Memory traces are only implemented in the Stimulus-response learning and Guided associative learning mechanisms.

Specifies the decay factor of fading memory traces. The value is a number between 0 and 1. The higher value, the longer the memory trace of each stimulus stays with the subject. A low value means it fades fast. The default is 0.

The value of the parameter trace is used in the decision function.


trace = v

where v is a scalar expression.


trace = v sets the decay factor to v.


trace = 0.5

sets the decay factor to 0.5.

@variables x = 0.5
trace = x + 0.1

sets the decay factor to 0.6.