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Different kinds of visual learning reflect different patterns of change in the brain

Outcome:  In two recent articles, Yetta Wong, Jonathan Folstein and Isabel Gauthier, members of the Temporal Dynamics Learning Center supported by NSF, compared two different kinds of learning traditionally called “perceptual expertise” and “perceptual learning”. The scientists bridged across very different training methods, to learn about how the kind of experience we have with an object category determines what we learn about them and which brain networks are responsible for the learning. The behavioral work (Wong et al., 2011) reveals that at least some degree of category-general perceptual expertise about object shape is acquired incidentally during a task where shape differences between objects are not relevant. The brain imaging work (Wong et al., in press) shows how different kinds of experience with the same objects can produce learning in very different brain networks.

Impact/benefits:
The work reveals the importance of the kind of experience we have with objects, rather than simply the appearance of the objects or the level of performance, in causing patterns of category-specialization in the brain. The results can help us understand how the brain supports learning of specialized perceptual skills of different kinds, from those involved in recognizing letters and numbers to the recognition of faces and complex objects.

Explanation:
Psychologists often focus their studies around very specific phenomena, such that entire areas of study become so specialized it can be hard to compare the results. This is the case of perceptual learning and perceptual expertise, two fields of visual training studies that both investigate how practice can improve visual performance. Behaviorally, perceptual expertise can result in improvements that generalize to similar objects in untrained tasks, whereas perceptual learning is often highly specific to training conditions. In the brain, perceptual expertise has been shown to change activity in high-level areas of the visual system thought to support complex object recognition, whereas perceptual learning has been associated with changes in primary visual cortex. Up to now, it was difficult to interpret these differences, because perceptual learning studies were typically done with a single simple target object, often shown in the periphery, while perceptual expertise studies involved many complex objects shown at the fovea. The present work bridged across these two areas by comparing two groups of people trained with the same set of moderately complex objects, shown in the periphery, but performing different training tasks.


Examples of objects the participants trained with in Wong et al. (2011, inpress)

 


Flattened maps for the two training groups in Wong et al., (in press), showing different kinds of learning effects in visual areas depending on training experience (in this case tested during a visual search task most similar to the PL training task). Orange areas showed an increase in activity specific to the trained category of objects, and blue areas shows a significant decrease specific to the trained category of objects.

 

Wong, Y. K., Folstein, J.R. & Gauthier, I. (2011). Task-irrelevant perceptual expertise, Journal of Vision, 11(14):3.

Wong, Y.K., Folstein, J.R., & Gauthier, I. (in press). The nature of experience determines object representations in the visual system. Journal of Experimental Psychology: General.