We spend quite a bit of time on critical thinking during the Schol preparation days. This is because of the need - identified by the examiner's report every year - for candidates to think critically about both the question (just what is the examiner asking me to do?) and their response to it (what, of all the information I have at my fingertips, is relevant here?). I thought it might be good to revisit one of the exercises I use.
This is based on one of Ben Goldacre's Badscience articles. It's based on an alternative therapy column in the UK. Here's the background information to the exercise:
A woman asks for advice on alternative therapy for her husband, who is going into hospital: "Is there any natural product or foodstuff he could take prior to surgery to boost his immune system enough to fight off any infection?"
The CAM advocate (CAM = complementary & alternative medicine) replies: "Brazilian scientists have investigated the potential of plant extracts in the battle agains... MRSA, & they suggest that the herb pau d'arco could have a role to play in protecting hospital patients from these infections. They identified active agents known as naphthoquinones, which, in laboratory tests, demonstrated not only good antibacterial activity against three different strains of the superbugs, but also more potency than similar, semi-synthetic chemicals that were investigated against the same strains... Take four [capsules] a day."
Then I ask the students to evaluate the claims of the therapist, then use your biological knowledge to discuss the advice given. What are the possible evolutionary & ecological outcomes of the proposed treatment? And then I leave them to brainstorm their ideas & develop an answer.
No, I'm not going to give you my take on the answer right now! Go & think about it. But - think carefully. Something that comes up every time I've used this particular exercise is suggestions about how this regime might interfere with the patient's health: the herbal treatment might interfere with other medication that he's on, or he might turn out to be allergic to it. These are valid concerns with respect to patient health (& it's why when you go into hospital you're asked to bring along any meds you're on, so the doctors can evaluate that first issue).
But they aren't relevant to the question. What are the possible evolutionary & ecological outcomes of the proposed treatment? This has nothing to do with the health concerns of the individual patient, & everything to do with the impact of the proposed treatment on the multitudinous bacteria that call his body 'home'. Now, in the light of this, how would you answer the question?