Researchers at The Australian National University have shed new light on synesthesia – the effect of hearing colors, seeing sounds and other cross-sensory phenomena.
Lead Researcher, ANU Research School of Psychology’s Dr Stephanie Goodhew, said the research found synesthetes had much stronger mental associations between related concepts.
“For them words like ‘doctor’ and ‘nurse’ are very closely associated, where ‘doctor’ and ‘table’ are very unrelated. Much more so than for people without the condition,” she said.
The findings could help researchers better understand the mysteries of synesthesia, which Dr Goodhew said affects an estimated one in every 100 people.
Dr Goodhew said synesthetes have stronger connections between different brain areas, particularly between what we think of as the language part of the brain and the color part of the brain. Those connections lead to a triggering effect, where a stimulus in one part of the brain would cause activity in another.
“Things like hearing shapes, so a triangle will trigger an experience of a sound or a color, or they might have a specific taste sensation when they hear a particular sound,” she said.
“One person reported that smells have certain shapes. For example the smell of fresh air is rectangular, coffee is a bubbly cloud shape and people could smell round or square.”
The research centered on measuring the extent that people with Synesthesia draw meaning between words.
“Going in we were actually predicting that synesthetes might have a more concrete style of thinking that does not emphasize conceptual-level relations between stimuli, given that they have very rigid parings between sensory experiences.
“We found exactly the opposite,” Dr Goodhew said.
Why we have chins
Look at a primate or a Neanderthal skull and compare it with a modern human’s. Notice anything missing? We have one feature that primates, Neanderthals, archaic humans – any species, for that matter – don’t possess: a chin.
“In some way, it seems trivial, but a reason why chins are so interesting is we’re the only ones who have them,” says Nathan Holton, who studies craniofacial features and mechanics at the University of Iowa. “It’s unique to us.”
New research led by Holton and colleagues at the UI posits that our chins don’t come from mechanical forces such as chewing, but instead results from an evolutionary adaptation involving face size and shape – possibly linked to changes in hormone levels as we became more societally domesticated.
The finding, if true, may help settle a debate that’s gone on intermittently for more than a century why modern humans have chins and how they came to be.
Using advanced facial and cranial biomechanical analyses with nearly 40 people whose measurements were plotted from toddlers to adults, the UI team concludes mechanical forces, including chewing, appear incapable of producing the resistance needed for new bone to be created in the lower mandible, or jaw area. Rather, they write in a paper published online in the Journal of Anatomy, it appears the chin’s emergence in modern humans arose from simple geometry: As our faces became smaller in our evolution from archaic humans to today – in fact, our faces are roughly 15 percent shorter than Neanderthals’ – the chin became a bony prominence, the adapted, pointy emblem at the bottom of our face.
“In short, we do not find any evidence that chins are tied to mechanical function and in some cases we find that chins are worse at resisting mechanical forces as we grow,” says Holton, assistant professor and anthropologist in the Department of Orthodontics at the UI College of Dentistry. “Overall, this suggests that chins are unlikely related to the need to dissipate stresses and strains and that other explanations are more likely to be correct.”