# behav: ADHD may have been a feature of nomadic exploration among hunter-gatherer societies

<< All mobile organisms forage for resources, choosing how and when to search for new opportunities by comparing current returns with the average for the environment. In humans, nomadic lifestyles favouring exploration have been associated with genetic mutations implicated in attention deficit hyperactivity disorder (ADHD), inviting the hypothesis that this condition may impact foraging decisions in the general population. >>️

David L. Barack, Vera U. Ludwig, et al. 

Attention deficits linked with proclivity to explore while foraging. Proc Royal Society B.  doi: 10.1098/ rspb.2022.2584. Feb 21, 2024. 

https://doi.org/10.1098/rspb.2022.2584     

<< Is it a legacy of the hunter-gatherer world? >> Arjun Ramakrishnan

Chen Ly. ADHD may have evolved to help foragers know when to cut their losses. newscientist.com Feb 21,2024.

https://www.newscientist.com/article/2418114-adhd-may-have-evolved-to-help-foragers-know-when-to-cut-their-losses

Also: nomads, bushmen, behav, uncertainty, curiosity, in https://www.inkgmr.net/kwrds.html

Keywords: adhd, nomads, hunter-gatherers, behavior, behaviour

# life; a hypothetical externalization of knowledge effects; humans are thought to have decreased in brain volume since the end of the last ice age (3,000 y.ago)

<< Human brain size nearly quadrupled in the six million years since Homo last shared a common ancestor with chimpanzees, but human brains are thought to have decreased in volume since the end of the last Ice Age. The timing and reason for this decrease is enigmatic. Here (AA) use change-point analysis to estimate the timing of changes in the rate of hominin brain evolution. (They) find that hominin brains experienced positive rate changes at 2.1 and 1.5 million years ago, coincident with the early evolution of Homo and technological innovations evident in the archeological record. But (AA) also find that human brain size reduction was surprisingly recent, occurring in the last 3,000 years. >>

Jeremy M. DeSilva, James F. A. Traniello, et al. When and Why Did Human Brains Decrease in Size? A New Change-Point Analysis and Insights From Brain Evolution in Ants. Front. Ecol. Evol.,  doi: 10.3389/ fevo.2021.742639. Oct 22, 2021. 

https://www.frontiersin.org/articles/10.3389/fevo.2021.742639/full

When and why did human brains decrease in size 3,000 years ago? Ants may hold clues. Frontiers. Oct 22, 2021.

https://phys.org/news/2021-10-human-brains-decrease-size-years.html

Also

keyword 'nomade' | 'nomad' | 'nomads' | 'nomadic' | 'hunter-gatherers' in FonT

https://flashontrack.blogspot.com/search?q=nomade

https://flashontrack.blogspot.com/search?q=nomad

https://flashontrack.blogspot.com/search?q=nomads

https://flashontrack.blogspot.com/search?q=nomadic

https://flashontrack.blogspot.com/search?q=hunter-gatherers

keyword 'nomade' | 'nomadi' in Notes (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=nomade

https://inkpi.blogspot.com/search?q=nomadi

keyword 'ctz' entities in FonT

https://flashontrack.blogspot.com/search?q=ctz

keywords: evolution, brain, brain size, nomads, post-nomads, sociocultural effects

# art: Nomadic masters; Neanderthals created art.

AA << analysed samples of red residues collected from the flowstone surface and compared them with iron oxide-rich deposits in the cave. They concluded that the ochre-based pigment was intentionally applied, i.e. painted -- by Neanderthals, as modern humans had yet to make their appearance on the European continent -- and that, importantly, it had probably been brought to the cave from an external source. >>

<< variations in pigment composition between samples were detected, corresponding to different dates of application, sometimes many thousands of years apart. Thus, it seems that many generations of Neanderthals visited this cave and coloured the draperies of the great flowstone formation with red ochre. >>

<< This behaviour indicates a motivation to return to the cave and symbolically mark the site, and it bears witness to the transmission of a tradition down through the generations. >>

Neanderthals indeed painted Andalusia’s Cueva de Ardales. CNRS. 

Aug 2, 2021. 

https://www.sciencedaily.com/releases/2021/08/210802160624.htm

Africa Pitarch Marti, Joao Zilhao, et al. The symbolic role of the underground world among Middle Paleolithic Neanderthals. PNAS. 118 (33) e2021495118; doi: 10.1073/ pnas.2021495118. Aug 17, 2021. 

https://www.pnas.org/content/118/33/e2021495118