Krystian Barzykowski, Rémi Rade, Agnieszka Niedzwienska, and Lia Kvavilashvili, ‘Why Are We Not Flooded by Involuntary Thoughts About the Past and Future? Testing the Cognitive Inhibition Dependency Hypothesis’, Psychological Research, 83 (2019), 666–683: https://doi.org/10.1007/s00426-018-1120-6

Let me tell you about myself and this. A while back I was assailed, as I often am, by an embarrassing memory. I was just walking along the street, and for some reason I was catapulted back to an awkward moment a long time ago. It’s innocuous, the sort of thing that the other people present almost absolutely certainly will not remember, and if they could be badgered into remembering, it would be meaningless. I am confident that lots of people would recognise this phenomenon, because I have done some reading about it; I also assume it varies from person to person. Some are struck more than others. But what sort of things are contained in that ‘more’, and what is their significance?
      I conducted a brief self-analysis and came to the following hasty conclusions. One, I think I am probably more prone to these than other people. Two, a rough estimate of my repertoire of embarrassing memories suggests that there are dozens of them, but I can’t summon up very many to order. Something between twenty and one hundred in regular rotation? Third, when in private they make me swear or wince or something, but I can control it in public.
      And fourth, well, that starts with a question: how often does one of these occur? And related to that, how often does any individual one occur? Well I thought a bit about the one that I had suffered most recently, and the adventurous best guess I could come up with was that I am having that memory pretty much all the time. Once I started thinking about it, I couldn’t really persuade myself that it is ever truly absent. Of course, I acknowledged, sometimes it becomes more present and can no longer be ignored, but these memories are anything but deeply buried. They are always on my fringes, or I am always on theirs.
      Having revealed my findings, I should reassure you that I consider myself a happy and generally functioning person and I hope others would more or less agree. My memories aren’t doing me any great harm. Some people must suffer much worse, and their perspective on the issues would have a different urgency. For my part, I wouldn’t mind being without embarrassing recollections, but they might have a function. I suppose they are serving as a legacy of a process of self-definition and socialization, little warning signs of the consequences of not watching my actions carefully enough. I think most come from teenage years or thereabouts, which would make sense. They are complemented by some recurring nice or neutral memories, which are less striking but still part of the pinball machine of personality. It’s an odd thought that some people might only have the reward equivalent, little flashbacks of moments of social success causing moments of quite smug joy as they get on with their lives.
      The question being asked in the paper cited above comes from an angle I hadn’t seen before. It is not why these intrusive unpleasant experiences occur, or why they can become a problem for some people, but why they are not occurring all the time for everyone, given that they arise for no strong reason at no particular time. Having decided that some of my own favourites are always there or thereabouts, why do I get to think about anything else? Barzykowski et al. start with a hypothesis, which is that possibly ‘activated thoughts are suppressed by the inhibitory control mechanism, and therefore depleting inhibitory control should enhance [their] frequency’. So they decided to create experimental situations in which inhibitory control was generally less active, such as when subjects were very tired, or when they had completed a collaborative task shown to decrease inhibition in previous studies, to see whether this resulted in more memories (and future thoughts too — the study took in different kinds of mental time travel).
      Well, they did not find a significant effect. Their reasonable hypothesis, that it is inhibitory control that stops us being swamped, was not rewarded. So what is it? It may be that it is quite difficult to make people do, or not do, such things outside the flow of regular experience, where our environments provide so many tiny triggers. Or it may be that the explanation for us not being overwhelmed with these thoughts is quite different, and potentially very interesting. I want to know more.
      The move I like to make in this blog is to say ‘well, literature has interesting examples of some related phenomena, and if we look at them closely enough we can pick out some interesting conclusions’. And I would like to make it in this case, but this post is quite long already, and I don’t have an example I am ready to cite yet. It may be too obvious to turn to those modernist writers who found ways of representing the flow of purposeful and purposeless thoughts, and see how they portray the conditions under which minds admit strong and strange memories — but I hope I will, at some point soon. You’ll be the first to know (if you ever come back to the blog, follow @WhatLitKnows on Twitter, or put your e-mail into the box on the right).