Non-verbal IQ Subtests Within the Leiter Assessment

The Leiter International Performance Scale (Leiter) was first published in 1940. It is a non-verbal intelligence test used widely among those who are hard of hearing, deaf, autistic, mentally handicapped, brain injured, intellectually superior, ESL, motor-involved, or have a speed and language deficit.

The Leiter can be used with cross-cultural applicability. While the original assessment was published for ages two through eighteen years, the revisions include expanded ages up to seventy-five years. It is widely recognized as one of the most highly rated nonverbal cognitive assessments.

The Leiter assessment is operational and empirical. It is not theoretical, and it has the ability to perform nonverbal mental manipulations that are very complex and related to conceptualization, visualization, and inductive reasoning.

The administration of the Leiter-3 is easy and doesn’t require speaking from either party nor does it require reading or writing from the examinee. It is engaging and has a series of game-like tasks that help to engage the examinee. The scoring is quick and objective, so the assessment is efficient.

Contents of the Leiter Assessment

The assessment includes nonverbal problem solving, spatial perception, classification of visual stimuli, attention to visual detail, and the relationships between and among these stimuli. Memory and attention are not directly assessed, but to some extent, they act substrates that provide a foundation for test-taking performance.

The Leiter assessment includes four subtests, all of which are required to calculate a nonverbal IQ. The fifth subtest may be used as a substitute in the event one of the other four are spoiled.  Two of the subtests calculate nonverbal memory, two calculate processing speed, and there is one nonverbal neuropsychological screener.

Subtest 1 – Figure Ground

The first subtest is similar to a visual recognition task in which the participant must use their short-term memory to scan a larger image for the smaller image embedded within it. It requires freedom from distractibility, cognitive flexibility, and an effective search strategy.

This subtest measures visual interference, involving visual recognition tasks that are compounded by distractions. To perform well, the individual needs visual closure and the ability to shift their attention between a discreet figure and a complex background.

Good inhibition prevents the individual from randomly pointing to a similar shape instead of focusing on the detail in the figures.  This subtest can help make qualitative clinical observations of a process like perceptual bias to one side of the page, misidentification of objects, perseveration, and noting only the most prominent objects.

Subtest 2 – Form Completion

The second subtest requires the individual to organize a series of disarranged or fragmented pieces. It demands flexibility so the individual can refer back and forth to different parts of the whole and arrive at a solution. This process is mostly deductive.

An individual’s working memory permits them to hold both the stimuli and possible responses in their mind simultaneously as the images are constructed and deconstructed. Harder items also have an underlying mental rotation component, and the entire subtest requires perceptual scanning, recognition, and perceiving fragmented percepts as a whole.

The Leiter Assessment is intended to assist in measuring the intelligence of someone who is largely nonverbal due to a variety of reasons. To purchase materials or for more information on the (Leiter-3) Leiter International Performance Scale, Third Edition, its components, or how it is scored, visit WPS Publish.