Image credit: Kommers (CC0)
People are constantly picking up patterns in the world around them, often without even trying. This is called implicit learning – a natural, unconscious process that helps us notice structure in things that might seem random at first. For example, we might start to recognize that certain shapes often appear together.
Scientists already know that when we learn something by actively thinking about it – called explicit learning – we can usually instantly apply that knowledge to new situations. That ability is known as generalization or transfer learning. However, it has been less clear whether generalization also happens through implicit learning and if time and sleep help shape or strengthen implicit memories over time.
To find out more, Garber and Fiser studied explicit and implicit visual learning tasks, in which 229 volunteers were presented with 20 abstract black shapes on a white background. During two learning phases, shapes were shown in fixed pairs, embedded within larger scenes composed of shapes– six pairs (same orientation) in phase one, and four pairs (two horizontal, two vertical) in phase two. Pair learning was assessed using a choice task. In each trial, participants viewed one real pair and one foil pair (mixed shapes from different pairs) and had to indicate the more familiar pair.
The experiments confirmed that when people learned with awareness, they could use the learned structure in new scenes right away. However, implicit learners did not transfer that knowledge immediately. Instead, they learned new patterns with different structures more easily than those that match the old ones. After 12 hours of sleep, though, they became able to apply the original structure. This suggests that sleep may play a specific role in reshaping unconscious knowledge to make it more flexible and useful.
Learning from patterns without thinking about it is important for everyone, from children and students to people starting new jobs or working in existing roles. A next step will be to test these findings in real-world settings using real-life situations and longer learning periods. Understanding how sleep timing and duration affect learning could help inform new strategies for improving education, training and even creative thinking.
