Intelligence (biology)

In biology, 'intelligence' in the broadest sense of the term refers to the ability of an organism to adapt to its environment through learning and its associated processes of storing and retrieving memories. 'Intelligence', in that sense, translates as the ability of an organism to exhibit such intelligent behavior (Stanovich 2009).

In a narrower sense, intelligence refers to the combination of cognitive abilities that enable a human to test well in a measurement of Intelligence Quotient (IQ).

The universality of intelligence among living systems
All living systems exhibit intelligent behavior, in that evolutionary forces generate organisms adapted to their environment, adapted for success in meeting their universal biological imperatives for survival and reproduction, requiring varieties of skills/functionalities differing among species and environments and capacities for learning and memory. A terrestrial green plant, for example, exhibits intelligent behavior when it bends its stalk in keeping with the movement of the sun, maximizing exposure of its leaves for capture of solar photon energy. A motile, free-swimming bacterium exhibits intelligent behavior when it actuates a unique swimming strategy that greatly facilitates its search for food. A vervet monkey exhibits intelligent behavior when it generates for itself and its conspecifcs a unique vocal warning signal for each type of predator it sees in the vicinity, allowing itself and its family to adopt the best defensive strategy for each type of predator.

In humans in particular, evolutionary forces operate in the service of sociocultural as well as biological imperatives, expressed by some biologists as imperatives for replication respectively of memes and genes.

Interindividual differences in intelligence within species reflect differences in the 'quality' of learning and memory, where quality may consist in efficiency, speed, capacity, and/or structure, among other factors, all of which remain under active investigation.

Introduction
Measuring the intelligence of an individual organism requires performing some kind of intelligence testing, in which case what the intelligence test measures defines 'intelligence' in that circumstance. In that regard, intelligence is what intelligence tests measure.

To say that intelligence is what intelligence tests measure is an incomplete statement but it is not vacuous. The content of a battery of test items is defined by what is common to the set of items which were used to construct it. These items are not chosen haphazardly but selected to convey, as far as our crude notion will allow, what we mean by the word 'intelligence'. In a real sense, this set of items is a way of saying what we mean by 'intelligence'. The crucial question is: what does this test battery measure? The answer to this question is our provisional definition of intelligence. Intelligence, we repeat, is a collective property of the set of items. If the individual items have meaning, so does the aggregate (Bartholomew 2004).

Commonly administered intelligence tests such as those that measure so-called Intelligence Quotient (IQ) or Scholastic Aptitude (SAT) fail to measure an important component of cognitive function, namely that relating to the ability for rational thought and decision making, thinking and decision making that work to serve the achievement of one's goals and to formulate goals in one's best interest biologically and socioculturally (Stanovich 2009).

Prerequisites
An organism exhibits intelligent behavior when it successfully adapts to the stimuli impacting upon it, however limited the informational content of the stimuli. The stimuli might result from events occurring internally, such as dehydration leading to a search for water, or recall of stored memories leading to self-interested social interactions. Or the stimuli might result from events occurring externally, such as odors leading to a search for food, or changes in market conditions leading reevaluation of investment strategies. Successful adaption implies behavioral responses that serve the short and long term biological and/or sociocultural interests of the organism, and the balance of short and long term interests.

· The role of sensory receptive ability
The ability of an organism to exhibit intelligent behavior depends in part on the width of its sensory input spectrum &mdash; the number of sensory input types &mdash; and in part on the character and breadth of the sensory input channels. The greater the number and types of sensory input channels, and the greater their informational density, the better chance the organism has to adapt to real-time changes in its surroundings (Agutter and Wheatley 2007).

· The role of behavioral response ability
The more different and effective ways an organism can respond behaviorally, the more flexibility it will have to adapt to changes in its surroundings.

· The role of input-to-output connectivity
The more dense and varied the neuronal connections between sensory input and behavioral output, including connections to memory, the more flexibility an organism will have to adapt to changes in its surroundings.

· The role of brain size
Larger brain size can permit greater capacity for processing the information needed to adjust behavioral output to input.