A fixed sequence from a low to high concentration results in lower carry over effects than the delivery of random or descending concentrations. Furthermore, a similar concentration sequence was used in all participants in order to reduce the variability of carry over effects across participants. Over four blocks tastes were administered three times in a balanced order. The order was counterbalanced across participants. Task blocks were alternated with rest periods of approximately 2 min. In order to minimize carry over effects that might arise between 1) taste qualities (e.g. effect of pleasant taste followed by an aversive taste and vice versa) and 2) taste concentrations (e.g. effect of intense taste followed by a weak taste) we used the current selected block design instead of an event-related design.