Data from: Positive and negative incentive contrasts lead to relative value perception in ants

Humans usually assess things not according to their absolute value, but
relative to reference points - a main tenant of Prospect Theory. For
example, people rate a new salary relative to previous salaries and
salaries of their peers, rather than absolute income. We demonstrate a
similar effect in an insect: ants expecting to find low quality food
showed higher acceptance of medium quality food than ants expecting medium
quality, and vice versa for high expectations. Further experiments
demonstrate that these contrast effects arise from cognitive rather than
mere sensory or pre-cognitive perceptual causes. Social information gained
inside the nest can also serve as a reference point: the quality of food
received from other ants affected the perceived value of food found later.
Value judgement is a key element in decision making, and thus relative
value perception strongly influences which option is chosen and ultimately
how all animals make decisions.