For those looking for a good summary of our recent publication, several outlets gave us solid coverage for expert and non-expert alike. Here is a short summary of the most useful write-ups:
The eLife digest itself was excellent – make sure to fill out the survey at the end to let eLife know what you think of the digests (I love them).
As you read the words on this page, you might also notice a growing feeling of confidence that you understand their meaning. Every day we make decisions based on ambiguous information and in response to factors over which we have little or no control. Yet rather than being constantly paralysed by doubt, we generally feel reasonably confident about our choices. So where does this feeling of confidence come from?
Computational models of human decision-making assume that our confidence depends on the quality of the information available to us: the less ambiguous this information, the more confident we should feel. According to this idea, the information on which we base our decisions is also the information that determines how confident we are that those decisions are correct. However, recent experiments suggest that this is not the whole story. Instead, our internal states — specifically how our heart is beating and how alert we are — may influence our confidence in our decisions without affecting the decisions themselves.
To test this possibility, Micah Allen and co-workers asked volunteers to decide whether dots on a screen were moving to the left or to the right, and to indicate how confident they were in their choice. As the task became objectively more difficult, the volunteers became less confident about their decisions. However, increasing the volunteers’ alertness or “arousal” levels immediately before a trial countered this effect, showing that task difficulty is not the only factor that determines confidence. Measures of arousal — specifically heart rate and pupil dilation — were also related to how confident the volunteers felt on each trial. These results suggest that unconscious processes might exert a subtle influence on our conscious, reflective decisions, independently of the accuracy of the decisions themselves.
The next step will be to develop more refined mathematical models of perception and decision-making to quantify the exact impact of arousal and other bodily sensations on confidence. The results may also be relevant to understanding clinical disorders, such as anxiety and depression, where changes in arousal might lock sufferers into an unrealistically certain or uncertain world.
The PNAS journal club also published a useful summary, including some great quotes from Phil Corlett and Rebecca Todd:
… Allen’s findings are “relevant to anyone whose job is to make difficult perceptual judgments trying to see signal in a lot of noise,” such as radiologists or baggage inspectors, says cognitive neuroscientist Rebecca Todd at the University of British Columbia in Vancouver, who did not take part in the research. Todd suggests that people who apply decision-making models to real world problems need to better account for the influence of internal or emotional states on confidence.
The fact that bodily states can influence confidence may even shed light on mental disorders, which often involve blunted or heightened signals from the body. Symptoms could result from how changes in sensory input affect perceptual decision-making, says cognitive neuroscientist and schizophrenia researcher Phil Corlett at Yale University, who did not participate in this study.
Corlett notes that some of the same ion channels involved in regulating heart rate are implicated in schizophrenia as well. “Maybe boosting heart rate might lead people with schizophrenia to see or hear things that aren’t present,” he speculates, adding that future work could analyze how people with mental disorders perform on these tasks…
I also wrote a blog post summarizing the article for The Conversation:
How do we become aware of our own thoughts and feelings? And what enables us to know when we’ve made a good or bad decision? Every day we are confronted with ambiguous situations. If we want to learn from our mistakes, it is important that we sometimes reflect on our decisions. Did I make the right choice when I leveraged my house mortgage against the market? Was that stop light green or red? Did I really hear a footstep in the attic, or was it just the wind?
When events are more uncertain, for example if our windscreen fogs up while driving, we are typically less confident in what we’ve seen or decided. This ability to consciously examine our own experiences, sometimes called introspection, is thought to depend on the brain appraising how reliable or “noisy” the information driving those experiences is. Some scientists and philosophers believe that this capacity for introspection is a necessary feature of consciousness itself, forging the crucial link between sensation and awareness.
One important theory is that the brain acts as a kind of statistician, weighting options by their reliability, to produce a feeling of confidence more or less in line with what we’ve actually seen, felt or done. And although this theory does a reasonably good job of explaining our confidence in a variety of settings, it neglects an important fact about our brains – they are situated within our bodies. Even now, as you read the words on this page, you might have some passing awareness of how your socks sit on your feet, how fast your heart is beating or if the room is the right temperature.
Even if you were not fully aware of these things, the body is always shaping how we experience ourselves and the world around us. That is to say experience is always from somewhere, embodied within a particular perspective. Indeed, recent research suggests that our conscious awareness of the world is very much dependent on exactly these kinds of internal bodily states. But what about confidence? Is it possible that when I reflect on what I’ve just seen or felt, my body is acting behind the scenes? …
The New Scientist took an interesting angle not as explored in the other write-ups, and also included a good response from Ariel Zylberberg:
“We were tricking the brain and changing the body in a way that had nothing to do with the task,” Allen says. In doing so, they showed that a person’s sense of confidence relies on internal as well as external signals – and the balance can be shifted by increasing your alertness.
Allen thinks the reaction to disgust suppressed the “noise” created by the more varied movement of the dots during the more difficult versions of the task. “They’re taking their own confidence as a cue and ignoring the stimulus in the world.”
“It’s surprising that they show that confidence can be motivated by processes inside a person, instead of what we tend to believe, which is that confidence should be motivated by external things that affect a decision,” says Ariel Zylberberg at Columbia University in New York. “Disgust leads to aversion. If you try a food and it’s disgusting, you walk away from it,” says Zylberberg. “Here, if you induce disgust, high confidence becomes lower and low confidence becomes higher. It could be that disgust is generating this repulsion.”
It is not clear whether it is the feeling of disgust that changes a person’s confidence in this way, or whether inducing alertness with a different emotion, such as anger or fear, would have the same effect.
You can find all the coverage for our article using these excellent services, altmetric & ImpactStory.
— Micah Allen (@neuroconscience) October 25, 2016