Which of the disciplines presented (see in Jenny Preece text for full scope) do you feel is most important to HCI?

Interactive design is a combination of many business, technical, psychological, educational, artistic, and engineering disciplines. Which of the disciplines presented (see in Jenny Preece text for full scope) do you feel is most important to HCI?
Requirements:
1.Intext citation
2.Google scholar references
3.APA Citation
References:
Blog Article: Adobe Inc. (2019, October 16). What is Interaction Design & How Does it Compare to UX? Retrieved from https://xd.adobe.com/ideas/ principles/human-computerinteraction/what-is-interactiondesign
Video: Don Norman’s The three ways that good design makes you happy @ https://youtu.be/RlQEoJaLQR A
Video: Cognition, Design, and Usability: An Primer for Technical Communicators @ https://youtu.be/p1vrgC04ab4