In The Master and His Emissary: The Divided Brain and the Making of the Western World, Iain McGilchrist says the right hemisphere of the brain processes incoming info as a whole, intuitively. Though this is obviously a form of cognition, what we typically think of as cognition is sequential logic, which, he says, is done in the left hemisphere.
How do we catch a baseball? If McGilchrist is right, it is with the right hemisphere's intuitive processing, not with left bain words such as, 'Let's see. I need to move a bit to the left. And now, raise my hand. Open the fingers. OK. Grab it!"
How does one drive a race car? Formula 1 champion Jim Clark was a "natural" driver. His friend and competitor Graham Hill was a "procedure" driver. How do these differ? Let's say you are going down a straight at 160, headed for a curve that can be negotiated at 60. You have to slow down by 100 mph. If you can wait until the last fraction of a second to brake, you gain advantage. Clark simply looked at track, sensed the speed of the car, pictured the profile of upcoming curve, and overlaid it with the car's ideal path around the curve. When something happened in his mind, his foot came off the gas and hit the brake. He didn't know why. He just sort of "knew" when to do that. Braking continued until the car's actual position matched the entry point of the projected path around the curve. Braking stopped and steering around the curve began.
Hill, on the other hand, used the markers. Approaching a curve, there are signs saying 100, 200, and 300. During practice for the race, a procedure driver hits the brake at the 300 (yards or meters) marker, and drives around the curve. If there is room to spare, next time around, when passing the 300 marker, he counts "one-thousand-one" and then hits the brake. Next time, he may count "one-thousand-one, one-thousand-two" and hit the brake. Next time he may brake at the 200 marker. Sooner or later, he comes up with a procedure for braking as late as possible for the curve.
Driving intuitively, Clark used the right brain. Hill used the left. Clark was faster than Hill, but occasionally spun-out. Though slower, Hill rarely spun-out. A natural driver can't tell you how they do what they do. A procedure driver can. Both are using cognitive processes. One is intuitive/visual cognition and the other is sequential/semantic cognition.
Fearful fliers say they can't see what holds the plane up. Their intuitive/visual logic tells them "if nothing is holding it up, it's got to fall." I used to tell them, "Bernoulli's principle holds the plane up. The top of the wing is bowed. Air flowing over it has a longer distance to travel than air flowing under the wing which is straight. As the air flows faster, its pressure decreases, so the air on the bottom of the wing (pressure unchanged) pushes harder upward than the air on the top of the wing (pressure lowered) is pushing downward."
That logical explanation got nowhere. The anxious flier's response might be, "Bernoulli, schmernoulli. Cut the crap; there's nothing holding the plane up. It's going to fall and I'm not getting in it."
When the visual right brain, with its intuitive logic, pictures the plane falling, that triggers the right amygdala to produce stress hormones. The hormones cause arousal. Arousal is often misinterpreted as fear. Fear is often taken as proof of the existence of danger.
The left side of the brain may "understand" why the plane flies. If so, it does not trigger the left amygdala. But, left hemisphere understanding has no effect on right hemisphere anxiety. Lleft hemisphere understanding cannot relieve the right hemisphere's distress.
When I finally realized I could get nowhere with left brain logic, I decided to give my anxious clients a way to "picture" what holds the plane up. This led to a highly effective antidote, "The Jello Exercise." See http://www.fearofflying.com/free-video/jello-exercise.shtml
This explains why CBT, as generally conceptualized, has no effect on moderate or high anxiety commonly triggered by the right amygdala. Though Bernoulli's principle satisfies the left brain, it has no effect on right brain. Similarly, to the degree that CBT is based on sequential/semantic logic, it cannot relieve anxiety produced by right brain intuitive/visual logic.
Can we extend CBT to include right brain logic? If we can expand our understand and our practice of CBT, we may be able to use it to treat right hemisphere anxiety. How would we practice "right brain CBT?" I believe the answer is to employ visually based interventions based on relationship:internalized links between the therapist's calming presence and what triggers the client's anxiety, or similar links between the client's existing calming internal objects and anxiety triggers. This approach is laid out in detail in Allan Schore's book The Science of the Art of Psychotherapy and, as this approach applies to phobia, in my book, SOAR: The Breakthrough Treatment for Fear of Flying.