summary: The researchers found that cuttlefish, like humans, can form false memories: by exposing them to overlapping features of different events, they could induce the squid to falsely remember seeing shrimp in places where there were no shrimp.
The findings suggest that cuttlefish reconstruct memories from individual details to optimize memory storage. Individual cuttlefish have different susceptibility to forming false memories, indicating differences in memory processing.
Key Facts:
- The cuttlefish are able to form false memories by reconstructing the details of individual sensors.
- The study used visual patterns and smells to implant false memories in squid.
- Among the squids, there was striking individual variation in susceptibility to false memories.
sauce: Cell Press
The details of what you saw, smelled, and felt during the event aren’t stored as a single memory. Rather, they’re coded separately and stored in your brain. To recall that memory, you have to put those pieces together again. If this isn’t done properly, or if the details are distorted, a false memory can be created.
Now, the researchers report in the journal iScience On July 17, evidence was found that cuttlefish can also create false memories.
“Forming a false memory is not the same as committing a memory error,” says Christelle Josée Alves of the University of Caen in Normandy, France.
The results suggest that the squids are not encoding events as a film strip, but rather mentally reconstructing them by linking different features that were present during the original event, says Josette Alves.
Squids are the only known invertebrates that possess an episodic-like memory. In other words, squids can remember and recall things that happened in the past. However, the underlying mechanisms involved in squids’ ability to recall past events were unknown. Does squids’ memory of past events depend on a reconstructive process?
To find out, Josette-Alves and her colleagues decided to try inducing false memories in the squid: if the squid rely on a reconstitution process for memories such as episodic memories, they reasoned, they should be more likely to form false memories.
To stimulate false memories, the researchers showed the squids a series of events that had many similarities. They wanted to see if the squids could remember putting their favorite shrimp into a particular tube, even if they hadn’t actually seen it. First, they showed the squids different tubes: one with shrimp, one with a less-preferred crab, and one that was empty. Each tube had a particular visual pattern.
The researchers then showed the animals two of the three tubes they had encountered previously – the shrimp tube and the empty tube – but this time they couldn’t see what was inside. They used visual patterns and smells to trick the animals into overlapping features.
The question was whether the squid would see the tube with shrimp in it for the second time and therefore mistakenly remember that there was shrimp in the tube when in fact it was empty.
To test it, the researchers had squid choose between an empty tube and a crab’s tube with no visible contents, and their choices suggested that false information about past events altered their memories.
Instead of choosing the tube containing the less-preferred crab, the squid chose the empty tube more often than expected, suggesting that they remembered that it contained a shrimp.
Although more research is needed, the findings suggest that cuttlefish can form false memories for visual information but not for smells, a memory strategy that the researchers suggest may reduce memory costs.
The researchers suggest that if the squid could store and reconstruct small components of memory, it might be possible to both optimize their memory and imagine different trait combinations in the future, but they also point out unexpected variability between individuals.
“What surprised us was that individuals seem to vary in their susceptibility to forming false memories,” said Josette Alves.
“Some people are unaffected by exposure to misleading events, while others form false memories. This phenomenon is common in our species, and this susceptibility varies both inter- and intra-individual.”
In future studies, it will be important to “better understand why not all individuals are more or less susceptible to false memory formation and whether it might vary within individuals depending on age, level of attention to the task, or even emotional state,” the researchers say.
About this memory research news
author: Christopher Behnke
sauce: Cell Press
contact: Christopher Behnke – Cell Press
image: Image courtesy of Neuroscience News
Original Research: Open access.
“Squid’s False MemoryBy Christer José Alves et al. iScience
Abstract
Squid’s False Memory
highlight
- Squid episodic memory is based on a reconstructive process
- Visually misleading events impair memory retrieval and create false memories.
- 80% of the squids remembered the previous event unless they were misled.
summary
Episodic memory is a process of reconstitution By itself: During the occurrence of an event, the features that make up that event are encoded and stored separately in the brain, and are reconstructed when the memory of the event is recalled.Even source monitoring processes (e.g., did I see it or smell it?) can make mistakes.
These memory errors occur especially when different events share some characteristics, resulting in overlaps that are difficult to distinguish, leading to the creation of false memories.Cuttlefish have the ability to remember specific events – what happened, when and where – in other words, episodic memory.
To investigate whether human episodic and other memories are based on reconstitution processes, we created a protocol to promote the formation of false memories.
Our results suggest that cuttlefish form visual but not olfactory false memories. These memory errors may be the first indication of the existence of a restructuring process in cephalopod memory.
