I am interested in how many calories are burned for certain mental
activities - (i.e., playing chess, reading the newspaper, etc.).  I am
not specifically interested in any one activity - just want to get an
idea for a range of mental activities.

Nordie2 --

In 1986, researchers isolated both the "at rest" and "active"
consumption of calories in the brain.  Since then we've learned quite
a bit about brain activities, particularly as PET scans have been
applied to monitor glucose consumption in the brain.

As a result, we know lots of things, including that:
*  energy consumption in the brain is related to learning.  In other
words, once you've learned something (like mastering that chess game),
the energy consumption goes down.

*  energy consumption in the brain is more than two times higher for
children under age 4.  This is no surprise because they are learning
and building brain structure.  The brain's energy consumption levels
around age 10 to 12.

Wayne State University
"Brain Surges," (DiCresce, undated)
http://www.med.wayne.edu/wayne%20medicine/wm97/brain.htm

* IQ can effect energy consumption.  After learning a task, lower IQ
people have to exert more energy to complete a task than high IQ
people who have learned the same task.


ENERGY CONSUMPTION
=====================

Energy consumption by the brain is 230-247 calories, based on 17
calories/gram and human brain sizes of 1,350-1,450 grams.  During
periods of peak performance, adults increase that energy consumption
by up to 50%, according to psychology lecturer Mark Moss, of the
University of Northumbria.

While this may not seem an extraordinary amount of energy, the brain
may use 30% of a body's total energy, while being only 2?3% of total
body mass.

Moss cites the original 1986 work of Siebert, Gessner, and Klasser on
the energy supply of the central nervous system in his thesis.  The
thesis, particularly the chapter 1 introduction, is a good and not
overly technical discussion of what we know about brain activity,
including descriptions of how PET scans are being used to monitor
glucose consumption in the brain.  I've linked the first chapter:

University of Northumbria
"Oxygen Administration, Cognitive Performance and Physiological Responses," 
(Mark C. Moss,  PhD Thesis 1999)
http://psychology.unn.ac.uk/mark/chapter1/chap1.htm


Google search strategy:
learning + "glucose consumption" + calories
"size of human brain"

Best regards,

Omnivorous-GA