Millions of people now get their news online. But with so much online content to consume and so little time to consume it, editors at news department know that writing “catchy” headlines is more important than ever. So, what makes a headline catchy? A new study published in Nature Human Behaviour found that negative emotion words in headlines made it more likely that consumers would click through and read the story. In contrast, positive emotion words decreased click rates.

The idea that people are more attentive to negative things is not a new one. Journalists have always had this intuition (直觉) and psychology studies have backed it up. People dislike losses more than they like gains, and they overweigh negative information in many contexts. Even infants pay more attention to negative stimuli. This negativity bias (偏见) makes some sense from an evolutionary perspective: If you miss out on an opportunity to search for some delicious berries, you will be sad... but if you accidentally eat a poison mushroom, you will be dead.

Why the dataset analyzed by Robertson and colleagues is so special? First of all, it is data on the number of clicks in response to more than 105,000 headlines on the news site Upworthy. Therefore, these are real decisions being made by real people. Moreover, Upworthy often tested out different headlines for the same exact story, so they essentially ran experiments on their users.

Not only does this paper tell us more about the factors that influence online news consumption, but it also showcases the nuanced (细微的) ways in which emotion influences decision-making. The researchers found that words about sadness increased click-through rates, but words about fear actually decreased them, and anger words had no significant effect. Now, we don’t know if people were actually feeling those emotions when they read the headlines, so we will need more studies to explore these effects further. However, given that different unconnected emotions might be associated with different assessments of one’s current situation, it makes sense that not all negative emotions would have the same effects on behavior. For example, previous research has shown that people are more optimistic and risk-seeking when they are angry, but they are more pessimistic and risk-averse (风险厌恶) when they are afraid.

The discovery that the universe is expanding was one of the great intellectual revolutions of the twentieth century. With hindsight(回过头看)， it is easy to wonder why no one had thought of it before. Newton,and others,should have realized that a static(静止的)universe would soon start to shrink under the influence of gravity. But suppose instead the universe is expanding.If it was expanding fairly slowly,the force of gravity would cause it eventually to stop expanding and to start shrinking. However, if it was expanding at more than a certain critical rate,gravity would never be strong enough to stop it,and the universe would continue to expand forever.

This is a bit like what happens when one fires a rocket upward from the surface of the earth. If it has a fairly low speed,gravity will eventually stop the rocket and it will start falling back. On the other hand, if the rocket has more than a certain critical speed, gravity will not be strong enough to pull it back, so it will keep going away from the earth forever.

This behavior of the universe could have been predicted from Newton's theory of gravity at any time in the nineteenth, the eighteenth, or even the late seventeenth centuries.Yet so strong was the belief in a static universe that it persisted into the early twentieth century.Even Einstein,when he formulated(构想) the general theory of relativity in 1915, was so sure that the universe had to be static that he modified his theory to make this possible,introducing a so-called cosmological constant(宇宙常数)into his equations. When Hubble's study of nearby galaxies showed that the universe was in fact expanding,Einstein regretted modifying his elegant theory and viewed the cosmological constant term as his "greatest mistake".

There are two kinds of memory: short-term and long-term. Information in long-term memory can be remembered at a later time when it is needed. The information may be kept for days or weeks. However, information in short-term memory is kept for only a few seconds, usually by repeating the information over and over. The following experiment shows how short-term memory has been studied.

Henning studied how students who are learning English as a second language remember vocabulary. The subjects in his experiment were 75 college students. They represented all levels of ability in English: beginning, intermediate (中等), and native speaking students.

To begin, the subjects listened to a recording of a native speaker reading a paragraph in English. Following the recording, the subjects took a 15-question test to see which words they remembered. Each question had four choices. The subjects had to circle the word they had heard in the recording, some of the questions had four choices that sound alike. For example, weather, whether, wither, and wetter are four words that sound alike. Some of the questions had four choices that have the same meaning. Method, way, manner, and system would be four words with the same meaning. Finally the subjects took a language proficiency test.

Henning found that students with a lower proficiency in English made more of their mistakes on words that sound alike; students with a higher proficiency made more of their mistakes on words that have the same meaning. Henning's results suggest that beginning students hold the sound of words in their short-term memory, and advanced students hold the meaning of words in their short-term memory.