When you think of the word ‘Infectious’, the first thing that comes to mind is some horrible disease, like chicken pox or HIV.

However, here are some strange things that you didn’t know were Infectious and they have nothing to do with diseases. And no, we’re not talking about yawning either!

1. Feeling Cold: A study found that just looking at someone who is feeling cold can make you feel cold yourself. Weird, right? The researchers showed participants videos of people putting their hands in both warm water and cold water, and they found that the participants’ hands were significantly colder while watching the latter. The researchers attributed this reaction to the fact that human beings are inherently social, so we empathise with others’ discomfort.

2. Emotions: Over the years, several studies have proved that a number of emotions including happiness, fear, loneliness and disgust are contagious. One study found that your good mood can improve your spouse’s mood by 8 percent, your friend’s mood by 25 percent and your neighbour’s mood by 34 percent. Research has showed that just smelling the sweaty garment of a person who is scared can make other people more fearful and alert, due to the pheromones in the person’s sweat. This same study also found that disgust was contagious in the same way. Loneliness is contagious as well, because a study found that lonely people tend to treat other people badly, and those people treat other people badly, and so on, leading to a vicious cycle that ends up isolating everybody.

3. Weight Loss and Weight Gain: As one person puts on weight, it is more likely that their spouse, friends and siblings will put on weight as well, according to a study. In fact, this effect was observed over social media, so the researchers concluded that as people put on weight, it changes the standards of what is acceptable, causing other people to be less conscious of their own eating and exercise habits in turn.On the other hand, weight loss is contagious as well, since another study found that surrounding yourself with healthy people makes you more likely to be healthy as well.

4. Cavities: This is technically a hygiene-related disease, but we’ve still included it on this list because we’re willing to bet that you had no idea that cavities were contagious from one person to the other! A cavity is basically the decay of a tooth because it is being broken down by harmful bacteria. By sharing food or utensils with another person, you can get their oral bacteria or pass some of yours to them, thereby resulting in the spread of cavities.

5. Generosity: A study found that people who had benefitted from somebody else’s generosity were much more likely to be generous to other people. The researchers believe that this is an evolutionary behaviour, because co-operation among members of a group increased their chances of survival considerably.

6. Cell Phone Usage This may sound strange at first, but try to think back to all the times that you were out with a friend and they were using their phone. What did you do?  You probably used your phone too! A study found that if one person is chatting or texting on their phone, the other person tends to feel excluded and starts using their phone as well. In some cases, seeing the other person using their phone reminded them of something they had to do and so they started to use their phone as well.

7. Stress: Just like certain emotions, stress is contagious as well. A study found that even looking at a co-worker who is stressed out can increase your stress levels considerably. This happens because your body is instinctively wired to look out for danger, and it tenses up and becomes alert at the first sign of it.8. Goals and Objects: If you’re honest with yourself, you can probably remember at least one occasion where you found something much more desirable after you found out that somebody else wanted it. A study asked people to rate how badly they wanted certain objects, and it concluded that people found objects much more desirable when they knew that other people wanted them.