eLife Episode 44: Sperm Competitions and Ancient Horses

How we feel about ourselves is largely dictated by what we think other people think of us. But just as important as someone else’s opinion is what we expect them to think of us. If we believe that someone should rate us highly and, in fact, they don’t, the dent to our confidence is much greater than a bad rating from someone we expect to mark us down. And Leiden University’s Geert-Jahn Will has identified where in the brain this happens…

Geert-Jahn - We know that our self-esteem is shaped by what other people think of us, but what we didn't know is how the brain keeps track of what other people think of us and then how this is integrated into our evaluation of our own worth. So we set out to study this. We asked healthy young people to perform a social evaluation task while they laid in an MRI scanner. And before they came to the lab they uploaded a personal profile to an online database and we told them that other people were going to look at this profile and that they were going to receive feedback from these people. And while they were in the scanner we showed them the feedback that they had received which actually was a computer algorithm so that we could control the feedback. And people received likes or dislikes in the forms of thumbs up and thumbs down symbols which represented whether the other person was interested to get to know them or whether they thought they were not so interesting. And then after every two or three judgments from these peers, they reported on their current level of self-esteem.

克里斯-现在他们知道莱克阀门ely judgment that the person was going to make or was the judgment completely blind to them?

Geert-Jahn - So what we were interested in is not just whether your self-esteem goes up and down. We were critically interested in expectations. So whether you expect to be liked by the other person and how that impacts how you feel about yourself when you received the feedback. The participants in our study interacted with different kinds of people which we subdivided into groups. We used these groups so that participants could learn whether some people were more likely or less likely to give positive feedback. And what we saw in the result is that participants started to expect to be liked by the people in the groups that mostly gave positive feedback and they started to expect to be disliked by those who were more likely to give negative feedback.

Chris - What about though how that impacts on their self-esteem. So if you say to someone you're going to get feedback from this person who usually, 90 percent of the time gives positive feedback but then you say actually they hated you. What does that do to their self-esteem?

Geert-Jahn - Yes, so that is exactly what we were interested in. What we saw is that when participants received a thumbs down by someone who is in general very positive, so when they expected to be like the most, their self-esteem went down the most and the opposite was also true. And we could quantify this sort of level of surprise using a mathematical model. What was sort of central to this mathematical model was prediction errors. They captured the difference between the feedback that you had expected to receive and the feedback you actually received. So we found that self-esteem changes were guided not only by whether other people like you but were especially dependent on whether you expected to be liked.

Chris - It's interesting this because we've all been there haven't we, we know that the professor of biochemistry is very hard to please, but when he or she gives us positive feedback we get a rush of self-esteem feeling very pleased with ourselves because we got feedback from a hard taskmaster.

Geert-Jahn - Exactly. So it seems very intuitive but what is the most innovative part of our study is that we can actually quantify these feelings using mathematical models. And this is important so that we can actually use the model to identify signals in the brain that sort of explain why our self-esteem goes up and down when we learn other people's judgments of us.

Chris - Yes indeed because you had these subjects in brain scanners while you were asking them to rate their esteem in response to this feedback. So what did you see? What was their brain doing in each case and how did that match up with how they were feeling about themselves?

Geert-Jahn——数学模型包含了prediction errors that people use to determine their self-esteem. And what we saw is that these prediction errors were tied to activity in parts of the brain that are very important for learning and valuation. And we could infer how people felt about themselves before they actually reported on how they felt. And we identified a signal in the ventral medial prefrontal cortex that sort of keeps track of how good you feel about yourself.

Chris - So is that where you see this going next? You now have this objective data showing our self-esteem centre in the prefrontal cortex. Could you now take that forward and so will let's look at certain psychiatric illnesses or problems of esteem and depression and see how those illnesses and also getting better from those illnesses are reflected in the behavior of these brain regions.

Geert-Jahn - Yes, so that is exactly the direction that I'm going in. We are currently looking at how these processes might be different in people with levels of self-esteem that are much lower. And then the next step would be to study this in people who suffer from psychiatric disorders such as depression. Ultimately I hope that we can use these insights to design new treatments or design new methods for diagnosis.

研究中心的研究人员existential risk, in Cambridge, given the rapid pace at which sciences like molecular biology are advancing, set out to identify the leading biological threats we are likely to face in the near future. Christian Boehm is one of the authors of the new report...

Christian - Basically what the Center for the Study of extension risk have done this in the previous year bring together an internationally renowned team of 27 experts in biological engineering in order to identify future trends in the field which fulfil three criteria, in essence. And these three criteria: First, the issue needed to be considered emerging but not widely known beyond a specialist field. Secondly, the issue needed to be scientifically plausible. And third, the issue needed to be of potential global impact and so we started off with a long list of 70 potential emerging issues and use a structured and iterative approach to narrow down to the 20 which we outline in more detail in the final report.

Chris - And just briefly can you pick on some of those 20 and tell us why they made it to that shortlist and give us a flavour of, of why they deserve to be there.

Christian - Unfortunately I may not have the time to talk about all the 20 issues in detail but there were some overarching themes if you will, which touched upon several of these issues and one of those that I am particularly excited about is a shift in the nature of biology from a natural science towards an information science. And this has to do with the fact that the costs of sequencing and synthesis of DNA is falling rapidly. Since 2003 the cost of sequencing DNA has come down a million fold and that means that the intrinsic value of any DNA sequence, primary not any more lies in a physical sample of the organism was derived from but rather in the information about the function this fragment of DNA has or the product it encodes. This has a variety of implications for both academic research and the future of our economy.

Chris - And so what do you advocate? Given that dramatic landscape shift, what are you saying we should do instead?

Christian -Well with respect to cyber-biosecurity which I think will be an emerging subdiscipline in biological engineering, it will become increasingly important to protect digital biological sequence information and several strategies for managing these risks. One could consider, first the implementation of industry-wide standards for information security. Secondly, potentially the recognition of public sequenced databases as critical infrastructure. And third, the collaboration with information technology experts when developing new biotechnology tools and services.

Chris - So having highlighted these particular priorities where do you hope this will take you next?

Christian - Our horizon scanning exercise was just a first step. Because of the broad nature of the issues which have touched upon covering issues relevant to health, food supply, energy, but also access ownership, benefit sharing, and many more there really should be follow up exercises, ideally in collaboration with policymakers to prioritize the most actionable items and explore them in more detail to then hopefully come to a fruitful collaboration between scientists and policymakers.

Chris - Many of the things that you've highlighted in the manuscript though, they're pretty big problems. You've mentioned things relevant to say, climate change and that kind of thing which already have a lot of attention focused on them. So to what extent is this highlighting new concerns, and to what extent is it just sort of cheerleading saying "yes we really do need to worry about these things that we know are important."

Christian - Well of course especially the issues which become relevant in the near term. That is approximately the next five years, may be well known generally speaking such as we're all well aware that climate change may impose a substantial threat to humanity, or that we need to substantially boost our food production in order to feed up to 9 billion people 'til 2050. But this report will highlight specific technologies and developments within biological engineering such as artificial photosynthesis or the genetic engineering of chloroplasts which will likely make a difference in addressing these problems.