E19. Jonathan Smallwood – The Wandering Mind

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My guest today is Professor Jonathan Smallwood (@the_mindwanders), Professor of Psychology at Queens University in Canada.

Jonny researches the neuroscience of the phenomenon of spontaneous, internally generated thought, as exemplified by mind-wandering and day-dreaming. To me, this is an interesting topic because it is; a) something that we do all the time, b) relevant to high-prevalence mental health conditions (such as rumination and worry in depression and anxiety), and c) is quite different from other most neuroscience areas that tend to be studied through specific tasks.

In this conversation, we discuss the function of mind-wandering, whether it makes us unhappy, its relationship to the default-mode network, the position of the default-mode network in the brain’s processing hierarchy and the challenges and opportunities of studying spontaneous thought.

Show Notes

0:05 – What does Jonny work on?

1:45 – What is the function of mind-wandering?

8:10 – Is a wandering mind an unhappy mind?

10:50 – What is the relationship between mind-wandering and repetitive negative thinking like rumination and worrying?

12:35 – Other than past-future and positive-negative, what other dimension characterise mind-wandering?

17:30 – What are the challenges and opportunities of working on such a diverse phenomena (i.e. mind-wandering)?

21:40 – What is the research on personality and mind-wandering?

23:30 – Is the mind either on-task or mind-wandering? Or are there other states?

24:30 – Is mind-wandering a phenomena related exclusively to the Default Mode Network?

29:25 – Does the Default Mode Network comprise regions that are significantly different in humans compared to other species?

31:15 – Can we say that animals mind-wander if they have a DMN?

34:20 – On the DMN as the top of the brain’s information processing hierarchy.

36:50 – On the relationship between spontaneous and controlled cognition.

40:20 – Advice to students interested in a career like Jonny’s.

44:30 – On what’s next for Jonny

55:50 – The role of the DMN in self and identity.

0:05 – What does Jonny work on?

Jonny studies how people organise their thoughts in the absence of the structure provided by the environment, and the neural systems that underpin such thinking. One example of such thinking is mind-wandering, where people experience thoughts unrelated to their current task or environment. 

1:45 – What is the function of mind-wandering?

Humans have lives that are very complicated, have a huge reliance on other people, and often involve endeavours that extend over long periods of time. The capacity of our minds to wander around is likely, at least in part, related to these aspects of our lives; mind-wandering often improves our ability to achieve complex, socially-intricate and temporally extended goals. That said, mind-wandering can also have negative consequences; mind-wandering can reduce performance on a given task (for example, studying) and if repetitive and negative can be maladaptive. So the adaptiveness of mind-wandering depends on the context and the nature of the thoughts, but the capacity to mind-wander itself is likely an adaptation to our complex lives and goals.

8:10 – Is a wandering mind an unhappy mind?

There are two parts to this issue. Firstly, one reason for the association of mind-wandering an unhappiness is that the mind wanders more when the environment is not the one it wants to be in. Another way to think about this is that when life is going well, we generally have less need to prepare and so mind-wander less. But notice that this relationship isn’t that mind-wandering causes unhappiness. 

A second factor for the association of mind-wandering an unhappiness is that there are types of thoughts that reduce people’s wellbeing. For example, past-oriented thinking has been more strongly associated with unhappiness than future-oriented thinking. Often this type of thinking dwells on something that went wrong. 

10:50 – What is the relationship between mind-wandering and repetitive negative thinking like rumination and worrying?

They are closely related. Generally, rumination and worry are thought about as traits, while mind-wandering is a specific state. So people who are high in rumination/worry can be thought of as experiencing a particular type of mind-wandering more frequently. 

12:35 – Other than past-future and positive-negative, what other dimension characterise mind-wandering?

A key dimension is the socialness of mind-wandering. Another is whether the thoughts tend to be in images or words. And these two dimension seem somewhat related – thoughts about other people tend to be more image based. 

Also, interestingly, brain regions that we might expect to be important for social processing have activity patters that are somewhat related to people’s tendency to engage in mind-wandering with a social dimension to it. For example, the VMPFC is involved in episodic social cognition (a type of mind-wandering), and people who engage in that type of thinking the most, show the largest neural responses to faces. 

17:30 – What are the challenges and opportunities of working on such a diverse phenomena (i.e. mind-wandering)?

Firstly, it means that the sort of questions that researchers need to investigate are more basic. They need to map out the landscape of mind-wandering, before they can focus on whether mind-wandering is adaptive (a better question would be what types of mind-wandering is adaptive). Jonny thinks this sort of map will help the field resolve apparent paradoxes such as mind-wandering being linked to both unhappiness and creativity.

Another challenge in mind-wandering research is that it is likely to vary greatly across cultures. Jonny states that if mind-wandering is a reflection of people’s life, goal’s and environment, then mind-wandering can be expected to vary more across cultures than, say, visual perception.

21:40 – What is the research on personality and mind-wandering?

Probably the main personality factor studied is neuroticism. This is the case as rumination and worry, forms of mind-wandering, are important in the study of depression and anxiety.

While not a personality trait, another aspect of individual difference that alters mind-wandering is age. Older people tend to mind-wander less than younger individuals. If one thinks about mind-wandering as simply a lapse in attention, then this finding is counter-intuitive (as older people tend to have reduced attentional capacities). However, this finding makes more sense if mind-wandering is thought of as (a neurally demanding process of) simulating the possible future scenarios or recalling and learning from past experiences.

23:30 – Is the mind either on-task or mind-wandering? Or are there other states?

There is another state where people are neither on-task nor mind-wandering. This state is often referred to as mind-blanking.

24:30 – Is mind-wandering a phenomena related exclusively to the Default Mode Network?

This is a hard question to answer because the Default Mode Network’s contribution to cognition is not yet fully understood. While it is certainly more active when people are less engaged with the outside world (when mind-wandering is more likely), the role of the Default Mode Network extends to a range of things not related to mind wandering. For example, the Posterior Cingulate, a node in the Default Mode Network, is highly active when people engage with detailed processing of the past.

Additionally, there are regions of the brain outside of the Default Mode Network that can contribute to mind-wandering. For example, Jonny’s colleagues have shown that the Dorsolateral Pre-Frontal Cortex (an area of the brain that isn’t considered part of the Default Mode Network) seems to reduce mind-wandering when a task is easy and increase it when a task is hard. That is, the Dorsolateral Pre-Frontal Cortex seems to play a regulatory function, altering mind-wandering activity according to the cogntivie demands of the environment/task.

29:25 – Does the Default Mode Network comprise regions that are significantly different in humans compared to other species?

Not necessarily. However, the DMN does operate differently in humans. In humans, relative to macaque monkeys, the posterior cingulate cortex and parts of the lateral parietal cortex are much more part of the default mode. We don’t yet understand why this has happened. Perhaps humans co-opted a brain region, that was used for external processing, for tasks that are much more reliant on memory and have a more imaginative component.

31:15 – Can we say that animals mind-wander if they have a DMN?

We can’t make that inference because each brain system is active in different types of activities. So rather than saying that animals can mind-wander if they have a DMN, we may only be able to say something like these animals can process information in a similar way. For example, they can weigh future possible actions.

34:20 – On the DMN as the top of the brain’s information processing hierarchy.

This idea derives from Daniel Marguiles’s observation that the hub of the DMN tend to be located between other sensory processing regions. This location could hold advantages in terms of information processing. For example, the location of the angular gyrus between the visual and auditory cortex could allow it to code common features to both sensory systems, and hence more abstract features. Or it might help both systems act more effectively together over time by allowing features present in one domain to help with processing in another domain. 

36:50 – On the relationship between spontaneous and controlled cognition.

Controlled cognition can be thought of as providing a filter or a goal that then influences the content on spontaneous cognition. Jonathan gives an example of how the content of spontaneous cognition can be influenced even without conscious control: after stepping away from trying to write something, the brain seems to (spontaneously) keep trying to solve the problem. Here, spontaneous cognition seems to play a role of organising our knowledge/information.

40:20 – Advice to students interested in a career like Jonny’s.

For those interested in researching spontaneous thought, Jonny advises that progress in the field is likely to be slow, so both curiousity and patience are important qualities. Tolerating uncertainty in general is important – you need to be able to work towards reducing uncertainty, but without knowing what the outcome will look like. Being certain about something too soon can lead you in the wrong direction.

44:30 – On what’s next for Jonny

Jonny is trying to understand the categories of thought that people have. He thinks that by better understanding the types of thoughts that people have, it will allow us to better understand the dynamics of cognition, including both its adaptive and maladaptive aspects. And he will continue to try to correlate the different types of thoughts to brain activity (using things like hidden Markov modelling).

55:50 – The role of the DMN in self and identity.

Jonny doesn’t think that it’s correct to consider the DMN as the self. One way to look at it might be to consider that the DMN might be required in things that require a lot of cortex to be involved. The self might be only a specific kind of complex thought process that the DMN supports. And because the DMN is involved in so many kinds of complex cognition, it is best to think of it as supporting a kind of function, rather than as a particular thing (ie. the self).

 

Episode Links and References

Jonny’s personal website and Twitter.

Jonathan Schooler’s research on how mind-wandering facilitates creative thinking.

Daniel Marguiles’s lab.

 

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