This post is in reaction to write-ups like this, this and this, which are clearly written by UI/UX practitioners who don’t understand interaction design.

You then get this type of nonsensical rationalization:

UX designers’ working world is concerned with the entire user journey, including aspects of branding, design, usability and function.

Here’s interaction design in two points:

  1. Every interaction goes through a Do-Feel-Know loop like this (taken from Bill Verplank’s Interaction Design Sketchbook):

Bill Verplank's Do-Feel-Know loop, of an interaction.2. Thus, interaction design’s main medium of design is human behavior, not technology.
> “A simpler way of thinking about Interaction Designers is that they are the shapers of behavior. Interaction Designers… all attempt to understand and later the things people do, the way they feel, and the things they think.”
> — Jon Kolko, “Thoughts on Interaction Design”, 2011

If interaction design is about shaping human behavior, then it overlaps with every aspect of human experience, including “aspects of branding, design, usability and function”.

Hence, it is a nonsensical rationalization to say that UX is larger than interaction design.

It is the other side of the exact same coin.