Summary: The brain exaggerates differences between similar events in order to encode them in memory. This results in divergent brain activity that allows for better memory performance.
In order to remember similar events, the brain exaggerates the difference between them. This results in divergent brain activity patterns but better memory performance, according to new research published in Journal of Neuroscience.
Memory is subjective. Different people recall the same event in unique ways, and people exaggerate the difference between similar events in their own life. Yet this type of bias can be advantageous when it helps the brain distinguish between similar things and prevent confusion.
In a study by Zhao et al., participants memorized different sets of faces paired with colored objects. Some objects were identical except for slight color differences.
At the start of training, the participants had a hard time distinguishing pairs when the objects were almost identical. However, after two days of practice and testing, performance improved.
Participants were then shown a face and imagined the corresponding object while the researchers measured their brain activity with fMRI. Recalling two similar objects resulted in different activity patterns in the intraparietal sulcus, a brain area involved in the subjective aspect of memory.
The more dissimilar the brain activity, the better the participants’ memory performance and the more they exaggerated the color difference in a post-scan test.
About this memory research news
Contact: Calli McMurray – SfN
Image: The image is credited to Zhao et al., JNeurosci 2021.
Original Research: Closed access.
“Adaptive Memory Distortions Are Predicted by Feature Representations in Parietal Cortex” by Yufei Zhao (赵雨菲), Avi J. H. Chanales and Brice A. Kuhl. Journal of Neuroscience
Adaptive Memory Distortions Are Predicted by Feature Representations in Parietal Cortex
Similarity between memories is a primary cause of interference and forgetting. Exaggerating subtle differences between memories is therefore a potential mechanism for reducing interference.
Here, we report a human fMRI study (n = 29, 19 female) that tested whether behavioral and neural expressions of memories are adaptively distorted to reduce interference.
Participants learned and repeatedly retrieved object images, some of which were identical except for subtle color differences. Behavioral measures of color memory revealed exaggeration of differences between similar objects.
Importantly, greater memory exaggeration was associated with lower memory interference. fMRI pattern analyses revealed that color information in parietal cortex was stronger during memory recall when color information was critical for discriminating competing memories. Moreover, greater representational distance between competing memories in parietal cortex predicted greater color memory exaggeration and lower memory interference.
Together, these findings reveal that competition between memories induces adaptive, feature-specific distortions in parietal representations and corresponding behavioral expressions.
Similarity between memories is a primary cause of interference and forgetting. Here, we show that when remembering highly similar objects, subtle differences in the features of these objects are exaggerated in memory in order to reduce interference. These memory distortions are reflected in, and predicted by, overlap of activity patterns in lateral parietal cortex.
These findings provide unique insight into how memory interference is resolved and specifically implicate lateral parietal cortex in representing feature-specific memory distortions.