It's a cliché of modern society: a couple go out for a romantic dinner but instead spend the evening looking at their Twitter feed.
Whether at the supermarket, in the doctor's office, or in bed at night, it can be tempting to pick up your phone and start scrolling through social media or text messages at any moment.
But anyone who has done so in the presence of a close friend, family member or romantic partner may have left that person feeling ignored, annoyed or even pushed away.
That's according to a growing body of research on "technoference," or the potential interference smartphones and other technologies can have in our face-to-face social interactions.
One recent study of 143 married women found more than three-quarters reported mobile phones frequently interfere with their relationships.
In a new paper, US researchers go beyond the idea that technology is simply attention-grabbing to suggest that there may be an evolutionary mismatch between smartphones and the social behaviours that help form and maintain close social relationships.
Humans are hard-wired to connect with others, the researchers argue, and over the course of evolutionary history, we have relied on close relationships with small networks of family and friends for survival as individuals and as a species.
These relationships were based on trust and cooperation, and this was built when people disclosed personal information about themselves and were responsive to others.
Smartphones, and the constant access they provide to text messaging and social media, made it easier than ever for people to disclose personal information and respond to others in their social networks.
"Smartphones and their affordances create new contexts for disclosing information about who we are and for being responsive to others, and these virtual connections may have downstream unwanted effects on our current relationships," University of Arizona psychology professor David Sbarra said.
"When you are distracted into or by the device, then your attention is divided, and being responsive to our partners - an essential ingredient for building intimacy - requires attention in the here and now."
Hangover myth busted
"Beer before wine and you'll feel fine; wine before beer and you'll feel queer" goes the age-old aphorism.
But scientists have now shown that it doesn't matter how you order your drinks - if you drink too much, you're still likely to be ill.
Most people will at some point in their life experience one of many the downsides of excess drinking: the hangover.
Hangover symptoms occur when higher-than-normal blood alcohol concentrations drop back to zero and surprisingly, the phenomenon is not particularly understood.
It is thought, however, that the underlying causes include dehydration, our immune response, and disturbances of our metabolism and hormone.
Hangovers are also likely to be influenced by ingredients other than the pure alcohol content: colourings and flavourings have been suggested as making hangovers worse, which might explain why, at the same alcohol concentration, bourbon causes a more severe hangover than vodka.
On the flipside, old folk remedies like the "hair of the dog", and sayings like "grape or grain, but never the twain" persist, with little evidence to support or refute them.
German and UK researchers set out to test them by recruiting 90 volunteers and splitting them into three groups.
The first group consumed around two and a half pints of beer followed by four large glasses of wine, the second drank the same amounts of alcohol, but in reverse order, while the third drank either only beer or only wine.
The researchers found that none of the three groups had a significantly different hangover score with different orders of alcoholic drinks.
Women tended to have slightly worse hangovers than men.
While neither blood and urine tests, nor factors such as age, sex, body weight, drinking habits and hangover frequency, helped to predict hangover intensity, vomiting and perceived drunkenness were associated with heavier hangover.
"Using white wine and lager beer, we didn't find any truth in the idea that drinking beer before wine gives you a milder hangover than the other way around," said study co-author Joran Kochling, of Witten/Herdecke University.
"The truth is that drinking too much of any alcoholic drink is likely to result in a hangover.
"The only reliable way of predicting how miserable you'll feel the next day is by how drunk you feel and whether you are sick. We should all pay attention to these red flags when drinking."
Why has the zebra got stripes?
Zebra stripes may be a defence against predators after all, but not the huge lions and leopards you might expect.
International research has revealed that the stripes may help to stop horse flies from landing on and biting zebras.
The flies were observed flying faster and failing to slow down when approaching zebras, tending to bounce off instead of land.
Because they landed less often on zebra stripes than horses with a single colour, horse coats in zebra patterns could make effective deterrents for biting flies in domesticated horses.