The study does not provide clear evidence about the direction of the effect.

Say, for example, a study found that chocolate consumption per capita is positively correlated with the number of Nobel Prize winners per 10 million residents, with the higher the chocolate consumption, the more Nobel Prize winners (Messerli, 2012).Д«eware: the interpretation of the nature of this correlation is not straightforward. Example 1: Chocolate consumption & Nobel Prize winners That is, by looking to see whether, as one variable increases, another variable also increases (a positive correlation) or decreases (a negative correlation). In research, this is typically done by correlating the variables of interest with each other. However, when things become complex, we try to break them down into the smallest units, investigate the relationships between them and put everything again together in order to draw general conclusions. Difficulty in establishing cause arises because behaviour and physiological processes are often the result of complex interactions between a multitude of factors. Now obviously the difficult task is to find the cause. It enables us to 1) explain the current situation, 2) predict future outcomes, and 3) to create interventions targeting the cause to change the outcome. Finding the real cause that triggers an outcome is important for three main reasons. LetвЂ™s say we want to know why I suffered from a headache yesterday, or why some genes facilitate the mutation of human cells into cancer cells. Consciously or subconsciously, weвЂ™re striving to find explanations in our surroundings about why things happen the way they happen.

Causation vs causality