 A second argument for preference change is based on the correlations between physiological changes and changes in behaviour. Changes in blood sugar levels, for example, are correlated to feeding behaviour, sexual behaviour varies with hormonal changes, and many behavioural patterns change with increasing age (for references and discussion, see Loewenstein 1996). These correlations are not deterministic; such behavioural changes can be resisted in many cases. It is plausible to incorporate these potential physiological effects as visceral preferences in the general preference framework, and to treat the relevant physiological changes as closely connected with preference changes.