This story was floating around early this year, but appears to have resurfaced again, despite its classic science fiction vibes – a Californian scientist believes that cultural shifts in human behaviour could be due to the presence of a cat parasite called Toxoplasma. Toxoplasma makes its hosts, usually rats, more active and less cautious and hence more likely to be eaten by a cat, where it can complete its lifecycle. Could it be that dormant Toxoplasma trapped in the dead-end host of a human body still creates a change in behaviour, leading to changes in human culture such as an increase in neurotic behaviours?