Only four articles since I’ve been away or else occupied for much of this month.

• According to the scientists covered in this article from the BBC, rats may be observed to feel regret. The experiment involved setting up lines for food and the rats could choose whether to stay in line or switch to a different one. When they realized that their new choice was worse than the previous one, they were observed pausing and looking back towards the reward they had passed over.
• This article from recode.net talks about how computer algorithms are being used to devise customized treatments for cancer patients. The process involves sequencing the DNA of both the patient’s normal cells and that of the cancerous ones to add to the usual wealth of data that is then fed into the algorithm to generate precisely the correct treatment. All this is still in the trials stage of course, but it’s one of the biggest steps yet towards the long talked-about era of personalized medicine.
• One of the biggest science news this month was the discovery of a truly massive body of water located deep beneath the Earth’s surface. This article for example from New Scientist provides details of how the underground has a total volume three times that of all the oceans on the surface, supporting the idea that all of the water currently on the surface gradually oozed out of the Earth’s interior rather than originating from comets.
• Facebook recently revealed that it had conducted an experiment in which it intentionally manipulated the emotions of its users by tweaking their news feeds to be either sadder or happier than normal. They then monitored the posts of these users to see if the emotional tone matched. This article from The Independent gives further details. The change in subsequent seems small but most people are more shocked that Facebook chose to perform such an experiment without notifying users and asking for their permission. Naturally this also raises the question of whether other online companies tweak the content received by their users in similar ways.