Psychologist: It is well known that becoming angry often induces temporary incidents of high blood pressure. A recent study further showed, however, that people who are easily angered are significantly more likely to have permanently high blood pressure than are people who have more tranquil personalities. Coupled with the long-established fact that those with permanently high blood pressure are especially likely to have heart disease, the recent findings indicate that heart disease can result from psychological factors.
Which one of the following would, if true, most weaken the psychologist’s argument?The argument concludes that
psychological factors can cause heart disease because being easily angered is associated with permanent high blood pressure, and high blood pressure is associated with heart disease. So the best weakening answer is the one that shows the anger is not causing the high blood pressure, but instead both may come from some nonpsychological cause.
(A) Those who are easily angered are less likely to recover fully from episodes of heart disease than are other people.
This does not weaken the argument. If anything, it suggests anger may make heart problems worse.
(B) Medication designed to control high blood pressure can greatly affect the moods of those who use it.
This is not the best answer. It suggests medication can affect mood, but the argument is about whether anger leads to high blood pressure and then heart disease.
(C) People with permanently high blood pressure who have tranquil personalities virtually never develop heart disease.
This weakens the link between high blood pressure and heart disease, but it is too extreme and oddly specific. It is not as direct as showing that anger and high blood pressure may have a common physical cause.
(D) Those who discover that they have heart disease tend to become more easily frustrated by small difficulties.
This attacks the direction between heart disease and anger, but the argument’s key step is anger -> high blood pressure -> heart disease. So this does not weaken the core reasoning very much.
(E) The physiological factors that cause permanently high blood pressure generally make people quick to anger.
This is the best answer. It gives an alternative explanation: the same physical factors may cause both high blood pressure and quick anger. If so, anger may not be causing high blood pressure, and the argument for a psychological cause of heart disease is much weaker.
Answer: (E)