Figure 1. Hypothetical scenarios shaping within-individual correlations (CORw) between state and risk-taking behaviour. Temporal changes in traits, specifically related to ageing, strongly shape within-individual trait correlations (a,b). (a) A positive within-individual trait correlation is expected when both individual state and behaviours decline with age due to physiological deterioration. (b) A negative within-individual trait correlation is expected when individuals are more likely to engage in risk-taking behaviour with decreasing future fitness expectations with age. However, within-individual trait correlations can occur even when traits do not change with age, but fluctuate based on (c) state dependence or (d) trade-off.