| This SciShow News video is supported by Shopify, an ecommerce platform that helps you start, grow, and manage your business. Head to shopify.com/scishowstarter to learn more and for a 14-day free trial of their new Starter Plan. [♪ INTRO] Today, we’re talking about everyone’s favorite topic: stress. Fortunately, we are also going to be talking about dogs. Because research published this week in the journal PLOS ONE has found that dogs can smell human stress. Which is an important clue to what makes our canine friends such good companions, as well as how they can provide support to people with anxiety- and stress-related conditions. Now, if you’re a dog owner, you might be thinking to yourself, yeah, of course my dog knows when I’m stressed! That’s why I have a dog! And there is research showing that dogs can mirror our emotions: dogs and their humans have similar long-term levels of cortisol, the main stress hormone. But believe it or not, scientists are not sure how dogs are detecting our stress. Some studies have asked dogs to smell people in different emotional states, like happy and fearful. But those studies didn’t really provide the “how”. So in order to measure whether the dogs can actually smell stress, these researchers wanted to develop a controlled experiment where the dogs would have to pick between odors, and where the owners weren’t in the room to read cues from. So, after the human participants gave baseline sweat and saliva samples, they were asked to do some math. They had to count backwards from 9000 by 17s without pen and paper. And just to make sure they were good and stressed out, there were two researchers supervising who said scary things like, “It’s very important that you perform the task as quickly and efficiently as possible.” After the math, participants were asked to give sweat and saliva samples again. Their samples were only used if they rated their stress at least two points higher on a scale from 1 to 10 than when they had started the test. Then, it was time to see what the dogs could do. There were four canine participants, named Treo, Winnie, Fingal, and Soot. The names weren’t important to the study, but I thought that you should know. Because they’re good dogs. In the experiment, the dog was always given three options to sniff. For the first phase, those options were “stressed human” and two blank samples. But, after ten trials learning the smell of stressed human, everything was wiped clean. The dogs got three new options: the stressed participant again, the same person when not stressed, and a blank control. And in 94% of trials, the dogs got it right. In 720 sniff tests of 36 people’s sweat and saliva, these four dogs could reliably tell the difference between the smell of a person who was sitting around and the stench of a person who had just done a bunch of math. Now, the study was designed to try to avoid potential confounds. For instance, the people the dogs were sniffing were not in the room to give visible or audible cues. The experiment was also double-blinded, meaning that the researcher working with the dog didn’t know the right answer either: there was another researcher behind a curtain who would signal when the dog got it right and should be rewarded. However, the study doesn’t necessarily mean that the dogs knew it was stress that they were smelling. The task was already something the dogs had been trained on, so they were just excited to be good dogs and do their jobs and get rewards. They didn’t respond to the stress-stink by becoming stressed themselves. But it does show that dogs can tell stressed people-stink from normal people-stink, which means that it might be how they do it IRL. The authors say this might help us train service dogs for things like anxiety and PTSD. Now that we know that they are detecting smell, specifically, that could help us teach them what to respond to, and make them better partners. And speaking of stress… if you feel like the pandemic has left you overall grouchier than you used to be, you may not be alone. Researchers publishing this week in the journal PLOS ONE were looking to see whether the COVID-19 pandemic caused shifts in people’s personalities. And not only did they find evidence of that shift, but it was bigger than they expected. Now, it’s important to say what we mean when we talk about your personality. This is a whole field of psychology with a long and complicated history, but generally, we’re talking about someone’s major psychological patterns and how they unfold across a lifetime. No test can wrap your personality up in a neat little bow, but the five-factor model of personality used in this paper is well-studied. It looks at: openness to experience, extraversion, and agreeableness, or how likely you are to be trusting and straightforward. It also considers conscientiousness, which is your likelihood of being responsible, organized, and disciplined, and neuroticism, which is a tendency to experience negative emotions and be vulnerable to stress. Previous studies have shown that while personal stressful events absolutely cause change to someone’s Big Five personality factors, collective events and natural disasters don’t tend to bring about widespread change in who we are. But these researchers thought the COVID-19 pandemic was big enough and global enough that it just might. Conveniently for the researchers, a longitudinal study of changes in the Big Five had been started in 2014, giving them a large pool of people to analyze – over 7,000! Everyone had been assessed at least once before and at least once during the pandemic. The survey asked about age, gender, education, and ethnicity, but did not fully account for race. The researchers looked first at 2020, starting in March. For no particular reason. That year, they found that neuroticism decreased, which matches up with other reports that a lot of people felt less anxious and stressed early on. And for the other four traits, there wasn’t a difference in 2020. But 2021 and 2022 were a different story. The decrease in neuroticism went away, and extraversion, openness, conscientiousness, and agreeableness all declined. The effect was even /more/ dramatic when the participants were divided into three age groups. Middle-aged and older adults continued to experience less neuroticism in 2021 and 2022, but younger adults under 30 had a significant increase in it compared to before the pandemic. Younger adults also showed a more dramatic decline in agreeableness and conscientiousness during that time. Now, it’s important to note that these effects were… pretty small. They only added up to one-tenth of a standard deviation’s worth of change. Which is a little hard to picture, but that’s how these things get measured. The takeaway is: that’s how much change we might normally expect to see in someone’s personality across ten years. So, it’s definitely not nothing. And, look, the authors are clear that it might not just be the pandemic. Any number of major social events in the last few years could have been significant stressors, and it’s not like that’s a short list. The authors also don’t know if these changes are here to stay, or if we could see reversals again in a couple of years. But if you have felt like the pandemic has changed you in some ways? You may not be alone in that. There are so many things to be stressed about during the COVID-19 pandemic, but figuring out how to sell products from your business should not be one of them. That’s where Shopify’s Starter Plan can help. Shopify is an e-commerce platform, which means they make it easy for you to sell cool stuff. I’ve been using Shopify for over ten years at DFTBA.com, which is like our main store, and a bunch of other ones including ComplexlyCalendars.com where you can get calendars from SciShow. But what they did not have when I started was a 5 dollar per month starter plan to get you going fast. With the Shopify Starter Plan, you just need an image and a product description. You’ll be ready to sell whatever you’re selling after just a few clicks. Then you can share your professional-looking online store on pretty much every social media, including tiktok, instagram, and snapchat. For a 14-day free trial of Shopify’s new Starter Plan, you can head to shopify.com/scishowstarter. Thank you to Shopify for supporting this SciShow News video and thanks to you for watching! [♪ OUTRO] | 此 SciShow 新闻视频由 Shopify 提供支持，Shopify 是 一个电子商务平台，可帮助您启动、 发展和管理您的业务。 前往 shopify.com/scishowstarter 了解 更多信息 并免费试用他们的新入门计划 14 天 。 [♪ 简介] 今天，我们要谈论每个人 最喜欢的话题：压力。 幸运的是，我们还将 谈论狗。 因为本周发表在 PLOS ONE 杂志上的 研究发现，狗可以闻到人类的压力。 这是一条重要线索，可以帮助我们了解是什么让我们的 犬类朋友成为如此 好的伙伴，以及它们如何为 患有焦虑和压力相关 疾病的人提供支持。 现在，如果你是狗主人，你可能会 想， 是的，我的狗当然知道我什么时候有压力！ 这就是我养狗的原因！ 并且有研究表明，狗可以 反映我们的情绪：狗和 它们的人类长期具有相似 的皮质醇水平，皮质醇是主要的压力荷尔蒙。 但信不信由你，科学家们 不确定狗是如何检测我们的压力的。 一些研究要求狗闻到 处于 不同情绪状态的人，比如快乐和 恐惧。 但这些研究并没有真正 提供“如何”。 因此，为了测量狗是否 真的能闻到压力， 这些研究人员想开发一个受控 实验，狗 必须在气味之间做出选择，而 主人不在房间里，也无法从中读取线索。 因此，在人类参与者提供基线 汗液和唾液样本后， 他们被要求做一些数学运算。 他们必须在 没有笔和纸的情况下从 9000 倒数 17 秒。 为了确保他们表现良好并承受 压力， 有两名研究人员进行监督，他们 说了一些可怕的话，比如， “ 尽可能快速有效地完成任务非常重要。” 数学运算后，参与者被要求 再次提供汗液和唾液样本。 只有当他们在 1 到 10 的等级上 对压力的评分比开始测试时至少高出两个点时，他们的样本才会被使用 然后，是时候看看狗能做 什么了。 有四只犬类参与者，分别是 Treo、Winnie、Fingal 和 Soot。 这些名字对这项研究并不重要， 但我认为你应该知道。 因为它们是好狗。 在实验中，狗总是被 给予三种嗅探选项。 对于第一阶段，这些选项是“有压力的 人”和两个空白样本。 但是，经过十次尝试学习压力人类的气味后 ， 一切都被擦拭干净了。 这些狗有三个新的选择：再次是有压力的 参与者， 没有压力的同一个人，以及空白 对照。 在 94% 的试验中，狗都做对了。 在对 36 个人的汗液和唾液进行的 720 次嗅探测试中 ，这四只狗能够 可靠地分辨出 坐在周围的人的气味 和刚刚完成一堆数学运算的人的恶臭 。 现在，这项研究旨在避免 潜在的混淆。 例如，狗正在嗅的人 不在房间里，无法给出可见或可听的提示。 该实验也是双盲的， 这意味着与狗一起工作的研究人员 也不知道正确答案： 幕后还有另一名研究人员 ，当狗答对并应该得到奖励时，他会发出信号 。 然而，这项研究并不一定 意味着狗知道它们闻到的是压力 。 这项任务已经是狗 受过训练的事情， 所以他们很高兴成为好狗 并完成他们的工作并获得奖励。 他们并没有通过让自己感到压力来应对压力恶臭 。 但它确实表明，狗可以分辨压力大的 人——正常人的臭味——臭味， 这意味着这可能是它们在 现实生活中是如何做到的。 作者说这可能有助于我们训练服务 犬 应对焦虑和创伤后应激障碍等问题。 现在我们知道他们正在检测气味， 特别是，这可以 帮助我们教他们对什么做出反应， 并使他们成为更好的合作伙伴。 说到压力……如果您觉得 大流行使您整体上 比以前更爱发牢骚，那么您可能并不孤单。 本周在 PLOS ONE 期刊上发表文章的研究 人员 正在研究 COVID-19 大流行是否会 导致人们性格的转变。 他们不仅找到了这种 转变的证据， 而且比他们预期的要大。 现在， 当我们谈论您的个性时，说出我们的意思很重要。 这是一个有着 悠久而复杂历史的完整心理学领域， 但总的来说，我们谈论的是一个人的 主要心理模式 以及它们如何在一生中展开。 没有任何测试可以将您的性格包裹在一个 整洁的小蝴蝶结中， 但本文中使用的五因素性格模型 得到了充分研究。 它着眼于：对经验的开放性、外向性 和宜人性， 或者您信任和直率的可能性有多大。 它还考虑了责任心，这 是您负责任、 有组织和有纪律的可能性，以及神经质， 这是一种 经历负面情绪和 容易受到压力影响的倾向。 先前的研究表明，虽然个人 压力事件绝对 会导致某人的大五人格 因素发生变化，但 集体事件和自然灾害 往往不会给我们带来广泛的 变化。 但这些研究人员认为 COVID-19 大流行病 足够大，也足够全球性，它 可能会发生。 对研究人员来说方便的是， 一项关于五巨头变化的纵向研究 已于 2014 年开始，这让 他们 可以分析大量人群——超过 7,000 人！ 每个人在大流行之前至少接受过一次评估，在大流行期间至少接受过一次评估 。 该调查询问了年龄、性别、教育程度 和种族，但没有完全考虑 种族。 研究人员首先着眼于从 3 月开始的 2020 年 。 没有特别的原因。 那一年，他们发现神经质减少了， 这与 其他报告相吻合，许多人在早期感到不那么 焦虑和压力。 对于其他四个特征， 2020 年没有差异。 但 2021 年和 2022 年情况不同。 神经质的下降消失了， 外向性、 开放性、尽责性和宜人性 都下降了。 当参与者被分成三个年龄组时，效果甚至/更/显着 。 中老年人 在 2021 年和 2022 年继续经历较少的神经质 ，但与大流行前相比，30 岁以下的年轻人神经质 显着增加 。 在那段时间里， 年轻人在宜人性和尽责性方面也表现出更为显着的 下降 现在，重要的是要注意这些 影响……非常小。 它们加起来只占标准 差变化价值的十分之一。 这有点难以想象，但这就是 衡量这些事情的方式。 要点是：这就是 我们 通常期望在十年内看到某人性格发生的变化 。 所以，这绝对不是什么都没有。 而且，看，作者很清楚这可能 不仅仅是大流行。 过去几年中发生的任何重大社会事件 都可能成为重大压力源，而且 这并不是一个简短的清单。 作者也不知道这些变化 是否会持续下去， 或者我们是否可以在几年内再次看到逆转 。 但是，您是否觉得大流行病 在某些方面改变了您？ 你可能并不孤单。 但弄清楚如何销售 您企业的产品 不应该是其中之一。 这就是 Shopify 的入门计划可以提供 帮助的地方。 Shopify 是一个电子商务平台， 这意味着它们可以让您轻松销售 很酷的东西。 我 在 DFTBA.com （就像我们的主要商店）和 许多其他商店（包括 您可以从 SciShow 获取日历 的 ComplexlyCalendars.com）上使用 Shopify 已有十多年了。 但是当我开始时他们没有的 是 每月 5 美元的入门计划，让 你快速前进。 使用 Shopify 入门计划，您只需要 一张图片和一段产品描述。 只需点击几下， 您就可以出售您要出售的任何东西 。 然后，您可以 在 几乎所有社交媒体（包括 tiktok、instagram 和 snapchat）上分享您外观专业的在线商店。 如需 Shopify 新入门计划的 14 天免费试用 ， 您可以前往 shopify.com/scishowstarter。 感谢 Shopify 支持此 SciShow 新闻视频 ，感谢您的观看！ [♪结尾] |
