The Posner and Petersen Model

The brain has no off switch.  The people trying to pay attention to you, or to your material, simply cannot switch off all the scanning systems which are likely to distract them.

But delving a bit deeper: what is going on in those brains, and can we use it to our own advantage?

Michael I Posner and Steven Petersen wrote a landmark paper in 1990 on The Attention System of the Human Brain.  They updated it in 2010.  The original paper suggested that the brain has three anatomically separate systems for:

  • General alertness
  • Focusing in on a thing which has been noticed
  • Deciding whether to take further action on that thing.

It’s quite tempting to start coming across as a neurologist at this point, but I’m not, I’ve just read a couple of books (eg Brain Rules by John Medina) and some articles on the internet, and I don’t even know if I mean neurologist, neuroscientist, cognitive scientist or molecular biologist.  I’ll settle for the term “gross amateur”.  Just to make that clear.  We’re talking about a lump of pinky-grey squidgy matter that few of us understand.

Anyway, Posner and Petersen’s model is fairly accessible.  It sets out the three systems as follows:

  • The Alerting or Arousal Network. This is the network which allows the brain to scan its environment.  This is also termed “intrinsic” or “tonic” alertness.  This radar system of the brain is based in the brain stem and right hemisphere.  It works better during the day than at night.  When the Alerting Network spots something that seems worth investigating, the brain starts to pay more attention by deploying..
  • The Orienting Network. This is the system which allows the conscious brain to “focus in” on something which has been flagged up by the Alerting Network.  This is a shift to “phasic alertness”.  The radar has picked something up, so these parts of the brain are tasked to go and have a look, and possibly to trigger..
  • The Executive or Detection Network. This has nothing to do with Business Class travel, or Pall Mall clubs, or the Freemasons.  This is a system which takes a decision on the thing you’ve just focused in on.  The choice is: ignore, or keep processing.  If the thing turns out to be harmless and uninteresting, the brain will go back to normal scanning mode – “as you were”.  But if it turns out to be important, then we start to see sustained attention being given, which means that short-term memory will start to get involved.

Posner and Peterson’s second paper, twenty years later, looked at the arguments for treating the Executive Network as two systems rather than one – but in general found that the explosion of new research in the last decades has mostly confirmed and expanded the model of separate systems.

So what?

Firstly, don’t drive at night.  Not just you, but all those other drivers out there, have got reduced intrinsic alertness.

Secondly, if you’re a teacher, trainer or anybody else aspiring i) to get onto people’s radar screen in the first place, ii) to catch their attention, and iii) to talk your way into the processing parts of their brain and push some buttons in short-term memory which might open the path to learning – you’ve got a real challenge.

The point is that sometimes we assume that getting someone’s attention is relatively straightforward.  But it isn’t, not neurologically.  And even if you succeed, the success may only be temporary – because the Alerting Network doesn’t stop scanning – and seconds or even milliseconds later, it may be tugging someone’s brain in a different direction again.

So the challenge is that you need to be noticed, you need to be investigated, and then you need to be considered important enough to be processed.   Not just once.  Not just when you introduce your first slide.  You need it to happen continuously, if you want continued attention.  You may need to be interesting several hundred times in a single session; when frankly most of us struggle to be interesting several hundred times in a year.

It turns out that “makes you think” is much more of a compliment than we ever imagined.


image credit: Pixabay



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