Some colors that people see late at night could cause signs of the condition mental health experts call clinical depression. That was the finding of a study that builds on earlier study findings. They show that individuals who live or work in low levels of light overnight can develop clinical depression.

Doctors use the words “clinical depression” to describe severe form of depression. Signs may include loss of interest or pleasure in most activities, low energy levels and thoughts of death or suicide.

In the new study, American investigators designed an experiment that exposed hamsters to different colors. The animals were separated into 4 groups. One group of hamsters was kept in the dark during their nighttime period. Another group was placed in blue light, a third group slept in white light. While a fourth was put in red light. After four weeks, the researchers noted how much sugary water the hamsters drank. They found that the more depressed animals drank the less amount of water.

Randy Nelson, who heads the Department of Neuroscience at Ohio State University, says animals that slept in blue and white light appeared to be the most depressed. “What we saw is these animals didn’t show any sleep disruptions at all but they did have messed up circadian clock genes (生物钟基因)and they did show sign of depression whereas if they were in the pale red light, they did not.” He says there’s a lot of blue in white light, which explains why the blue light and white light hamsters appear to be more depressed than the hamsters that see red light or darkness.

Mr Nelson has suggestions for people who work late at night, or those who like to stay up late.

“My recommendation is if you are just living a typical mostly active life during the day, mostly inactive at night, you need to limit exposure to TVs which are quite bluish in the light they give off and computer screens and things like that. You can get filtered glass, you can get filters (过滤器) on your computer screen and filters on your eReaders to put it more in the reddish light.”

If you were to throw, say a banana peel out of your car while driving along the motorway, that would be a completely harmless action, due to the fact that it’s part of a fruit — right? Actually, no. A banana peel can take up to two years to biodegrade, and with a third of motorists admitting to littering while driving, that’s a whole lot of thrown-away banana peels, or much worse. An orange peel and a cigarette butt have a similar biodegrading term to that of a banana, but tin or aluminum cans last up to 100 years; and plastic bottles last forever, as do glass bottles, Styrofoam cups and plastic bags.

Despite the fact that longer-lasting materials will serve to damage the environment and its animals for longer, we can’t only measure the severity of a certain type of rubbish by its lifetime. For example, despite having a fairly short biodegrading span, more than 120 tons of cigarette-related litter is thrown away in the UK every day. Similarly, our regular littering here and there has caused the UK’s rat population to increase by 60 million. This suddenly isn’t so mysterious when you consider that since the 1960s our annual littering has increased by an astonishing 500 percent.

It’s not a cheap habit either: UK taxpayers shelve out £500 million in order to keep our streets clean, and when you include our green spaces, that goes up to £1 billion. So, it’s not surprising that if caught fly-tipping you could face a £20,000 fine or even jail time and, if you disposed of something dangerous, the court could give you five years to serve.

To take back our beautiful countryside and cities we need to do more than simply not leaving rubbish where it ought not to be. We need a pride makeover. We need to truly care more about the world around us.

Have you ever made eye contact with a robot? It can be a very strange experience. Scientists even have a name for the feeling—the mysterious valley.

Now, researchers in Italy have found that it is more than just a feeling. They ran an experiment that showed how a robot’s gaze (凝视) can trick people into thinking they are socially interacting with a human being. That experience can slow a person’s ability to make decisions. “Gaze is an extremely important social signal that we employ on a day-to-day basis when interacting with others,” said Professor Agnieszka Wykowska. “The question is whether the robot’s gaze will cause very similar mechanisms in the human brain as another human’s gaze would,” Wykowska told Reuters.

The team asked 40 people to play a video game, chicken. In the game, each player has to decide whether to permit a car to drive straight toward another car or to turn to avoid a crash. The people were playing against a human-like robot sitting across from them.

During breaks in the game, players had to look at the robot. Sometimes the robot would look back and other times it would look away. As the interactions happened, the scientists collected data on behavior and brain activity. “Our results show that, actually, the human brain processes the robot’s gaze as a social signal, and that signal has an impact on the way we’re making decisions, on the strategies we use in the game and also on our responses,” Wykowska said. “The gaze of the robot affected decisions by delaying them, so humans were much slower in making the decisions in the game,” she added.

The findings could be useful in helping to decide where and how human-like robots might be placed in the future. When we understand when and how robots change social behavior, we can decide which sort of context is beneficial to humans and in which context this should not occur.