Honing in on Headaches

Let's dive into some Naked Neuroscience news, with cognitive neuroscientist Duncan Astle and perceptual psychologist Helen Keyes. First up, as lockdown continues here in the UK, Cambridge University’s Duncan Astle highlighted a perhaps quite pertinent paper about roaming. Duncan told me that the evidence suggests when animals are free to roam in enriched environments, they have greater wellbeing. So can the same be said for us humans? Does being able to go exploring relate to our mood? Well that’s the question the paper he looked at wanted to answer...

Duncan - They took a group of subjects, about 130 of them, and they supplied them with a geo-location tracker. And this tracked their movements around town over a period of three to four months. During that time, they would also send mini surveys to their mobile phones on a regular basis to check up on their mood. After they collected the data, they were able to calculate something called roaming entropy or R.E. It's just a way of providing a measure of how much you move about. And what they found is that subjects' mood was significantly related to their RE. When roaming entropy was higher, their mood was also higher. So on the days where they moved around a lot, they tended to report being in a better mood or having better affect. Secondly, looking across days, they found that mood tended to be highest when those days took in novel locations. And in fact, actually this explains subjects' mood over and above the basic roaming entropy finding. So there's something particularly strong about novelty. And thirdly, what they could do is take into account the socioeconomic diversity of the places that people visited. And they found that when there was a greater diversity of places visited, that was also associated with greater mood.

So two important findings. One is about the novelty. And one is about the diversity of the places that people are going. And both of these things seem to be associated with people's mood.

Katie - Does it make a difference how you move around? Cause I would assume if you're walking around compared to say driving in the car, that would make you feel better. Is the tracker about how you move or just where you're going?

邓肯——我不认为追踪给他们level of granularity. I guess it checks your locations on a minute by minute basis. So in theory, they could use that to work out speed.

Katie - OK, but this isn't about exercise, this is about going to different places, regardless of how you get there, right?

邓肯-是的他们控制了that. One question you might be starting to think is - is it that novelty boosts mood, or is it that when you're in a better mood, you sort of seek out novel places? The answer from their data seems to be that it's both and they can test that by doing what's called a lagged analysis. So for example, they could see whether your mood today is influenced by the novelty of locations from yesterday. Or they could test whether your mood today will influence the novelty of the locations you go to tomorrow. And what they're able to show is that actually all of those relationships were significant. So the lag works in all directions, implying that these things are kind of mutually beneficial to each other. So for instance, when you're starting to feel in a better mood, you seek out more novel places. And in turn seeking out more novel places will have a subsequent beneficial effect on your mood the subsequent day. So you can imagine quite quickly how people can get themselves into positive cycles or negative cycles.

And then finally, half of the subjects went into an MRI scanner. And in particular they were focusing on a part of the brain called the ventral striatum, which is an area that lots of people have implicated in affect and mood. And what they did was to test which areas in the brain are functionally connected with this area, the ventral striatum, in a way that moderates the relationship between someone's roaming behaviour and their mood. And they find there was one particular location, the hippocampus, heavily involved in spatial navigation. So in subjects who have strong coupling between the hippocampus and the ventral striatum, those subjects seem to show a stronger coupling between their roaming behaviors and their mood, implying that there's some kind of neurological basis or neuroscientific basis that mirrors the behavioural relationship between the roaming behaviour and the mood.

Katie - So does that mean for some people, going somewhere else and seeking out a novel environment might be really, really good for your mental wellbeing?

Duncan - Yeah. I can think of lots of different potential explanations. So one is the one that you just said, right? Some people, these areas are just naturally better connected. And as a result, the more mutual benefit, the information can flow more easily between the two. Another account is that this relationship is kind of trained over time. So that the more you do one or the more you kind of co-activate these different brain areas, the more they become functionally coupled. And so what you're seeing in the brain scanner is kind of the after effect of repeatedly co-activating these two different brain areas. But I think it's nice to demonstrate that there is some neuroscientific instantiation of what's obviously happening out there in the real world, in terms of people's experience.

Katie - It feels quite intuitive, that link between seeking novel places and feeling quite good. Does this explain why I really like going on holiday?

邓肯-已坏,我想可能会有很多原因ns why you like going on holiday, depending on what you do when you get there. I think there's lots of ways in which navigation is kind of beneficial for your mood. So I don't know about you, but when I'm trying to find somewhere, it really gets my mind off whatever was going on in the place I just left. And it allows me to somehow mentally sort of draw a line or kind of demarcate what was a particular attentional episode and start a new one. And I can imagine that being able to do that physically in terms of your navigation could have all sorts of mental benefits as well. And I think that whilst we're all currently in lockdown, I suspect that we're not able to do that. And that is one reason why people's moods have been really altered by their experience.

Katie - Helen, do you want to chip in with anything?

Helen - I think it's really interesting in terms of some of the studies we've covered in the last few months around mindfulness and using things like video games to actively take your mind off of a situation, for example off of work stress and how that can really encourage mindfulness and improve your mood and mental wellbeing. It seems to tie in really nicely the idea that both novelty and diversity are improving moods here. Because that is the link isn't it? Novel and diverse places will engage you in a way that is likely to take your mind off your worries, more so than trudging around the same old places again and again. And I think it is probably a significant worry at the moment and that it's not very easy for us to encounter novel or diverse situations. And we probably will see quite a large effect on mood as a result.

Anglia Ruskin University's Helen Keyes been delving into confirmation bias this month, which is essentially being more likely to take on board, and, Helen told me, even remember, information that confirms our beliefs. And the paper she’s been looking at seeks to understand this on a neural level. Could the confirmation bias be explained by how the brain likes to take in new information? Well the authors got subjects to do a visual task - to look at moving dots on a screen, decide which way they were moving, and decide how confident they were in that decision. Then, when faced with more moving dots, the scientists wanted to see if people’s degree of confidence in the first dot decision related to how they approached the new information. Helen told me more...

Helen - So the authors of this study recorded 28 participants using MEG, or magnetoencephalography, which records neural activity with really tight timing precision. And participants were shown a series of dots on a screen for about 350 milliseconds. And some of the dots will be moving rightwards or leftwards. And the rest of the dots on the screen will just be moving randomly. Your task is simply to say whether the dots are generally moving rightwards or leftwards. A participant had to indicate their decision. And then importantly, they had to give a rating on their confidence in their decision. Then they received a second sample of dots. The dots were moving in the same way as in the first session. And they were then asked again which direction the dots were moving in and their confidence level.

Because the authors were recording MEG, they were able to look specifically at brain responses, which are known to be involved in evidence accumulation. And they found that if you're a participant and you really felt that these dots were moving in a leftward direction, and you were confident in that, when you saw the next set of dots, your neural activity in these areas that are involved in accumulating evidence was really high, if the evidence agreed with you. So I'll say that again. If the second set of dots agreed with what you believed, agreed with your assertion that these dots were moving in a leftward basis, these parts of your brain that are involved in taking in this information were really active. If the new evidence disconfirmed your decision, so if you thought they were going left, and the second set of dots show that they were going right, those parts of your brain involved in taking in new information, basically just, they just dismiss this information. They were not active.

Really, for relatively unimportant, non-politically motivated decisions, just about dots moving across the screen, people showed a really strong confirmation bias where they tended to favour incorporating new evidence that fit with their initial decision, and ignoring evidence that disconfirmed it. So it shows that this confirmation bias happens, at least in part, at a neural level. And it does suggest that maybe holding a high level of confidence in your decisions makes you more likely to disregard potentially useful information, if it kind of disagrees with your initial decision. This isn't necessarily a negative thing. There's reason to believe this might be to stop us dithering and to enable us to move forward with our decisions.

Katie - See, that's my problem, Helen. I am an ultimate ditherer. I always thought that this was about efficiency. You know, the idea being that the brain only has so much processing power. So why not just use a shortcut? Is that relevant?

Helen - I think it's absolutely relevant. I think it's the brain's way of using your heuristics and saying, "well, you're confident in this decision, I'm just going to direct my resources towards this in an efficient way. And off you go down this path and I'll support you in that". Thank you brain for being very supportive of my decisions.

Katie - Do you think this could open up opportunities to unpick some of the confirmation bias? Is it possible to work on it as a skill, to be less biased in this way?

Helen - It absolutely is. So most of the research prior to this, on the confirmation bias, has been, you know, around this behavioural response. Why is it, for example, that people hold particular political beliefs? Or for example, if somebody is racist or has a very entrenched opinion, there is work done there to show that these entrenched opinions can be challenged and lessened and opinions can be changed. What might be quite interesting is to see when is that happening at the neural level? At what stage is it that we can make that opinion change happen? So how much new evidence or what type of new evidence, or in what new way can we present new evidence that challenges people's deeply held beliefs, that at some stages is going to be absorbed or taken on board in the way we would hope, rather than disregarded.

Katie - Duncan, is there anything you want to add?

Duncan - Yeah, I was gonna ask how confident we are that the mechanisms that govern these dots are the same as other sorts of biases? So let's imagine that there's a really controversial celebrity, and I think they're great and Helen thinks they're awful. I might selectively take on board all the wonderful things that I see in the news. And it kind of reinforces my impression of that person. It might engage all sorts of different kind of emotional processes. How well do you think that kind of confirmation bias translates to, you know, whether the dots are moving left or right on the screen?

海伦-有更多的工作要做,但当我们take together the huge body of evidence, behaviourally, around what you're describing, we haven't tied that to the neural level. So this is the first type of study looking at whether this confidence effects your decision making and your ability to take onboard new information at a neural level. So yes, the next stage will be to take it back up to that world view level stuff. But what I like about this is we've taken out that motivation altogether in this study. There's no reason why - you know, I might see myself reflected in this particular celebrity and therefore it'd be self-protective to think they were doing a great job. We've removed all that. There's not really these other reasons why people should believe these dots are moving left or right. So we'll work back upwards from there, I think, and do bigger studies on this.