[{"id":310,"title":"Adaptive myopia: how nearsightedness on land helps us underwater","sha":"68fb154b91d5c73a3c794081b7773663","user_id":null,"state":"published","body":"Myopia, or nearsightedness, is a common condition in humans, making it an interesting trait to study from an evolutionary perspective. Although the morphology of the human eye evolved under conditions whereby light entered predominantly through air, we propose that the high prevalence of myopia might be partially attributed to an ancestral past tied to a reliance on seeing in aquatic conditions. Specifically, myopia likely provided an advantage to humans living in environments conducive to foraging and fishing underwater. Four lines of evidence support this hypothesis. First, semi-aquatic mammals are myopic when looking through air [(see)](http://www.ncbi.nlm.nih.gov/pubmed/17516421). Second, humans with myopia see better underwater compared to those with ordinary vision [(see)](http://www.ncbi.nlm.nih.gov/pubmed/24013866). Third, human populations evolving in close association to aquatic environments with clear water (Southeast Asia) have a higher prevalence of myopia than those that evolved without such an association [(see)] (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3740568/). Fourth, the Moken people of Austronesia evolved a cultural adaptation to enhance underwater vision far better than Europeans by learning how to constrict their pupils to produce a myopic condition [(see)] (http://www.ncbi.nlm.nih.gov/pubmed/12747831). While myopia is largely considered detrimental and a byproduct of developing within modern environments, these points suggest that the prevalence of this condition may also be attributed to an underlying adaptive value.","created_at":"2016-05-31T19:20:34.462Z","updated_at":"2016-06-04T02:48:39.639Z","zenodo_id":120433,"doi":"http://dx.doi.org/10.5281/zenodo.54735","subject":null,"tags":["vision","scuba","snorkeling","spearfishing"],"vote_count":1,"view_count":1,"score":1.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":319,"title":"Handgrip strength and semen quality","sha":"98a3818c907dd052d48d9b8c480216dc","user_id":null,"state":"published","body":"Handgrip strength (HGS) is a significant predictor of health and vitality in both men and women, with higher HGS being associated with lower rates of disability, morbidity, mortality, and even dementia ([see](http://archinte.jamanetwork.com/article.aspx?articleid=410366)). For men, HGS is also correlated with variables related to social dominance and sexual behavior ([see](http://www.sciencedirect.com/science/article/pii/S1090513807000669)), as well as sex-specific body morphology and facial attractiveness ([see](http://evp.sagepub.com/content/6/3/147470490800600311.short)). Given these combined connections with health and intrasexual competition, HGS appears to be an indicator of overall genetic quality in males. Here, we hypothesize that HGS should also predict semen quality. In support of this hypothesis, it has been shown that semen quality is positively correlated with longevity ([see](http://aje.oxfordjournals.org/content/170/5/559.short)) and facial attractiveness ([see](http://www.sciencedirect.com/science/article/pii/S1090513803000138)). Due to the fact that HGS is an easily obtainable and non-invasive behavioral measure, we suggest that it could be used as a preliminary method to screen men for semen quality at fertility clinics and sperm banks.  ","created_at":"2016-07-11T19:54:14.309Z","updated_at":"2016-07-12T06:08:49.823Z","zenodo_id":128036,"doi":"http://dx.doi.org/10.5281/zenodo.57460","subject":null,"tags":["fertility","biomarker","fitness indicator"],"vote_count":0,"view_count":1,"score":0.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":772,"title":"Contagious yawning as a cure for hiccups","sha":"90385a47fabdc8427f5c33cd9d8280f6","user_id":null,"state":"published","body":"[Numerous treatments](https://pubmed.ncbi.nlm.nih.gov/1477559/) have been proposed for the relief of persistent or intractable hiccups, i.e., cases in which hiccups last for several days or up to two months or longer. Some of these treatments include [medication](https://pubmed.ncbi.nlm.nih.gov/2314596/), [acupuncture](https://pubmed.ncbi.nlm.nih.gov/16399541/), [vagus nerve stimulation](https://pubmed.ncbi.nlm.nih.gov/15926725/), and even [rectal massages](https://pubmed.ncbi.nlm.nih.gov/2299306/). Hiccups that fail to reach such extreme duration are far more common, yet remain irritating and famously lack a cure. Here, I propose (contagious) yawning as a candidate. In particular, I hypothesize that the extended stretching and lowering of the diaphragm during yawning, which cannot be replicated simply with deep breathing, could disrupt the spasmodic contractions of the diaphragm and inspiratory intercostal muscles that characterize [hiccups](https://pubmed.ncbi.nlm.nih.gov/1477559/). This hypothesis is consistent with the longstanding [idea](https://www.hup.harvard.edu/catalog.php?isbn=9780674284135) (traced back to the time of Plato) that bouts of sneezing can stop hiccups, since sneezing is thought to be a derived feature of yawning. Sneezes and yawns have [similar motor patterns](https://www.hup.harvard.edu/catalog.php?isbn=9780674284135), including an initial long inspiration, tilting of the head, gaping of the jaw, and an exhalation. Unlike sneezing, however, yawning has the advantage of being reliably triggered through contagion by viewing, hearing, and/or thinking about yawns. ","created_at":"2020-07-17T17:33:45.682Z","updated_at":"2020-07-19T06:01:12.881Z","zenodo_id":3951203,"doi":"https://doi.org/10.5281/zenodo.3951203","subject":null,"tags":["behavioral medicine; complex reflex; treatment"],"vote_count":0,"view_count":1,"score":0.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null}]