Tag: optical illusion

Categories : Mental HealthTags : Leave a comment

Psychologists Reveal Magicians’ Secret Trick: A Low Risk of Depression

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Photo by Fengyou Wan on Unsplash

Magicians are less likely to suffer from the mental health challenges faced by other creative people, like musicians and comedians, according to a new study published in the journal BJPsych Open. From comedians like Robin Williams, to poets and painters like Sylvia Plath and Van Gogh, many famous names have had well-publicised mental health disorders.

While not fully understood, there is growing evidence of a link between these health challenges and creativity. This new research led by Aberystwyth University shows that on some key measures, magicians are apparently an exception to this trend.

The study measured the psychological traits of 195 magicians and 233 people from the general population and compared with data from other creative groups. The academics’ work shows that on three key measures of psychosis or degrees of losing contact with reality, magicians are significantly less likely to suffer than artists, musicians and comedians. Magicians were less likely than all other creatives to have unusual experiences, such as hallucinations or cognitive disorganisation, which can make it hard to concentrate. Indeed, on many measures magicians appear to be less prone to these conditions than the general population. Their mental health profiles are most similar to those of mathematicians and scientists.

Dr Gil Greengross from the Department of Psychology at Aberystwyth University commented: “There is a common perception that many creative people have mental illnesses, and such illnesses make them more creative. This is the first study to show a creative group with lower scores on psychotic traits than the general population. Our research shows that members of at least one creative group, magicians, do not exhibit higher levels of mental disorders. The results demonstrate that the association between creativity and psychopathology is more complex than previously thought, and different kinds of creative work could be associated with either high or low psychoticism or autistic traits.

“The study highlights the unique characteristics of magicians, and the possible myriad associations between creativity and mental disorders among creative groups. One thing that distinguishes magicians from most other performing artists is the precision required in their performances. So, compared to other performers, it is more difficult to overcome errors. Magic tricks are largely ‘all or nothing’ acts that culminate in an ‘aha’ moment of surprise and awe. Failed magic tricks leave a greater impact than unfunny jokes, and are harder to compensate for, as they are few and far between. So, in addition to requiring highly technical skills, regardless of the type of magic performed, the high stakes of magic performances make magicians a unique creative group to study amongst all artistic professions.”

Dr Greengross from Aberystwyth University added: “What distinguishes magicians from most other creative people is that they not only create their own magic tricks but also perform them, while most creative groups are either creators or performers. For example, poets, writers, composers and choreographers create something that will be consumed or performed by others. In contrast, actors, musicians and dancers perform and interpret the creation of others. Magicians, like comedians and singer-songwriters, are one of the rare groups that do both.

“Magicians scored low on impulsive nonconformity, a trait that is associated with anti-social behaviour and lower self-control. These traits are valuable for many creative groups such as writers, poets and comedians whose creative acts are often edgy and challenge conventional wisdom. Magicians can also be equally innovative and push the limits of what is thought to be possible in magic, such as David Copperfield’s famous flying illusion. However, many magicians perform familiar tricks or some variations of them without feeling the need to innovate.”

Source: Aberystwyth University

Categories : NeurologyTags : Leave a comment

Optical Illusions Originate in the Retina, not the Brain

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The bar in the middle is all one grey level, but it appears lighter on the left and darker on the right due to the background. Credit Jolyon Troscianko

Numerous visual illusions are caused by limits in the way our eyes and visual neurones work – rather than more complex psychological processes, as demonstrated by new research published in PLOS Computational Biology.

Researchers examined illusions in which an object’s surroundings affect the way we see its colour or pattern. Scientists and philosophers have long debated whether these illusions are caused by neural processing in the eye and low-level visual centres in the brain, or involve higher-level mental processes such as context and prior knowledge.

In the new study Dr Jolyon Troscianko, from the University of Exeter, co-developed a model that suggests simple limits to neural responses – not deeper psychological processes – explain these illusions.

“Our eyes send messages to the brain by making neurones fire faster or slower,” said Dr Troscianko. “However, there’s a limit to how quickly they can fire, and previous research hasn’t considered how the limit might affect the ways we see colour.”

The model combines this “limited bandwidth” with information on how humans perceive patterns at different scales, together with an assumption that our vision performs best when we are looking at natural scenes.

The model was developed by researchers from the Universities of Exeter and Sussex to predict how animals see colour, but it was also found to correctly predict many visual illusions seen by humans.

“This throws into the air a lot of long-held assumptions about how visual illusions work,” Dr Troscianko said.

He said the findings also shed light on the popularity of high-definition televisions.

“Modern high dynamic range televisions create bright white regions that are over 10 000 times brighter than their darkest black, approaching the contrast levels of natural scenes,” Dr Troscianko added.

“How our eyes and brains can handle this contrast is a puzzle because tests show that the highest contrasts we humans can see at a single spatial scale is around 200:1.

“Even more confusingly, the neurones connecting our eyes to our brains can only handle contrasts of about 10:1.

“Our model shows how neurones with such limited contrast bandwidth can combine their signals to allow us to see these enormous contrasts, but the information is ‘compressed’ – resulting in visual illusions.

“The model shows how our neurones are precisely evolved to use of every bit of capacity.

“For example, some neurones are sensitive to very tiny differences in grey levels at medium-sized scales, but are easily overwhelmed by high contrasts.

“Meanwhile, neurones coding for contrasts at larger or smaller scales are much less sensitive, but can work over a much wider range of contrasts, giving deep black-and-white differences.

“Ultimately this shows how a system with a severely limited neural bandwidth and sensitivity can perceive contrasts larger than 10 000:1.”

Source: University of Exeter

Categories : NeurologyTags : Leave a comment

Illusion Tricks Pupils into Dilating

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Looking at this image, do you perceive that the central black hole is expanding, as if you’re moving into a dark environment, or falling into a hole? If so, you’re not alone: a new study published in Frontiers in Human Neuroscience shows that this ‘expanding hole’ illusion, which is new to science, is perceived by approximately 86% of people.

The study’s first author, Professor Bruno Laeng at the University of Oslo, explained: “The ‘expanding hole’ is a highly dynamic illusion: The circular smear or shadow gradient of the central black hole evokes a marked impression of optic flow, as if the observer were heading forward into a hole or tunnel.”

Optical illusions aren’t simple curiosities: researchers study them to better understand the complex processes our visual system uses to anticipate and make sense of the visual world.

In the new study, Prof Laeng and colleagues demonstrated that the ‘expanding hole’ illusion deceives the brain so well that it even prompts a dilation reflex of the pupils to let in more light, just as if the observer was entering a dark area.

“Here we show based on the new ‘expanding hole’ illusion that that the pupil reacts to how we perceive light – even if this ‘light’ is imaginary like in the illusion – and not just to the amount of light energy that actually enters the eye. The illusion of the expanding hole prompts a corresponding dilation of the pupil, as it would happen if darkness really increased,” said Prof Laeng.

Prof Laeng and colleagues explored how the colour of the hole (besides black: blue, cyan, green, magenta, red, yellow, or white) and of the surrounding dots affect how strongly we mentally and physiologically react to the illusion. On a screen they presented variations of the “expanding hole” image to 50 women and men with normal vision, asking them to rate subjectively how strongly they perceived the illusion. While participants gazed at the image, the researchers measured their eye movements and their pupils’ unconscious constrictions and dilations. As controls, the participants were shown “scrambled” versions of the expanding hole image, with equal luminance and colours, but without any pattern.

The illusion appeared most effective when the hole was black. Fourteen percent of participants didn’t perceive any illusory expansion when the hole was black, while 20% didn’t if the hole was in color. Among those who did perceive an expansion, the subjective strength of the illusion differed markedly.

The researchers also found that black holes promoted strong reflex dilations of the participants’ pupils, while coloured holes prompted pupil to constriction. For black holes, but not for coloured holes, the stronger participants rated their perception of the illusion, the more their pupil diameter tended to change.

Minority not susceptible

Just why a minority seem unsusceptible to the “expanding hole” illusion is still unclear. It is also not known whether other vertebrate species, or even nonvertebrate animals with camera eyes such as octopuses, might perceive the same illusion as we do.

“Our results show that pupils’ dilation or contraction reflex is not a closed-loop mechanism, like a photocell opening a door, impervious to any other information than the actual amount of light stimulating the photoreceptor. Rather, the eye adjusts to perceived and even imagined light, not simply to physical energy. Future studies could reveal other types of physiological or bodily changes that can ‘throw light’ onto how illusions work,” concluded Prof Laeng.

Source: Frontiers