Inspection time refers to the exposure duration required for a human subject to reliably identify a simple stimulus. Typically a stimulus made up of two parallel lines differing in length and joined at the tops by a cross bar is presented (similar to the Greek letter Pi). The ability to quickly detect the identity of a stimulus is moderately

heritable Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic inf ...

and correlates with the subject's IQ.

Overview

If asked which of the two lines in the figure below is longer; the left or the right, almost all non-visually impaired subjects can answer correctly 100% of the time. If, however, the stimulus is backward masked after a short period of time, the proportion of correct responses declines as the exposure duration reduces, and reliable individual differences emerge in the percent identified correctly at different intervals. The task itself was proposed by

Doug Vickers Doug is a male personal name (or, depending on which definition of "personal name" one uses, part of a personal name). It is sometimes a given name (or "first name"), but more often it is hypocorism (affectionate variation of a personal name) which ...

as a measure of the rate of accumulation of information. Ted Nettelbeck, Chris Brand and others demonstrated it related quite strongly to psychometric intelligence, especially across the lower part of the IQ range suggesting that differences in intelligence may reflect, in part, differences in the rate of

information processing Information processing is the change (processing) of information in any manner detectable by an observer. As such, it is a process that ''describes'' everything that happens (changes) in the universe, from the falling of a rock (a change in posi ...

- a theory proposed by

Arthur Jensen Arthur Robert Jensen (August 24, 1923 – October 22, 2012) was an American psychologist and writer. He was a professor of educational psychology at the University of California, Berkeley. Jensen was known for his work in psychometrics an ...

. One version of the inspection time stimuli is shown below (1) with the stimulus (short left given as an example), which is replaced by a mask (2). (3) indicates the opportunity for the subject to report which stimulus they saw at their leisure. image:Illustration of inspection time stimulus.png

Genetics

Inspection time is moderately

; this work on the heritability of IT from Nick Martin's group also demonstrated, however, that perceptual speed does not have a causal role in

intelligence Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as the a ...

, but rather that IQ and IT are distinct reflections of some shared biological processes.

References

{{reflist Methodology

Overview

Genetics

See also

References