GMAT Critical Reasoning (CR) | Re: Psychologist: In a study, researchers gave 100 volunteers a psychologi

this is interesting
the key to succeed on CR (for evaluate, weaken, strengthen, flaw, assumption question) is ability to criticize the argument before going to answer choices. this is call prethinking on e gmat course.

after practicing a few problems, we realize some flaw and begin know how to criticize.
I think there are two way to criticize:
1. is logic of argument is good
2. is the presenting of evidence is good

this is causal argument and we normally criticize by thinking that there is