{"id":789856,"date":"2026-07-09T05:32:07","date_gmt":"2026-07-09T05:32:07","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/789856\/"},"modified":"2026-07-09T05:32:07","modified_gmt":"2026-07-09T05:32:07","slug":"science-journal-human-brain-evolved-for-no-particular-reason","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/789856\/","title":{"rendered":"Science Journal: Human Brain Evolved \u201cFor No Particular Reason\u201d"},"content":{"rendered":"

Evolutionary biology has lots of problems. But one problem that most folks think the field doesn\u2019t have is coming up with a reason for why humans evolved bigger brains. After all, we\u2019ve heard countless times that bigger brains evolved to allow for higher intelligence in our hominid ancestors, because higher intelligence was selected to help our ancestors to better survive and reproduce. These kinds of arguments are everywhere \u2014 here are a few typical examples:<\/p>\n

A 2007 chapter titled \u201cThe Evolution of Brain Size and Intelligence\u201d in an MIT Press book reads: \u201cIt is reasonable to hypothesize that bigger brains evolved based on natural selection for increased intelligence.\u201d (Rushton and Ankney, 2007<\/a>)<\/p>\n

A 2025 paper in Philosophical Transactions of the Royal Society B states that \u201chominin brain expansion underpinned large increases in cognitive abilities.\u201d (Gonz\u00e1lez-Forero and G\u00f3mez-Robles, 2025<\/a>)<\/p>\n

According to a 2011 paper in Frontiers in Human Neuroscience, \u201cAn increase in brain size could also result in an increase in the complexity of its functions. \u2026 the evolution of encephalization essentially involves an increase in the brain\u2019s capacity to process information.\u201d (Cairo, 2011<\/a>)<\/p>\n

A new article <\/a>at Phys.org notes: \u201cFor decades, researchers generally assumed that these changes were the result of sustained, directed natural selection; larger brains were favored because they improved cognitive abilities.\u201d<\/p>\n

It\u2019s so simple it\u2019s a no brainer (pun intended!): Bigger brains evolved to make us smarter, a trait that was gradually favored by natural selection over time. And yet, even here evolutionary theory is apparently not supported by the evidence.<\/p>\n

\u201cNo Particular Reason\u201d<\/p>\n

According to an article in New Scientist, \u201cHuman brains may have got bigger for no particular reason<\/a>.\u201d Says science writer Michael Marshall, \u201cthere is no evidence that evolution strongly favoured big brains in the past 2 million years of human evolution, according to a new analysis of fossil skulls.\u201d<\/p>\n

The article cites a newly published study <\/a>in Nature Communications, by anthropologist Mark Hubbe and paleoanthropologist Katerina Harvati, which notes that although brain size in Homo does get bigger over time, the changes appear to be \u201cstochastic\u201d \u2014 i.e., random \u2014\u00a0and \u201cdid not support gradual directional selection as a driving force.\u201d In other words, the old idea that natural selection gradually favored bigger and bigger brains in our ancestors is not supported by the evidence. This is a big deal, to put it mildly, because it means what virtually every \u201cman on the street\u201d believes about human brain evolution is simply not true.<\/p>\n

Random and Constrained Evolution<\/p>\n

Instead, the study finds that random evolution \u2014 not natural selection \u2014 is the reason our brains got bigger \u2014 and there were other forces that prevented continued growth in brain size. New Scientist summarizes the findings this way:<\/p>\n

The changes in size and shape of the braincase were best explained by neutral evolution. This means random mutations affected the size and shape and changes accumulated over time, without the new braincase designs ever being advantageous compared with the old ones. There was also evidence of stasis: evolution pressuring the braincase to stay roughly the same shape and size.<\/p>\n

The technical paper summarizes the findings as follows:<\/p>\n

In conclusion, our results are consistent with previous work suggesting a limited role for gradual directional selection in human evolution and underscore the importance of stabilizing selection and constraints, which our analyses strongly supported relative to other evolutionary processes. The cranial morphology of the genus Homo was therefore likely shaped by factors constraining the accumulation of variation (i.e., that promoted evolutionary stasis), as well as by stochastic processes.<\/p>\n

Think Bigger<\/p>\n

The human brain is \u201cthe most complex object in the known universe,\u201d according to famed neuroscientist Christof Koch<\/a>. And now we\u2019re being told that evolution claims this momentously important organ arose \u201cfor no particular reason.\u201d Just wow.<\/p>\n

In more technical terms, this study is fascinating because it shows that one of humanity\u2019s defining traits is not well explained by the idea of incremental, selection-driven increases gradually making our ancestors smarter over time. To resort to \u201cstochastic,\u201d \u201cneutral,\u201d \u201crandom\u201d evolutionary processes \u2014 or as New Scientist puts it, evolution \u201cfor no particular reason\u201d \u2014 is to admit that they have no compelling Darwinian narrative for why our bigger and smarter brains arose. It is tantamount to saying the human brain, chief marvel in the cosmos as far as we can tell, evolved because, well, why the heck not?<\/p>\n

Apart from that incredibly uncompelling conclusion, the study supports a core ID postulate: that change in living systems isn\u2019t unlimited. As the technical paper finds, there are \u201cevolutionary limits constraining their potential to evolve new phenotypes,\u201d in this case referring to limits on our ability to evolve bigger, smarter brains.<\/p>\n

All this goes to show that sometimes even the problems you think evolution has solved turn out to be anything but.<\/p>\n","protected":false},"excerpt":{"rendered":"Evolutionary biology has lots of problems. But one problem that most folks think the field doesn\u2019t have is…\n","protected":false},"author":2,"featured_media":789857,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,66],"class_list":["post-789856","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/789856","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=789856"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/789856\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/789857"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=789856"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=789856"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=789856"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}