If you've ever started a sentence with, " If I were you…"or found yourself scratching your head at a colleague's headache over a decision when the answer is crystal-clear, there's a scientific reason behind it. Our own decision-making abilities can become declined over the course of the day causing indecision or poor choices, but choosing on behalf of someone else is an enjoyable task that doesn't suffer the same trouble.

The problem is "decision fatigue (疲劳)", a psychological phenomenon that greatly damages the quality of your choices after a long day of decision making, says Evan Polman, a leading psychologist.

Physicians who have been on the job for several hours, for example, are more likely to prescribe antibiotics (抗生素) to patients when it's unwise to do so. "Presumably (据推测) it's because it's simple and easy to write a prescription and consider a patient case closed rather than investigate further," Polman says.

But decision fatigue goes away when you are making the decision for someone else. When people imagine themselves as advisers and imagine their own choices as belonging to someone else, they feel less tired and rely less on decision shortcuts to make those choices. "By taking upon the role of adviser rather than decision maker, one does not suffer the consequences of decision fatigue," he says. "It's as if there's something fun and liberating about making someone else's choice. "

Getting input from others not only offers a fresh perspective and thought process; it often also includes riskier choices. While this sounds undesirable, it can be quite good, says Polman. "When people experience decision fatigue-when they are tired of making choices-they have a tendency to choose to go with the status quo, " he says. "But it can be problematic, since a change in the course of action can sometimes be important and lead to a positive outcome. "

Flowing through winding streets of London were smells, so common during the Great Plague (瘟疫) of the 17th century that they almost meant the plague itself, historians said. For hundreds of years, people believed that disease was spread not through tiny drops or insect bites, but through taking in unpleasant smells. To purify the air around them, they would burn rosemary and hot tar.

Now, as the world faces another widespread outbreak, a team of historians and scientists from six European countries is seeking to identify and categorize the most common smells of daily life across Europe from the 16th century to the early 20th century and to study what changes in smells over time reveal about society.

The project will search through more than 250,000 images and thousands of texts, including medical textbooks, novels and magazines in seven languages. Researchers will use machine learning and AI to analyze references to smells. Once they are cataloged, researchers, working with chemists and perfumers, will re-create roughly 120 smells with the hope that museums will incorporate some of them into exhibits to make visits more immersive (沉浸式的) or memorable to museum-goers. The use of smells in exhibits could also make museums more accessible for blind people and those with limited sight, historians said.

"With smell, you can open up questions about national culture, global culture and differences between communities," said Dr. Inger Leemans, a professor of cultural history at Vrije University Amsterdam. He said that introducing smells into museums or classrooms leads people to open up in discussions in ways they do not always do when discussing other issiues of national identity. "It is such an open topic and what we want to do is think about how we can bring history to the nose."

A robot with a sense of touch may one day feel "pain", both its own physical pain and sympathy for the pain of its human companions. Such touchy-feely robots are still far off, but advances in robotic touch-sensing are bringing that possibility closer to reality.

Sensors set in soft, artificial skin that can detect both a gentle touch and a painful strike have been hooked up to a robot that can then signal emotions, Asada reported February 15 at the annual meeting of the American Association for the Advancement of Science. This artificial "pain nervous system", as Asada calls it, may be a small building block for a machine that could ultimately experience pain. Such a feeling might also allow a robot to "sympathize" with a human companion's suffering.

Asada, an engineer at Osaka University, and his colleagues have designed touch sensors that reliably pick up a range of touches. In a robot system named Affect to, a realistic-looking child's head, these touch and pain signals can be converted to emotional facial expressions.

A touch-sensitive, soft material, as opposed to a rigid metal surface, allows richer interactions between a machine and the world, says neuroscientist King son Man at the University of Southern California. Artificial skin" allows the possibility of engagement in truly intelligent ways".

Such a system, Asada says, might ultimately lead to robots that can recognize the pain of others, a valuable skill for robots designed to help care for people in need, the elderly, for instance. "But there is an important distinction between a robot that responds in a predictable way to a painful strike and a robot that's capable of approximating an internal feeling, "says Damasio, a neuroscientist also at the University of Southern California. "A robot with sensors that can detect touch and pain is along the lines of having a robot, for example, that smiles when you talk to it, " Damasio says. "While that's an interesting development, it's not the same thing as a robot designed to compute some sort of internal experience, "he says.