Serial memory is a unique human trait

summary: New research reveals a potentially unique human ability to recognize and remember sequence information. Despite being our closest relatives, bonobos struggle to learn to order stimuli the same way humans do.

This discovery contributes to the understanding of cognitive differences between humans and other animals, explaining why humans only possess certain cultural abilities such as language and advanced planning. This sequential memory may be the building block behind many unique human behaviors and abilities.

Key facts:

1. The study reveals that bonobos, our closest relatives, cannot remember the order of visual stimuli as effectively as humans.
2. Previous research has indicated that the ability to recognize and retrieve sequential data is a uniquely human ability, and is essential for advanced language and planning.
3. The research adds weight to the sequential memory hypothesis, which posits that this ability evolved during human prehistory.

source: Stockholm University

Remembering the order of information is essential for anyone when participating in conversations, planning daily life, or undergoing education. A new study published in the scientific journal Plus one, indicates that this ability may be unique to humans. Even humans’ closest relatives, such as bonobos, don’t learn order in the same way.

“The study contributes another piece of the puzzle to the question of how mental abilities differ between humans and other animals, and why humans only speak languages, plan space travel, and learn to exploit Earth so efficiently that we now pose a serious threat.” “Organisms pose a threat to countless other forms of life,” says Johan Lind, associate professor of ethology and deputy director of the Center for Cultural Evolution at Stockholm University. Since September also Associate Professor of Ethics at Linköping University.

Previous research at Stockholm University has suggested that only humans have the ability to recognize and remember so-called sequence information, and that this ability is a fundamental building block that underlies uniquely human cultural capabilities.

But previously, this sequencing memory hypothesis had not been tested in humans’ closest relatives, the great apes. New experiments now show that the bonobo, a great ape, also struggles with learning to order stimuli.

In the recently published book The Human Evolutionary Transition: From Animal Intelligence to Culture (Princeton University Press), ethicists Magnus Enquist and Johan Lind of Stockholm University, and Stefano Ghirlanda, a researcher in psychology at Brooklyn College in New York, lay out a new theory for how human beings into cultural beings. The central idea concerns the difference in how humans and other animals recognize and remember sequence information.

“We have previously analyzed a large number of studies indicating that only humans faithfully recognize and remember sequence information. Although we analyzed data from a number of mammals and birds, including monkeys, there was Lack of information from our closest relatives, the other great apes.”

In a series of experiments, the memory capabilities of bonobos and humans were tested by having them tap on computer screens to, among other things, learn to distinguish between short sequences, including pressing right if the yellow square came before the blue square, or pressing the left of the square shown blue before the yellow square.

“The study shows that bonobos forget that they have actually seen a blue square five to ten seconds after it disappears from the screen, and that they have great difficulty learning to distinguish sequences of the blue square before the yellow square from the yellow square.” “They receive special training,” says Vera Finken, associated with Stockholm University and now a PhD student in Great Britain at Newcastle University’s Institute of Biological Sciences. “It’s a box before a blue box, even though they’ve been trained for thousands of experiments.”

In contrast, the study shows, humans learned to distinguish between short sequences almost immediately. However, we have yet to explain exactly how our closest relatives can remember and use serial information.

“We now know that our closest relatives do not share the same mental continuum capabilities as humans. Even if the results indicate that their working memory works in principle the same way as rats and pigeons, says Magnus Enquist, professor emeritus and co-founder of the Center for Cultural Evolution, No one has actually proven that yet.”

The new findings provide further support for the sequence memory hypothesis, which says that during human prehistory, the ability to remember and process sequences evolved, a necessary mechanism for many uniquely human phenomena such as language, the ability to plan, and sequential reasoning.

About this memory research news

author: Jonella Norden
source: Stockholm University
communication: Jonella Norden – Stockholm University
picture: Image credited to Neuroscience News

Original search: open access.
“A memory test of stimulus sequences in great apes” by Johan Lind et al. Plus one

a summary

Memory test of stimulus sequences in great apes

Determining the cognitive capacities underlying human evolutionary transformation is challenging, and many hypotheses exist as to what makes humans capable of, for example, producing and understanding language, preparing meals, and having culture on a large scale.

Rather than describing the processes by which information is processed, recent studies have indicated that there are key differences between humans and other animals in how information is recognized and remembered.

Such constraints may act as a bottleneck for information processing and subsequent behaviour, proving important for understanding differences between humans and other animals.

We briefly discuss the different sequential aspects of cognition and behavior and the importance of distinguishing between simultaneous and sequential inputs, and conclude that there are no clear tests on non-human great apes.

Here, we test the memory of the stimulus sequences hypothesis with three tests in bonobos and one test in humans. Our results show that bonobos’ general working memory declines rapidly, and that they fail to recognize the difference between the order of the two stimuli even after more than 2,000 trials, supporting previous findings in other animals.

However, as expected, humans resolve the same serial distinction almost instantly. Explicitly testing whether bonobos represented stimulus sequences as an unstructured set of memory traces was not useful, as no differences were found between responses to the different investigation tests.

However, overall, this first experimental study of sequence discrimination on non-human great apes supports the idea that non-human animals, including our closest relatives, lack memory for stimulus sequences.

It may be this ability that distinguishes humans from other animals and could be one of the reasons behind the emergence of human culture.