Moral psychology isn't always an easy thing to study. Experiments that actually puts people in what feels like a real scenario may get realistic results, but researchers must always balance the benefits of what we could learn with the safety and well-being of the people they study. Often what we learn from moral psychology experiments doesn't make humans look good.
We are imperfect creatures. But the more we learn about why and how we make the moral choices that we do, the better we'll be able to tackle difficult questions in the future.

So far the volunteers have successfully been losing lost weight, but now the honeymoon period is over. It is the final two months of the diet, and their minds and bodies are fighting back. Dr Chris van Tulleken and Professor Tanya Byron find out if the new personalised diets will help them stay on course, and the experts reveal the scientific secrets to permanent dieting success.

Everyone always wants to be able to choose - but who really makes these choices? And do we really want to have more choices? Michael Stevens finds out as he explores decision-making.

It is time to see if personalised dieting will work in normal life. The volunteers have been given one of three diets to follow - based on their genes, their hormones and their psychology. But now they are back at home, trying to stick to their personalised diets with all the stresses and temptations of real life. Dr Chris van Tulleken and Professor Tanya Byron discover how our genetic makeup can make temptation difficult to resist, how understanding the brain reveals what makes us comfort eat and what science can tell us about why we make disastrous food choices.

The episode is a journey through the human gut and the process of turning food into energy to keep the body going. Humans have turned eating into culture, a way to celebrate our roots, to bring us together. But food is really just one thing: Fuel. It's where you get the power to live your life. Even when you're sitting completely still, your body needs a lot of energy to stay on. But nowhere is the need for fuel more apparent than when you push yourself to the absolute limit. And the microbiome, the bacteria living in our gut, plays a great role in all this.

What makes us human is the squishy triple-pounder inside our heads. It lets us build skyscrapers, and lift a special few of us into space. We are the only species on this planet that can construct realities in our mind and then go actually build it. The story of how our mind evolved on this one strange rock is one of chance, coincidence and impossible odds.
This episode is an investigation into the mystery of the human brain and the chain of events that produced the anomaly of human intelligence.