Tricking the brain: how magic works

23_GustavKuhn.jpgGustav Kuhn is a Senior Lecturer at Goldsmiths, University of London. The main focus of his research is attention and awareness and in particular how attention and eye movements are influenced by social factors. Related to this, he has a keen interest in the science of magic and use magic to investigate a wide range of cognitive mechanisms, such as attention, memory, illusions, and beliefs. Read on…

This article was originally published on The Conversation. Read the original article.

The magician snaps his fingers and a ball disappears right in front of your eyes. How is this possible, you ask yourself? You have a pretty good understanding of how objects behave and you know from experience that objects cannot simply disappear into thin air, yet this is exactly what you see. Magic is one of the oldest art forms and since written records began, magicians have baffled and amazed their audiences by creating illusions of the impossible. While most of their tricks remain precious secrets, scientists, myself among them, have started studying magic to gain insights into how and why our minds are so easily deceived.

Magic allows you to experience the impossible. It creates a conflict between the things you think can happen and the things that you experience. While some magicians would like you to believe that they possess real magical powers, the true secret behind magic lies in clever psychological techniques that exploit limitations in the way our brains work. Many of these limitations are very counter-intuitive which is why we can experience the magical wonder of the impossible.

How? Let’s start with the basics. Vision is our most trusted sense, and influences many of our thoughts and behaviours. In fact, vision is so important that we often don’t believe things until we see them with our own eyes. But it turns out that our visual experiences are far less reliable than we intuitively think. It’s relatively easy to distort your perceptual experience and these distortions become very apparent when we look at visual illusion.

Visual illusions occur when there is a mismatch between your perceptual experience and the true state of the world. In the Müller-Lyer illusion, for example, the top line appears shorter than the bottom, although they are exactly the same length.

Seeing the future

We are often surprised by how these illusions deceive us, but it turns out that pretty much all of our perception is an illusion, whether we’re walking down the street or attempting to suss the latest card trick. Intuitively, we think of our eyes as simply capturing truthful images of the world. But in reality, our visual experience results from complex neuronal processes that make clever estimates about what the world is like. And as with all predictions, they are never 100% correct. This leads to errors, and it is these errors that magicians have mastered and exploit.

For example, the vanishing ball illusion is one trick that colleagues and I have studied. In this trick, a magician throws a ball in the air a couple of times and then makes it seem to disappear by pretending to throw it again when in fact it remains secretly concealed inside his hand. What is surprising about this illusion is that most people – almost two thirds – experience an illusory ball being tossed up in the air at the third throw, even though it never leaves the magician’s hand. We experience this “ghost ball” because we see what we believe is going to happen, rather than what has actually taken place. The illusion shows that people perceive things that they believe will happen in the future, even when this belief is completely unfounded.

Ignoring the present

A further misconception about visual experience relates to the amount of detail that we think we are aware of. Intuitively we feel that we are aware of most of our surroundings, but this vivid and detailed subjective experience turns out to be another powerful illusion, equally counter-intuitive and therefore equally open to exploitation by magicians.

Processing large amounts of information is computationally expensive: if you want to process lots of visual information, you need large brains. But large brains come at a cost, since they require large heads and lots of food to support them. So instead of evolving into creatures with humongous brains, we developed extremely efficient strategies that allow us to prioritise aspects of the environment that are of importance, while ignoring things that are less relevant.

What this means is that unless you are paying close attention to something you simply won’t see it. Phenomena such as inattentional blindness or change blindness result from this, where people fail to spot very obvious changes simply because they don’t attend to them. These very powerful examples illustrate that if people are sufficiently distracted they can fail to see a gorilla even when one is right in front of their eyes.

Magicians frequently exploit these attentional limitations by misdirecting your attention and so preventing you from seeing their secret moves. In some of our research we have shown show how this can be used to prevent you from seeing fully visible events.

In the lighter trick, for example, a magician is seated at a table across from the viewer (a). He picks up the lighter and flicks it on (c–f). He pretends to take the flame away and make it vanish, providing a gaze cue as misdirection away from his other hand. At (f), the lighter is visibly dropped into his lap (g–h). The lighter appears to have vanished. Although the lighter is dropped in full view, half of the viewers completely fail to see this happen because they are distracted.

What this, and other tricks show, is that people often fail to see things even when they are looking straight at them. So don’t be so sure to trust your vision in the future. You never know what’s really happening.


There are also drawbacks to being bilingual

juliaouzia_profilephoto-1Dr. Julia Ouzia is a Teaching Fellow at Goldsmiths.The main objective of her work is to understand the cognitive functioning of individuals who use two or more languages in everyday life. Specifically, her research has focused on the impact of adverse emotional states and traits on cognition, spoken language comprehension in the presence of interference, probabilistic learning abilities, and metacognitive efficiency of bilingual individuals.

From a methodological standpoint, she is interested in using multi-dimensional approaches involving a variety of psychometric and behavioural paradigms, as well as other research methods, such as eye tracking, in order to achieve a comprehensive understanding of the bilingual mind. Here she, with colleague Tomas Folke, looks at some of the draw backs of bilingualism as researched at Anglia Ruskin University.

This article was originally published on The Conversation. Read the original article.

The ability to speak more than one language certainly has its perks. It enables you to work in another country, for example, interact with people while travelling, or consume foreign media.

Bilingualism is very common – current estimates are that more than half of the world’s population is bilingual and that this prevalence is rising.

Cognitive psychologists have been interested in how bilingualism shapes the mind for almost a century. There are those who suggest that in order to speak in one language, bilinguals have to suppress the influence of the other. Research from the past three decades has argued that this unique form of language processing “trains the brain” in the use of non-verbal abilities known as “executive functions” such as ignoring irrelevant information or shifting attention.

Bilinguals of different ages and cultural backgrounds have been shown to be faster and more accurate than their monolingual peers when performing cognitive tasks demanding these abilities. Furthermore, it has been argued that bilingualism may lead to a delayed onset of symptoms associated with dementia.

But the scientific community recently has become increasingly sceptical of the bilingual advantage hypothesis. One of the main points of criticism is that differences between monolinguals and bilinguals when it comes to executive function are not always apparent. This has generated a heated debate, especially in the Bilingualism Forum of the scientific journal Cortex, about whether bilingualism is associated with cognitive advantages or not.

Fresh challenge

It appears that research on bilingualism is at a turning point. We need to pursue a new approach to understand, beyond those individual examples of executive functions, how the bilingual mind works. We have attempted to address this challenge by testing whether bilinguals and monolinguals differ in terms of how accurately they can assess their own performance.

Might come in handy in parts of Wales.

This ability is called metacognition and is associated with, but separate from, other areas where bilinguals have been shown to have an advantage. Surprisingly, however, we found that bilinguals had less insight into their performance than their monolingual peers.

Joining the dots

In an effort to find out whether bilinguals also display advantages in other cognitive abilities (beyond executive function), we evaluated metacognitive processing in young adult monolinguals and bilinguals. Metacognition is the ability to evaluate one’s own cognitive performance or simply to have “thoughts about thoughts”.

This ability is a crucial function of everyday life, when we have to make decisions where the outcomes are not immediate. For example, when an entrepreneur reviews their company’s performance, they need to take into account a variety of factors – including, for example, revenues and expenses – in order to evaluate whether the company is doing well. Confidence in their ideas and performance can be the determining factor in whether they decide to keep investing time in their company or give up and apply for another job (the so-called “exploitation exploration trade-off”).

In our research, we presented participants with a situation in which they had to observe two circles on a screen and guess which one contained more dots. Sometimes the difference was obvious, making the decision easy, while at other times the decision was very difficult (for example, one circle contained 50 dots and the other 49). Participants were then asked to determine how confident they were in their decision on a scale from less to more confident than normal.

Illustration of the metacognition paradigm employed by Folke et al., 2016.
Folkes et al, 2016, Author provided

Over the course of two experiments, we found that bilinguals and monolinguals were equally likely to choose the circle containing the highest number of dots. However, monolinguals were better able than bilinguals to discriminate between when they were right and when they were wrong. In other words, bilinguals had less insight into their performance than monolinguals. This went against our initial predictions, as we expected to find a bilingual advantage in metacognitive processing. These results indicate that bilingualism may be associated with cognitive disadvantages as well as benefits.

What’s next?

The Multilanguage & Cognition lab (MULTAC) at Anglia Ruskin University is currently undertaking a three-year project funded by the Leverhulme Trust to enhance our understanding of the bilingual mind.

The lab has already published evidence of cognitive advantages associated with bilingualism, suggesting that bilinguals are better at filtering out verbal interference as well as visual attention, specifically spotting the difference in a visuo-spatial working memory task.

This new research indicates that bilingual people may experience a disadvantage in metacognition. We hope that this new direction in bilingualism research will encourage further attention and enable us to resolve theoretical debate through the adoption of open-minded, empirically driven exploration of cognitive effects (both positive and negative) that may be associated with learning more than one language.

Julia tweets monolingually from @JuliaOuzia

Tomas Folke, is a PhD candidate, University of Cambridge


What happens when people with autism grow old?

14_rebeccacharltonDr. Rebecca Charlton is Senior Lecturer (Associate Professor) in the Department of Psychology at Goldsmiths University of London. Her research focuses on age-related conditions and falls into three areas: Typical Ageing, Depression, and Ageing in Developmental Disorders. Using cognitive and neuroimaging methods, she examines the relationship between cognitive decline and changes in the brain. She conducts research into ageing with developmental disorders, in particular how individuals’ with Autism Spectrum Disorders will be affected by age-related brain, cognitive or social changes. Here she talks to The Conversation about just that.

If you mention autism to most people they will think about children, but it is a lifelong diagnosis. Children with autism grow up to be adults with autism. Little is known about how the symptoms change with age. This is because autism is a relatively new disorder, first described in 1943 and not regularly identified until the 1970s. It is only now that those people first diagnosed are reaching older age that we can start to learn whether the disorder changes over a lifetime.

There have been some suggestions that symptoms may reduce as people get older. These reports, describing fewer difficulties with older age, are often from people with autism themselves and from their families. But how much evidence is there for this? Our latest research provides some answers, and also raises some new questions.

Working with the Autism Diagnostic Research Centre in Southampton we assessed 146 adults who were referred to the centre seeking a diagnosis of autism between 2008 and 2015, and who consented to take part in the research. People were aged between 18 and 74 years old. A hundred of these adults were diagnosed with autism, and 46 people did not receive a diagnosis. This gave us an opportunity to explore the subtle differences between people who receive a diagnosis and those who don’t, even though they may have some other similar difficulties.

Our analysis showed that age and severity of autism were linked; that is, as age increased so did the severity of autism symptoms in social situations, communication and flexible thinking (such as coping with change or generating new ideas or solutions). We also found that older people with autism were more likely than younger people to extract rules from situations or prefer structure (for example, wanting to know how committees are organised or always following the same routine during a task).

This pattern did not occur in the group of 46 people who didn’t have autism. Whether this tendency to extract rules is a “worsening” of autism symptoms or a general trend among all older people is not yet clear.

Strategies for life

It may seem surprising that people who received a diagnosis much later in life had more severe symptoms, as we might expect people with severe symptoms to be more likely to seek a diagnosis earlier in life. What we found was that the older adults with autism performed better than the young adults with autism on some cognitive tests we carried out. The group diagnosed with autism were faster on tests measuring speed of thinking during a task and did better when dealing with visual and shape information. Perhaps these abilities have helped adults with autism develop strategies across their lives that have helped them to cope with their symptoms which may explain why they were not diagnosed until adulthood.

Older adults with autism performed better on cognitive tests than younger adults.

When the group with autism was compared with the group without autism, we found that rates of depression and anxiety were high in both groups. A third of adults diagnosed with autism report high levels of depression or anxiety – rates much higher than in the general population. Depression among older adults is a risk factor for developing problems in memory and cognition. Given the high rates of depression among people with autism, it may be important for doctors to monitor mood during ageing to ensure that individuals are not at risk for cognitive decline due to depression.

The people described in our research are not typical of people with autism. They all had cognitive abilities in the normal range and did not receive a diagnosis in childhood when autism is most often recognised. Despite this, older people in the study showed more severe symptoms of autism. This might suggest that symptoms of autism become more severe with age. However, reporting more symptoms could also reflect a change in self-awareness. Better self-awareness is generally a good thing, but might lead to greater realisation of one’s own difficulties.

It isn’t yet clear whether people with autism age in the same way as people without autism – it’s still early days, given the relative age of the disorder. Ageing may also be different for each person with autism. People with autism may have developed strategies to help them age better, or may be at risk for depression and cognitive decline. In future work, we aim to see people every few years so we can understand how they change over time.

We all deserve to age as well as we can. It’s only by understanding how people with autism change as they get older, that we can start to put services in place to support them.

The Conversation

Rebecca Ann Charlton, Senior Lecturer, Goldsmiths, University of London

This article was originally published on The Conversation. Read the original article.

Memory and sense of self may play more of a role in autism than we thought

lornaimageLorna Goddard, Goldsmiths, University of London

It’s well-known that those with autism spectrum disorders including Asperger’s syndrome develop difficulties with social communication and show stereotyped patterns of behaviour. Less well-studied but equally characteristic features are a weaker sense of self and mood disorders such as depression and anxiety. These are connected with a weaker ability to recall personal memories, known as autobiographical memory.

Research now suggests that autobiographical memory’s role in creating a sense of self may be a key element behind the development of autistic characteristics.

Autism is much more common in men than in women, to the extent that one theory of autism explains it as the result of an “extreme male” brain, where autistic females are assumed to be more masculinised. Historically, however, research participants have been predominantly male, which has left gaps in our knowledge about autism in women and girls. Psychologists have suggested that the criteria used for diagnosing autism may suffer from a male bias, meaning that many women and girls go undiagnosed until much later in life, if at all

What we remember of ourselves

This is supported by research that suggests women with autism develop different characteristics than autistic males – particularly in respect to autobiographical memory.

Personal memories play a key role in many of the psychological functions that are affected in those on the autistic spectrum. Personal memories help us form a picture of who we are and our sense of self. They help us predict how others might think, feel and behave and, when faced with personal problems, our past experiences provide insight into what strategies we might use to cope or achieve our goals. Sharing personal memories in conversation helps us to connect with others. Recalling positive memories when we feel down can help lift us up, while dwelling on negative personal memories can induce depression.

What’s become clear from studies of autobiographical memory in autism is that while those with autism may have an excellent memory for factual information, the process of storing and recalling specific personal experiences, such as those that happened on a particular day in a particular place, is much more difficult. Instead, their memories tend to record their experience in general terms, rather than the specifics of the occasion. This might be due in part to their more repetitive lifestyle, in which there are less occasions that stick out as memorable, but also because they are less self-aware and less likely to self-reflect. However, our research suggests that this memory impairment may be exclusive to autistic males.

Missing or indistinct memories can add to the sense of otherness, confusion and anxiety experienced by autistic people.

Divided by memory

We examined the personal memories of 12 girls and 12 boys with autism, and compared them with an equal number of girls and boys of similar IQ and verbal ability without autism. We asked them to remember specific events in response to emotional and neutral cue words such as “happy” and “fast”. We also asked them to recall in as much detail as they could their earliest memories, and recollections from other periods of their life.

We know that girls tend to demonstrate better verbal skills and are better at recognising emotions. Might this affect the content and degree of detail they could recall from their own memories? We also wondered whether any gender differences we might find would be replicated between boys and girls with autism, or whether autistic girls would be more like boys – as predicted by the extreme male brain theory.

What we found was that autism did lead to less specific and less detailed memories, but only for the boys. The girls with autism performed more like non-autistic girls – not only were their memories more specific and more detailed than the autistic boys, but like the girls without autism, their memories contained more references to their emotional states than both the autistic and non-autistic boys. So rather than an extreme male brain, the girls with autism were more like girls without autism.

This better autobiographical memory might be one reason why autistic females are often better at masking the difficulties they have with communication and socialising with others, and so are more likely to go undiagnosed. Of course, this poses the question that if they have the building blocks of good communication – access to detailed personal memories – why are they still autistic?

There is some evidence to suggest that the automatic connection between our memories and knowing who we are, and how to use this information to inform how we act in problematic situations, is weaker in those with autism. This means that while women with autism can recall the past, they may not be using their experience to help them understand themselves and solve personal problems.

Even though they may be better able to socialise than boys with autism, this may come at a cost, as greater social interaction brings with it more personal problems, and when problems seem overwhelming this can lead to depression. Indeed, recent research suggests that among those with autism, depression in more common in women than men. This gender difference with respect to personal memories is an aspect of autistic characteristics that has been little studied, and should be explored further.

Lorna Goddard, Lecturer in Psychology, Goldsmiths, University of London

This article was originally published on The Conversation. Read the original article.

I like the way you move: The social neuroscience of dance

Guido-Orgs-1ADr. Guido Orgs received his training in both Performing Dance (Folkwang University of the Arts) and Psychology (University of Dusseldorf). After completion of his PhD in Cognitive Neuroscience, he performed with German Dance Company NEUER TANZ/VA WÖLFL. At the Institute of Cognitive Neuroscience, UCL, he conducted research on how we perceive other people’s movements and how the brain mechanisms of movement perception underlie the aesthetics of dance and the performing arts.

Since September 2015 he is a Lecturer in Psychology at Goldsmiths, University of London teaching Psychology of the Arts and Neuroaesthetics. Funded by an ESRC transformative research grant he currently investigates synchrony in performing dance, collaborating with Choreographer Matthias Sperling  Dr Annemieke Apergis-Schoute, Cambridge University, and Dr Daniel Richardson, UCL. Here, he explores dance as a means of social bonding.  

Why do human and other animals dance? Across all known cultures people dance, to worship, to entertain, to show off, or simply to have fun. Despite its universal nature, dance has been rarely studied by Psychologists and Cognitive Neuroscientists alike. This is surprising, given that dance shares many similarities with music and language.

Evolution suggests at least two potential reasons for why people dance. Firstly, to have sex: Many bird species engage in very complex choreographies of sound and movement to attract mating partners, for example the Australian Lyrebird. Secondly dancing in groups might foster bonding between group members. People who move together, begin to like each other.

Dance for social cohesion

We recently completed a research project in which we asked groups of people to perform a series of choreographic tasks. In one condition people were asked to swing their arms together in synchrony. In a second condition, groups performed the same choreographic tasks asynchronously. Using smart watches, we measured each participant’s movements and computed how much the group moved in unison. Following these dance workshops, participants completed a range of tasks that measured how much the group had bonded. Participants who synchronised with each other most successfully, liked each other more than participants who hadn’t synchronized with each other. We also asked group members to decide to to go to a restaurant together and choose from a range of options.

The time that participants took to decide on a restaurant depended on how well they had synchronised before. The more successfully movements were coordinated in a group, the longer did it take for group members to make a decision. Presumably, this is because more opinions were heard and the group found it more difficult to reach a compromise. In groups that hadn’t bonded so well, decisions were made faster, perhaps with less consideration for individual opinions.

But is participants’ movement as well as synchrony important?

Dancing together thus helps to form social bonds. Yet, especially in Western societies, relatively few people perform or engage in dancing or making music themselves. Most people assume a more passive role, watching other people dance or making music together, whether live, on the internet or TV in shows such as BBC’s “Strictly Come Dancing”. Do some of the prosocial effects of dancing together translate to the engagement of audiences with performative art?

Group Study at Brunel 22515 IMG_4616 copy

Group Study performance

In collaboration with Choreographer Matthias Sperling we recently investigated this question: Does movement synchrony predict the spectator’s enjoyment of a live performance? We developed a piece for ten performers “Group study”. The piece was based on the same choreographic tasks that were used in our previous study on the social effects of synchrony. Ten performers performed these tasks in synchrony or in asynchrony, while audiences rated their enjoyment of the performance using tablet computers.

Indeed, movement synchrony on stage predicted how much spectators enjoyed the performance, but only if spectators engaged with the performance as whole. Spectators who didn’t like the performance, also disliked watching moments of high synchrony. In contrast spectators who enjoyed the performance also enjoyed moments of high synchrony the most. Spectators who were indifferent to the performance as a whole, neither enjoyed synchrony nor asynchrony. In other words, if spectators didn’t’ care about watching the performance, they also didn’t care about synchrony. Arguably, watching dance is not everyone’s cup of tea…


If you’d like to hear more about the social neuroscience of dance, come and visit us at Siobhan Davies Dance Studios on the 27th of May, 7 pm. You will be able to explore some of the choreographic tasks that we use in our research and hear more about our research! Tickets may be bought online here.




Memory Loss: It’s not all amnesia

imageDr. Ashok Jansari is a Lecturer in the Department of Psychology, researching cognitive neuropsychology, particularly memory/amesia, face recognition and assessment of executive functions. While we break between  terms, here is a post by Ashok, originally published in The Conversation.


Short-term memory, long-term memory, amnesia, dementia, Alzheimer’s – people often use these terms incorrectly. The reason is partly because memory is one of the most complex mental abilities. It involves experiencing the current moment through the five senses, holding that experience for a fraction of a second, filtering just a proportion of this through to the next stage, consciously holding this information for perhaps 90 seconds, and then either losing the experience or somehow successfully making enough of an impression in the mind that it can be evoked at a later time.

Classical amnesia

When people complain of having terrible short-term memory, they are usually referring to not being able to hold onto information for more than a couple of weeks. This difficulty is actually to do with the information not having been stored very efficiently in long-term memory, resulting in rapid forgetting. Real short-term memory is literally what you can hold onto in your consciousness. They can last for just seconds: you’re in a lift, for example, and remember that you’ve already hit the button to go to the floor you need. You won’t recall this for any longer than you need to.

The most famous memory-impaired person ever studied, Henry Molaison (referred to as “HM” in the medical literature) had a part of his brain called the hippocampi surgically removed to try and alleviate the devastating epilepsy he suffered from. Following the operation, Molaison did not create a single new long-term memory until he died 50 years later.

Despite this profound impairment, if Molaison was given a string of digits and asked to recall them in the same order, he would have remembered the same number (about seven) that you and I could, and that was because in “classical amnesia” short-term memory is fully intact.

Post-traumatic amnesia

The amnesia that Molaison suffered from is very different to the post-traumatic amnesia that can result from head trauma. This tends to be solely for a period of minutes or hours (sometimes days) following a blow to the head.

With post-traumatic amnesia, even if information is transferred successfully into long-term memory, it is still fragile and susceptible to forgetting if the brain’s normal “house-keeping” procedures are disrupted by a physically traumatic event.

Psychogenic fugue

Different still is a “psychogenic fugue”. This is when a person is unaware of their own identity. It’s as if their entire personal memory has been wiped clean. Despite this, they are perfectly able to create new memories.

This little-understood condition is probably caused by an emotionally-traumatic event which causes the personal “psyche” to do a “systems-shutdown”, making access to any personally-relevant information impossible. Examples of this include the “Piano Man” who was found on the Kent coast without any awareness of who he was, despite remembering how to play the piano, and the recent case of Edgar Latulip who hadn’t known who he was for 30 years but then suddenly seemed to recover his memories.

Given the current lack of understanding of the condition, a neuropsychologist or a neuropsychiatrist can have a difficult job trying to ascertain how genuine the amnesia is. This is especially the case when there is a suspicion that the person might be malingering or faking the memory loss for some sort of gain, for example financial compensation.

A famous example was that of John Darwin who had disappeared after going out canoeing on his own and had been presumed to have drowned. A number of years later, a man walked into a police station and said that he thought he might be John but he didn’t have any knowledge of who he was. While this could have been a case of psychogenic fugue, when recent photos emerged of him and his wife in Panama, it became obvious that his death had been staged for a big life insurance claim, allowing the couple to move to Panama.


Equally complex is dementia, which is a group of degenerative disorders of which Alzheimer’s is the best known. Each type of dementia has a unique impact on a person’s abilities. While the gradual erosion of both creating new memories and retrieving old ones is an aspect that people associate with dementia, this is simply because the brain abnormality will be affecting quite diverse regions. This will sometimes include areas that are involved in memory storage and retrieval.

However, the signature of each dementia will depend on where these other areas are and what those areas specialise in. For example, in frontotemporal dementia, memory is largely unaffected but the change is in personality and behaviour. But in semantic dementia, the problems are more linguistic and cause difficulty recognising family and friends.

Given the huge complexity of human memory, it is unsurprising that there is so much confusion among the public regarding different types of memory. Sometimes even the professionals get it wrong.

Dr. Ashok Jansari remembers to tweet  @ashokjansari