Signing

The speed at which sign language users understand what others are ‘saying’ to them depends on whether the conversation partners are left- or right-handed, a new study has found.

Researchers at the University of Birmingham worked with British Sign Language (BSL) signers to see how differences in sign production affect sign comprehension. In BSL a signer’s dominant hand produces all one-handed signs and ‘leads’ when producing two-handed signs.

They discovered that in general right- and left-handed signers respond faster when they were watching a right-handed signer.

However, left-handed signers responded more quickly to complex two-handed signs made by signers who ‘led’ with their left hand. Similarly, right-handed signers reacted more swiftly to two-handed signs from fellow right-handers.

PhD student Freya Watkins and Dr. Robin Thompson published their research in the journal Cognition.

Dr Robin Thompson commented: “Had all signers performed better to right-handed input, it would suggest that how signers produce their own signs is not important for understanding. This is because right-handed signers are most common and signers are most used to seeing right-handed signs.

“However, as left-handed signers are better at understanding fellow left-handers for two-handed signs, the findings suggest that how people produce their own signs plays a part in how quickly they can understand others’ signing.”

Forty-three Deaf fluent BSL signers took part in the experiment, which had both right and left-handed participants make judgements about signs produced by left or right-handed sign models.

Participants were shown a picture followed by the sign for common words such as ‘chocolate’, ‘guitar’ and ‘desk’, and then were asked to decide if the picture and sign matched. The question was whether or not handedness during sign production would influence sign comprehension.

The results are in line with a weak version of the motor theory of speech perception, that people perceive spoken words in part by checking in with their own production system, but only when comprehension becomes difficult, for example in a noisy environment.

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Another Language Another Time

Language has such a powerful effect, it can influence the way in which we experience time, according to a new study.

Professor Panos Athanasopoulos, a linguist from Lancaster University and Professor Emanuel Bylund, a linguist from Stellenbosch University and Stockholm University, have discovered that people who speak two languages fluently think about time differently depending on the language context in which they are estimating the duration of events.

The finding, reported in the ‘Journal of Experimental Psychology: General‘, published by the American Psychological Association, reports the first evidence of cognitive flexibility in people who speak two languages.

Bilinguals go back and forth between their languages rapidly and often, unconsciously, a phenomenon called code-switching.

But different languages also embody different worldviews, different ways of organising the world around us. And time is a case in point. For example, Swedish and English speakers prefer to mark the duration of events by referring to physical distances, e.g. a short break, a long wedding, etc. The passage of time is perceived as distance travelled.

But Greek and Spanish speakers tend to mark time by referring to physical quantities, e.g. a small break, a big wedding. The passage of time is perceived as growing volume.

The study found that bilinguals seemed to flexibly utilise both ways of marking duration, depending on the language context. This alters how they experience the passage of time.

In the study, Professor Bylund and Professor Athanasopoulos asked Spanish-Swedish bilinguals to estimate how much time had passed while watching either a line growing across a screen or a container being filled.

At the same time, participants were prompted with either the word ‘duración’ (the Spanish word for duration) or ‘tid’ (the Swedish word for duration).

When watching containers filling up and prompted by the Spanish prompt word, bilinguals based their time estimates of how full the containers were, perceiving time as volume. They were unaffected by the lines growing on screens.

Conversely, when given the Swedish prompt word, bilinguals suddenly switched their behaviour, with their time estimates becoming influenced by the distance the lines had travelled, but not by how much the containers had filled.

“By learning a new language, you suddenly become attuned to perceptual dimensions that you weren’t aware of before,” says Professor Athanasopoulos. “The fact that bilinguals go between these different ways of estimating time effortlessly and unconsciously fits in with a growing body of evidence demonstrating the ease with which language can creep into our most basic senses, including our emotions, our visual perception, and now it turns out, our sense of time.

“But it also shows that bilinguals are more flexible thinkers, and there is evidence to suggest that mentally going back and forth between different languages on a daily basis confers advantages on the ability to learn and multi-task, and even long term benefits for mental well-being.”

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Rock Collecting

An international group that includes an University of Kansas researcher, has discovered a brownish piece of split limestone in a site in Croatia that suggests Neanderthals 130,000 years ago collected the rock that stands out among all other items in the cave.

“If we were walking and picked up this rock, we would have taken it home,” said David Frayer, a professor emeritus of anthropology who was part of the study. “It is an interesting rock.”

The finding is important he said, because it adds to other recent evidence that Neanderthals were capable on their own, of incorporating symbolic objects into their culture. The rock was collected more than 100 years ago from the Krapina Neanderthal site, which has items preserved in the Croatian Natural History Museum in Zagreb, where in recent years the research team has re-examined them.

The group’s findings on the collected rock at Krapina were published recently in the French journal Comptes Rendus Palevol. Davorka Radovčić, curator at the Croatian Natural History Museum, was the study’s lead author, and Frayer is the corresponding author.

The same research group in a widely recognized 2015 study published a PLOS ONE article about a set of eagle talons from the same Neanderthal site that included cut marks and were fashioned into a piece of jewelry.

“People have often defined Neanderthals as being devoid of any kind of aesthetic feelings, and yet we know that at this site they collected eagle talons and they collected this rock. At other sites, researchers have found they collected shells and used pigments on shells,” Frayer said. “There’s a little bit of evidence out there to suggest that they weren’t the big, dumb creatures that everybody thinks they were.”

Similar to the Neanderthal jewelry discovery at Krapina, Frayer credits Radovčić’s keen eye in examining all items found at that the site, originally excavated between 1899-1905 and found to contain Neanderthal bones.

The cave at the Krapina site was sandstone, so the split limestone rock stuck out as not deriving from the cave, Frayer said. None of the more than 1,000 lithic items collected from Krapina resemble the rock, but the original archaeologists apparently did nothing more with the rock other than to collect it.

Frayer said the limestone rock which is roughly five inches long, four inches high and about a half-inch thick, did not have any striking platforms or other areas of preparation on the rock’s edge, so the research team assumed it was not broken apart.

“The fact that it wasn’t modified, to us, it meant that it was brought there for a purpose other than being used as a tool,” Frayer said.

There was a small triangular flake that fits with the rock, but the break appeared to be fresh and likely happened well after the specimen was deposited into the sediments of the Krapina site. Perhaps it occurred during transport or storage after the excavation around 1900, he said.

The look of the rock also caught the researchers’ eye as many inclusions or black lines on it stood out from the brown limestone. Perhaps that is what made the Neanderthal want to collect it in the first place.

“It looked like it is important,” Frayer said. “We went back through all the collected items to make sure there weren’t other rocks like it. It just sat there for 100 years like most of the other stuff from the site. The original archaeologists had described stone tools, but didn’t pay any attention to this one.”

They suspect a Neanderthal collected the rock from a site a few kilometres north of the Krapina site where there were known outcrops of biopelmicritic grey limestone. Either the Neanderthal found it there or the Krapinica stream transported it closer to the site.

The discovery of the rock collection is likely minor compared with other discoveries, such as more modern humans 25,000 years ago making cave paintings in France. However, Frayer said it added to a body of evidence that Neanderthals were capable of assigning symbolic significance to objects and went to the effort of collecting them.

The discovery could also provide more clues as to how modern humans developed these traits, he said.

“It adds to the number of other recent studies about Neanderthals doing things that are thought to be unique to modern Homo sapiens,” Frayer said. “We contend they had a curiosity and symbolic-like capacities typical of modern humans.”

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Spindletop

In 1901, a drilling derrick at Spindletop Hill near Beaumont, Texas produced an enormous gusher of crude oil, coating the landscape for hundreds of feet and signalling the advent of the American oil industry. The geyser was discovered at a depth of over 1,000 feet, flowed at an initial rate of approximately 100,000 barrels a day and took nine days to cap. Following the discovery, petroleum, which until that time had been used in the U.S. primarily as a lubricant and in kerosene for lamps, would become the main fuel source for new inventions such as cars and airplanes; coal-powered forms of transportation including ships and trains would also convert to the liquid fuel.

Crude oil, which became the world’s first trillion-dollar industry, is a natural mix of hundreds of different hydrocarbon compounds trapped in underground rock. The hydrocarbons were formed millions of years ago when tiny aquatic plants and animals died and settled on the bottoms of ancient waterways, creating a thick layer of organic material. Sediment later covered this material, putting heat and pressure on it and transforming it into the petroleum that comes out of the ground today.

In the early 1890s, Texas businessman and amateur geologist Patillo Higgins became convinced there was a large pool of oil under a salt-dome formation south of Beaumont. He and several partners established the Gladys City Oil, Gas and Manufacturing Company and made several unsuccessful drilling attempts before Higgins left the company. In 1899, Higgins leased a tract of land at Spindletop to mining engineer Anthony Lucas. The Lucas gusher blew on January 10, 1901 and ushered in the liquid fuel age. Unfortunately for Higgins, he’d lost his ownership stake by that point.

Beaumont became a “black gold” boomtown, its population tripling in three months. The town filled up with oil workers, investors, merchants and con men (leading some people to dub it “Swindletop”). Within a year, there were more than 285 actives wells at Spindletop and an estimated 500 oil and land companies operating in the area, including some that are major players today: Humble (now Exxon), the Texas Company (Texaco) and Magnolia Petroleum Company (Mobil).

Spindletop experienced a second boom starting in the mid-1920s when more oil was discovered at deeper depths. In the 1950s, Spindletop was mined for sulphur. Today, only a few oil wells still operate in the area.

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Just A Throw Away

Throwing is one of the most complex actions humans perform. Even tossing a crumpled piece of paper into a waste basket two feet away requires a series of complex neurological and mechanical calculations. Should you toss overhand or underhand? How fast should you throw? At what angle should you hold your arm?

Applied mathematicians at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) decided to use mathematical models to figure out the best strategies to throw something at a target.

“There are many different ways to get an object to a target,” said L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, Physics and Organismic and Evolutionary Biology at SEAS and senior author of the study. “How do you choose? Our hypothesis was that you choose based on a strategy that minimises the error at the target while giving yourself the greatest room for error at the release.”

The team found that while underhand throws are best for reaching a target close by and above the shoulder, overhand throws are more accurate for targets below the shoulder, like a waste paper basket and are more forgiving to errors over long distances.

The research is published in Royal Society Open Science.

As all pitchers, quarterbacks and bowlers know, once an object is released, the thrower loses control over where it goes. Mahadevan and M. Venkadesan of Yale University, analysed the parabolic trajectories of thrown objects to understand how release errors affect the accuracy of the throw.

“We asked, how do errors introduced in the release of the thrown object propagate at the location of the target, as a function of the distance, orientation and height of the target,” said Mahadevan, who is also a core faculty member of the Wyss Institute of Biologically Inspired Engineering at Harvard University.

The researchers also modelled the trade-off between speed and accuracy when throwing an object.

The team found that regardless of the target location, the most accurate throw is slightly faster than the minimum speed needed to reach the target. The faster the throw, the less likely it is to be accurate, which explains why even the best pitchers still throw a lot of balls. The researchers found that at both high speeds and longer distances, the overarm throw beats the underhand throw in accuracy.

The findings shed light on how humans evolved to throw, said Mahadevan. After all, the ability to hit a target with a thrown object was key to human evolution. Without claws or sharp teeth, humans’ ability to throw a stone or spear was a primary method of hunting for food.

“This research demonstrates the theoretically best way to throw. But most of us are not born throwers of anything. We learn how to throw through trial and error,” said Mahadevan. “Now, we have a mathematical framework to think about how learning about the physical world requires interacting with the world. We can’t think about tasks unless we think about the way in which we interact with the physicality of the environment.”

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