Table 1. Five learning tasks of differing complexity on which chemical networks were evolved.

Task	Typical Inputs by Environment Type		Network required to determine:
	Unassociated	Associated
Clocked [Non-associative]	S pulses alone	S→C pulse pairs	Do C pulses occur?
Noisy Clocked [Non-associative]	S pulses alone	S→C pulse pairs	Do C pulses occur more often than S pulses alone?
Non-Clocked [True Associative]	S and C pulses with independent timing	S→C pulse pairs	Do C pulses tend to occur shortly after S pulses?
AB-BA [True Associative]	C→S pulse pairs	S→C pulse pairs	Do S→C pulse pairs tend to occur more often than C→S pulses, over an extended period?
2-bit Environment [True Associative]	C→C, C→S and S→S pulse pairs	S→C pulse pairs	Do more S→C pulse pairs occur than any other type of input event?