The human memory can be even more unreliable than previously thought, with people able to form false memories of events within seconds of them occurring, likely influenced by their expectations of what should happen, Gizmodo reports.
This phenomenon is called "short-term memory illusions," wherein the human brain reimagines events to fit preconceptions instead of accurately recording them. The study, titled "Seeing Ɔ, remembering C: Illusions in short-term memory," was published in the journal PLOS One
How Accurate Are the Memories?
Researchers studied the accuracy of short-term memory by recruiting 534 volunteers for four experiments. According to Live Science, each experiment involved memorizing a sequence of Latin alphabet letters presented in a circle.
Participants had to remember the letter's identity and direction, which sometimes involved mirrored images facing backward. Some participants were shown irrelevant letters before their memory was tested. After answering, they had to rate their confidence in their answer.
Results showed that participants were wrong 20% of the time when asked to recall what they saw just a half second ago. This increased to 30% when asked three seconds later. Participants who responded with high confidence had flipped the letter to its regular position 37% of the time, even though they were explicitly warned about mirrored letters appearing in the test.
The researchers repeated the tests with a separate cohort of 348 people, who also showed the tendency to mentally flip mirrored letters. This suggests that the human brain records experiences based on preset notions, which enable the brain to generate better predictions about the world and ignore peculiarities that do not fit with one's preconceptions.
The study's authors wrote that these memory illusions resulted from world knowledge rather than visual similarities. They also stated that their next steps are to design experiments to demonstrate similar short-term memory adjustments in real-world settings and for other types of memory beyond visual and language-related stimuli.
Elizabeth Loftus and Misinformation
Several studies have shown how easily memories can be manipulated. Perhaps one of the famous theories about it is Elizabeth Loftus' misinformation. She theorizes that memories might not be as reliable as most people think.
The renowned professor at the University of California, Irvine, who specializes in human memory, suggests that memories are not necessarily permanent. She warns that memories can be modified or even fabricated, which means that recollections of past events and experiences are not always trustworthy. Despite the initial belief that memories remain unaltered, Loftus stresses the potential for manipulation of our recollections.
But the terms false memory and misinformation effect should not be interchanged. As per The Decision Lab, a false memory is a memory of an event that is entirely or partially distorted.
On the other hand, the misinformation effect happens when memories are altered after exposure to misleading information.Whereas false memory was displayed in the recent study, Loftus' misinformation effect can be seen in witnesses recalling events based on how they answer questions thrown at them in court.
Experiments on the misinformation effect reveal how many fake or traumatic false memories can be planted in someone's mind and can change memories. Scientists continue to explore the misinformation effect until this day to look for more factors that could promote or reduce it.
RELATED ARTICLE: Brain Rotates Sensory Information to Prevent Overwriting Short-Term Memory
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