Brain Science Podcast discussion

BSP 72 will be coming out on January 26, 2011. It is an interview with the authors of "Sleights of Mind: What the Neuroscience of Magic Reveals about Our Everyday Deceptions" by Stephen L. Macknik, Susana Martinez-Conde, Sandra Blakeslee.

BSP 72 is now live. Click here for the show notes.

I look forward to your feedback and comments.

The new BSP on 'Sleights of Mind' was good -- you really get some good guests.
One comment: I would agree that we can attend to only one thing at a time within any single faculty (vision, auditory, tactile) and that multi-tasking does not work that way, but we are routinely able to attend to one thing visually while listening to another or feeling something. Perhaps the book explains it better. Have you ever seen a juggler who can ride a bike and tell jokes at the same time?

To Ginger: Your comment about the ability to execute multiple automatic actions is well taken.

Elkhonon Goldberg in the "Executive Brain" (and in BSP 17) talked about brain hemisphere specialization. He described the right hemisphere as being one large, highly flexible neural network, capable of creatively assessing new situations and developing adaptive strategies, but requiring significant effort. He then described how, when a skill or sequence of actions is repeated, it gets programmed into the left hemisphere, and thereafter it can be done easily with much reduced mental effort.

I wonder: does the 'spotlight of attention' require the right hemisphere?

I found Tim's comment interesting "...older driver's actually see more than younger drivers. And that is why they have difficulty driving. It may be that viewing the background creates more noise for the brain to process and related multi=tasking results...."
Could that be why teenagers rooms are usually a mess - the mess actually is unseen by them?
Is this change in mental attention with age just an artefact of the ageing brain or is there any evolutionary advantage?

Here is my original reply to Bill's first post (message 3)I think the key to doing something like riding a bike while juggling is for one activity to on automatic; like the way we drive after much experience. If the juggler is also telling jokes than his juggling has also become so well-learned that it too is automatic (which means that it is being managed by parts of his brain outside the so-called "spotlight of attention.")

One thing the book did emphasize was that our "spotlight of attention" can only focus on one thing at a time. That is a key to many magic tricks.

But, You make a good point about the difference between attending to something from two different senses, rather than two things from the same sense. This seems to be why trying to talk on a cell phone (even hands-free) while driving isn't safe. We apparently devote some of our visual resources to imagining the person at the other end. This doesn't happen when talking to someone in the car with us (not to mention the fact that a passenger can usually see when we need to shut up.

Bill, I have not read anything about a specific role for the right hemisphere, but there seems to be significant evidence that many important brain functions require BOTH hemispheres for optimal functioning. I assume that this is true for attention.

Peter wrote: "I found Tim's comment interesting "...older driver's actually see more than younger drivers. And that is why they have difficulty driving. It may be that viewing the background creates more noise f..."
I don't think evolution has much influence on the traits of aging since these have little to do with reproductive fitness.

@Bill who wrote, "...we can attend to only one thing at a time within any single faculty (vision, auditory, tactile)..."

"any single faculty" can attend to multiple tasks at once(or at very small time slices). Multi tasking is no problem if most tasks are automated(not new). It is multi interpretive thought that is difficult.

I can juggle tennis balls and am amazed at how much I can do, visually, independent of juggling, as long as my peripheral vision includes any tiny snapshot of each ball's arc. The automation of the task of calculating where to catch each ball is so quick that my eye and brain can spend much more time doing other things.

For instance, I can tell an onlooker to choose one of the juggling balls and it surprises them when I immediately toss it to them. I can focus on their eyes and even see when they have trouble following a single ball's trajectory. It is fun to chide them for loosing track.

While juggling, if I close my eyes I am lucky to catch the next one or two throws. Blinking my eyes open for as short a snapshot as possible still gives me enough information to catch everything in sight.

Each of our senses can "attend" to multiple things but the amount and complexity of processing interpretations in the brain are limited. I can more easily concentrate on driving (mostly visual interpretations) if it is quiet -- without music or conversation to interpret. Holding a cell conversation while driving on the highway is easy but in the city -- not so much.

So it is not the raw senses that are limited. It is deeper than that. It is the amount of interpretive thought applied that limits multi-tasking. Interpreting unique sensory input takes a great deal of brain bandwidth.

On a pedantic note and one not related to the show content, Brown should really be listed under the magician rather than the scientist category within the show notes.

I think I can agree with everything said so far. In summary, I conclude that there is a certain limited mental resource. It can be spread among skills already mastered (at least where each separate task relies primarily upon a different sense faculty), or exclusively focused on the some novel or demanding task at the expense attention to other input(s). In the latter case, it may correspond to the "spotlight of attention" exploited so successfully in misdirection by illusionists.

Thanks Peter Ginger, Rick!

Another thing: the illusionist engages the "Play" circuit in emotions [Panksepp] along with the mating circuitry (the skantily clad assistant) or fear (in a water illusion, or with a tiger, or shoving a sword through the box), so our unconscious mental resources are also fully occupied. In most tricks, little of the audience's limited mental resource is left for logic.