Hedonic

(adj.) Of, relating to, or characterized by pleasure.

Examples:

1. After studying neuroscience, June realized many of her hedonic feelings are related to her ability to choose.

2. June understood what they meant by  being on an “hedonic treadmill” when the pleasure she felt from buying a new pair of shoes quickly wore off to leave her looking for another source of happiness.

3. June splashed in the ocean purely for the hedonic thrill of it.