Rosa Rubicondior: Refuting Creationism - Ability to Perform Complex Tasks Had Already Evolved Before Chimps and Hominins Split

Male chimp cracking nuts.

Photo: Dora Biro.

Study shows that chimpanzees perform the same complex behaviours that have brought humans success | University of Oxford

Time and again, science is showing that characteristics which were once considered uniquely human, and therefore, according to creationists, evidence that humans are a special creation, distinct from all other animals, are in fact shared with other animals.

Instead of being evidence of unique creation, they are evidence of common origins and descent with modification.

On such human characteristic is the ability to perform complex tasks, involving tool use, in organised sequence, and adapt those sequences if necessary to complete the task. In other words, to plan a strategy for achieving a specific goal.

However, a new study has shown that chimpanzees also have this ability, suggesting it was present in the common ancestor before chimps and Hominins diverged some 6 million years ago.

A recent paper in PeeJ says, "Many of the complex behaviours of humans involve the production of nonadjacent dependencies between sequence elements, which in part can be generated through the hierarchical organization of sequences* " What does this mean and what evidence is there that this is an evolved behaviour? The statement refers to the ability of humans to understand and produce patterns where elements in a sequence are related to each other, but not adjacent. This is a hallmark of hierarchical organization, where elements are grouped into nested structures. This ability is fundamental to many human behaviors, such as:

Language: Sentences often contain dependencies between words that are not next to each other. For example, in "The cat that chased the mouse is black," the subject "The cat" is linked to the verb "is," skipping the intervening clause "that chased the mouse."
Music: Musical compositions often involve recurring motifs or themes that reappear after unrelated segments.
Social Behavior: Understanding relationships within complex social networks often involves recognizing indirect connections.
Evidence for Evolution of this Behavior

There are several lines of evidence suggesting that the ability to process nonadjacent dependencies is an evolved trait:

Comparative Studies in Animals:

Some animals show limited ability to recognize nonadjacent dependencies, but humans excel at it. For instance, experiments with primates, birds, and other animals have shown that while they can learn adjacent patterns (e.g., A → B → C), they struggle with nonadjacent patterns (e.g., A → C with B as an intervening element).
Studies on songbirds suggest some capacity for hierarchical organization in their songs, but it is less complex than human language.

Developmental Evidence:

Human infants as young as 7 months can detect nonadjacent dependencies in artificial grammar experiments, suggesting this ability emerges early in development and is likely innate.
This ability improves with age, as children acquire more complex linguistic and cognitive skills.

Neurobiological Evidence:

The human brain has specialized regions, such as Broca's area, associated with processing hierarchical structures in language.
Neuroimaging studies show that processing nonadjacent dependencies activates specific neural circuits, suggesting a biological basis for this ability.

Genetic Evidence:

Genes associated with language and cognitive abilities, such as FOXP2, have undergone selection in humans. Mutations in these genes can impair hierarchical processing, supporting the idea that this trait is genetically encoded.

Cultural Evolution:

The development of languages and other cultural artifacts over time reflects the ability to process and create hierarchical structures. The universality of complex grammar across human languages suggests an evolutionary basis.

Why It Matters
The ability to process nonadjacent dependencies is thought to provide a significant adaptive advantage, enabling humans to communicate complex ideas, solve problems, and navigate intricate social environments. It likely co-evolved with other cognitive capacities, such as memory and abstract reasoning, making it a cornerstone of human intelligence.

The study, led by researchers from Oxford university, is published in the journal PeerJ, and described in a University of Oxford news item:

Study shows that chimpanzees perform the same complex behaviours that have brought humans success
A new study led by the University of Oxford suggests that the fundamental abilities underlying human language and technological culture may have evolved before humans and apes diverged millions of years ago. The findings have been published in the journal PeerJ.
Many human behaviours are more complex than those of other animals, involving the production of elaborate sequences (such as spoken language, or tool manufacturing). These sequences include the ability to organise behaviours by hierarchical chunks, and to understand relationships between distantly separated elements.

For example, even relatively simple human behaviours like making a cup of tea or coffee require carrying out a series of individual actions in the right order (e.g. boiling the kettle before pouring the water out). We break such tasks down into solvable chunks (e.g. boil the kettle, get the milk and teabag, etc), composed of individual actions (e.g. ‘grasp’, ‘pull’, ‘twist’, ‘pour’). Importantly, we can separate related actions by other chunks of behaviour (e.g. you might have to stop and clean up some spilt milk before you continue). It was unknown whether the ability to flexibly organize behaviours in this way is unique to humans, or also present in other primates.

In this new study, the researchers investigated the actions of wild chimpanzees – our closest relatives – whilst using tools, and whether these appeared to be organised into sequences with similar properties (rather than a series of simple, reflex-like responses).

The study used data from a decades-long database of video footage depicting wild chimpanzees in the Bossou forest, Guinea, where chimps were recorded cracking hard-shelled nuts using a hammer and anvil stones. This is one of the most complex documented naturally-occurring tool use behaviours of any animal in the wild. The researchers recorded the sequences of actions chimps performed (e.g. grasp nut, pass through hands, place on anvil, etc.) – totalling around 8,260 actions for over 300 nuts.

Using state-of-the-art statistical models, they found that relationships emerged between chimpanzees' sequential actions which matched those found in human behaviours. Half of adult chimpanzees appeared to associate actions that were much further along the sequence than expected if actions were simply being linked together one-by-one. This provides further evidence that chimpanzees plan action sequences, and then adjust their performance on the fly.

Understanding how these relationships emerge during action organization will be the next key goal of this research, but these could involve behaviours such as chimpanzees pausing sequences to readjust tools before continuing, or bringing several nuts over to stone tools that are then cracked in one long sequence. This would be further evidence of human-like technical flexibility.

Additionally, the results suggest that the majority of chimpanzees organise actions similarly to humans, through the production of repeatable 'chunks'. However, this result did not hold for every chimpanzee, and this variation between individuals may suggest that these strategies for organising behaviours may not be universal in the way they are for humans.

Interestingly, even the youngest chimpanzees in our study showed signs of organizing behaviors by chunks of actions. This suggests that this system of behavioral organization could be something which emerges very early in life.

Our results suggest that the sequences of actions that wild chimpanzees use to perform their tool-use behaviours share many properties with those of humans, and so likely evolved before the last common ancestors of humans and chimps. Archaeological evidence from other studies suggests that chimpanzees have been using stone tools for thousands of years, in a similar manner to today. Further research is needed to understand why humans can produce new technologies at such fast rates, whereas the tool-use behaviours of chimpanzees seem to change very slowly.

Dr Elliot Howard-Spink, lead author
Department of Biology
University of Oxford
now Max Planck Institute of Animal Behavior.

As many great apes perform dextrous and technical foraging behaviours, it is likely that the capacity for these complex sequences is shared across ape species. More research is needed to validate this theory, and is a key goal for the team moving forward.

The researchers also plan to investigate how actions are grouped into higher-order chunks by chimpanzees during tool-use. This research will aim to clarify the rules that chimpanzees follow when generating their tool use behaviours. They will also investigate how these structures emerge during development and are shaped across adult lives.

The study ‘Nonadjacent dependencies and sequential structure of chimpanzee action during a natural tool-use task’ has been published in the journal PeerJ. The research was led by the University of Oxford with an international collaboration across the UK, US, Germany, Switzerland, and Japan.

Abstract

Many of the complex behaviours of humans involve the production of nonadjacent dependencies between sequence elements, which in part can be generated through the hierarchical organization of sequences. To understand how these structural properties of human behaviours evolved, we can gain valuable insight from studying the sequential behaviours of nonhuman animals. Among the behaviours of nonhuman apes, tool use has been hypothesised to be a domain of behaviour which likely involves hierarchical organization, and may therefore possess nonadjacent dependencies between sequential actions. However thus far, evidence supporting hierarchical organization of great-ape tool use comes from methodologies which have been criticised in their objectivity. Additionally, the extent to which nonadjacent dependencies appear in primate action sequences during tool use has not been formally investigated. We used estimations of mutual information (MI)—a measure of dependency strength between sequence elements—to evaluate both the extent to which wild chimpanzees produce nonadjacent dependencies during a naturalistic tool-use task (nut cracking), as well as how sequences of actions are likely organized during tool use. Half of adult chimpanzees produced nonadjacent dependencies at significantly greater sequential distances than comparable, nonhierarchical Markov models once repeated actions had been accounted for. Additionally, for the majority of chimpanzees, MI decay with increasing sequential distance included a power-law relationship, which is a key indicator that the action sequences produced by chimpanzees likely entail some degree of hierarchical organization. Our analysis offered the greatest support for a system of organization where short subroutines of actions (2–8 actions long) are hierarchically arranged into longer sequences—a finding which is consistent with previous qualitative descriptions of ape tool-use behaviours. Interindividual variability was detected within our analysis in both the maximum distance dependencies were detected, and the most likely structuring mechanism for sequential action organization. We discuss these results in light of possible interindividual variation in the systems of action organization used by chimpanzees during tool use, in addition to methodological considerations for applications of MI estimations to sequential behaviours. Moreover, we discuss our main findings alongside hypotheses for the coevolution of complex syntax in language and tool-action across hominin evolutionary history.

Howard-Spink E, Hayashi M, Matsuzawa T, Schofield D, Gruber T, Biro D. 2024.
Nonadjacent dependencies and sequential structure of chimpanzee action during a natural tool-use task. PeerJ 12:e18484 https://doi.org/10.7717/peerj.18484

Copyright: © 2024 The authors.
Published by PeerJ Inc. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

Here we have another example of something creationists claim to be uniquely human and so evidence of special creation, turning out to be nothing of the sort and instead is evidence of our evolution from the common ancestor of humans and chimpanzees.

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