Aug 12 2008

How Confident Are You?

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Comments: 14

Confidence in our beliefs is just another neurological function. We all have knowledge and we mentally assign a level of confidence in each piece of knowledge we think we have. Sometimes the assignation of confidence level is conscious – we may be asked how sure we are about something. And sometimes it is not conscious but it affects our behavior.

Often different individuals may even confront each other on their relative levels of confidence, when they each believe contradictory information. This conflict is sometimes encapsulated in the phrase, “You wanna bet?”

For the critical thinker it is important to avoid unjustified confidence, and to understand what factors may lead us to a high degree of confidence when we are in fact wrong. For example, we often assign a high degree of confidence to memories that are vivid and accessible, but the evidence shows that these factors do not predict accuracy. A memory may feel completely real, but be completely wrong.

Skeptics often encounter the “confidence” defense – we are asked to believe anecdotal accounts based upon the reporter’s confidence in their accuracy. I have been told many times by believers that they were absolutely certain about specific facts of a case that turned out to be demonstrably wrong. In these cases it seemed to me that confidence derived from a desire to believe, and therefore have a clean story in support of the belief. But confidence is an effective form of persuasion – we tend to trust other people’s confidence, even when we shouldn’t.

Science has largely quantified confidence – that is, after all, was science is largely about: having a high degree of confidence in our explanations about the natural world.

Neuroscientists are now looking at confidence as a specific neurological function. The work is still preliminary, but appears to be bearing fruit. A new study published in Nature in entitled: “Neural correlates, computation and behavioural impact of decision confidence.” They used a rat model of confidence in which they exposed rats to two different odors and if they chose the stronger of the two they were given a reward. The two odors either varied greatly in strength, in which case the distinction was easy, and it is assumed that the rat’s confidence in their choice was therefore high; or the odors were not very different, making the choice difficult and confidence low.

What they found was that activity in the orbitofrontal cortex correlated with uncertainty. This suggests that this part of the brain is involved in making us feel less confident (or more cautious) about our conclusions. Of course, as the title of the paper admits, this is a correlational study. Causation in neuroscience is often a very complex question, and much more study will need to be done to put this correlation into a proper context.

They also showed that the rats in this study were more likely to abort a trial and start a new one when the odor difference was small, and their confidence uncertain. So their model of confidence did correlate with a measurable behavior as well.

These kinds of studies, along with psychological studies, have the potential to greatly inform our thinking about confidence.  What I am specifically interested in, as a skeptic, is the conscious and subconscious calculations that go into our assessment of confidence in what we think we know. If those calculations are flawed then they can result in unfounded confidence, which is a barrier to doubt, questioning, and investigation – all things critical to skepticism.

What “confidence heuristics” do we rely upon day to day? We already know that we trust our own memories more than we should. Also, we share in other people’s confidence – if they seem confident then we believe them. We also seem to hold a higher confidence in beliefs in which we are emotionally invested.

But I bet there are more subtle heuristics, or rules of thumb, that we evolved to follow in arriving at our confidence levels. This is an area of research with which I am not very familiar, and I am not sure how much there actually is. I plan to explore this further, but if anyone is familiar with such research please provide some links.

Meanwhile, it’s a good idea to at least question our own confidence – to ask why we are so confident in a particular belief, and if that justification is rational.

14 responses so far

14 Responses to “How Confident Are You?”

  1. Tom Nielsenon 12 Aug 2008 at 3:02 pm

    I think the reason why we tend to defend our memories with such confidence, is because we don’t like the ramifications of us not being able to trust them.

    Memories constitutes such a huge part of our identity and reality, and because you can say that our memories are a product of our perception, we make the link that it’s our perception that cannot be trusted. And we have all seen The Matrix… scary stuff. The social consequences of being known to have a fallible link to “the real world”, is also pretty severe, thus one is not inclined to admit that one might remember falsely.

  2. DevilsAdvocateon 12 Aug 2008 at 4:18 pm

    “Trust nothing on authority – especially your own.” ~Martin Richer


    There would seem to be an inherent ‘override’ mechanism built into the neural system, to whatever extent the CNS is ultimately revealed to affect or process confidence in beliefs, as evidenced by so many people who hold sincere belief in the demonstrably untrue and often patently absurd. The set of religious beliefs certainly reveal instances where the implications and extrapolations of false beliefs nonetheless are held to be of higher value that the facts of things. Then again, a belief wouldn’t serve much purpose if it could be easily changed after having been fully seated and relied upon, lest we too easily move away from a factual belief based on confidence in new information which is unknowingly false.

    When she was about 5 years old, my youngest daughter found me scanning the pages of a Gray’s Anatomy, a gift intended for my RN wife. It was a cross-sectioned view of the human brain, of a sort familiar to anyone who’s taken a biology course.

    She looked at all the blood vessels and lobes and such, and told me, “Daddy, it’s a mess in there!”

    And I replied, “You have no idea, punkin. No idea.”

    All that extensively evolved hardware and it so often seems we barely know how to use it, lol.

  3. cuervoon 13 Aug 2008 at 12:27 pm

    It’s interesting the amount of ‘memory bleed’ that I’ve noticed over the years between myself and my brother. There are certain events from our childhood that I was positive had happened to me, but had actually been his experiences. Most bizarre is that I had even developed vague visual memories of some of the events.
    How queer.

  4. DevilsAdvocateon 13 Aug 2008 at 2:51 pm

    What is even more amazing is how my memories actually affect the objective, empirical reality. Case in point:

    A large mouth bass I caught in the early 1990s from my dock on the Tar River weighed 8 lbs 5 oz and required a spirited but brief battle to pull him out of the weed beds. However, in repeated tellings of the tale over the past 15 years, this fish has actually grown in size to upwards of 11 or 12 lbs and the battle it took to land him has stretched to 8, 10, even 15 minutes, often involving substantial personal injury to me, the angler. All my fishing pals are as astounded by this as I am.

    We figure that another 5-10 years of story-telling will make this fish the all-time record holder for large mouth bass in North Carolina. Beyond that, who knows?

  5. Roy Nileson 13 Aug 2008 at 3:09 pm

    Our memory has evolved from an ancient function that allowed fish an afterlife where they never stopped growing. Fish have thusly remained confident that there is a heaven.

  6. cuervoon 13 Aug 2008 at 6:47 pm

    I even seem to remember that I successfully ‘pleasured’ a young lady once, many years ago. I surely can’t trust that memory.

  7. tooth fairyon 13 Aug 2008 at 8:35 pm

    as you said the other week on the podcast steve that there are two main portions of the brain that light up when recalling a memory the ‘jist’ and the ‘detail’ are given by either. Would it be worth speculating that there are aother factors too? obviously a confirmation bias but also memories that are painful or for some reason we’ve filed them away could we manafacture instances instead of these memories? turning the bad into the good? and then how would the two portions of the brain function to give a memory that is mostly fake and manafactured becasue it’s there to avoid remembering a not so good time of your life? are these two seperate parts of the brain able to overcome a lifespan of confidence in this fabricated memory? i can’t wait to see the applications of this stream of investigation though.

  8. tooth fairyon 13 Aug 2008 at 8:37 pm

    bad post sorry-i exhausted my ability to make a well informed decision to post that or not because i spent an hour deciding on if i would have a cookie or a piece of cake 🙂

  9. Diane Henryon 14 Aug 2008 at 12:18 am

    My sister and I both absolutely remember the giant tree in the front yard of our old house being cut down after we moved away and we were both upset by that. Surprise! The tree still stands–the family joke now is that if both of us remember an event, it didn’t happen.

  10. Niels Kjaeron 14 Aug 2008 at 10:29 am

    I am as confident as I want to. A bit of doubt once in a while keeps me alive. A bit of Synsepalum dulcificum and the world tastes like a cookie.

    (Sorry, I’m reading Finnegans Wake at the moment;-)

  11. clgoodon 17 Aug 2008 at 6:46 pm

    I’m sure this is the best post ever.

    Reminds me of something my dad used to say:

    “Only a jackass is positive.”

    “Are you sure?”


  12. Knowledge « Sequituron 18 Aug 2008 at 9:55 pm

    […] the exhaust before you climb inside. The more our senses agree about a common phenomenon, the more confidence we ascribe to our assessment of that […]

  13. Capsicles « Mantecanauton 22 Aug 2008 at 9:27 pm

    […] Memory is fallible. […]

  14. Von 30 Nov 2008 at 6:42 pm

    I know this is a months-old entry, but I found something that might be helpful. Confidence and heuristics have a lot to do with cognitive science and psychology. I wrote an analysis on this paper for my cognitive science class, and it immediately made me think of skepticism.

    The conclusion of Rozenblit & Keil’s paper is that people overestimate their ability to explain how devices work or natural phenomena occur. (They are overconfident.) They are accurate in predicting how well they can recount narratives or perform procedures, though.

    Rozenblit, L. & Keil, F. (2006). The misunderstood limits of folk science: an illusion of explanatory depth. Cognitive Science, 26, 521-562.

    This is also interesting:
    Lee, M & Dry, M. (2006). Decision Making and Confidence Given Uncertain Advice. Cognitive Science, 30, 1081-1095.

    I don’t know if there is a lot there (I’m only a student, sorry) but what is currently being published is intriguing.

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