The Placebo Effect

Hi everyone, I’m back after a bit of a break – will try and get back in the routine of regular posts!

This week’s post is something I’ve been wanted to blog about for ages: the Placebo effect. This is well known, having been the subject of films, TV documentaries, and a televised experiment by Derren Brown. When you think of placebos, I bet the majority of you imagine a sugar pill, which when taken, helps reduce negative symptoms.  However, there is far more to placebos than this, and their existence can cause some problems when developing effective new treatments.

So to start off, what is a placebo? A placebo can be considered any substance, (a sugar pill, water, injection of saline solution) which normally has no medical effect on the body, although when disguised as a plausible treatment, causes a very real response.

Interestingly, the effects of a placebo are increased with the perceived impact of the ‘medicine’. So for example, taking 2 sugar pills will create a larger effect than just taking one, having an injection of saline solution will create a larger effect than taking pills, etc.

This seems to point to an explanation for the placebo effect – our expectations. We think taking a tablet will get rid of our headache, and so it does, whether or not that tablet actually includes any active ingredients. This could be due to classical conditioning: that the act of taking a pill has been linked with the lessening of pain, and so taking a sugar pill results in the conditioned response of pain reducing (Stockhorst et al 2000). Placebos can have a similar affect on the brain as taking the real medication, for example Fuente-Fernández et al (2001) investigated it with patient with Parkinson’s disease, and found that taking a placebo caused a similar amount of dopamine to be released as L-Dopa – the drug used to manage symptoms of PD by increasing the amount of dopamine in the brain.

As I mentioned earlier, the existence of the placebo effect has a large impact on clinical trials investigating the effectiveness of new medicines. For example, say you have invented a new drug which could be used to treat anxiety, and have just begun trialling it on human participants. How do you know that any reported improvements in symptoms are due to the active ingredients in the drug, and not simply that taking the drug has caused an improvement via the placebo effect?

Fortunately, you can get around this problem by carefully designing your study. Most studies have a control group who don’t receive any treatment, whilst those in the intervention group do. However, to rule out the placebo effect, there needs to be an active control group, who receive exactly the same intervention apart from the drug they are actually given is a placebo. That way if there is an improvement in the active control group it can be attributed to the placebo effect. For the drug to be considered effective, participants in the intervention group should have a larger improvement, and this different can be attributed to the active ingredient in the drug.

placebo effect

As well as affecting drug trials, the placebo effect can also affect studies into psychological treatments, and here is it much more difficult to control for. Boot et al (2013) recommend that an active control group isn’t enough, you really need to try to make participants’ expectations the same in both the intervention and the control groups. As you can imagine, this is a lot more difficult for psychological interventions as it is a lot harder to hide what kind of treatment each group are getting.

Although this makes research more complicated, setting up studies with adequate controls are needed for us to be able to take proper conclusions from them.. or we could be spending a lot of time and effort to design something which doesn’t have any special effects at all!

 

The McCollough Effect

It’s always a good feeling when I find out about a new illusion that I can share on here – this week’s Brainteaser is another about colour after-effects: The Mccullough Effect.

What makes this different to other colour after-effects is that the stimuli used in adaptation is simpler than the final illusion. This effect was discovered by Celeste McCollough in 1965, and involves alternating black and white lines (known as ‘gratings’) which are viewed as coloured after a period of adaptation. Try it for yourselves here:

First, stare at these images for a minute or so then look at the grid below

McCollough Effect 1

McCollough Effect 2

What you should notice is that these gratings now look coloured, when they are in fact black and white! The vertical lines should look red, whilst the horizontal ones look green.

What is so interesting about these after effects is that unlike others (e.g. here), this effect lasts not just for a few minutes but for hours, or even days. Some studies (e.g. Jones & Holding, 1975) have shown that adaptation for 10 minutes can lead to after effects months later!

Scientists are still not certain which part of the visual system is responsible for this effect or why it is so long-lasting. One theory is that it takes place due to neurons in V1 – the first part of the visual cortex which receives information from the optic nerve via the Lateral Geniculate Nucleus. Only neurons in early visual cortex are sensitive enough for this type of adaptation to occur. A possible reason why this effect lasts for so long could be simply that the adaptation stimulus is rare, so is not seen in the environment for us to de-adapt, whilst others believe this shows a form of associative learning. However, the exact mechanisms are still up for debate.

 

 

 

Are we getting smarter?

Hello everyone, sorry for the lack of blogging over the last month or so – I’ve been doing some extra work in my free time which I’m sure I’ll share on here once it’s published! But I’ve got a bit of a break between deadlines, so I’m back with this post about intelligence and IQ tests which will aim to answer the question: are we getting smarter?

Let’s start off with a bit about IQ tests. There are several which are regularly used in scientific research, such as Raven’s matrices, the Weschler Intelligence Scales, and the Stanford-Binet Intelligence Scale. See how you get on with these example questions and scroll to the bottom for answers!

Raven’s Matrices:

This is a progressive IQ test, with questions becoming harder as you progress through the test. Easier questions at the beginning are used to test children – I’ve done used this before for a research project and it’s relatively simple to explain meaning young children can’t be confused by long written instructions. It is a non-verbal test made of 60 multiple choice questions which measures ‘fluid intelligence’ – or reasoning. Participants are shown a geometric design with a missing piece, and have to choose from multiple options which piece fits best. Have a go at these and see how you get on..

a)

RAPM2

b)

RAPM31

Weschler Adult Intelligence Scale

This test measures cognitive abilities, with the most recent edition – the WAIS-IV, including 4 IQ sub scales: Verbal comprehension, Perceptual reasoning, Working memory and Processing speed. Like the Raven’s matrices, this scale has been adapted for use with children and is also used in a clinical setting, for example when testing for developmental disorders or dementia. See an example below:

c)WAIS-IV_Visual_Puzzles

So how did you get on? Composite scores from answering all of the questions in these intelligence tests are combined to give a score of Intelligence Quotient, or IQ. IQ tests such as the ones above are developed to give a median score of 100 with each standard deviation of 15 IQ points. This is often illustrated in a bell curve, as shown below:

bell-curve-normal-distribution-iq

But are we getting smarter? A scientist called James Flynn has documented the fact that as a population, we are performing better at IQ tests over time. This has therefore become known as the Flynn Effect. Using Weschler tests, it has been estimated that IQ increases by about 3 points per decade. IQ tests such as these have undergone several revisions over time (the first Weschler test was developed in 1939), and scores are standardised using testers to give a median of 100. When these new test subjects take the older versions of the test, they usually score significantly higher than 100, implying our intelligence is increasing. Possible explanations for this increase include better schooling, better nutrition and health. However, there is some debate about whether people are really  getting more intelligent, or are just getting better at taking intelligence tests!

Thanks for reading, I hope you enjoyed this post. I should be back to regular uploads soon!

Answers: a) 3, b) 8, c)1,3,6.

Smell and Memory

I’m sure this has happened to you before – you’re walking down the street and you smell something that takes you back to a holiday, or a time when you were younger. It could be the smell of a sweet shop or someone’s perfume, and you are taken straight back to a moment from years ago. But why are smells so linked to memories?

A simple answer is that this link is due to how the brain is organised. Our sense of smell is triggered by a molecule that enters our nose and binds to the hair-like projections (cilia) on neurons at the top of your nasal passage. These neurons project to a part of the brain called the olfactory bulb, which run along the front of the brain, at the bottom. This structure is thought to be involved in interpreting these signals and processing information about smells.

What’s interesting about the olfactory bulb is that it’s the one part of the brain responsible for our senses that has projections to and from the areas of our brain responsible for memory and emotion – the hippocampus and amygdala. You can see this from the image below:

HowSmellWorks01

 

This explains why smells can trigger memories and emotions. The hippocampus is responsible for our episodic memories in particular – personal memories about our lives, which is why it is this type of memory activated by smell. One theory about why these connections exist between the hippocampus and the olfactory bulb is that they enable us to recognise smells from previous experience.

Studies have shown that using smells to trigger memories can be more effective than cuing them with words. For example, Maylor et al (2002) asked young and old adults to recall autobiographical memories associated with 6 cue words. They were then shown the same words and were asked to recall new memories, and for half of these words the appropriate smell was presented too. The researchers found that for both age groups, the participants recalled twice as many memories when the smell was presented too, showing the large impact of smell and memory recall.

 

Phobias Part 2 – treatments

This week’s post is the second in a 2 part series about phobias, and will focus on different types of treatment, and what works. If you haven’t already, read part 1 (see here) for more information on types of phobias and possible causes.

If you’r a regular reading of my blog, you may remember that a while back I did a post on Cognitive Behavioural Therapy (CBT) and how that can be used to treat people with phobias. The main principle is to reduce the anxiety felt by encountering the phobia stimulus, be it crowds, flying, or needles. By teaching the patient breathing exercises to help them relax and working to change the thoughts (cognitions) about the phobic stimulus, therapists can help the patient to work towards overcoming their fear. The behavioural part of this technique is gradual exposure to the thing the patient is afraid of, whilst the patient works hard to control their breathing and stay calm. This exposure can help towards changing thoughts which contribute to the phobia such as ‘if I’m in a room with a dog it will bite me’, which in turn reduces fear.

For example, take a look at the diagram below which shows how phobias remain if the fears aren’t challenged. If therapy targets the thoughts, and tests the fear, then it is likely the phobia will be treated successfully.

aaaa

Another form of exposure therapy which has been used to treat phobias is known as ‘flooding’. Unlike in CBT, where the individual is gradually exposed to their fear, in this technique they are put straight in the worst situation they could imagine. This uses more behavioural techniques – as the body cannot sustain a physiological stress response for a long period of time, people begin to notice they feel calmer, even though they are in the presence of their fear. An example would be putting someone who was scared of birds in a room full of them! This also enables the individual to confront their worst fear and learn that nothing bad happens when they are in that situation.

Thanks for reading – there won’t be a post next week as I’ve got 2 interviews but I’ll be back the week after!

Phobias

Hi everyone, this week’s post will be the first of two – all about phobias. This first post will cover causes and types of phobias, and the next on will talk more about treatments. And, as no post about phobias is complete without a quick phobia quiz – what do you think these phobias are? (scroll down for answers!)

  1. Agrizoophobia
  2. Suriphobia
  3. Enetophobia
  4. Coulrophobia
  5. Phasmophobia

 

abc
by BromeliaCarnivor

Answers:

  1. Fear of wild animals
  2. Fear of mice
  3. Fear of pins
  4. Fear of clowns
  5. Fear of ghosts

 

Although some of these phobias are unusual, some are more common than others – with Arachnophobia (fear of spiders) probably being one of the most well known. However, there is an important distinction between people who simply don’t like spiders, and would prefer not to be in the same room as them, or not want to touch them, and people who are  afraid of spiders i.e. have Arachnophobia. Sufferers of this phobia will experience extreme anxiety and panic if they come into contact with a spider, or even just look at a picture of one. This is a much more severe reaction.

According to the mental health charity Mind, there can be different reasons for a phobia to develop, from learned experiences to genetics. However, although it is true that some people develop phobias after a bad experience e.g. developing a fear of driving after a car crash, this does not occur for everyone with a phobia. Phobias can also be learnt, from observing other people’s reactions, for example if when you were young your older sibling always screamed and ran away from wasps, you might learn to do the same and develop a phobia of them, even if you’ve never been stung.

One famous (and very unethical) experiment on whether a baby could be given a specific phobia was carried out in the 1920’s by Watson & Raynor. The infant – ‘Little Albert’ had no fears or phobias at the start of the experiment, and the researchers wanted to investigate whether he could be given a phobia of white rats. As this picture shows, before the experiment started, he wasn’t frightened.

albert-rat

This study used principles of classical conditioning to give him a phobia – every time he was given a white rat, a loud noise was made by striking a metal bar with a hammer. Understandably, this noise scared him and made him cry. After this happened several times, he began to become upset when he was presented with the rat alone – the rat had become the conditioned stimulus (to read more about classical conditioning, see my blog post here). They also found that his phobia become generalised to other things that were white an furry, such as a white rabbit or when the experimenter wore a big white beard! No one is really sure what happened to Albert after this experiment, and whether his phobia continued into the rest of his life. It’s safe to say however that experiments like this one would not be allowed to take place now.

Thanks for reading and don’t forget to check back next week for Phobias Part 2.

Face Illusion

Hi everyone,

I haven’t done a Brainteaser for a while, so I thought I’d share with you this clip from QI to see how you get on!

 

What you should notice, is that when the face is pointed towards you, it appears to be 3D and facing you, regardless of whether or not you are seeing the concave side of the image or not.

This illusion is known as ‘cognitively impenetrable’ because no matter how hard we try to see the face as pointing away from us, our brain always shows us the opposite – in this illusion having knowledge of how it works does not affect it at all.

This therefore shows how powerful the illusion is, and as Stephen Fry mentions in the clip, it shows how automatically we perceive faces, and how biased we are to perceive stimuli as faces. (For more information on this topic, check out my post here)

He also mentions that this ability is thought to be innate – babies only a few hours old have shown to prefer to look at images of faces rather than other stimuli (e.g. Batki et al 2000) and look at whole faces, rather than faces with scrambled features (but otherwise identical) e.g Goren et al (1975).

These results show that infants must have some sort of knowledge about faces and social interactions when they enter the world. Further evidence to support this is shown in a famous study by Meltzoff & Moore (1977) in which young infants – only a few weeks old were about to imitate facial expressions – shown in the well-known image below. This shows how important social interactions are to us at such a young age, as they provide the basis for our further development.

Classic77 Meltzoff_legend (3)

 

 

The Mind’s Eye

For the vast majority of you, if I asked you, right now, to imagine a beach – all golden sands and blue sky then I doubt it would be a problem. We ‘see’ the beach with our mind’s eye, even though there is no beach in front of us, and it’s most likely still grey and raining outside. The fact that our mind can generate images this lifelike is extraordinary, and something which I will explore more in this week’s post.

Something also interesting about our ability to generate these mental images, is that we can manipulate them in our minds. We do not see a flat, 2D object, but something we can move, or interact with. This was investigated in one study by Shepard & Metzler (1971) which used novel shapes so that previous experiences could not affect the results. Participants were shown pairs of shapes like the ones in the image below, and were asked to decide whether they were the same shape, or mirror images of each other, as quickly as possible.

123
As you can see, this requires some concentration! The researchers found that there was a strong linear relationship between the time it took for participants to respond and the angle of rotation. From this, they concluded that people rotate mental images at about 60º per second.

Interestingly, other studies have shown that this rotation speed of mental imagery is affected by the laws of physics – which at first glance seems improbable. I mean if you’re imagining something, why can’t you move it however you’d like? Parsons (1987) found that people find it difficult to rotate a mental image if it is physically difficult for this to happen – they used the example of imagining a foot rotating from someone’s ankle.

This effect is thought to occur as mental imagery, such as the examples above, rely on motor imagery – neuroimaging studies have shown that the motor cortex is active when we perform mental image rotation. As physical movement is constrained by the laws of physics, so are our transformations of mental images.

Mental imagery is also strongly related to visual perception, as shown in this early experiment by Perky (1910). Participants were asked to imagine the image of a given object on the dark screen in front of them, however they didn’t know that a faint picture of that object was also projected onto the screen. They found that although the participants do not notice the projected picture, they report that the image they’re imagining has the same properties as this picture e.g. the same rotation and size. This result suggests there must be some overlap between our mental imagery and our perceptions. More recent studies have also shown our mental imagery has some of the same properties as our visual perception, such as increased sensitively to the lower visual field.

Now, go back to your mental image of the beach, and try to imagine what life would be like if you kept really trying to conjure up that image, but were always unable to. Although most of us take our ability to have mental imagery for granted, a small percentage of people are unable to visualise mental images. This is known as aphantasia, and people with this condition are unable to visualise aspects of a memory, although they will be able to describe it. Scientists who have studied this condition believe that there is a spectrum of the vividness of which people experience mental imagery, with aphantasia being at the bottom.

Thanks for reading, and please subscribe if you don’t want to miss out on a new post every Thursday!

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.

lateralization-langauge-areas

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.