But it could influence the longer term effect that they're studying. They address this issue in the section "Secondary Analyses": > In a secondary analysis, we

But it could influence the longer term effect that they're studying. They address this issue in the section "Secondary Analyses": > In a secondary analysis, we asked whether cognitive performance predicted chocolate consumption rather than the other way round. This analysis was conducted on a sample of participants who had completed a cognitive assessment in waves 1-4 of the MSLS, but also completed the dietary questionnaire at wave 6, a mean of 18.0 years later. Cognition was assessed using the Wechsler Adult Intelligence Scale (WAIS)... There were no significant associations between chocolate intake and the total WAIS... Seems like the chocolate eaters weren't more intelligent to begin with.