Testing Visual Array Threshold

It is very important to determine the exact number of items in a presentation that a child can look at and recognize (Christine Roman –Lantzy “Complexity of Array”).  I need to always be sure a child can discriminate one item from others as a visual skill before I use larger arrays for teaching. To begin to assess this, I use that child’s very favorite item in a decreasing number of dissimilar items.  I present that favorite item in an array of 6 items, then 5 items, then 4 items, then 3 items and finally 2 items until I see the child look towards and recognize their favorite. I conduct this assessment over a series of days, taking data on the attributes of the presented items (in the same environment), the number of items and the time the child needed to find their favorite one. If they have the ability to reach, I look at the quality of reaching (direct reach while looking, direct reach while looking away, sweeping reach while looking or sweeping reach while looking away).  Once I have data about the child’s abilities with increasing arrays, I can make recommendations to the team about the number of items that can be visually tolerated for recognition to occur.

Finally, I would want to test this array tolerance with items that are similar to one another as well but if I am testing this at all, it means I am concerned about this tolerance of array.  The recommendation for dissimilar materials is always in place for ease of discrimination in all situations with all alert states and in all environments.

Throughout this testing, I use dissimilar materials; all different from one another in color, shape and size. Recommendations to the team must include a suggestion for any array, especially with symbol systems, to highlight the need for items used to be of great dissimilarity.



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