Oh, excuse me! Have you ever yawned because somebody else yawned? You aren't especially tired, yet suddenly your mouth opens wide and a big yawn comes out. This phenomenon is known as contagious yawning. And while scientists still don't fully understand why it happens, there are many hypotheses currently being researched. Let's take a look at a few of the most prevalent ones, beginning with two physiological hypotheses before moving to a psychological one. Our first physiological hypothesis states that contagious yawning is triggered by a specific stimulus, an initial yawn. This is called fixed action pattern. Think of fixed action pattern like a reflex. Your yawn makes me yawn. Similar to a domino effect, one person's yawn triggers a yawn in a person nearby that has observed the act. Once this reflex is triggered, it must run its course. Have you ever tried to stop a yawn once it has begun? Basically impossible! Another physiological hypothesis is known as non-conscious mimicry, or the chameleon effect. This occurs when you imitate someone's behavior without knowing it, a subtle and unintentional copycat maneuver. People tend to mimic each other's postures. If you are seated across from someone that has their legs crossed, you might cross your own legs. This hypothesis suggests that we yawn when we see someone else yawn because we are unconsciously copying his or her behavior. Scientists believe that this chameleon effect is possible because of a special set of neurons known as mirror neurons. Mirror neurons are a type of brain cell that responds equally when we perform an action as when we see someone else perform the same action. These neurons are important for learning and self-awareness. For example, watching someone do something physical, like knitting or putting on lipstick, can help you do those same actions more accurately. Neuroimaging studies using fMRI, functional magnetic resonance imaging, show us that when we seem someone yawn or even hear their yawn, a specific area of the brain housing these mirror neurons tends to light up, which, in turn, causes us to respond with the same action: a yawn! Our psychological hypothesis also involves the work of these mirror neurons. We will call it the empathy yawn. Empathy is the ability to understand what someone else is feeling and partake in their emotion, a crucial ability for social animals like us. Recently, neuroscientists have found that a subset of mirror neurons allows us to empathize with others' feelings at a deeper level. (Yawn) Scientists discovered this empathetic response to yawning while testing the first hypothesis we mentioned, fixed action pattern. This study was set up to show that dogs would enact a yawn reflex at the mere sound of a human yawn. While their study showed this to be true, they found something else interesting. Dogs yawned more frequently at familiar yawns, such as from their owners, than at unfamiliar yawns from strangers. Following this research, other studies on humans and primates have also shown that contagious yawning occurs more frequently among friends than strangers. In fact, contagious yawning starts occurring when we are about four or five years old, at the point when children develop the ability to identify others' emotions properly. Still, while newer scientific studies aim to prove that contagious yawning is based on this capacity for empathy, more research is needed to shed light on what exactly is going on. It's possible that the answer lies in another hypothesis altogether. The next time you get caught in a yawn, take a second to think about what just happened. Were you thinking about a yawn? Did someone near you yawn? Was that person a stranger or someone close? And are you yawning right now? (Yawn) (Lip smacking)
Oh, izvinite! Da li ste ikada zevali zato što neko drugi zeva? Niste posebno umorni, a ipak, vaša usta se odjednom širom otvaraju i veliko zevanje izleti. Ova pojava je poznata kao zarazno zevanje. Dok naučnici još uvek ne razumeju u potpunosti zašto se to dešava, postoji mnogo hipoteza koje se trenutno istražuju. Hajde da bacimo pogled na one preovlađujuće, počevši sa dve fiziološke hipoteze pre nego što pređemo na psihološke. Naša prva fiziološka hipoteza tvrdi da je zarazno zevanje izazvano posebnim podsticajem, početnim zevanjem. Ovo se zove obrazac fiksne radnje. Razmišljajte o obrascu fiksne radnje kao o refleksu. Vaše zevanje me tera da zevam. Slično efektu domina, zevanje jedne osobe podstiče zevanje kod osobe u blizini koja posmatra čin. Kada je ovaj refleks aktiviran, mora ići svojim tokom. Da li ste ikada pokušali da zaustavite zevanje kada je počelo? U suštini je nemoguće! Druga fiziološka hipoteza poznata je kao nesvesna mimikrija, ili efekat kameleona. Ovo se dešava kada oponašate nekog bez sopstvenog znanja, što je suptilan i nenameran potez imitatora. Ljudi teže da podražavaju jedni druge. Ako sedite preko puta nekog ko je prekrstio noge, možda ćete i vi prekrstiti vaše noge. Ova hipoteza sugeriše da zevamo kada vidimo nekog drugog da isto to radi jer nesvesno imitiramo njegovo ili njeno ponašanje. Naučnici veruju da je efekat kameleona moguć zbog posebne grupe neurona, poznatih kao neuroni ogledala. Neuroni ogledala su moždane ćelije koje reaguju isto kada izvodimo radnju i kada vidimo da neko drugi izvodi istu radnju. Ovi neuroni su važni za učenje i samosvest. Na primer, posmatranje nekog ko fizički radi nešto kao što je pletenje ili stavljanje karmina, može vam pomoći da te radnje radite pravilnije. Studije neurovizualizacije koristeći fMRI, stvaranje slika kroz funkcionalnu magnetnu rezonancu, pokazuju da kada vidimo nekoga da zeva, ili čak čujemo zevanje, specifičan deo mozga gde se nalaze ovi neuroni ogledala sklon je da se aktivira, što nas zauzvrat tera da odgovorimo istom akcijom: zevanjem. I naša psihološka hipoteza uključuje rad ovih neurona ogledala. Nazvaćemo ga empatičnim zevanjem. Empatija je mogućnost razumevanja onoga što neko drugi oseća i učestvovanje u njihovim emocijama, što je jako bitna sposobnost društvenih životinja kao što smo mi. Nedavno, neuronaučnici su otkrili da nam podgrupa neurona ogledala dozvoljava da osetimo empatiju sa tuđim osećajima na dubljem nivou. (Zevanje) Naučnici su otkrili ovaj empatijski odgovor na zevanje dok su testirali prvu hipotezu koju smo pomenuli, obrazac fiksirane radnje. Ova studija je započeta da bi se pokazalo da psi oponašaju refleks zevanja na sam zvuk ljudskog zevanja. Dok je njihova studija pokazala da je ovo tačno, pronašli su još nešto interesantno. Psi su češće zevali kada bi čuli poznato zevanje, kao što je zevanje njihovih vlasnika, nego kada čuju nepoznato zevanje stranaca. Prateći ovo istraživanje, druge studije vezane za ljude i primate takođe su pokazale da se zarazno zevanje javlja učestalije među prijateljima, nego među strancima. U stvari, zarazno zevanje se javlja kada imamo četiri ili pet godina, u trenutku kada deca razviju sposobnost da propisno primete tuđe emocije. Ipak, dok novije naučne studije teže da dokažu da se zarazno zevanje zasniva na kapacitetu empatije, potrebno je više istraživanja da bi se rasvetlilo šta se zaista dešava. Moguće je da odgovor u potpunosti leži u drugoj hipotezi. Sledećeg puta kada uhvatite sebe kako zevate, zastanite na trenutak da razmislite šta se upravo desilo. Da li ste razmišljali o zevanju? Da li je neko blizu vas zevao? Da li je ta osoba stranac ili neko blizak? Da li upravo zevate? (Zevanje) (Mljackanje)