Category: Perception

Hallucinations are surprisingly common and varied experiences

By Emma Young

Many mentally well people experience hallucinations. An estimated 6 – 15% of us hear, see, feel or even smell things that aren’t real. But there has been little research into what those hallucinations are like — and how they might differ from those experienced by people with psychosis. Now Mascha M.J. Linszen at Utrecht University and her colleagues report the results of a large study of more than 10,000 people aged 14 to 88. The work, published in Schizophrenia, throws up a few surprises among a host of interesting findings.

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Here’s how actors differ in their ability to read their own bodily signals

By Emma Young

How is it that some people can slip into another character so perfectly that they win acting plaudits, while the rest of us struggle to act at all?

Good actors have to convincingly convey a range of emotions. And one way that we feel and control our own emotions is by tuning into bodily signals — such as the more rapid heartbeat that comes with excitement, joy or fear. So, reasoned Peter Sokol-Hessner at the University of Denver and colleagues, perhaps actors are better at sensing these signals — a process known as interoception.

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We unconsciously pay more attention to someone who has dilated pupils

By Emma Young

How do you know when someone else is paying attention to you? If they’re staring at you intensely, that’s a pretty obvious giveaway. But there are also far subtler signals — such as the size of their pupils.

As Clara Colombatto and Brian Scholl at Yale University note in a new paper in the Journal of Experimental Psychology: General, our pupils automatically and uncontrollably dilate when we’re emotionally aroused, working something out, or just attending to something. Pupil size has been used as an objective indicator of all these things in a wealth of recent studies.

But if another person is directing their attention towards you, you need to know about it. It might be attention that you should reciprocate, to build a relationship, or it might signal a potential threat. So, Colombatto and Scholl wondered, “If the apprehension of pupil size is so helpful to scientists, might it be similarly helpful to us in everyday life?”

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We Seem To Treat Physical Warmth As A Sign Of Safety

By Emma Young

When we learn that something in our environment signals Threat!, we start to react to every encounter with the “fight or flight”, or “fear”, response. Recent work has shown, though, that the presence of someone we’re close to — a friend or partner, say, — can reduce or even eliminate this response. Our brains seem to treat such people as a powerful “safety” signal.

This was thought to be a unique effect. But now a team led by Erica Hornstein at UCLA has shown that physical warmth does the same thing. The work, published in Emotion, was prompted by research finding that we implicitly associate physical warmth with social support. It has potential implications for treating anxiety disorders, especially for people who live alone — or who find it hard to unlearn links between certain stimuli and threat, as can happen with post-traumatic stress disorder (PTSD).

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Body Maps Reveal The Range Of Sensations And Feelings Experienced During Hallucinations

By Emma L. Barratt

Most research into hallucinations focuses on unimodal hallucinations — hallucinatory experiences that only affect one sensory modality, such as hearing or touch. But for decades there has been evidence that multimodal hallucinations (which affect more than one sense at once) may be quite common. One of the main challenges in investigating them, however, has been capturing and communicating the wide array of features that comprise multimodal experiences.

However, thanks to new research in EClinicalMedicine from Katie Melvin and colleagues at the University of Leicester, this may be about to change. To improve our understanding of the feelings and sensations associated with hallucinations, the team gathered a group of participants to create what they dubbed MUSE maps — visual and written representations of what hallucinations feel like throughout (and around) the body. Not only do their findings suggest that most hallucinations seem to have emotional and multisensory components, but their new method offers a more intuitive way to communicate and understand hallucinatory experiences.

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Patients Occasionally Experience Sexual Hallucinations While Under Conscious Sedation

By Emma L. Barratt

Since anaesthetics were first used in 1846 there have been reports of sexual hallucinations during medical procedures. And, though there’s been much discussion about the relationship between anaesthesia and these hallucinations, awareness of this side effect amongst both clinicians and academics remains somewhat low. The consequences of clinicians being accused of sexual misconduct that was in actuality a hallucination can extremely be serious; some have lost their licenses to practice, despite being acquitted.

But even with the high-stakes consequences of sexual hallucinations, there has been relatively little published on the matter, making it difficult to understand the phenomenon as a whole. However, Alex Orchard and Ellie Heidari at Guy’s and St Thoman’s NHS Trust and King College London have synthesised the scattered existing literature on sexual hallucinations while under conscious sedation in their recent review. The resulting paper not only theorises as to risk factors which may prompt such hallucinations, but also suggests practical ways that may help clinicians avoid and manage their occurrence.

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Audio Technique Makes People Feel That Their Doppelganger Is In The Room With Them

By Emma L. Barratt

Hallucinatory experiences are pretty common, despite widespread beliefs to the contrary. Researchers estimate that around 40% of the population regularly experience hallucinations to some degree, whether that be feeling your phone vibrate only to find no notifications, or a full-on out of body experience.

Though hallucinations are common, some are harder to study than others. One of the trickiest has been autoscopic hallucinations, during which people experience a doppelganger of all or part of their body in the space around them.

Though this hallucination has been reported to clinicians, its rarity has made it difficult to observe in an experimental setting — so researchers have instead attempted to induce the phenomenon in the lab. Now, Marte Roel Lesur and team at the University of Zurich have developed a way to experimentally induce it in people who have no history of hallucinations using only auditory cues.

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Here’s How Psychologists Are Using Robots To Study The “Uncanny Valley”

By Emma L. Barratt

Mentioning the uncanny valley often brings one thing to mind — creepy dolls. The phenomenon, in which near-human-looking faces produce an inexplicable uneasy reaction in those who view them, was actually first described as an issue faced by roboticists. But the faces of dolls in particular are a cultural touchstone for uncanny feelings — at least in part due to their (over)use as a spooking-device in hundreds of horror movies over the years.

As such, psychological research has been conducted on the subtleties that non-human facial structure and expression can have on producing feelings of unease in those who view them. However, the uncanny valley isn’t just confined to faces, and its effects are not confined to just a horror movie device. For example, research from Burcu Urgen of Bilkent University demonstrates that biological-like motion can also trigger uncanny feelings, which poses real issues for those pushing the frontiers of robotics.

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Rage Over Repetitive Movements? It Could Be Misokinesia

By Emma L. Barratt

You may be aware of misophonia — an automatic, intense hatred of certain types of sounds, such as chewing, tapping, and breathing, to name a few. Misophonia entered mainstream awareness relatively recently, but hot on its heels is an extremely similar condition which relates not to sound, but to movement: misokinesia.

There are several well-established online support groups for those who relate to having strong negative affective responses to certain types of stimuli — typically small, repetitive movements, such as leg shaking or finger tapping. And, while it appears to be widespread, there has been a lack of dedicated research into the phenomenon — until now.

To properly introduce this under-recognised condition, Sumeet Jaswal and her colleagues based at the University of British Columbia recently published a set of studies in Scientific Reports which aimed to establish key facts about the prevalence of misokinesia and what may cause it.

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Blind And Sighted People Understand Colour Similarly

By Emma L. Barratt

Colour is generally thought of as something experienced only by those with sight. It’s often assumed that those who’re born blind can learn facts about colours — that a banana is yellow, say — but won’t have the same complex understanding of colour that sighted people have.

But new research in PNAS from Judy Kim and colleagues at Johns Hopkins University shows that this is not the case. Instead, the researchers find that blind people have a rich understanding of colour developed through language alone.

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