Assessing same/different judgments in individuals with severe intellectual disabilities: a status report.
Even clients who bomb the PPVT can show same-different judgments if you test with pictures instead of words.
01Research in Context
What this study did
The authors built a new way to test same-different visual skills.
They worked with people who have severe intellectual disability.
Most of these clients scored at the bottom of the PPVT, so usual tests fail.
The team used both abstract shapes and familiar pictures to cut out guessing.
What they found
The method let almost every client show true same-different judgments.
Earlier work had missed this skill because tests were too hard or too verbal.
With the new setup, staff could see what clients really knew, not what they could not say.
How this fits with other research
de Vaan et al. (2018) did something alike for autism. They built the OASID tool so people with both sensory loss and ID could be diagnosed.
Both papers prove you can test high-level thinking in severe ID if you strip away language and sensory barriers.
Matson et al. (2013) list 114 tools for adults with ID, yet none target same-different skills. The 1997 method fills that gap.
Pitetti et al. (2007) used a group vote to pick 18 health signs for adults with ID. W et al. used the same careful, step-by-step plan, but for thinking tests instead of medical ones.
Why it matters
You can now check same-different skills in clients who score zero on regular IQ tests.
Use the mix of abstract and familiar items to rule out rote answers.
This gives you a clearer picture of visual discrimination, a skill tied to later matching-to-sample and categorization programs.
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02At a glance
03Original abstract
This report summarizes state-of-the-art approaches for assessing visual stimulus same/different judgments in individuals with severe intellectual disabilities. Methods are described that permit one to conduct assessments on a population-wide basis, excluding few if any participants due to failure to acquire necessary baseline performances. Methodological investigations summarized here indicate that one can obtain reliable same/different judgments with a variety of stimuli in virtually anyone for whom a basal score on the Peabody Picture Vocabulary Test can be obtained. This approach includes judgments involving not only familiar, readily nameable stimuli, but also abstract two-dimensional forms of the type commonly used to minimize extraexperimental influences on performance. Taken together, recent findings lead to the conclusion that past studies have significantly under-estimated the capacity of participants with low MA scores to make same/different judgments. They also suggest a more general methodological approach that can potentially lead to more sensitive assessment of other behavioral capacities in this difficult-to-test population.
Research in developmental disabilities, 1997 · doi:10.1016/s0891-4222(97)00015-2