Our emails are a dead giveaway. The words we use in the messages we send can reveal not just our gender but also our emotions and maybe even our personality traits.

and colleagues from the , used sentiment analysis to uncover the feelings buried inside email. “It’s an efficient way of generating data about the emotional content of huge amounts of text,” says Mohammad. “There’s been a lot of research based on positive and negative emotion, but with all this data available it makes sense to understand what we can learn from all the emotions.”

The team created a huge “sentiment” database using crowdsourcing by hiring workers for Amazon’s Mechanical Turk to pair 24,200 words with emotions – “ice cream” paired with “joy”, for instance, and “gardening” with “peace”. Comparing the words used in a corpus of 32,045 emails made public after the to this database, made it possible to assess emotional tone and how it varied with gender.

The results showed a marked difference between sexes. Women had a tendency to use words relating to joy or sadness, while men favoured those associated with fear or trust. Both sexes used more joyous and cheerful words when writing to women, and men used more anticipatory language when writing to women, such as “prepare” or “hope”.

The team also tried to discern personality traits from emotional content. “If you’re angry occasionally, that’s fine,” explains Mohammad. “But if you’re angry all the time, it’s part of your personality.” Armed with a different database of 585 emotions and associated words generated from tweets and hashtags, the team taught an algorithm to try and identify personality types from a short piece of written text.

Thousands of samples – short stream of consciousness essays, each judged by psychologists to represent one of the Big Five personality traits of extroversion, neuroticism, agreeability, conscientiousness or openness – were used to train the algorithm to match combinations of emotions to traits. When tested, its analyses of unseen essays agreed with the psychologists the majority of the time.

Predicting personality traits and gender of an otherwise anonymous individual could help spot warning signs of depression, the researchers claim, or even help with forensic analysis of online crime. But there’s an even bigger picture, too. “If you wanted to know about how the latest iPhone release was received, deep emotional analysis of social media could provide incredibly rich insight,” says Mohammad.

Further work is required before the findings can be used more widely. “Overall it’s very impressive and interesting research,” says , at the University of Wolverhampton, UK. But he cautions that because the email data belonged to a very specific group of people, the results may not apply more widely.

Journal References: ,

Correction: When this article was first published on 27 September 2013, an error crept in. Analyses of unseen essays agreed with psychologists the majority of the time rather than 99 per cent of the time.

Reports of the future’s arrival have been greatly exaggerated (Image: Alamy)

, Design Museum, London, until 3 November.

An exhibition on manufacturing’s future and an evangelical book on nanotechnology highlight that the directions we’ll take are very much up for grabs

See more in our gallery: “Future objects: The changing face of everyday items“

THERE’S a quiet revolution taking place in factories worldwide.

In 2013, manufacturing may still resemble old mass-production assembly lines, but increasingly, technological advance means they are producing customised items that need never be the same twice. And that is changing how designers and manufacturers think, as the focus shifts from homogeneous products to end users and their desire for individuality. Designers are now keen to have us co-design products, and even manufacture them at home.

But when it comes to how these changes will affect us, neither we nor manufacturers have a clear idea, it seems. So an exhibition celebrating new design and manufacturing at London’s Design Museum should be timely.

Called The Future is Here: A New Industrial Revolution, its remit is to explore how the boundaries between designer, manufacturer and consumer are becoming blurred.

There is certainly no shortage of ideas and ways forward. Mass customisation is a recurring motif in the exhibition, which showcases consumer concepts such as Mi Adidas, a website that allows customers to design their own trainers from the sole up. Then there are more unusual initiatives, like the smart production line of US electric vehicle manufacturer Tesla Motors, shown on video. Its robots receive different commands car-by-car to create unique vehicles. And there’s UCODO (User Co-Designed Object), a website where anyone can customise a design by shape, size and colour.

The exhibition also highlights how users can become an integral part of manufacturing. That may mean bringing digital life to products such as brewing kits or home-lighting systems through the use of a tiny Raspberry Pi computer or Arduino circuit boards. These open-source electronic kits can control just about any DIY hardware project.

Or it can involve getting seriously hands-on with 3D printing. Part of the appeal of the much-hyped 3D-printing revolution is in manufacturing objects from a digital model, and the Design Museum has 3D printers you can play with.

But while the exhibition brims with ideas, areas such as nanotechnology, flexible electronics and biomanufacturing are under-represented. Perhaps things are changing so fast that a pick-and-mix was the best the curators could hope for, but it leaves the show struggling to present a future it claims is “here”.

Instead, the emphasis on current, if novel, processes creates a feeling of faddishness rather than coherent prediction.

Luckily we can at least address the lack of nanotechnology with K. Eric Drexler’s latest book, Radical Abundance. A long-standing nano evangelist, this time Drexler focuses on the engineering that will take nanotechnology from a vague scientific discipline to the mainstream. To deliver on its early promise, he says, scientists must copy engineers and make stuff that “just works”.

Drexler’s suggestions resonate with at least one of the exhibits. Take his “microblocks”. This idea turns science into production and employs a cascade of thousands of tiny robotic cells. Each builds components at the molecular level, feeding those components to increasingly larger robots until a full-size product is created. It may be the ultimate customisable production line, allowing designers to tweak products from the molecular level up. Tesla Motors’ production line may be a step in this direction.

Drexler also expects that such bottom-up techniques will eventually let us use radically different, abundant materials such as carbon, nitrogen and silicon oxide rather than scarcer elements such as zinc and tin. That in turn will let us manufacture products far more economically – financially and environmentally.

Bold claims abound, but they highlight a sticking point with both Drexler’s book and the Design Museum’s future-gazing: of course many of the ideas and products are exciting, but neither book nor exhibition presents a compelling enough sense of what the future might actually look like.

Not only will new technologies change the way we live, but the mere anticipation of change may be enough to shape expectations and outcomes, warns Drexler. And while custom-producing from home has great appeal, he fears our enthusiasm might run wild and see us turn our homes into factories, churning out disposable goods that we tire of in days.

“We could turn our homes into factories, churning out disposable goods that we tire of in days”

A way out of this scenario is offered in one of the other strands running through the exhibition: “emotionally durable design”. The Optimist’s Toaster, for instance, was designed so that its material value and longevity (evident in its date-stamped, all-aluminium build) signal that it should last for generations. This idea extends to digital electronics. For example, a Sony concept device called Wandular would use software updates and hardware plug-ins to ensure that it is cherished over a lifetime, while its functionality keeps pace.

But once again, the exhibition’s curators seem unsure what to back. Next to the Optimist’s Toaster, for example, sits a pair of Puma trainers designed to biodegrade. These shoes are a totally different approach to tackling the problem of discarding old objects in favour of new. Ultimately, the exhibition does little to help us work out whether the great shift will drive us deeper into disposability or return us to a tradition of looking after our possessions.

Soldiers experience high-pressure shock waves and immense forces during explosions in the field, but research suggests brain trauma is caused merely by the sudden head movements.

It has been unclear whether trauma from explosions is caused through high-pressure shock waves penetrating the skull, or through another mechanism. Now a team of researchers from Boston University have performed post mortems on soldiers to establish how traumatic brain injury occurs during explosions.

Many blast victims develop symptoms consistent with chronic traumatic encephalopathy (CTE), a degenerative brain disease that can cause memory problems, depression and learning difficulties. However, CTE is usually caused by repeated concussions such as those experienced by American football players – not one-off blasts.

“The damage in football players has been linked to acceleration forces due to head impact,” explains , a medical engineer who worked on the project at Boston University before moving to the University of Oxford. “Our goal was to see if the same mechanism was responsible for blast injury.”

Cleveland and his colleagues performed a post mortem analysis of brains from four soldiers who had experienced blasts. They compared the brains to those of American footballers and a wrestler who all had a history of repetitive concussive injury, as well as with a person with no brain trauma. They found firm evidence of CTE, as indicated by abnormal deposits of the protein tau in the brain of the soldiers, which was indistinguishable from CTE in the athletes.

Shock force

The team also sought to establish the mechanics behind brain trauma. They exposed mice to shock forces equivalent to humans subjected to improvised explosive devices (IEDs), and measured head oscillations using high-speed cameras.

Mice that had experienced the blast took longer to navigate a maze than unexposed mice, and they showed signs of memory retention problems. Further examination revealed the presence of tau deposits within their brains consistent with CTE.

When their heads were restrained to prevent movement, though, no brain damage or memory problems were observed. “It was the movement of the head, not the passage of the shockwave, that produced the damage,” explains Cleveland.

The finding may impact the way that we protect troops. “In the past, the main effort has focused on designing helmets to prevent shock-wave transmission into the head,” says Cleveland. “But based on our results, providing resistance to head motion would be far more effective.”

, at the University of Oxford, is impressed. “It’s a well-conducted study, and it’s good to finally have definitive research about the effects of explosion on brain function,” she says.

Wild also suggests the results could have wider implications. “Those suffering traumatic brain injury are at increased risk of developing post-traumatic stress disorder and respond less well to conventional treatments for it,” she explains. “This finding could help reduce the incidence of PTSD in soldiers.”

, DOI: 10.1126/scitranslmed.3003716

Read more: “Nine lost treasures – and why science wants them back“

It was one of the most terrifying weapons ever made. But the secret ingredients and technology required to make the incendiary substance “Greek fire” has defeated scientific minds ever since the 12th century.

Greek fire was a flaming mixture fired from the ships of the Byzantine empire from the 7th century. The fire would cling to flesh and was impossible to extinguish with water. This deadly concoction was created by a family of chemists and engineers from Constantinople, and the secret recipe died with them.

John Haldon from Princeton University has a hunch though: he suspects it was a petroleum-based liquid modified to increase its potency. He thinks the key ingredients were a highly flammable light crude oil called naphtha, and pine resin, which is sticky and would have made the mixture burn hotter and longer.

But there was more to the mystery of Greek fire than its ingredients alone. “When enemies captured elements of the equipment, they just weren’t able to work out how to use it to recreate the same effects,” explains Haldon. Historians have the same problem, but they’ve deduced that a bronze pump probably pressurised heated oil, which was then ejected through a nozzle and ignited. In 2002, a reconstruction was built for a National Geographic TV programme, using a mixture of light crude oil and pine resin. Their flame destroyed a ship in minutes.

Uncertainties remain because the secret was never written down, but the power of Greek fire is beyond doubt. “It was definitely an effective weapon of terror,” says Haldon.

“If the skin of this creature turned up, it could explain sightings of sea serpents”