Tuesday, December 1, 2009

Your IQ Means Nothing

"The teenager accused of murdering a 21-year-old man in 2005 has a below-average level of intelligence, making it more likely he could be influenced by an older gang member, a psychologist testified Monday.

Dr. Rahn Minagawa testified that he performed an IQ test on defendant Josue Orozco, 19, in October and found Orozco scored an 81, indicating a much-lower-than-average intelligence but not mental retardation.

Minagawa, a San Diego-based psychologist who testified for the defense Monday, said Orozco's low intelligence would likely make him 'more vulnerable' to the influence of an 'original gangster.'
" (1).

IQ is an antiquated concept. Many people, included the above-mentioned douchebag Dr. Minagawa, believe that IQ is a unitary construct. It's not. The number is useless.

First the basics. IQ or full-scale IQ (FSIQ) is a composite of separate, smaller composites. For example, the WAIS FSIQ is made up of the Verbal Comprehension Index (VCI), Perceptual Reasoning Index (PRI), Working Memory Index (WMI), and the Processing Speed Index (PSI). The sub-composite scales convey more information than the FSIQ, but they too also obscure a lot of clinical information tool.

Here's how useless an IQ score is. The article notes that Orozco's IQ is 81. I recently had a patient (young male with similar demographic characteristics as Orozco). His FSIQ was also 81.

If I only told my patient that his IQ was 81, what could he do with that information? Other than believe that he is stupid, nothing. If I made treatment recommendations based his IQ, what could I suggest? Nothing.

My patient's full profile breaks down to this when he is compared to people of a similar age (Orozco's IQ is age based):

FSIQ = 81 (mild-deficit)
VCI = 90 (low average)
PRI = 76 (mild deficit)
WMI = 86 (low average)
PSI = 84 (mild deficit)

On the surface, his scores seem pretty poor.

Here's the rub, test performance is influence by other factors other than age. Factors like ethnicity, level of education, and gender also affect test performance.

Instead of comparing my patient's results to people of a similar age, let's look at what happens when I compare his results to a population with similar age, education, gender, and ethnic background.

FSIQ = 86 (low average)
VCI = 97 (average)
PRI = 79 (mild deficit)
WMI = 91 (average)
PSI = 91 (average)

His scores improved! Only his PRI is still in the mild-deficit range (he had a right-parietal lesion). Does this alter my interpretation? What about our murderer? Let's pretended that these are his test scores. If his age-matched IQ of 81 means that he is "more likely" to be influenced by an OG, does that mean his demo-corrected IQ makes him less gullible? Not even close.

Why not? Because IQ has nothing to do with social psychology. IQ cannot predict one's ability to make decisions. Even tests designed to assess decision making cannot predict one's ability to make decisions.

In this case, it's Orozco's position within the gang that makes him more likely to be influence by an older gang member. His age at the time of the crime (14) better explains his gullibility than his lousy IQ score. Bottom line: This psychologist is an idiot!

I use to take a combination of Ambien CR, diazepam, Restoril, diphenhydramine, and bourbon to sleep at night. I have an IQ of 140. Like I said, it's a useless number.


EastCoaster said...

I thought it was kind of dumb too, though it does reveal my poor visual-spatial skills.

My experience of testing was traumatic. She came up with a diagnosis of non-verbal learning disorder--after a case conference. I knew that I had problems and wanted help figuring out learning how to work with space and objects in 3 dimensions. Instead, I got a recommendation that I pursue a career with a set schedule, routine and very little variety. It felt like a death sentence. Fortunately my psychiatrist was having none of it--despite my weaknesses in gestalt reasoning.

How do you feel about its usefulness at the extreme lower end? As a moral matter, I am opposed to the death penalty in general, but I find it particularly barbaric in individuals with limited cognitive capabilities. I'm not familiar with thw scoring--except that 100 is average. I'd be very opposed to executing someone with an IQ of 20 or 30 myself.

NeuroPsych said...

It seems odd that she would make a vocational recommendation like (unless that was the referral reason). Did she based it on the psychiatric history you described in another post? I hope she gave you more than a IQ test to base any recommendations on.

NVLD is not yet an "official" diagnosis (that doesn't preclude its existence). Asperger's is considered the protoypical NVLD with deficits in motor coordination, visuospatial processing and social pragmatics.

When your IQ is in the 20-30 (profound mental retardation), clearly one's comprehension, reasoning, is impaired. You basically bomb every test.

Anonymous said...

I've just found your site and very much enjoy your close readings of drug trials - this comment is only to point out a few distracting errors of grammar that crop up in nearly every paragraph:

Let's pretended that

more likely to be influence[d] by

I use[d] to take

etc. If you're trying to preserve anonymity, this kind of tic is a dead giveaway.

Aristotle said...

I agree that IQs are not important. Anyone can memorize the answers to the great questions, but only the truly gifted can ask these questions. And if an IQ does not measure creativity, then what is the point! What this world needs is new ideas not just old ideas restated! I hope this makes all of you think and ask your own great questions.

Aristotle said...

I have always thought that an IQ meant nothing. If they do not measure the creativity and ability to ask questions, then what is the point? Anyone can memorize answers, but it takes great intuition to ask be able to ask a great question.