Shanks and St. John examine evidence for independent explicit and implicit learning systems in humans. They argue that while some researchers claim to have found unconscious learning, the evidence is not conclusive. They distinguish between learning with and without awareness, and between learning abstract rules versus memorizing instances. Implicit learning is assumed to involve unconscious rule acquisition, but they find that unconscious learning has not been clearly established in most areas. They suggest that the distinction between instance and rule learning is a more meaningful way to classify human learning. They discuss various computational models of these two forms of learning. They also consider the relationship between learning and memory, noting that dissociable memory systems may imply dissociable learning systems. However, research on learning and memory has often proceeded independently. They review evidence for unconscious learning, including subliminal stimuli, conditioning, artificial grammar learning, and reaction time tasks. They find that while some studies suggest dissociable learning systems, others do not. They also discuss the criteria for establishing unconscious learning, noting that verbal reports may not be a reliable measure of awareness. They conclude that the evidence for dissociable learning systems is not yet conclusive.Shanks and St. John examine evidence for independent explicit and implicit learning systems in humans. They argue that while some researchers claim to have found unconscious learning, the evidence is not conclusive. They distinguish between learning with and without awareness, and between learning abstract rules versus memorizing instances. Implicit learning is assumed to involve unconscious rule acquisition, but they find that unconscious learning has not been clearly established in most areas. They suggest that the distinction between instance and rule learning is a more meaningful way to classify human learning. They discuss various computational models of these two forms of learning. They also consider the relationship between learning and memory, noting that dissociable memory systems may imply dissociable learning systems. However, research on learning and memory has often proceeded independently. They review evidence for unconscious learning, including subliminal stimuli, conditioning, artificial grammar learning, and reaction time tasks. They find that while some studies suggest dissociable learning systems, others do not. They also discuss the criteria for establishing unconscious learning, noting that verbal reports may not be a reliable measure of awareness. They conclude that the evidence for dissociable learning systems is not yet conclusive.