In a groundbreaking study conducted by researchers at Eötvös Loránd University, scientists have taken significant strides in understanding the organization and aging patterns of our canine companions. Their findings provide evidence that dogs possess a key component of intelligence known as the general cognitive factor, or ‘g factor,’ which mirrors the human version, especially in relation to aging. The research was recently published in GeroScience.
The ‘g factor’ represents a core intelligence that influences an individual’s overall cognitive performance across a variety of tasks. This concept stems from the observation that people who perform well on one type of cognitive task tend to perform well on others, suggesting the existence of a common underlying ability or factor that contributes to these performances.
Previous research has shown that, like humans, older dogs can exhibit symptoms reminiscent of dementia, making them a valuable model for studying cognitive aging. However, studies have typically focused on cognitive changes in isolation, without exploring how different cognitive abilities might interrelate or how age impacts these abilities across a broader spectrum. This study aimed to fill these gaps, investigating the potential existence of a general cognitive factor in dogs.
“Personally, I was interested because my favorite topic in dog ethology is personality and individual consistent behavioral patterns,” said Borbála Turcsán, one of the lead authors of the study and a postdoctoral researcher in the Department of Ethology. “Unlike personality, cognition has been investigated so far as one ability at a time.”
“This project offered me the opportunity to investigate if there are associations between different cognitive abilities indicating the existence of higher-level cognitive domains in dogs (including a potential g factor-candidate), and if they are also consistent over long periods of time. If such higher-level factors exist (and they do), it opens new research directions with lots of interesting questions. One of them we could investigate in the course of our study was the number of independent age effects on dog cognition, but there are plenty of others.”
The study included 129 dogs of various breeds, ensuring a sample that reflected a broad spectrum of the canine population. These dogs ranged in age, providing a representative cross-section for examining cognitive abilities across different life stages. Before embarking on the cognitive tests, each dog underwent a preliminary assessment to ensure they were free from major sensory impairments or physical conditions that could impede their ability to complete the tasks, ensuring the integrity of the test results.
At the heart of the research was a battery of ten cognitive tests designed to probe various dimensions of canine intelligence, including associative learning, memory, problem-solving abilities, and social cognition. These tasks were chosen based on their potential relevance to the general cognitive abilities observed in other species, including humans.
The cognitive test battery was conducted in a controlled environment, with the sequence of tasks standardized for all participants to minimize any carry-over effects from one task to another. This rigorous approach allowed the researchers to capture a comprehensive snapshot of each dog’s cognitive capabilities.
One of the most significant findings from this study was the identification of a g factor in dogs. This factor emerged from the analysis as a significant contributor to variance across different cognitive domains, indicating that it represents a central component of intelligence rather than a collection of unrelated cognitive skills.
Further analysis revealed a hierarchical structure of canine cognition, with specific cognitive abilities feeding into broader cognitive domains, which in turn contribute to the general cognitive factor. This structure mirrors the hierarchical organization of human intelligence. In dogs, two distinct cognitive domains were identified — individual problem-solving and associative learning — each contributing to the overarching ‘g factor.’
Dogs that scored high on the g factor were more adventurous and curious about unknown environments, showed a heightened interest in new objects or situations, and excelled in learning new tasks compared to their lower-scoring counterparts. This propensity for exploration, novelty, and learning aligns closely with traits associated with the g factor in humans.
Additionally, the researchers investigated the relationship between the canine g factor and personality traits, utilizing questionnaires completed by the dog owners. The results underscored a clear pattern: higher g factor scores were consistently linked with increased levels of activity, a greater willingness to engage in training, and higher trainability. This relationship between the canine g factor and key personality traits further cemented the resemblance between canine and human general intelligence.
“The findings suggest that the cognitive abilities of dogs are interconnected rather than independent,” Turcsán told PsyPost. “If a dog excels in one cognitive skill, it is likely to perform well in others too. Similar to humans, dogs exhibit what is known as a general cognitive factor (g factor). This overarching factor encompasses and influences various cognitive abilities and resembles the human g in many ways.”
Importantly, the general cognitive factor showed a decline with age, highlighting a vulnerability in cognitive organization that transcends species. This aspect of the findings is particularly poignant, as it suggests that the decline in general cognitive abilities with age is a common phenomenon across species. Health issues were also found to modulate the relationship between age and the general cognitive factor, suggesting that cognitive decline with age might be more pronounced in dogs with poorer health.
“It is well-known that as dogs age, their attention, learning ability, and memory naturally decline. However, if cognitive abilities are interconnected, it’s plausible that their decline with age is not independent but rather linked to a common underlying factor behind the deterioration of various abilities,” explained Zsófia Bognár, a PhD student and the other lead author of the study.
“This new research highlights intriguing parallels between human and canine ageing, further strengthening the argument that dogs serve as an excellent model species for ageing research,” added Enikő Kubinyi, leader of the MTA-ELTE Companion Animal Research Group and the Senior Family Dog Project.
But the researchers cautions against directly comparing the intelligence of different dog breeds based on the canine ‘g factor.’
“One significant caveat is the ‘breed question’ — that is, determining which breed is the most intelligent,” Turcsán explained. “Since the canine g factor provides a potential common metric for comparing dogs’ cognitive performance, questions naturally arise regarding potential breed differences. However, it is important to note that comparing human populations typically involves standardized scores (such as the IQ score) rather than raw test performance values, as individual characteristics (such as age and education) can significantly influence performance. So, similarly, standardized scores would need to be developed for dogs before meaningful comparisons could be made across breeds and individuals.”
“Furthermore, breed selection in dogs could further complicate comparisons. Many dog breeds have been selectively bred for their social cognitive skills, such as sensitivity to and compliance with human guidance, rather than individual problem-solving abilities. However, the g factor, both in dogs and humans, does not encompass social cognitive abilities. Therefore, any results of breed comparisons should be interpreted with caution, as they could be misleading.”
The research provides valuable insights that could inform future studies and interventions aimed at enhancing cognitive health in dogs. The study also opens up new questions about the neurobiological underpinnings of the general cognitive factor and its age-related changes. But the continuation of this line of research is in doubt due to existing limitations on resources.
“This five-year study, involving at least a dozen students and researchers from the Senior Family Dog Project, has yielded significant results culminating in this paper and its recently published counterpart in the same journal,” Turcsán said. “While this line of research has generated numerous intriguing questions, it demands considerable resources and manpower to conduct, resources that are currently lacking. As a result, it remains uncertain whether we will be able to return to work on this topic in the future.”
The study, “Age-related effects on a hierarchical structure of canine cognition,” was authored by Zsófia Bognár, Borbála Turcsán, Tamás Faragó, Dóra Szabó, Ivaylo Borislavov Iotchev, and Enikő Kubinyi.
