Extinction context is learned by pigeons, not given by the environment.

The saying "context is everything" underscores the importance of interpreting things, be they quotes, events, actions, or stimuli, not in isolation but in the light of a bigger picture - their context. This is evident even in fundamental forms of learning such as extinction learning where, in contextual renewal, an extinguished response reoccurs if the context is changed. But what exactly is context? Is context given by stimuli with inherent properties making them context or, what are the circumstances that allow a stimulus to become "contextual"? Even though the answer may seem intuitively trivial, the literature only provides competing and vague definitions. Using a modified ABA paradigm, we assessed how competing stimuli induced contextual renewal during extinction learning in seven pigeons (Columba livia). Furthermore, we controlled the timing of these stimuli and found it to be crucial; with the right contiguity, even small local stimuli resulted in the strongest contextual renewal. This result challenges definitions of context as 'a backdrop where learning occurs'. Instead, we propose that context can be understood mechanistically as a learned stimulus property. Therefore, context truly is everything and anything.