Operational Definitions

James Card

COGS2300 Cognitive Simulations

Spring 1998

Operational Definitions

Operational definitions provide the criteria by which a determination can be made in an experimental setting whether a particular condition is true or not. Thus the operational definition of "foo" would describe the properties of foo and specify which of them must be present and to what degree in order for something to properly be called foo.

Tree

Has or had life
While living is composed of

root(s) anchored in soil
a single woody stem called a trunk which extends approximately vertically from the soil

trunk extends from soil without branching for a minimum of 10% of above-ground total height of tree
during early stages of life cycle (seedling and sapling) the trunk is not woody and the plant is not said to be a tree

multiple woody branches extending laterally from the trunk
leaves appended to branches or trunk (may seasonally shed leaves)
may also include

flowers appended to branches
fruit appended to branches

When no longer living will probably not have leaves, flowers, or fruit
May be submarine?
Size of mature plant may range from less than one foot to more than 300 feet in height, a few inches to more than 100 feet in diameter of crown (maximum reach of spread branches) and less than one inch to more than eight feet in trunk diameter at ground level.
For most trees, the color of leaves is usually green, color may change to various shades of yellow, orange, red, crimson, or brown prior to seasonal shedding of leaves. Some varieties of trees have leaves which are usually reddish in color regardless of season.
The subterranean portion of a tree is similar in size to the portion which is above ground.

Electron

This is a mythical theoretical construction which is supposed to be a basic electrically-charged particle which is a part of all atoms of all known physical elements. It is claimed be "an elementary particle consisting of a charge of negative electricity equal to about 1.602 x 10^-19 coulomb and having a mass when at rest of about 9.109534 x 10^-28 gram".

I have no idea how I would go about identifying one if ever I did happen to encounter it. Perhaps I could take the police officer's approach and command it to stop and identify itself. If it then says "I am an electron", and that statement is supported by examinations under sodium pentathol, hypnosis, and a polygraph exam we would have a valid self-identification and be able to say confidently that this entity believes itself to be an electron. If that were also supported by the non-conflicting corroborating testimony of three unbiased expert witnesses who are trained observers and certified as capable of identifying electrons we might then say that there is sufficient evidence to say (with a 95% confidence level) that this is an electron. And if we also measure the little critter while he or she is stopped and find that his or her mass is about 9.109534 x 10^-28 gram and he or she has a negative electic charge of about 1.602 x 10^-19 coulomb then we can declare with absolute certainty that this is probably an electron.

Actually, this is so far out of my field of experience that I could not begin to write a real operational definition. I would suppose that measures of electric charge and mass would be the primary criteria, but I have no idea how to make those measurements.