In psychology, fixation refers to an obsessive interest or feeling about someone or something. It can also refer to the inability to see a problem from a new perspective; by employing a different mental set.
Related terms
Cognitive Rigidity: This term refers to difficulty in changing mental sets or strategies when circumstances demand it.
Obsession: An idea or thought that continually preoccupies one's mind, often linked with anxiety disorders.
Perseveration: The repetition of a particular response, such as a word, phrase, or gesture, despite the absence or cessation of a stimulus.