Summary: Scientists have discovered that cuttlefish can create false memories, similar to humans. By exposing cuttlefish to overlapping features of different events, they made the creatures falsely remember seeing shrimp where there were none.
This finding suggests that cuttlefish reconstruct memories from discrete details, thereby optimizing memory storage. Individual cuttlefish showed different propensities to form false memories, indicating differences in memory processing.
Key facts:
- Cuttlefish can create false memories by reconstructing discrete sensory details.
- The study used visual patterns and smells to trick cuttlefish into false memories.
- There were significant individual differences in susceptibility to false memories among cuttlefish.
Source: Cell Press
During an event, details such as what you saw, felt, and felt are not stored as a single memory. Rather, they are encoded and stored separately in your brain. To get this memory, these pieces must be put back together. When this is not done in the right way or the details are distorted, it can lead to the creation of false memories.
Now researchers report in the journal iScience On July 17, they have evidence that cuttlefish can also create false memories.
“Creating false memories is different from memory errors,” said Christelle Jozet-Alves of the University of Caen in Normandy, France.
The results suggest that cuttlefish do not encode events like film strips, but rather mentally reconstruct the event by connecting different features that were present during the original event, says Jozet-Alves.
Cuttlefish have been recognized as the only invertebrates to have episodic memory. In other words, they can remember and recall what happened to them in the past. But the underlying mechanisms involved in their ability to recall previous events were unknown. Does cuttlefish memory for past events depend on the reconstruction process?
To find out, Jozet-Alves and colleagues decided to try to induce false memories in cuttlefish. If animals rely on a reconstruction process for their episodic memories, they reasoned, then they should be prone to forming false memories.
To encourage false memories, researchers exposed cuttlefish to consecutive events with many common features. They wanted to see if they could get the cuttlefish to remember seeing their favorite food – shrimp – in a particular test tube, even though they hadn’t. First, they showed the cuttlefish different test tubes, one with shrimp, one with the less-preferred crab, and one empty. Each tube had a specific visual pattern.
Next, they showed two of the three test tubes they had encountered before: the shrimp test tube and the empty test tube, but this time the contents of the test tubes were not visible. They tried to trick the animals with visual patterns and smells, creating overlapping elements.
The question was whether the cuttlefish would falsely remember the shrimp in a tube that was actually empty because they had seen the tube a second time in the presence of the shrimp tube.
To test this, they had the cuttlefish choose between an empty tube and a crab tube with invisible contents. And their choices indicated that misleading information in those past events had altered their memories.
Instead of choosing the tube containing their less-preferred crab, the cuttlefish sometimes chose the empty tube more often than otherwise expected, suggesting they thought they remembered it contained shrimp.
Although more studies are needed, the findings suggest that cuttlefish can form false memories for visual information, but not for smells. The researchers suggest that this memory strategy may reduce memory costs.
If cuttlefish can store the smaller building blocks of memories and then reconstruct them, it could optimize memory while allowing them to imagine different combinations of functions in the future, the researchers suggest. However, they also noted an unexpected amount of variation between individuals.
“What was surprising was that the susceptibility to form false memories seems to vary between individuals,” Jozet-Alves said.
“Some appeared intact when exposed to misleading events, while others developed false memories. This phenomenon is commonly found in our own species, where this susceptibility varies between and among individuals.’
In future studies, they say, it will be important to “better understand why all individuals are not as sensitive to false memory formation and whether it may change for an individual depending on their age, level of attention to the task, or even their emotional state.”
About this memory research report
Author: Christopher Benke
Source: Cell Press
Contact: Christopher Benke – Cell Press
Picture: Image is credited to Neuroscience News
Original Research: Open access.
“False memories in cuttlefish” by Christelle Jozet-Alves et al. iScience
Abstract
False memories in cuttlefish
Highlighting
- Episodic memory in cuttlefish is based on reconstruction processes
- Visual misleading events impair memory retrieval and create false memories
- 80% of cuttlefish remembered the previous event when not misled
summary
Episodic memory is a reconstructive process by itself: during an event, its constituent elements are encoded and stored separately in the brain and then reconstructed when the memory of the event is retrieved. Even source monitoring processes (eg did I see it or smell it?) can make some mistakes.
These mnemonic errors occur especially when different events share several features, leading to hard-to-distinguish overlaps, leading to the creation of false memories. Cuttlefish have the ability to remember specific events about what happened where and when, called episodic memory.
To investigate whether this memory, like human episodic memory, is based on reconstruction processes, we developed a protocol supporting false memory formation.
Our results suggest that cuttlefish form visual false memories but not olfactory false memories. These memory errors may be the first indication of the presence of reconstruction processes in the memory of cephalopods.