Final answer:
The software layer is where humans interact with computers through the User Interface, dealing with human-software interactions and decision-making processes in automated systems from the users' perspective.
Step-by-step explanation:
The layer that deals with how humans interact with computers is typically associated with the User Interface (UI), which is not explicitly listed in the options provided. However, out of the given choices, software is the most relevant because it encompasses the applications and systems that users directly interact with, including the UI. The UI is a critical component of software that includes human software interactions in complex automated systems, particularly focusing on the decision-making processes of workers as they are supported by the software system.
When examining interactions with computers, analysts consider various levels - the physical level, which deals with the electronic changes inside the machine from an engineer's perspective; the design level, which pertains to the programmer's view of running a program; and the commonsense level, which is the user's perspective of the computer performing tasks like word processing or solving equations. A human factors psychologist studying a worker's interaction with a search engine would likely be analyzing these interactions at the software level to enhance user experience and efficiency.