Other people's stress may change our brains in the same way that our own stress does.
That's been suggested by a Canadian study in mice that gives more credence to the theory that stress can be contagious.
But whether it has lasting effects in the brain is unknown - and the same study found second-hand stress could be reversed in female mice following a social interaction, but not in males.
The University of Calgary scientists split the mice into pairs of males and females,
removed one mouse from each, exposed it to mild stress and returned it to its partner.
They then examined the responses of stress-related brain cells in all the mice to see what the differences had been.
This revealed how the changes observed in those mice taken away were identical to those of the partner left behind.
Next, the team used an approach that allowed them to silence the stress-linked neurons, preventing the changes in the brain from happening during stressful events.
Remarkably, when they used this effect only on one of the pairs, it stopped the transfer
from that of the stressed mouse.
This showed how the release of a chemical signal - or "alarm pheromone" - could alert the partner, who could in turn alert others.
That begged the question: was the same true in us?
"We readily communicate our stress to others, sometimes without even knowing it," said study leader Dr Jaideep Bains, of the university's Hotchkiss Brain Institute.
"There is even evidence that some symptoms of stress can persist in family and loved ones of individuals who suffer from PTSD.
"On the flip side, the ability to sense another's emotional state is a key part of creating and building social bonds."
Is the pursuit of happiness making you unhappy?
Bob Dylan wrote: "Happiness is but a state of mind; anytime you want, you can cross the state line."
He may have been partly right and partly wrong there: achieving true happiness takes time and effort, but maybe not as much as we think.
And pyschologists now suggest those who chase it hard feel like they don't have enough time in the day, which paradoxically leaves them feeling unhappy.
A fascinating new US and Canadian study trawled through academic papers to take a closer look at this idea.
In those earlier studies, some participants were either asked to list things that would make them happier or asked to try to make themselves feel happy while watching a dull movie about building bridges - thus demonstrating happiness as goal pursuit.
The other participants came to think of happiness as a goal they had already accomplished, achieved by watching a slapstick comedy instead, or listing items showing that they were already happy.
Afterwards, all participants reported how much free time they felt they had.
The findings eventually showed that a person's perception of time scarcity was influenced by their pursuit of - often unattainable - happiness.
The feeling that time was scarce lessened for participants who maintained that they had attained their goal of being happy to some degree.
"Time seems to vanish amid the pursuit of happiness, but only when seen as a goal requiring continued pursuit," explain the researchers, from Rutgers University and the University of Toronto Scarborough.
"This finding adds depth to the growing body of work suggesting that the pursuit of happiness can ironically undermine well-being."
The findings may also imply that while happiness can impair positive emotions, it doesn't necessarily need to.
Instead, if someone believes they have achieved happiness, they are left with the time to appreciate this, for instance, by keeping a gratitude journal.
The research further underscored how people have different concepts about happiness, which in turn may well influence how they perceive the time they have to achieve happiness.
"Because engaging in experiences and savouring the associated feelings requires more time compared with merely, for instance, buying material goods, feeling a lack of time also leads people to prefer material possessions rather than enjoying leisure experiences," the researchers added.
"By encouraging people to worry less about pursuing happiness as a never-ending goal, successful interventions might just end up giving them more time and, in turn, more happiness."
What might alien music sound like?
We might think of the cantina song from Star Wars or the five-tone theme from Close Encounters of The Third Kind.
But scientists have seriously asked the question - and whether it might be structured hierarchically, like our own music's verses and choruses, or whether we'd even be able to appreciate it at all.
A team from Germany's Max Planck Institute for Human Cognitive and Brain Sciences suggest that might be possible.
But it was a bit more complicated than that: it hinged on what are termed "local" and "non-local dependencies" - and how our brain might process them.
In language and music, dependencies are conceptual threads that bind two things together.
"Non-local" dependencies are those that bind non-adjacent items - such as two verses in a pop song broken up a by a chorus in between.
When we hear the second verse, we know we've heard it before, and composers use this device to build up our expectations and make us respond emotionally.
Researchers have linked this effect to "Broca's area" - a small patch of our cerebral cortex just above the temple, on the left side of the brain, that's critical for speech production and for the processing of dependencies in language.
For example, Broca's area is active when we detect "violations" to our well-learned grammatical rules.
Surprisingly, despite Broca's area being one of the most studied human brain regions, neuroscientists are still not exactly sure what the same region does, on the other side of the brain.
Theory suggests the right hemisphere equivalent, or homologue, of Broca's area plays a similar role but for the processing of music, instead of language.
But researchers have had difficulty demonstrating this, partly due to an inability to tease apart contributions of local and non-local dependencies to the structural hierarchy of the music.
That's where the alien music came in.
Because we don't of course have authentic music from a distant world, the researchers developed their own weird genre, described as "randomly generated combinations of tone-triplets that were combined in a palindrome-like manner".
Though that may not sound very pleasant, the short stimuli were actually quite pleasing to the ear - and they allowed the team to overcome the confounding hurtle of local dependencies.
There were sequences chucked in there that conformed to a fabricated musical grammar as well as sequences that did not - and MRI scans of musicians used as participants in the study showed they were able to process them all the same.
This ultimately opened the door to determining where in the brain musical, non-local, dependencies were processed.
And it generally proved the team's hypothesis that the brain has one area for processing language and a similar area on the other side for processing music, with a little help from another part of the brain called the inferior frontal gyrus.