There were two types of errors a participant could make: an error of commission (pressing a key when the number 8 was presented) and an error of omission (giving no response when any other number 1 through 9 was presented) (Hilton & Head, 2012). The number of errors and reaction times were recorded. The post-earthquake SARA was followed by the Depression Anxiety Stress Scale (DADS-21; Henry & Crawford, 2005, as died in Hilton game; Head, 2012), a self-report examining the participant’s emotional stability, sleep hours, gender, anxiety and depression (Hilton ; head, 2012).
Results showed a significant increase in errors of omission after the earthquake than before, while differences in errors of commission and response times before and after the earthquake saw no statistically significant differences. Therefore, human performance may be negatively affected following a natural disaster. Though the present study was successful in demonstrating an increase in the errors made on the SARA and high levels of reported stress on the DADS-21 after the earthquake, this is there was no control group.
The increase in errors on the SARA or the reported stress on the DADS-21 following the earthquake could have been caused by other unknown factors or just purely been a coincidence. By having a control group, consisting of participants who did not experience the earthquake and were not affected by it, perform the SARA and DADS-21 and comparing their results to that of the experimental roof would allow the experimenter to see whether the earths quake did actually have an affect on human performance.
Obviously, due to the nature of the experiment in that the earthquake could not be predicted, the DADS-21 was only administered after the earthquake. Therefore, it is hard to say whether changes in emotional stability, depression or anxiety of the participants occurred as a direct result of the earthquake since there is nothing to compare the results to prior to it happening.