Many symptoms of mental illnesses are affected by organic factors such as a deficiency in a compound in the brain. Wh...

shunhe on August 19, 2020

Hi @izzy,

Thanks for the question! So let’s take a look at the stimulus first. We’re told that many symptoms of mental illness are affected by organic factors like a deficiency in a compound in the brain. But there’s variation among different countries in the incidence of these symptoms. So, the argument concludes, the organic factors aren’t distributed evenly around the globe.

Now we’re asked for a flaw in the stimulus. And before we even look at the answer choices, we should have an idea of what this is in our heads. And here, it’s pretty obvious: the argument’s ignoring that there might be other things that affect the symptoms of mental illness other than the organic factors! Any answer choice that doesn’t mention that is going to have to be a wrong one, because that is the main flaw with this argument that needs to be addressed.

Now (B) tells us that the flaw is that the argument neglects the possibility that nutritional factors that contribute to deficiencies in compounds in the brain vary from culture to culture. But this is just another effect of the cause suggested in the argument, that the organic factors vary, which would lead to different nutritional factors. So even if the argument ignores this, it’s not really a flaw, and so it isn’t the right answer.

(D) tells us that the flaw is that the argument presumes, without providing justification, that any change in brain chemistry manifests itself as a change in mental condition. In other words, the argument assumes this. But does the argument actually assume this? Where is this mentioned, that any change at all is a change in mental condition? This isn’t something the author even assumes, and so saying that the author assuming it is a flaw is going to be wrong, and so (D) is incorrect.

Hope this helps! Feel free to ask any other questions that you might have.

izzy on August 20, 2020

Thank you!