verbal vs performance iq

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I've read that IQ type can be one of the differences in the great debate between AS and HFA - performance IQ higher in HFA, verbal IQ higher in AS. Does anyone know how big the gap usually is? My performance score is 10 points higher than my verbal score - not a very big difference. (I actually expected it to be the other way around, verbal score to be higher, based on the questions they were asking as it went along... although I do fit the HFA profile more than AS.)

A "clinically significant" difference is generally considered to be 15 points or more, although some people believe it should be 20 points or more. Regardless, you're right that 10 points is not a large difference. Mine is 39 points, actually (I have NLD).

I have a 15 pt. difference between performance (higher) and verbal (lower). I was told that is significant, but since all of my scores were above average, I didn't have a leaning disability. In practical terms, the difference created many problems for me in school, and still does to some extent.

Z

Mine's never been tested, but I suspect I'd fall under the "clinically significant" range. I think.

Yup, this was my experience as well. Even a 39 point difference didn't provoke further investigation when I was a child (I sought further testing on my own initiative as an adult), because my performance IQ is 108, which although it is significantly depressed compared to my verbal IQ of 147, still falls within the normal range. I guess what people fail to take into consideration is that the person's strengths compensate to a degree for their weaknesses while taking an IQ test, especially since the IQ test items are not totally specific in which skills they target. When my basic processing skills are tested (ex. visual processing, spatial processing, etc.), my nonverbal skills fall into the impaired range. Thus, although my performance IQ is normal, I still experience significant problems in everyday life related to my poor nonverbal skills.

What they've found, actually, is that the differences between them can be non-significant for many autistic people. But that there can be significant patterns of areas of strength and difficulty in subtests among different groupings of autistic people. The subtest patterns end up supposedly being more important than the overall verbal vs. performance patterns.

True. This is the case for NLD as well. It is very important to look at the range of individual subtest scores. For me, my performance subtest scores are 10-13, while my verbal subtest scores are 17-19. However, not everyone's strengths and weaknesses fall neatly into the performance/verbal categories.

For reference, the standard deviation of full-scale scores is 15 points (the cut-off for clinically significant differences), while the standard deviation for subtest scores is 3 points. So it doesn't work out exactly, because the highest possible subtest score (19) is equal to a full-scale score of 145, while the highest full-scale IQ you can have is actually 160. So subtest scores don't correspond in a 1 to 1 manner with full-scale scores. But in general, a difference of 3 points or more between subtest scores would be significant (although you would look for a pattern of strengths and weaknesses- one outlying subtest score doesn't mean much). This is true of the Wechsler IQ tests only by the way- the Stanford-Binet scale is slightly different.

Last edited by LostInSpace on 23 Mar 2008, 8:55 pm, edited 2 times in total.

I've been trying to reconcile the great difficulty I can have with math, writing, etc. I call it my internal disparity. When some things come so easily and others are quite difficult, it doesn't really matter that all are above average. Growing up, the disparate ability levels left me thinking I wasn't too bright, and I gave up on some academic subjects.

LostInSpace, do you find that when you are under stress, that segments of your thinking decrease or go blank? This happens to me with verbal ability and has led to some dramatically decreasing test scores.

Z

Generally for me, since my verbal skills are so vital in mediating my navigation of non-verbal tasks, the result of stress is that my verbal skills punk out on me and I can no longer make sense of the task/problem. I'm not sure if that's what you mean or not.

It's like the verbal somersaults necessary to solve a particular nonverbal problem exceed my working memory capacity, and I'm just left holding a bunch of thought strands that I can't reconcile. While I'm very good at using my verbal skills to compensate for my lack of nonverbal ability, there is a limit to what I can handle. The verbal acrobatics get so convoluted and complex that I can't keep up the balancing act and everything ceases to make sense. This happens most often when I am driving, although it also occurs when I'm bumbling through statistics or higher-level math. When people try to ask me questions about driving routes, I tend to get frustrated, and then shut-down and become uncommunicative because I often can't even understand their question, let alone answer it.

If you're close to the bottom or top in your scores, the difference is less important also because you can't really tell how big it might be. The tests are aimed mostly at the people who can answer average-range questions in all subtests. If you can't, or if you find them very easy (like LostInSpace on the verbal section), the tests can't really quantify how far from the average you are, or how far from the score you're comparing to. You might be right there, or you might be miles away. (It's like vision, where the test can see more color and texture in front of it than it can in its periphery.)

But even when there are strong associations between one profile and one disorder, testers are and should be hesitant to place too much emphasis on IQ test results. Just this difference does not give any sure indication of one disorder over another, even if the difference is huge. Especially if the profile is so blunt as Performance versus Verbal, and especially if they have found that it doesn't necessarily hold for the targeted group. Unless the definition of autistic vs. Asperger's be this difference, using it (or a guess of where the patient would fall based on it) to differentiate between patients and then use those patients as the basis for this decision's validity is circular.

It would be nice if very large differences were always a basis for concern, though - no matter the score. I can certainly see how people with large differences might feel more acutely how much they lag in certain areas.

I think that MUST be what he means. The SAME happens with me. I think that must be the one constant in meltdowns. And I am now calling it a meltdown, in autistic circles. But yeah! It is like the part of my mind that assesses problems, and knows what it can do is still active, but frustrated because the resources are not available or are limited. I may even run incorrect tests, and keep trying to correct a problem that never existed.

The brain is just too complicated. I wish I DID know a lot more about it. I'm over 40 years old, and STILL learning basic things about it, though many things are hidden from the young that find access so much easier.

Oh well, one person has a sig that basically says that "If the brain was simple enough to understand, we wouldn't be smart enough to understand it"! I guess that is just a fact of life.

This is EXACTLY what I mean, and I've never met anyone who had the same difficulty. A couple of years ago I took a timed IQ test, and having a time limit sent me into a verbal "meltdown." There was a story problem that I couldn't comprehend - the phrase "the day before yesterday" became unfathomable. I tried graphing it out, but I simply couldn't understand those four words. It was shocking to have verbal ability essentially disappear, but at that point I realized that a mechanism in my brain shut down during stress. That realization - that I really wasn't stupid - was wonderful for me.

Z

Do you know what those patterns are? Admittedly, the test I did was online but supposedly it's a (shortened) combination of the Stanford-Binet and WAIS.

Full-scale iq 124
Verbal 119
Performance 129

Picture section/abstract reasoning 14
Vocabulary section/verbal recall 15
Recall section/symbol recall 19
Relationship section/verbal reasoning 12
Arithmetic section/mental arithmetic 18

It's funny that you mention that particular phrase as problematic, because it reminds me of something similar which happened to me in class one day. It was a class in the speech therapy department, and we were discussing assessment measures for people who have had strokes. One of the questions (an example of a complex yes/no question) was "Do you peel a banana after you eat it?"

I just could not work out what the answer would be. Eventually I figured it out, but it took me several minutes. What's interesting is that both of our examples have to do with temporal relationships, which are difficult for those with nonverbal deficits. For instance, my mom had the worst time trying to teach me how to tell time, and even after (with much laborious effort) I was able to read a clock, I still couldn't understand phrases like "ten till two" or "a quarter past three." It took still more work for my mom to break down those terms until I could understand them. It makes sense that when we're not at the top of our game, such temporal relationships might still throw us for a loop.

I'm sorry you had such a difficult time with the IQ test. Stress/anxiety can definitely have a major impact on functioning. I had a similar experience while I was being tested for NLD. While I mainly did extremely well on the verbal sections, I had difficulty with one test of auditory recall (not a strength of mine anyway). It was the California Verbal Learning Test, in which the tester reads a list of words, and then you must recall as many as possible. There are a number of sections, including multiple trials of immediate recall, delayed recall, and recognition. Well, the tester noted that my scores for this particular test showed an interesting pattern.

Each time the format of the test changed (ex. from immediate to delayed recall), my scores would plunge into the moderate impairment range, and then they would creep back upwards across multiple trials, until they would plunge again when the test format changed. Due to this pattern, the tester hypothesized that my difficulty was due to anxiety. It's true that when I am barraged with auditory information, I tend to shut down and not absorb much (when I can read it however, I'm tops). She noted that my apparent "lack of attention" during these tasks (she wrote that in the report, although it doesn't agree with my memory of the experience at all) was likely an attempt to manage my anxiety.

Would someone explain for me what the difference between verbal and performance is? I've never taken an IQ test or heard about these two areas.

Well, it certainly seems like you performed better on portions of the test which required visual/spatial skills rather than verbal skills. I'm assuming that the "relationship" section is akin to the similarities subtest on the Wechsler (in which you name similarities between apparently disparate concepts), and does not have to do with social relationships. In addition, your abstract reasoning skills, while in the high average to superior range, do not appear to be as well developed as your other nonverbal skills (such as visual memory), which are in the very superior range. Bear in mind though that this is just one abbreviated test (and an online test no less), so take the results with a grain of salt.