As we all know, SONA is the system by which much of Bangor’s Psychology research recruits its participants. However there are several problems that arise through the use of SONA and they are due to bias that occurs from the way SONA is designed. For example, an obvious thing to point out would be that SONA relies heavily on the student population of Bangor. Although the student population is an incredibly useful tool for research there are problems associated with using us, such as sampling bias. There is also a problem that exists in the was SONA is actually structured, the fact that we select which studies we participate in can lead to selection bias. Both of these bias’ could potentially have serious effects on the results of a study.
The fact that SONA relies on Psychology students causes a major amount of bias to enter the data, more specifically, sampling bias. Sampling bias occurs when the sample taken and researched is not random (http://www.medilexicon.com/medicaldictionary.php?t=10087). This means, for example, that if a researcher conducts a study and aims for the results to be generalised to a large population but only middle-aged women are tested, the results will be biased towards that group. It becomes apparent now that studies using SONA encounter a problem, they have a sampling bias towards students. This is a problem because students are generally WEIRD-er than a random sample from a population. Weird is an anagram for Western; students studied on are usually from Western European and North American cultures. Educated; due to the required qualifications to become a student, we are, as a group, highly educated. Industrialised; this refers to our desire to attain a highly paid job after we complete our time as students and are studying to attain this goal. Rich; comparative to much of the developing world, students are relatively well off. And Democratic; this to me is much the same as Western, as most of the countries included in that umbrella are Democratic and the population is raised as such. This idea was originally created by Henrich et. al. A summary of their paper can be found here (http://neuroanthropology.net/2010/07/10/we-agree-its-weird-but-is-it-weird-enough/). Coupling the implications of sampling bias with the assumptions of “WEIRD” students, it can be suggested that Psychological studies that rely on SONA suffer from a huge selection bias, this can affect the external validity of the study with extreme cases resulting in the study being no longer generalisable.
There is another type of bias that creeps into SONA studies is selection bias. Selection bias is an error that occurs due to the type of people who sign up for a study. For example, report rates of child abuse are susceptible to selection bias as differing cultures have differing views of what should be reported (http://www.ncbi.nlm.nih.gov/pubmed/9504213). Selection bias in studies means that people sign up for studies that they wish to participate in and this can affect the results (if you search wikipedia for participation bias there’s a funny example, but when I references wikipedia last time people laughed at me so I won’t link it here). With regards to SONA, when we are fulfilling our credits we are allowed to choose the specific study that we are interested in completing and often choose studies that we think would be easy or rewarding. If, for example you suffer from fatigue when viewing stereo 3D images then you would understandably be less likely to sign up for a study which was researching these images, this could be detrimental to the study if, for the purposes of the study the researchers needed to include participants who suffered from fatigue. Again this bias can affect the generalisability and the external validity of the study. This selection bias could really only be avoided in SONA if we were randomly assigned to studies as this would ensure we were not choosing only the studies that appealed to us (I also know this is wouldn’t work for various reasons, but it would deal with the bias).
Despite the great use SONA serves Psychological research there are problems that can arise through its use. The pool of participants it uses is comprised of students which means that results will be biased towards the student population. This can cause problems with external validity and generalisability, which ideally would not occur. Furthermore the ability to pick and choose which studies suit us the best can potentially cause selection bias which again can cause external validity issues.