Anthropomorphic design is an antipattern where developers design software components as if they were people.

Description

In his book “Thinking Fast and Slow”, Daniel Kahneman comments that by using “System 1” and “System 2” to describe the way we think he commits the sin of anthropomorphism. “System 1” and “System 2” behave to a certain degree as people when in reality there is no direct mapping to a physical item, e.g. a neuron, to one of the two systems. He still thinks it helps us understand how our mind works, because we are better equipped to think about interactions between people than to handle abstract concepts.

Anthropomorphic design with regards to software components is when we think of software components as people. This usually comes together with:

• a common terminology for the components e.g.: the AbcManager, the DceManager, the XyzManager
• have a common, heavy runtime layer used to communicate e.g. COM, or message queues
• in addition to their own core functionality, they communicate with their peers

Example

The Application requires three new components: a DatabaseManager, a EmailManager and a LogManager. Each component has, to start with, a clear role: e.g. the DatabaseManager is a data access layer for a database, the EmailManager sends email and the LogManager writes log entries to a file.

Over time however the requirements change: the database manager needs to send an email if the database is full. The DatabaseManager takes a reference to the EmailManager and uses it to send an email when the database is full. Requirements change again: the email manager needs to log an entry every time an email is send, and the logger needs to log to the database in addition to a log file.

In the diagram above the DatabaseManager is more like a person: in addition to doing all that has to do with the database it also talks to/uses the EmailManager. This is very much like John talking to Paul as part of completing a task.

Alternative

The option would have been to refactor the three original entities into more entities with single responsibilities.

The new DatabaseManager only puts the DatabaseLayer and Emailer together. The new DatabaseLayer only deals with the database. As we’re going further away from an anthropomorphic design we end up with more components and we need more words to describe the functionality of each component, but each component is individually simpler.