These exclusion criteria have been chosen on the basis that these are factors that can affect cognitive performance. Given that the cognitive tests involve learning English words, only participants who have English as their first language can be included because different cognitive processes are used when learning in a non-native language (Wong et al., 2004). Ethnicity can influence glucose regulation and risk of diabetes. Given that part of this research is examining the relationship between glucose regulation and cognition it is important that potential confounds such as ethnicity/genetic propensity to diabetes are controlled for.