A cultural side effect: learning to read interferes with identity processing of familiar objects

Area of Science:

• Cognitive Neuroscience
• Visual Perception
• Developmental Psychology

Background:

• The neuronal recycling hypothesis proposes that cultural inventions like reading repurpose existing neural circuits.
• Literacy acquisition involves learning to discriminate mirror-image letters, potentially impacting general visual processing.

Purpose of the Study:

• To investigate if reading acquisition incurs a cost for recognizing non-linguistic visual materials.
• To determine if the ability to differentiate mirror images interferes with object identity judgments.
• To examine how interference strength varies with the type of visual material (objects vs. shapes).

Main Methods:

• Adult participants (illiterate, late-literate, early-literate) performed an identity-based same-different task.
• Stimuli included physically identical, mirrored, or plane-rotated images of familiar objects and geometric shapes.
• An orientation-independent comparison assessed interference from irrelevant visual variations.

Main Results:

• Interference from orientation variations was greater for plane rotations than mirror images, and for geometric shapes than familiar objects.
• Illiterate adults showed near-immunity to mirror variations for familiar objects.
• Literacy acquisition, particularly unlearning mirror-image generalization, negatively impacts object recognition.

Conclusions:

• The process of learning to read has a cost for the visual ventral object recognition stream.
• Neural recycling for literacy involves exaptation, repurposing visual systems for new functions at a functional cost.
• Literacy acquisition alters fundamental visual processing capabilities, demonstrating a trade-off in neural adaptation.