Sentience quotient

The sentience quotient concept was introduced by Robert A. Freitas Jr. in the late 1970s. It defines sentience as the relationship between the information processing rate (bit/s) of each individual processing unit (neuron), the weight/size of a single unit and the total number of processing units (expressed as mass).

This is a non-standard usage of the word "sentience" which in standard usage relates to an individual organism's capacity to perceive the world subjectively (The word "sentience" is derived from the Latin "sentire" meaning "to feel" and is closely related to the word "sentiment." Intelligence or cognitive capacity is better denoted by the word "sapience" and not "sentience.")

The potential and total processing capacity of a brain, based on the amount of neurons and the processing rate and mass of a single one, combined with its design (myelin coating and specialized areas and so on) and programming, lays the foundations of the brain level of the individual. Not just in humans, but in all organisms, even artificial ones such as computers (although their "brain" is not based on neurons).

The sentience quotient (SQ) of an individual is a measure of the of an individual brain, not its relative intelligence, and is defined as:

where I is the information processing rate (bits/s) and M is the mass of the brain (kg). The lower limit of SQ is approximately −70, while the upper (quantum) limit is about 50.

According to this equation, humans have an SQ of +13. A human neuron has an average mass of about 10⁻¹⁰ kg and one neuron can process 1000-3000 bit/s, giving us an SQ rating of +13. All other animals with a nervous system (or all "neuronal sentience") from insects to mammals, cluster within several points of the human value. Plants cluster around an SQ of −2. Carnivorous plants have an SQ of +1, while the Cray-1 had an SQ of +9. IBM Watson, which achieves 80 TFLOPS (using 64-bit words) and consists of 90 IBM Power 750 weighing approximately 100 kilograms (220 lb) each, has an SQ in the range of +11—+12.

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