Question

Urban Brains and Rural Brains A study published in 2010 showed that city dwellers have a 21 % higher risk of developing anxiety disorders and a 39% higher risk of developing mood disorders than those who live in the country. A follow-up study published in 2011 used brain scans of city dwellers and country dwellers as they took a difficult math test.1 To increase the stress of the participants, those conducting the study tried to humiliate the participants by telling them how poorly they were doing on the test.The brain scans showed very different levels of activity in stress centers of the brain, with the urban dwellers having greater brain activity than rural dwellers in areas that react to stress. "A New York state of mind", The Economist, June 25,2011, p.94 (a) Is the 2010 study an experiment or an observational study? Experiment Observational study b) Can we conclude from the 2010 study that living in a city increases a person's likelihood of developing an anxiety disorder or mood disorder? Yes No

Answer 1

a) Observational study

No intervention is made by the researcher and hence, it is observational.

b) No

There is no substantial evidence here to validate the claim. Confounding variable or sampling error can also result in such observations and hence, we cannot draw a conclusion based on the information available.

c) Experiment

Here, the researcher is intervening with the actions of the participants. So, it is an experiment.

d) Yes

The levels of brain activity were different for the two groups. So, we can conclude that living in a city increases activity in stress centers of the brain when a person is under stress.