion of left-handers, and that during school, a high proportion of children who excel at maths are left-handed.

Annoyingly, there don’t seem to be answers to all my questions about left handedness, and there is still a way to go to establish the genetic basis and to understand how the brain is organised in left handed individuals. Regardless, I hope you found this post interesting and let me know in the comments if there’s anything else you’d like me to feature on this blog.





How to stick to your New Year’s Resolutions

Hi everyone, I’m back after a bit of a break for Christmas with a post that’s pretty relevant to this time of year.. how to stick to your New Year’s resolutions. If you want to exercise more, or stop smoking, then look no further -this is the post for you.

When we write down our resolutions, we tend to picture ourselves in a few months time, and how happy/healthier we will feel. But year after year, we fail to accomplish these goals – stats have shown that as many as 80% of New Year’s resolutions remain incomplete. If you seem to fall into this category, then I’ve linked an excellent article above from the UK Mental Health Foundation about how to make goals that will work for you.

So once you’ve decided on your realistic goal, for example getting more exercise, how can you use psychology to predict your success? One well known model is social psychology is the Theory of Planned Behaviour, developed by Icek Azjen (1991). This theory aimed to improve the predictive abilities of previous theories by adding the influence of our behavioural intentions. The process of changing behaviours according to this model is shown in the flow chart below:


As you can see from this diagram, this theory distinguishes between 3 different types of beliefs: behavioural, normative, and control. So therefore, our intentions to change behaviour are influenced by:

  1. Our attitudes towards that behaviour e.g. ‘I believe that exercising more will benefit me.. exercising is a positive behaviour’
  2. Other people’s attitudes towards this behaviour (subjective norm) e.g. ‘My family think I should exercise more.. most people view exercise as a positive behaviour’
  3. Our perceived control beliefs about the behaviour e.g. ‘I know I will be able to make time for exercise if I try’.

These beliefs then impact our intention to change our behaviours – for example if we believe that exercising more will benefit us, something which others agree with, and we believe we will be able to carry out the behaviour successfully, then our intention to change will be stronger. Therefore, we will be more likely to change our behaviour and achieve our goal. Studies have shown that it is our perceived behavioural control which mainly improves the prediction of actually carrying out behaviours from the intention to change, and is mainly applied to health behaviours such as stopping smoking or drinking too much.

I hope you found this post useful and that it will help you achieve your resolutions this year – let’s lower that 80%!

How to make the perfect gin and tonic

As it’s the holiday season and a lot of you may be thinking about throwing Christmas parties, I thought I’d do a relevant post this week – about how psychology can be used to enhance our perceptions of food and drink.

There’s actually been a lot of a research on this topic, which is then used by restaurants to make us enjoy our dining experience more, and ultimately spend more money!

Much of this research has been carried out by a psychologist called Charles Spence, who found that the way we perceive our food and drink affects its taste. He was part of a research team which found that the weight of a glass affects our perception of the drink inside, with lightness associated with cheapness – therefore, if you put your gin and tonic in a heavier glass, people will assume the quality of the alcohol is better, and so will prefer its taste. People also prefer wine if it came from a heavier bottle, and beer if it is drank from a bottle rather than a can.


The feel of the quality of the cup or glass also has an effect on people’s perception of its contents. For example, Krishna and Morrin (2008) found that when people were served water in a flimsy plastic cup, but either drank it with a straw (without touching the cup) or picked the cup up, the participants who did not touch the cup rated the water as being of a better quality.

This effect of the weight and quality of the container  on perception has also been found to occur with food. In one study (Piqueras-Fiszman et al 2011), participants tasted yoghurt which was put in 3 bowls, which were identical apart from the fact they were different weights. They had to hold the bowl as they ate, and had to rate each yoghurt on which one they preferred (the yoghurts were of course, exactly the same). Results showed that the yoghurt from the heaviest bowl was liked 13% more by the participants than yoghurt from the lightest bowl.

So why does this effect occur? It is thought to be in part due to sensation transference, with perceptions of the glass or bowl being high quality and expensive being transferred to the food or drink they are containing. As well as this, the drinker needs to be aware of the shape or size of the glass, in order to make a judgement about its quality. Again, higher quality of material = higher quality judgement on the contents.

So what is the secret to making the perfect gin and tonic? Put it in a heavier glass and enjoy!



Following on from the post about my dissertation.. now on to the next thing that’s been taking up quite a lot of my time this year – my research project. For this part of my degree, I had to carry out my own experiment on something which had not been shown before, and analyse the results.

I chose to look into nostalgic memories, and in particular, do we feel nostalgic from reading someone else’s nostalgic memories? It seemed like there was a bit of a gap in the research that had been done so far: although we know the functions of nostalgia (e.g. self esteem) and features of nostalgic memories (e.g. loved ones), not much work had been done on ways of making people feel nostalgic.

To start, I should probably make clear what nostalgia is: it is defined as a
“sentimental longing or wistful affection for a period in the past”

The problem I identified with existing research was that most experiments manipulated nostalgia by asking participants to write down a nostalgic or ordinary memory, reading words that describe nostalgia and writing a memory based on them, or by listening to a nostalgic or ordinary song. These methods are fine if you then want to find out about effects of nostalgia, but are they equally effective in inducing nostalgia?
Nostalgia is also a very social emotion, and a study has shown that thinking of a nostalgic memory involving an out-group member leads to fewer feelings of prejudice towards that person (Turner et al, 2012). If nostalgia is a social emotion, then I hypothesised that reading someone else’s nostalgic memories could cause you to feel nostalgic. There had only been one study which found that nostalgia could be induced by reading someone else’s old love letters, or looking at their old photos. I decided to present participants with an actual nostalgic (or ordinary) memory narrative from someone else, and told participants the memory was from someone similar or dissimilar to them in age (to see whether similarity affected results). I compared how effective this method was with a previous method of making people feel nostalgic – giving participants a list of words that described nostalgia, or were more general, and asked them to write a memory based on these features.

My hypotheses:
1. That reading the nostalgic memory would make people feel nostalgic (compared to reading an ordinary memory).
2. That participants who were told the nostalgic memory was from someone similar to them would feel more nostalgic than those who were told it was from someone different.
3. That this method would be effective, but more nostalgia would be induced from writing your own memory in the comparison condition.

The reason I thought that similarity would effect results was because of principles shown in social psychology – it has been found that when people are categorised into groups, they will automatically perceive themselves as being more similar to other in-group members, and therefore more dissimilar from out-group members (Tajfel & Turner, 1979). Therefore, the perceived similarity of the reader to the person who wrote the memory could increase the amount of nostalgia transferred to the reader of the narrative. I called this a similarity-based “transfer effect” of nostalgia.

Design of Experiment:
– 121 participants, all between the ages of 16 and 24 (so I could manipulate similarity by age)
– Participants split into 6 groups: nostalgia similar, nostalgia dissimilar, ordinary similar, ordinary dissimilar, central features (write memory) and peripheral features (write memory).
– At the top of the memory narratives, a sentence explained this was ‘an actual memory from someone aged 20 (similar condition) or 60 (dissimilar condition).
– After participants had either read the memory, or read the features and written their own memory, they then completed a questionnaire to assess how nostalgic they felt.

What I found:

Hypothesis 1: Reading someone else’s nostalgic memory did make people feel more nostalgic than those who read an ordinary memory.

Hypothesis 2: Similarity had an effect on the amount of nostalgia people felt: participants in the nostalgia similar condition felt more nostalgia than participants in the nostalgia dissimilar condition – EVEN THOUGH the memory was the same, the age of writer differed.This is shown by the graph below.


Hypothesis 3: The participants who wrote their own memory based on central features of nostalgia felt more nostalgic than participants who had read a nostalgic memory. However, there was no difference between the central and peripheral conditions, which differed from the original study (Hepper et al, 2012), who found peripheral features did not induce nostalgia. The graph below shows the results for this, and hypothesis 1: more nostalgia felt by participants who read someone else’s nostalgic memory than someone’s ordinary memory.


The results of my experiment are the first to show that people can be made to feel nostalgic by reading someone else’s nostalgic memory, and that the amount of nostalgia felt depends on how similar the writer of the memory is to the reader. Therefore, it sets the basis for more research to be done on different ways of manipulating similarity and other ways of inducing nostalgia.

Hope you found this interesting and let me know if you’ve got any questions – I know this is a really complicated experiment!


Stress is not an uncommon emotion. In fact at uni it’s rare if a day goes by without someone (or let’s be honest, myself) complaining how stressed they are about a deadline/job application/exams. But what is stress? Why does it affect some people more than others, and is there anything we can do about it?

Types of stress:

There is debate about this, but putting it simply there are two different types of stress: acute, and chronic.
Acute stress has a sudden onset, and triggers the ‘fight or flight’ response, in which the brain releases adrenaline. This causes heart rate and blood pressure to increase, while functions which are seen as non essential, such as digestion, are decreased. This response prepares the body for danger.
In contrast, chronic stress is more long-term, and therefore has different effects on the body. The hypothalamus releases the neurotransmitter ACTH which causes the adrenal cortex to release cortisol. This makes sure the body has a source of energy, but weakens the immune system.

Both of these stress responses are illustrated in the diagram below:


Acute and Chronic Stress Responses


Effects of stress:

As implied by the fact that chronic stress weakens the immune system, stress makes you more likely to become ill, and slows healing. For example, Marucha et al (1998) found that students showed slower wound healing during the exam period than at other times of the year. Glaser et al (1989) found that students also reported more illnesses during this time.

Reducing the impact of stress:

Luckily, there are factors which can reduce the effects of stress. One of these is mood: Stone et al (1987) found that being in a positive mood is associated with more secretion of immunoglobin – a type of antibody which fights infection.

Other cognitive coping strategies include:
1. Problem-focused strategy: attempting to change the external situation, often through some planned action.
2. Emotion-focused strategy: attempting the change our own emotional reaction to the situation.
3. Avoidance.

Strategy number 2 is thought to be the most effective.

Why does stress not affect some people as severely?:

One theory was developed by Kobasa (1979) – the personality trait of ‘hardiness’. People high in this trait have a relative resistance to stress as they:
– believe in personal control over events
– have a commitment to full involvement in life
– enjoy challenges and opportunities.

One study found that executives who scored highly in these factors were less likely to become ill than others when exposed to the same amount of stress.

Another theory is that people who are less affected by stress have an ‘internal locus of control’, which means they believe they have personal control over events, rather than believing in external factors, such as luck (Hurrell & Murphy, 1991).

I hope you liked this post – if there’s any topic you’d like me to write about then let me know in the comments!

Pro-social behaviour

Would you help a stranger if it looked like they were in trouble? What if there were lots of other people around, and you thought they would be better suited to help, or they just didn’t look that worried?

Most people would be certain that regardless of the circumstances, they’d help someone in need. But is this actually the case?

Pro-social behaviour is when someone actively tries to help someone else, motivated by egoism (to benefit them) or altruism (to benefit someone else).

Helping in emergencies

Helping (or not) depends on certain factors:

– noticing that something is wrong

– defining it as an emergency

– deciding whether or not to take personal responsibility

– deciding what type of help to give

– implementing the decision.

If any of the first 3 steps don’t happen, then the victim will not be helped.

Latané and Darley (1976) identified 3 processes which cause people not to help in social situations:

  1. Diffusion of responsibility: the more people present, the more people think that they don’t need to help, as someone else will.
  2. Pluralistic ignorance: if there is high ambiguity about the situation then bystanders feel more uncertainty, and are less likely to help. As each bystander hesitates, they ‘model’ passivity for the others.
  3. Evaluation apprehension: other people being present causes you to feel uneasy, as they will witness your intervention if you choose to help.

These researchers provided evidence for this theory in a study in which participants were sat in a room while they completed a questionnaire. White smoke then started coming into the room through a vent, and they observed what the participant would do if they were alone, with two passive confederates (actors who were told not to react) or three naive participants.

If the participant was alone, then about 75% reported the smoke after 4 minutes. However, if they were with the two passive confederates, only 10% reported the smoke. This shows the influence of others on our behaviour.

Why do some people help?

Several studies have shown that being in a good mood increases your likelihood of helping. Isen and Levin (1972) used a mood induction method of failing or succeeding at a task to make participants in a good or bad mood. A confederate then dropped their books nearby. They found that participants in a good mood were more likely to help than those in a bad mood, and suggested that this is because their attention is turned outwards so will notice if someone needs help.

There is also a certain personality trait which makes people more likely to help. Isen et al (1997) identified 4 personality variables which are high in people who show pro-social behaviour:

  1. Social responsibility
  2. Belief in a just world
  3. Empathy and concern with others’ welfare
  4. Self-efficacy – confidence that their actions will be successful.

I hope you found this post interesting, did it made you think about when you would help others? Leave me a comment and let me know!

Obedience to authority

Bit of a change from neuroscience now to look at one of the most famous areas of social psychology. This aspect was made famous by a series of highly controversial experiments by Stanley Milgram in the 1960s, which investigated why people obey authority figures.

To set the scene a bit, a lot of the social psychology work in the 50s and 60s looked at aspects of obedience, as following the 2nd World War people wanted to know why some of the officers carried out orders to kill innocent people without question – were they just evil?

In his first experiment, Milgram recruited male participants and told them they were taking part in a study investigating the effects of punishment on learning (when it was infact measuring obedience) . They met with another participant, who was actually an actor, and lots were drawn to see who would be the ‘learner’ and who would be the ‘teacher’. These lots were fixed so that the participant always played the role of the teacher.

The diagram below shows the set up of the experiment:

T = teacher

L= learner

E = experimenter (or actor who player part of a scientist) – this is the authority figure.

The teacher was told that the learner had to memorise word associations, and that they were to test them. If the learner got an answer wrong, they had to give them an electric shock. No shocks were actually administered, but the teacher was given a sample shock at 45v so they’d think the apparatus was real.

Here’s the clever bit of this experiment: each time the learner got a question wrong, the strength of the shock increased by 15v, and the teacher did this by pressing down another switch on the generator (shown below). This gave the participant high levels of control over their actions, but the fact that it was only a small increase each time encouraged them to carry on getting higher.

As you can see, there are labels under the switches explaining how dangerous the shocks are. These were there to see if the participants would realise the harm they were potentially inflicting on the learner. When shocks were carried out, the learner could be heard shouting in pain, demanding to be let out when they reached 300v, and then falling silent and refusing to answer. The participant was told to treat any unanswered question as a wrong answer, so the shock value increased further.

Before the experiment, it was thought that only 1/1000 people would continue to give a lethal strength shock to the learner… in fact 2/3 carried on right until 450v, marked XXX on the machine.

But why would these people potentially cause so much harm to another person? This experiment shows how powerful following orders can become – if at any time the participants became uncomfortable and questioned if the learner was okay, the ‘scientist’ would say something along the lines of “the experiment requires you must continue”. Only if the participant questioned 5 times was the experiment stopped.

The participants clearly felt obliged to obey the authority figure, perhaps because he looked official in a white lab coat or the fact that the study was carried out in Yale University, with a high reputation. Also, the fact that they were paid before the experiment could have meant they felt like they had to carry on.

It is clear that these participants were not evil – it is very unlikely that the sample all happened to be psychopaths. But they would still give another person a lethal shock if told to by an authority figure.

To quote Milgram himself: “Ordinary people, simply doing their jobs, and without any particular hostility on their part, can become agents in a terrible destructive process”.