Neurophilosophy

Apparent motion steers the wandering mind

DAYDREAMING is a critical component of conscious experience. The mind can perform mental time travel – it occasionally strays from the present moment, to recollect an experience from the near or distant past, or to imagine an event that has not yet taken place. We know that thinking about the future is dependant on memory, because patients with amnesia cannot imagine new experiences. It involves piecing together fragments of past experiences to generate a plausible simulation of what might happen. This may have been an important development in human evolution, as it enables us anticipate a likely outcome and to plan the best possible course of action. 

Space and time are intimately linked in the mind, and this is reflected in our metaphors. We often say that we are thinking back to a past event, or looking forward to one that will take place in the future. But the mind and body are also closely linked: think about a past experience, and you might find yourself moving backwards. A new study suggests that this can be reversed, by showing that apparent motion can influence the direction of the mind’s wanderings. Thus, moving backwards could evoke long lost memories, while moving forward might make you think about the future.

Psychologist Lynden Miles and his colleagues at the University of Aberdeen’s Social Cognition Lab recruited 26 undergraduates, and told them that the experiment was designed to investigate vigilance in a dynamic environment. The participants were asked to sit in front of a large screen, on which they were shown an animated pattern consisting of about a thousand white dots positioned randomly on a black background. For one group of participants, the dots moved towards the centre of the screen, to simulate forward movement. For the other, the dots moved in the opposite direction, giving the impression of backward movement.

The participants were required to monitor these moving displays for specific targets, and told to click the mouse button as quickly as possible whenever they detected one of the target, but to withhold clicking when they saw the other. But the designated targets were rare, appearing just six times during each 6-minute display. The task was designed to be mundane, in order to increase the likelihood that the participants’ thoughts would wander while they performed it.

Afterwards, the participants were asked if they had experienced any unrelated thoughts while they viewed the display. The 25 who reported that they had daydreamed during the task were asked to dismiss those thoughts that were anchored in the present moment, and to consider only those that related to the past or future. They were then asked to indicate the proportion of past- and future-related daydreams on a horizontal line. If, for example, their thoughts consisted solely of daydreams related to the past, they were to mark the extreme left end of the scale.

Remarkably, it was found that the direction of illusory motion in the moving displays modulated the direction of the participants’ mental time travel. Those participants who had viewed the display with apparent backward motion reported that the daydreams they had experienced during the task consisted mainly, or solely, of memories of the past, while those who viewed the display with apparent forward motion reported thoughts related to the future. The displays used in the study produced an illusory sense of motion, so real movements could possibly have a stronger effect. 

Last month, Dutch researchers reported that bodily motion influences the emotional content of recalled memories, and Miles and his colleagues have previously demonstrated that mental time travel is associated with physical movements through space. In a study published in January, they showed that past thoughts are linked to backward movements, and future thoughts to forward movements. The new findings show that the reverse is also true: apparent movement through space influenced the temporal focus of the participants’ thoughts. This all suggests that the capacity of mental time travel is firmly grounded in physical representations of space, and that the relationship between the two is reciprocal and bi-directional.

The way in which the mind integrates abstract concepts of time and concrete representations of space may be influenced by cultural factors. When mapping time onto space, we often think of events that have not yet occurred as being located in front of the body, whereas those which have already passed are thought of as being located behind. This is reflected in metaphors such as looking forward, but this is not true for everyone. In the Aymara ethnic group of the Andes and Altiplano regions of South America, for example, the mental relationship between space and time is reversed. By convention, Aymara speakers refer to past (or known) events as being located at the fore, and future (unknown) events as being behind, so the way in which movements influence the direction of mental time travel may also be reversed.

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Miles, L. K., et al (2010). The Meandering Mind: Vection and Mental Time Travel. PLoS One 5 (5): e10825. doi:10.1371/ journal.pone.0010825. [Full text]

Schacter, D. L, et al (2007). Remembering the past to imagine the future: the prospective brain. Nat. Rev. Neurosci. 8: 657-661. [PDF]

Comments

  1. #1 NoAstronomer
    May 27, 2010

    and the control group saw …

  2. #2 Jockaira
    May 27, 2010

    “… animated pattern consisting of about a thousand white dots positioned randomly on a black background. For one group of participants, the dots moved towards the centre of the screen, to simulate forward movement. For the other, the dots moved in the opposite direction, giving the impression of backward movement.”

    I don’t know about you, but this pattern of dots moving towards the center against a black background would make me feel as if I were moving backwards, and the dots moving away from the center, as if I were moving forwards.

    Is this a simple error in your sentence composition or is my reality model an error?

  3. #3 Ian Kemmish
    May 28, 2010

    Why go all the way to the Andes? The Ancient Greeks also correctly saw us as travelling backwards through time, surveying all the events we had passed, unable to see the events looming up behind us.

    The question is why a) the balance between the two views in different cultures isn’t 50% (or maybe it is and you’re just not looking hard enough!), and b) why the less natural view is the one which predominates.

  4. #4 .:*Mandy*:.
    May 29, 2010

    As an undergraduate in Civil Engineering who only slightly flirts with Neuroscience, I can only say: wow!
    Really.

    Although I signed up to your RSS about a month ago (got to know your blog from a Frontline Assembly fanmade video on YouTube), this is the first time I read a post of yours fully.

    Guess it’s scientifically confirmed what my mom says when I’m talking about my issues: “Don’t look down while you’re talking; look up! Raise your chin!”. And I really feel better when I raise my head up. It makes most of my issues go away. Funny, eh?

    Anyways, I’ll be reading more of your stuff. Keep up the good work!

    Greetings from Brazil

  5. #5 Victor MacGill
    May 30, 2010

    The Maori of New Zealand also say their directions are reversed. They talk of walking backwards into the future.

    We do so much forward travel in our lives in cars, aeroplanes, boats whatever. I wonder if it has made us more future looking than we were in past generations?

  6. #6 AL
    May 30, 2010

    and the control group saw …

    What would the control group be controlling for, and what bias would occur without this group?

  7. #7 Tim Harris
    May 30, 2010

    I do suggest you look into training for actors, where the links between bodily movement, thought and emotion have been exploited for many years. It’s nice to see scientists catching up with us.

  8. #8 Anonymous
    May 30, 2010

    What about before (where fore means front) and after (where aft means back)?

  9. #9 Alan
    May 31, 2010

    Nice article, but you’ve got something wrong. Dots moving toward the middle of the screen will give an illusion of backward movement, not forward. If you take a look at figure 1 in the article you’ll see what I mean.

  10. #10 Alan
    May 31, 2010

    “We do so much forward travel in our lives in cars, aeroplanes, boats whatever. I wonder if it has made us more future looking than we were in past generations?”

    Of course, as is well known, the Maori mostly travel backwards.

  11. #11 John
    June 3, 2010

    Ian, you silly. Future-forward and past-backwards is way more intuitive than the reverse. While “driving backwards and hoping to infer enough not to crash” is indeed an apt metaphor for how we live our lives, if you ask any ape they’re gonna say that the future is the direction they’re walking in and the past is what’s behind them. Cerebral philosophical ironies got nothin on pragmatic intuition.

  12. #12 Warren Davies
    June 5, 2010

    So if you’re on a long train ride and have some planning to do, sit on a forward facing seat, but if you’ve got some personal reflection to do, sit in a backwards facing one?

  13. #13 peter_ga
    June 6, 2010

    I suppose the brain does have a problem locating information. Computers have similar problems. Have been reading Freud’s “The psychopathology of everyday life” where he noted that if a key fact slips out of conscious recall, all the proper names that also get keyed by that fact also tend to be lost.

    Obviously one way to locate information is to orient it spatially in a 2D space, with the basic 2D mechanics already in place due to the visual processing pathway. Most animals would live in a 2D territory with food and boundaries located at points therein, so using a 2D spatial orientation is a natural way for the brain to store information, although there has to be some way to map the information so it has 2D coordinates.

    One imagines that this mapping would tend to be cultural rather than genetic, simply because of the variety of the mappings that might occur and the need to adapt to circumstance, so it is no wonder that some culture exists somewhere that does it differently by reversing the temporal-spatial mapping.

    I wonder if there is some way to lay out the key facts of say quantum mechanics in a 2D space so that it becomes easier for the mind to comprehend them.

  14. #14 Mousehulhu
    June 7, 2010

    Mandy,
    There’s actually scientific evidence for that too! I can’t find the original article, but here’s an NYT story: http://www.nytimes.com/1989/07/18/science/a-feel-good-theory-a-smile-affects-mood.html

  15. #15 alan cox
    June 9, 2010

    The Balance procedure (TBP) is a technique my wife and I created to test your self for self limiting beliefs,to do this place one hand on your heart/thymus center and ask yourself a question. As an example you could say (I am healthy) and if you have a self belief thats says (Oh no your not) you will feel yourself swaying backwards. To change those self beliefs you apply our technique (TBP) by placing both hands on same center now breathe in for 7 seconds hold breath for 7 seconds and as you breath out say the word Balance, and you will find yourself swaying forward this forward swaying will also help change those self limiting beliefs.
    Reading through the article Apparent motion you can see that (TBP) is a great way to prove this theory well i think it is. Alan.

  16. #16 CZhang
    June 19, 2010

    “Ian, you silly.” Don’t be so quick.

    In Mandarin Chinese which is spoken by ard 20% of the population,

    http://en.wikipedia.org/wiki/Arrow_of_time:
    The association of “behind = past” and “ahead = future” is itself culturally determined. For example, the Chinese and the Aymara people both associate “ahead = past” and “behind = future”.[8] In Chinese, for instance, the term “the day after tomorrow” literally means “behind day”(hou2 tian1) while “the day before yesterday” is referred to as “front day(qian2 tian1)”.[citation needed]. <-I can attest to this as I’m of Chinese ethnicity and a speaker of Mandarin Chinese.

  17. #17 haig
    June 19, 2010

    “That which we call thinking is the evolutionary internalization of movement” – Rodolfo Llinás

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