Quite a rich trove of articles this month but once again the really fascinating stuff are in the life sciences.

• Easily the most significant and controversial finding of this month’s batch is the discovery in China of a human skull that dates from a million years ago. The skull found in Hubei province and called Yunxian 2 was originally assumed to belong to a member of Homo erectus. New analysis now suggests that it was actually a member of Homo longi who was thought to have lived alongside Neanderthals and Homo sapiens. If true, this sets the timeline of the evolution of large-brained humans back by at least half a million years. Some are using this finding to challenge the established provenance of humans as being from Africa but it’s more likely evidence that there is still so much more that we don’t know.
• One of the key symptoms of schizophrenia is auditory hallucinations, hearing things that aren’t there. One explanation for what is going on is that the patients are unable to distinguish between inner speech and external voices. A new study tests this hypothesis using EEG to monitor brain activity while they were asked to internally produce a sound without speaking it out loud and while listening to an audible syllable without doing anything else. The team found that patients known to have auditory hallucinations had brain activity that suggests they experience inner speech as more real than external sounds.
• Here’s something that won’t occur to most people but will likely seem like a horror story once they hear about it. Some children suffer from epilepsy so severe that the treatment consists of surgically disconnecting the part of the brain in which the seizures originate from the rest of the brain. Yet the tissue remains intact and remains alive. One team wanted to find out whether the part that gets disconnected still has some awareness. So they took EEG readings of both the intact brain and the disconnected region before the surgery and at regular intervals afterwards. Thankfully the results aren’t horrifying. Electrical activity in the intact portion of the brain showed no changes but in the severed portion, the EEG showed slow rhythms called delta waves which are consistent with deep sleep. So it’s not dead but at least it isn’t fully aware all the time.
• Finally here’s an article about similarities in sounds made by birds of different species separated by vast distances and how the phenomenon provides new insight into the development of human language. The researchers found that more than 20 different bird species across four continents produce nearly identical “whining” vocalizations when they spot parasitic birds. They performed playback experiments which showed that birds who hear the calls for the first time will come to investigate the sound. They are then able to learn and reproduce that sound in the future. This suggests a novel pathway for how languages might have developed.