Scientists have believed for ages that larger bodies correspond to larger minds. However, recent findings contradict this idea, indicating that these organs can only grow to a certain size. But this does not hold for people. Large brain sizes are the result of our brains evolving 23 times quicker than those of other mammals, according to a study that was published in the journal Nature Ecology & Evolution. The study's principal author, Chris Venditti of the University of Reading in the United Kingdom, clarified that it was assumed that there was a linear link between the brain and the body, meaning that an animal's size would correspond to its brain size. However, the study revealed that the size of a brain may have a physical limit.

Modern Science Breaking Old And Rusty Myths:

The brain is an amazing organ; differences in its size have profound effects on cognition, behavior, social interaction, and eventually, mankind, as co-author Joanna Baker of the University of Reading told 'Down To Earth'. She did, however, note that despite decades of research, there is still much we don't know about the evolution of brain size. In order to obtain specific answers on the evolution of brain size, Baker and colleagues gathered and examined a dataset of body and brain sizes from about 1,500 species. They also concentrated on looking for any abrupt changes in the pace of evolution of the relative sizes of the brains. Their research revealed that there is a curvilinear association between body size and brain size. This implies, in Baker's opinion, that although brain size increases with bodily size, this growth is limited. She continued, saying that "the largest mammals have smaller brains than expected for their body size."


Size Of The Brains and How the Size Evolved is Still an Area of Research ~ (Source: Google Images) 

Although the researchers are unsure of the exact cause, they believe that larger-than-average brains may be too much for animals to sustain. Compared to the smallest mammals, the largest mammals see a 44% decrease in brain size change per unit of body mass. Additionally, the study discovered that the quick change in brain size was more noticeable in primates, rodents, and carnivores.

The relative brain sizes of these three groups, including humans, tend to increase over time. “We discovered a phenomenal acceleration in the rate of evolution along the branch leading to our species — associated with a massive increase in relative brain size,” Baker noted. The cause of this development is yet unknown to the researchers. However, Baker believes that these animals—possibly more so than other groups—display a great deal of ecological and behavioral diversity. “We also see more social behaviors amongst these groups — some of the exemplars of sociality fall within these clades (for instance, humans, meerkats, and mole rats),” she highlighted. It remains to be seen whether the large brains of rodents, carnivores, and primates are driven by common causes such as diet, life history, or behavior, or nuanced patterns within each group, she added.

Example of Bats ~ Bats exhibited the contrary pattern. Since they initially developed, their brain size has shrunk, indicating a very slow pace of relative brain mass evolution—roughly 2.5 times slower than that of other mammals. The researchers clarify that the difficulties associated with flying could be the cause of this. Further research is required on other factors, such as food and hibernation. The team's next goal is to comprehend why there is a limit to brain sizes. We investigated a few possible causes, such as an energy restriction. or a limitation on the ability of neurons? However, thus far, we have come up empty. For next studies on brain evolution, solving this riddle is essential," said Baker.

The Bottom Line ~  So What Determines a Person's Intelligence?

More recent research has led many experts to conclude that brain shape, not size, determines an individual's IQ. Many experts argue that an individual's intelligence is determined by the molecular activity at the synapses, the communication junctions between neurons where nerve impulses pass, and the underlying structure of the brain. 

The brain is the most incredible act of creation wherein it possesses limitless possibilities. More innovative research can lead to unraveling abilities and reasoning on how we live our daily routines!