It's Sunday; so here's your weekly recap of the top 5 discoveries about our past (and future) from the last 7 days
- Oxytocin is something to fear; at least if you're male. New research has revealed that this hormone - normally associated with affection, sex and bonding - also helps men be scared of stuff. Exposing them to increased levels of oxytocin allowed them learn to fear things faster and better. Given it's established link with socialising, the researchers hypothesise that this may have evolved to help people to learn - and thus avoid - faux pas
- The human hand is still evolving; but not because of anything we're doing. Climate is actually to blame. In colder environments populations are developing shorter limbs to reduce surface area and thus heat loss. It turns out this reduction in limb size also extends to the hands; with them becoming shorter over time.
- One of the first sorts of symbolic artefacts our ancestors began making were necklaces; made by threading shells onto string. Researchers have identified that they overwhelming preferred shells from the genus Nassarius. More interestingly; this preference persisted for tens of thousands of years across continents. Wherever our ancestors could get some Nassarius for their necklaces they did. Quite why they liked this one genus so much is unknown.
- Sleep seems to have evolved to clear metabolites. However, our big brains are structure in such a way that this can be done (a little bit) during the day. As such we can go for longer than many other species before needing to go into sleep-mode.
- Finally; it was discovered our ancestors may have had a sweet tooth. Specifically for honey. Fire (and the smoke it produces) is typically needed to keep bees sedate so honey can be stolen from their hives. However, ethnographic research has identified that some plants can perform a similar function; raising the possibility our ancestors were stealing honey before the invention of fire. Of course, just because they could have doesn't mean they actually did.
Oh; and as an amusing little P.S. The Institute for Creation Research - one of the largest creationist organisations in the world - has been thoroughly confused by the latest fossil discoveries out of Africa. The resulting grasping at straws is pretty amusing.