It’s hard to avoid the articles telling us that ‘eating chocolate improves brain function’ and that it helps protect against ‘normal age-related decline’. It sounds too good to be true right? Before we all go tell our parent to grab a box of chocolates for our studying, let us step back and think critically about this sweet conundrum.
One particular study we’ll be exploring today is one published this year in February in a peer-reviewed journal, ‘Appetite’, found that ‘memory and abstract thinking improved in those reporting more chocolate consumption’. Looks good so far. But, these effects were not influenced by factors such as age, weight and general health measures. So what does this study show us? It’s an example of correlation versus causation. In this case, the study is purely correlational, meaning it shows there is an association between people who regularly eat chocolate and scoring better on brain function tests. But this doesn’t support that chocolate consumption directly improves brain function. Why? Because there are other factors which weren’t controlled, like age, weight and health measures. These factors by themselves may not cause the found correlation, but generally speaking the people who consumed more chocolate had better diets and drank less alcohol. As well as this both groups relied on their memory to report their chocolate consumption levels, which leaves a lot to be desired in terms of scientific accuracy of this study.
So yes, there are flaws with this paper, but aren’t there flaws in every single piece of good research? Yes, but let’s dig a little deeper and explore the other aspects of this research. Sample size is another important facet of good experimental design, and here 968 participants were from Maine-Syracuse Longitudinal Study, which has followed the same group of New Yorkers for more than 35 years. So the sample size is acceptable and it also seems that the duration of these experiments seems to be substantial. Surprisingly, there was no differentiation made between the types of chocolate which was consumed, such as dark, milk or white. The researchers also compared those who rarely ate chocolate and those who ate chocolate. One would assume a 50/50 split however, there are a greater number of people in the study (631 people) who ate chocolate at least once a week and only 337 people who rarely ate chocolate. This could skew the data in favour of those who frequently ate chocolate simply because the sample size allowed for a more solid set of data whereas the smaller sample size of comparison could be skewed with outliers.
The final aspect to this research conducted was the testing of the brain function with various tests. These included spatial memory, abstracting reasoning, working memory and attention. The results were taken and then analysed, with people who had dementia excluded due to their serious cognitive impairment which could skew the results. This is an example of good experimental design here, accounting for the unforeseen circumstances of the experiment and justifiably removing these outliers in the data to provide a more accurate summary and conclusion. So we went through a majority of the facets of this research but what does this mean? Can I eat more chocolate to improve brain function? It’s really hard to say. The data is far from ideal and perhaps we need to wait for another study to say for sure if there is a causation relationship rather than a correlation.