Category: Perception

The idea that humans have a poor sense of smell is an outdated myth, argues new review

The Nose For Wine
It’s estimated that humans may be able to distinguish up to a trillion different smells

By Alex Fradera

In the early 1950s, while investigating rabbits’ sense of smell by recording the activity of their brain cells, the scientist Lord Adrian noticed something curious. As his team mixed up odours of increasing strength, to see at what point the rabbits’ neurons fired in response, they found the critical threshold appeared around the same point that they were able to smell the odour themselves: in other words, this suggested that the smell had become noticeable to animal and man at the same time.

On publication of the research, Lord Adrian mentioned his observation, but it didn’t provoke a serious response, presumably because informed scientists knew that the human sense of smell is generally pathetic. Everyone knew… but they knew wrong. In a new review in Science, John McGann, who runs the Rutgers Laboratory on the Neurobiology of Sensory Cognition, takes us through the historical misunderstandings to reach the truth about what the human nose knows.

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These nine cognitive psychology findings all passed a stringent test of their replicability

By Christian Jarrett

The failure to reproduce established psychology findings on renewed testing, including some famous effects, has been well-publicised and has led to talk of a crisis in the field. However, psychology is a vast topic and there’s a possibility that the findings from some sub-disciplines may be more robust than others, in the sense of replicating reliably, even in unfavourable circumstances, such as when the participants have been tested on the same effect before.

A new paper currently available as a preprint at PsyArXiv has tested whether this might be the case for nine key findings from cognitive psychology, related to perception, memory and learning. Rolf Zwaan at Erasumus University Rotterdam and his colleagues found that all nine effects replicated reliably. “These results represent good news for the field of psychology,” they said.

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Having an open-minded personality manifests at a basic level of visual perception

Rene Descartes' diagram of the human brain and eye, 1692.By Christian Jarrett

Openness to Experience is one of the so-called Big Five personality traits and, among other things, it’s associated with being more creative, curious and appreciative of the arts. Like all the traits, where you score has important implications – for instance, there’s recent evidence that being more Open is associated with having more “cognitive reserve”, which gives you protection from the harmful effects of dementia.

Openness correlates with, but is distinct from, intelligence, and psychologists are trying to find out more about what the basis of Openness is at a cognitive and neural level. A new paper in Journal of Research in Personality shows that the trait runs deep, even affecting a very basic aspect of visual perception. It seems Open people literally see the world differently.

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Neural changes after taking psychedelic drugs may reflect “heightened consciousness”

Girl's Portrait With Crazy Hair - Lifestyle Concept.By Emma Young

Is there anything psychedelic drugs can’t do? A recent wave of scientific scrutiny has revealed that they can elicit “spiritual” experiences, alleviate end-of-life angst, and perhaps treat depression – and they might achieve at least some of all this by “heightening consciousness”, according to a new paper published in the journal Scientific Reports.

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Looks like we’re going to have to re-write the textbooks on split-brain patients

Screen Shot 2017-05-03 at 12.47.36
Figure from Pinto et al 2017, via ResearchGate

By Christian Jarrett

Back in the 1960s, Nobel-prize winning research shook our understanding of what it means to be a conscious entity. Epilepsy patients who’d had the thick bundle of nerves connecting their two brain hemispheres either severed or removed (as a drastic treatment for their epilepsy) responded in laboratory tasks as if they had two separate minds.

It’s an unsettling idea that has appeared in psychology textbooks for decades. But dig into the original studies and you’ll find the evidence for split brains leading to split minds was mostly descriptive. Now a team of researchers led by Yair Pinto at the University of Amsterdam has conducted systematic testing of two split-brain patients over several years, specifically to find out whether the division of their brains has also separated their consciousness. In fact, the results, published recently in the journal Brain, suggest their consciousness remains unified. It may be time to rewrite the textbooks.

Continue reading “Looks like we’re going to have to re-write the textbooks on split-brain patients”

Experienced meditators have enhanced control over their eye movements

Young Woman Profile Close upBy Alex Fradera

Mindfulness meditation seems to improve the control we have over our eyes, probably because of its known beneficial effects on attentional systems in the brain. That’s according to research published recently in Consciousness and Cognition.

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A scientific measure of our visual imagination suggests it is surprisingly limited

The ThinkerBy Alex Fradera

The human mind has been so successful in transforming the material world that it is easy to forget that it too is subject to its own constraints. From biases in our judgment to the imperfection of our memory, psychology has done useful work mapping out many of these limits, yet when it comes to the human imagination, most of us still like to see it as something boundless. But new research in the journal Cognition, on the capacity of our visual imagination, suggests that we soon hit its limits.

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Psychologists are figuring out why some of us find echolocation easier than others

Blindman's BluffBy Christian Jarrett

Daniel Kish’s life reads like the origins story out of a super hero comic book. To treat his cancer, doctors removed both Kish’s eyes when he was aged one. Later, as a child, he taught himself to echolocate like a bat. Using the echoes from his own clicking sounds he detects the world around him. He can even cycle busy streets and it’s his life’s mission to empower other blind children by teaching them echolocation or what he calls flashsonar.

Psychologists studying the skill have found that it is eminently teachable, for blind people and the sighted. But what’s also become clear is that there is a huge amount of variation between individuals: some people, blind or sighted, seem to pick it up easily while others struggle. A new study in Experimental Brain Research is among the first to try to find out which mental abilities, if any, correlate with echolocation aptitude. The findings could help screening to see who is likely to benefit from echolocation and offer clues to how to help those who struggle.

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Bad news for passport control: face-matching is harder than we realised

Passport Officer at Airport SecurityBy Alex Fradera

Experiments suggest that telling if two unfamiliar faces are the same or different is no easy task. Such research has sometimes presented participants with full body shots, has more commonly used cropped shots of people’s heads, but almost never placed the faces in a formal context, such as on a photographic ID card. But these are the situations in which face-to-photo matching is most relevant, when a shop assistant squints at a driver’s license before selling alcohol to a twitchy youth, or an emigration official scrutinises passports before their holders pass ports. Moreover, it’s plausible that the task is harder when juggling extra information, something already found in the realm of fingerprint matching, where biographical information can lead to more erroneous matches because it triggers observer prejudices. A new article in Applied Cognitive Psychology confirms these fears, suggesting that our real-world capacity to spot fakes in their natural setting is even worse than imagined.

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Autistic people’s social difficulties linked to unusual processing of touch

Man hand pushing a digital screen on office backgroundBy guest blogger Helge Hasselmann

Besides problems with social interactions, it has been known for a while that many people with autism experience sensory difficulties, such as hypersensitivity to sounds, light or touch. With sensory impairment now officially included in diagnostic manuals, researchers have been trying to see if there’s a link between the sensory and social symptoms. Such a link would make intuitive sense: For instance, it is easy to imagine that if someone experienced sensory stimuli more strongly, they would shun social interaction due to their complexity. More specifically, you would expect them to struggle with filtering out and making sense of social cues against the backdrop of sensory overload.

Past research has suggested that tactile hyper-responsiveness in particular may be relevant. The correct processing of tactile information plays an important role in differentiating yourself from others (so-called “self-other discrimination”), a crucial requirement for social cognition. In fact, touch may be unique among the senses because there is a clear difference in the tactile feedback received when you touch something compared to when you see someone else touch something. Now a study in Social Cognitive and Affective Neuroscience has used recordings of participants’ brain waves to provide more evidence that tactile sensations are processed differently in people with autism and that this may contribute to their social difficulties.

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