WEBVTT 00:00:06.059 --> 00:00:09.800 Welcome to the bed. We'll go ahead and give you 00:00:09.800 --> 00:00:12.580 the story. This is all going to happen super 00:00:12.580 --> 00:00:46.569 fast. Welcome to the emergency room. Welcome 00:00:46.569 --> 00:00:51.509 back to the deep dive. Today we are tackling 00:00:51.509 --> 00:00:55.299 a beast and if If you're a nursing student or 00:00:55.299 --> 00:00:57.460 maybe a clinician who's brushing up on pediatrics, 00:00:57.719 --> 00:00:59.320 you know exactly what I'm talking about. Oh, 00:00:59.320 --> 00:01:01.100 yeah. We're talking about the infant year. It 00:01:01.100 --> 00:01:04.219 is a massive topic. It's sort of the Everest 00:01:04.219 --> 00:01:07.739 of the pediatric curriculum. It feels so overwhelming. 00:01:07.840 --> 00:01:09.500 I was looking through the stack of sources for 00:01:09.500 --> 00:01:12.480 this. We've got the ATI pediatric nursing texts, 00:01:12.760 --> 00:01:15.780 growth charts, vital science protocols, a developmental 00:01:15.780 --> 00:01:19.920 theory from Piaget and Erickson. And honestly, 00:01:20.060 --> 00:01:21.920 at first glance, it just feels like you're trying 00:01:21.920 --> 00:01:25.040 to Memorize a phone book a phone book exactly. 00:01:25.040 --> 00:01:27.840 It's just rows of data at two months They do 00:01:27.840 --> 00:01:29.680 this at four months. They do that at six months. 00:01:29.700 --> 00:01:32.599 They eat this it feels totally random It does 00:01:32.599 --> 00:01:35.180 they're just trying to cram these lists of reflexes 00:01:35.180 --> 00:01:37.599 and weights into your brain before an exam Hoping 00:01:37.599 --> 00:01:40.219 you don't mix up the more Oh reflex with the 00:01:40.219 --> 00:01:42.480 babinski. It feels like there is no logic to 00:01:42.480 --> 00:01:45.719 it just a series of isolated facts. And that 00:01:45.719 --> 00:01:48.219 is the trap. That is the rote memorization trap, 00:01:48.340 --> 00:01:51.780 100%. If you try to memorize every single bullet 00:01:51.780 --> 00:01:54.200 point in a pediatric textbook as its own little 00:01:54.200 --> 00:01:56.700 island, you are going to burn out. And honestly, 00:01:56.939 --> 00:01:59.500 you're probably going to miss the critical questions 00:01:59.500 --> 00:02:01.780 on the exam because you aren't seeing the pattern. 00:02:02.140 --> 00:02:04.620 You're looking at the trees, but the exam questions 00:02:04.620 --> 00:02:07.680 and the real life babies, they're the forest. 00:02:08.259 --> 00:02:10.860 So what's our strategy today? Right. Because 00:02:10.860 --> 00:02:13.939 we promised an 80 -20 guide. Right. the Pareto 00:02:13.939 --> 00:02:17.620 principle. We are going to focus on the 20 % 00:02:17.620 --> 00:02:20.500 of the concepts that explain 80 % of what happens 00:02:20.500 --> 00:02:23.340 clinically. We aren't just going to list milestones. 00:02:23.500 --> 00:02:25.599 We are going to look at the why. We're going 00:02:25.599 --> 00:02:28.340 to integrate the physical growth with how they 00:02:28.340 --> 00:02:30.759 think, that's Piaget, and how they feel, that's 00:02:30.759 --> 00:02:32.659 Ericsson. So instead of just saying keep the 00:02:32.659 --> 00:02:36.219 crib rails up, we're going to explain the... 00:02:36.120 --> 00:02:38.659 the biological mechanism that makes the crib 00:02:38.659 --> 00:02:41.240 rails necessary at a specific month. Exactly. 00:02:41.360 --> 00:02:43.300 If you understand how an infant moves and how 00:02:43.300 --> 00:02:45.620 they process information, you don't need to memorize 00:02:45.620 --> 00:02:47.699 the safety risks. And can predict them. You can 00:02:47.699 --> 00:02:49.539 predict them. You can walk into a room, look 00:02:49.539 --> 00:02:51.460 at a baby, and know exactly what they're about 00:02:51.460 --> 00:02:53.780 to try and do to hurt themselves. I love that. 00:02:54.099 --> 00:02:56.780 Predicting instead of memorizing. So our mission 00:02:56.780 --> 00:02:58.919 today is to take a deep dive into the infant 00:02:58.919 --> 00:03:01.840 from birth to one year and build a logical framework 00:03:01.840 --> 00:03:04.020 for all those cute baby moments so you can actually 00:03:04.020 --> 00:03:05.759 use them in a clinical setting. Let's do it. 00:03:06.060 --> 00:03:08.180 Okay, let's start with the big picture. Before 00:03:08.180 --> 00:03:10.560 we get into the nitty -gritty of what happens 00:03:10.560 --> 00:03:12.979 at month four, we need to understand the theme 00:03:12.979 --> 00:03:15.240 of this entire year. Right. If you had to put 00:03:15.240 --> 00:03:17.800 a title on the first year of life, what is it? 00:03:18.000 --> 00:03:21.419 The theme is rapid growth and integration. This 00:03:21.419 --> 00:03:24.219 is the fastest a human being will ever grow after 00:03:24.219 --> 00:03:28.020 birth. It is explosive. It's metabolic chaos 00:03:28.020 --> 00:03:30.620 in the best way. And for a nurse, that growth 00:03:30.620 --> 00:03:32.979 isn't just about clothes not fitting. It's about 00:03:32.979 --> 00:03:36.080 metrics. We call these the rules of thumb. OK, 00:03:36.159 --> 00:03:38.800 give me the cheat codes. Because on an exam, 00:03:38.800 --> 00:03:41.360 you get these scenarios like a baby weighed seven 00:03:41.360 --> 00:03:43.360 pounds at birth. How much should they weigh now? 00:03:43.419 --> 00:03:46.039 And you have to do the math. Precisely. So here 00:03:46.039 --> 00:03:48.020 is the golden rule for weight. And this comes 00:03:48.020 --> 00:03:50.099 straight from the growth monitoring protocols. 00:03:50.500 --> 00:03:52.740 An infant's birth weight should double by about 00:03:52.740 --> 00:03:55.800 four to six months of age. Doubled by six months. 00:03:56.539 --> 00:03:59.219 That seems incredibly fast when you think about 00:03:59.219 --> 00:04:01.560 adult weight gain. It is. I mean, imagine if 00:04:01.560 --> 00:04:04.500 you doubled your weight in six months. It's metabolically 00:04:04.500 --> 00:04:07.500 demanding. It requires an immense amount of caloric 00:04:07.500 --> 00:04:09.319 intake relative to their size. And what about 00:04:09.319 --> 00:04:11.719 by the end of the year? And then by 12 months, 00:04:12.000 --> 00:04:14.159 that birth weight should triple. Tripled by a 00:04:14.159 --> 00:04:16.699 year. So let's play that out. If I'm born at 00:04:16.699 --> 00:04:19.810 seven pounds, You're looking at around 14 pounds 00:04:19.810 --> 00:04:22.810 by that six -month mark and 21 pounds by your 00:04:22.810 --> 00:04:25.569 first birthday. OK. Now, why does this matter 00:04:25.569 --> 00:04:27.970 clinically? Because if a child is significantly 00:04:27.970 --> 00:04:30.709 under that, we're looking at failure to thrive, 00:04:31.290 --> 00:04:34.069 malnutrition, or maybe a cardiac issue, burning 00:04:34.069 --> 00:04:37.589 too many calories. If they're way over, we are 00:04:37.589 --> 00:04:39.610 looking at obesity risks. So they're not just 00:04:39.610 --> 00:04:42.410 trivia numbers? Not at all. They are the primary 00:04:42.410 --> 00:04:44.529 indicators of health. What about height? Or I 00:04:44.529 --> 00:04:46.370 guess we call it length. So they can't stand 00:04:46.370 --> 00:04:48.509 up yet. Right. We measure crown to heel length. 00:04:48.629 --> 00:04:50.990 The rule there is that it increases by about 00:04:50.990 --> 00:04:53.750 50 % by 12 months. So they are getting longer, 00:04:53.949 --> 00:04:56.069 faster than you might expect. They are stretching 00:04:56.069 --> 00:04:59.310 out. But the really interesting metric, and the 00:04:59.310 --> 00:05:02.750 one that freaks parents out sometimes, is the 00:05:02.750 --> 00:05:05.160 head. The head circumference. I feel like every 00:05:05.160 --> 00:05:07.079 parent stresses about the percentile of the head. 00:05:07.160 --> 00:05:09.540 They do, but for us, it's about intracranial 00:05:09.540 --> 00:05:12.500 dynamics. In the first year, the head circumference 00:05:12.500 --> 00:05:15.879 grows by about 10 centimeters. That is massive 00:05:15.879 --> 00:05:18.959 structural expansion. Wow. And there's a physiological 00:05:18.959 --> 00:05:21.459 reason for that. Yeah. The brain weight doubles 00:05:21.459 --> 00:05:24.300 by six months of age. Wait, say that again. The 00:05:24.300 --> 00:05:26.939 brain weight doubles in just six months. It does. 00:05:27.240 --> 00:05:29.339 That's why the head is so big compared to the 00:05:29.339 --> 00:05:32.699 body. It's housing this rapidly expanding supercomputer. 00:05:33.019 --> 00:05:35.019 So the skull has to be able to accommodate that. 00:05:35.240 --> 00:05:38.079 Exactly. The skull can't be fused shut yet. If 00:05:38.079 --> 00:05:40.620 the skull was a solid bone helmet like ours, 00:05:41.019 --> 00:05:43.560 the brain would get crushed. Hence the fontanels. 00:05:43.819 --> 00:05:46.860 The soft spots. Exactly. They're basically expansion 00:05:46.860 --> 00:05:49.420 joints. They allow the plates of the skull to 00:05:49.420 --> 00:05:51.360 shift during birth to fit through the canal. 00:05:51.620 --> 00:05:53.600 And then they allow the plates to spread apart 00:05:53.600 --> 00:05:56.240 as the brain grows. And this is a classic exam 00:05:56.240 --> 00:05:58.579 question. When do they close? I always get these 00:05:58.579 --> 00:06:01.060 mixed up. It's so easy to mix them up. So let's 00:06:01.060 --> 00:06:03.699 separate them. You have the posterior fontanel. 00:06:03.699 --> 00:06:05.600 That's the one on the back of the head. OK. That 00:06:05.600 --> 00:06:08.360 one is smaller, triangular usually, and closes 00:06:08.360 --> 00:06:10.480 pretty quickly, usually by about two months of 00:06:10.480 --> 00:06:13.100 age. OK. Posterior by two months. Back of the 00:06:13.100 --> 00:06:15.839 head. Closes first. Then you have the anterior 00:06:15.839 --> 00:06:18.019 fontanel, the big diamond -shaped one on top. 00:06:18.319 --> 00:06:21.180 That stays open much longer to allow for all 00:06:21.180 --> 00:06:23.040 that brain growth we just talked about. Right. 00:06:23.279 --> 00:06:26.139 It closes between 12 and 18 months. 12 to 18 00:06:26.139 --> 00:06:28.740 months. Got it. So if you have a six -month -old 00:06:28.740 --> 00:06:32.000 with a fused anterior fontanel, that's a problem. 00:06:32.170 --> 00:06:35.550 Big problem. That's craniosynostosis premature 00:06:35.550 --> 00:06:38.750 fusion. It can restrict brain growth and requires 00:06:38.750 --> 00:06:41.209 surgery to reopen the sutures. And on the flip 00:06:41.209 --> 00:06:43.790 side? On the flip side, if you have an 18 -month 00:06:43.790 --> 00:06:46.009 -old and it's still wide open or bulging, that 00:06:46.009 --> 00:06:48.970 could be hypothyroidism or increased intracranial 00:06:48.970 --> 00:06:51.730 pressure. The fontanel is like a window into 00:06:51.730 --> 00:06:55.029 the brain status. Now, you mentioned integration 00:06:55.029 --> 00:06:57.329 as part of the theme. I want to talk about the 00:06:57.329 --> 00:06:59.829 direction of this growth because I remember reading 00:06:59.829 --> 00:07:03.670 about Cephalocoddle and proximadistal. And those 00:07:03.670 --> 00:07:05.730 sound like fancy Latin words that are easy to 00:07:05.730 --> 00:07:08.629 gloss over. They are fancy words, but they are 00:07:08.629 --> 00:07:11.930 the Rosetta Stone for motor skills. If you understand 00:07:11.930 --> 00:07:14.449 these two words, you don't need to memorize the 00:07:14.449 --> 00:07:17.050 order of milestones. It becomes obvious. Okay, 00:07:17.250 --> 00:07:19.470 break down cephalocoddle for us. Cephalocoddle 00:07:19.470 --> 00:07:22.290 literally means head to tail. Cephalo is head, 00:07:22.449 --> 00:07:24.579 coddle is tail. Head to tail. Simple enough. 00:07:24.819 --> 00:07:27.420 Oh, it means neuromuscular control starts at 00:07:27.420 --> 00:07:29.980 the head and moves down the body. Think about 00:07:29.980 --> 00:07:32.540 a newborn. What is the floppy part? The head. 00:07:32.779 --> 00:07:34.959 The head. The very first thing they have to learn 00:07:34.959 --> 00:07:37.779 to control is the neck. Right. They can't do 00:07:37.779 --> 00:07:39.720 anything else until the neck is stable. Once 00:07:39.720 --> 00:07:41.680 they get the neck, the signal travels down to 00:07:41.680 --> 00:07:43.759 the shoulders, then the trunk, then the hips, 00:07:43.879 --> 00:07:47.339 and finally the legs and feet. That is why a 00:07:47.339 --> 00:07:49.720 baby can lift their head way before they can 00:07:49.720 --> 00:07:52.040 sit, and they can sit way before they can walk. 00:07:52.439 --> 00:07:54.759 The software update installs from the top down. 00:07:55.139 --> 00:07:57.319 That makes so much sense. You don't get the walking 00:07:57.319 --> 00:07:59.319 update until the sitting update is complete. 00:07:59.560 --> 00:08:02.259 It's a progressive download. Exactly. And the 00:08:02.259 --> 00:08:04.560 second direction is proximal distal. That means 00:08:04.560 --> 00:08:07.639 center to out, or near to far. So from the core 00:08:07.639 --> 00:08:11.240 out to the fingertips. Yes. Think about coordination. 00:08:11.579 --> 00:08:14.779 An infant can flail their whole arm using the 00:08:14.779 --> 00:08:17.240 shoulder and shoulder muscles months before they 00:08:17.240 --> 00:08:19.180 can control their hand. OK. And they can use 00:08:19.180 --> 00:08:21.600 their whole hand to rake an object months before 00:08:21.600 --> 00:08:23.160 they can use their individual fingers to pick 00:08:23.160 --> 00:08:25.620 up a cheerio. Because the shoulder is proximal, 00:08:25.620 --> 00:08:28.360 closer to the center, and the fingers are distal, 00:08:28.500 --> 00:08:30.899 further away. You got it. So when you see a question 00:08:30.899 --> 00:08:34.250 asking which skill comes first, waving bye -bye, 00:08:34.389 --> 00:08:37.230 or picking up a raisin. You just ask yourself, 00:08:37.889 --> 00:08:40.389 which uses muscles closer to the center? Waving. 00:08:40.509 --> 00:08:42.490 That's mostly arm and wrist. Waving is mostly 00:08:42.490 --> 00:08:44.629 arm, wrist. Picking up a raisin is fingertips. 00:08:45.009 --> 00:08:47.350 Waving comes first. OK. That is the roadmap, 00:08:47.789 --> 00:08:50.809 head to tail, center to out. Let's apply this. 00:08:50.830 --> 00:08:52.789 I want to walk through the timeline, looking 00:08:52.789 --> 00:08:55.370 at what the child can do and cannot do at key 00:08:55.370 --> 00:08:57.450 stages. Let's start with the two -month -old. 00:08:57.750 --> 00:09:00.330 The two -month -old is squarely in that head 00:09:00.330 --> 00:09:02.950 stage of cephalocautal development. So what are 00:09:02.950 --> 00:09:05.450 we seeing physically? Well, if you put them in 00:09:05.450 --> 00:09:09.070 a prone position on their tummy, they can lift 00:09:09.070 --> 00:09:10.889 their head up a bit off the mattress. It's a 00:09:10.889 --> 00:09:13.830 huge milestone. It means the neck muscles are 00:09:13.830 --> 00:09:17.210 coming online, but they cannot support themselves 00:09:17.210 --> 00:09:20.110 sitting. If you pull them up to sit, the head 00:09:20.110 --> 00:09:22.610 lags behind. That head lag is very prominent. 00:09:22.710 --> 00:09:24.889 What about socially? Are they interacting yet? 00:09:24.950 --> 00:09:26.850 This is the sweet spot for the social smile. 00:09:26.970 --> 00:09:29.690 Ah, yes. Around two months, they start smiling 00:09:29.690 --> 00:09:32.350 back at you purposefully. Before this, a smile 00:09:32.350 --> 00:09:35.549 usually meant gas. Now it means connection. But 00:09:35.549 --> 00:09:37.570 despite that smile, they're still dominated by 00:09:37.570 --> 00:09:39.690 reflexes, right? The source material lists a 00:09:39.690 --> 00:09:42.850 whole bunch. Moro, rooting, suck, tonic neck. 00:09:43.230 --> 00:09:45.570 Yes, and this is crucial for the 80 -20 learner. 00:09:46.169 --> 00:09:48.850 We tend to think of reflexes as just things babies 00:09:48.850 --> 00:09:52.899 do, but clinically they are placeholders. Primitive 00:09:52.899 --> 00:09:55.019 reflexes, like the moro startle reflex where 00:09:55.019 --> 00:09:57.679 they throw their arms back, or the rooting reflex 00:09:57.679 --> 00:09:59.419 where they turn toward a touch on the cheek, 00:09:59.600 --> 00:10:02.860 are involuntary. For voluntary movement to take 00:10:02.860 --> 00:10:05.899 over, these reflexes must disappear. They have 00:10:05.899 --> 00:10:08.299 to go away? They have to! Think about it. You 00:10:08.299 --> 00:10:11.379 can't voluntarily grab a toy if your hand automatically 00:10:11.379 --> 00:10:13.379 clamps shut every time something touches your 00:10:13.379 --> 00:10:16.620 palm. That's the palmar grasp. You can't learn 00:10:16.620 --> 00:10:19.460 to roll over efficiently if your arm shoots out 00:10:19.460 --> 00:10:21.240 in a fencing position every time you turn your 00:10:21.240 --> 00:10:24.100 head, which is the tonic neck reflex. So seeing 00:10:24.100 --> 00:10:26.980 these reflexes fade is actually a sign of neurological 00:10:26.980 --> 00:10:29.879 maturation. Exactly. If a 12 -month -old still 00:10:29.879 --> 00:10:32.899 has a strong moro reflex, that's a red flag for 00:10:32.899 --> 00:10:35.139 cerebral palsy or other neurological issues. 00:10:35.620 --> 00:10:37.860 The voluntary system hasn't taken over. It's 00:10:37.860 --> 00:10:40.159 like the operating system failed to update from 00:10:40.159 --> 00:10:42.919 beta to live. OK, moving on. Let's go to the 00:10:42.919 --> 00:10:45.159 four to six month window. I feel like this is 00:10:45.159 --> 00:10:47.820 where things get active. This is the roller stage. 00:10:48.860 --> 00:10:51.340 And some distinct things happen here regarding 00:10:51.340 --> 00:10:54.059 rolling. The sources are specific on the direction 00:10:54.059 --> 00:10:57.139 of the roll. Which comes first? Typically, an 00:10:57.139 --> 00:11:01.399 infant rolls from prone, so tummy, to supine, 00:11:01.559 --> 00:11:04.159 which is on their back, around five months. It's 00:11:04.159 --> 00:11:06.139 a bit easier to push up with those developing 00:11:06.139 --> 00:11:08.240 arm muscles, and then gravity kind of helps you 00:11:08.240 --> 00:11:11.200 flip over. Right. Rolling from supine, so back, 00:11:11.399 --> 00:11:13.899 to prone, which is tummy, usually happens a bit 00:11:13.899 --> 00:11:15.820 later, around six months, because it requires 00:11:15.820 --> 00:11:18.299 more abdominal control to fight gravity and flip 00:11:18.299 --> 00:11:20.100 onto your stomach. So back to front is harder. 00:11:20.320 --> 00:11:23.379 Correct. And developmentally, they're also starting 00:11:23.379 --> 00:11:26.899 to sit, but it's the tripod sit. The tripod sit. 00:11:27.220 --> 00:11:30.059 By six months, they can sit alone. But they have 00:11:30.059 --> 00:11:32.139 to lean forward on their hands to prop themselves 00:11:32.139 --> 00:11:34.720 up. They aren't fully upright yet. The trunk 00:11:34.720 --> 00:11:37.139 update isn't quite finished. What about their 00:11:37.139 --> 00:11:39.700 hands? Proxima Distal says they should be getting 00:11:39.700 --> 00:11:42.159 better control. They are. They can hold a bottle 00:11:42.159 --> 00:11:44.200 with two hands now, bringing the hands to the 00:11:44.200 --> 00:11:47.960 midline. They can bat at objects. And they bring 00:11:47.960 --> 00:11:50.659 everything to their mouths. Of course. That center 00:11:50.659 --> 00:11:53.139 to out control has reached the palms. Which brings 00:11:53.139 --> 00:11:56.000 us to the nine month old. This feels like a huge 00:11:56.000 --> 00:11:58.559 turning point in the notes. The nylon gold is 00:11:58.559 --> 00:12:02.019 the mobile explorer. The biggest gross motor 00:12:02.019 --> 00:12:04.879 milestone here is sitting unsupported, no hands 00:12:04.879 --> 00:12:07.000 on the floor. That's a big one. They sit upright, 00:12:07.320 --> 00:12:09.279 their back is strong, and they can turn to play 00:12:09.279 --> 00:12:11.559 with toys. And they aren't stuck in one place 00:12:11.559 --> 00:12:14.539 anymore. No, they are crawling. Some are pulling 00:12:14.539 --> 00:12:16.840 to a stand against the coffee table. They're 00:12:16.840 --> 00:12:19.960 realizing the world is accessible. But the most 00:12:19.960 --> 00:12:22.320 critical update here, the one that changes safety 00:12:22.320 --> 00:12:25.620 risks entirely, is in the hands. This is the 00:12:25.620 --> 00:12:28.480 debut of the pincer grasp. The pincer grasp. 00:12:29.200 --> 00:12:31.919 Why is this so significant? It starts as a crude 00:12:31.919 --> 00:12:34.799 pincer grasp at eight or nine months. This means 00:12:34.799 --> 00:12:37.440 using the thumb and maybe two fingers to rake 00:12:37.440 --> 00:12:40.080 or grab a small object. Before this, they just 00:12:40.080 --> 00:12:42.559 used the whole palm like a claw machine. Now 00:12:42.559 --> 00:12:44.720 they can pick up smaller things. Which sounds 00:12:44.720 --> 00:12:47.100 great for feeding, but terrifying for safety. 00:12:47.320 --> 00:12:49.460 It changes the entire safety landscape. We'll 00:12:49.460 --> 00:12:51.879 get to that. But yes, suddenly the lint on the 00:12:51.879 --> 00:12:54.240 carpet, the button that fell off a shirt, it's 00:12:54.240 --> 00:12:56.299 all accessible. Finally, the 12 -month -old, 00:12:56.620 --> 00:12:59.100 the birthday boy or girl. The vertical child. 00:12:59.799 --> 00:13:02.019 By 12 months, they're usually walking with help 00:13:02.019 --> 00:13:04.559 or cruising, shuffling along the furniture holding 00:13:04.559 --> 00:13:07.559 on. Some might take their first independent steps. 00:13:07.799 --> 00:13:10.740 And the hands. Has the pincer grasp changed? 00:13:10.879 --> 00:13:13.639 The pincer grasp becomes a fine pincer grasp. 00:13:13.799 --> 00:13:16.360 They can pick up a single cheerio with just the 00:13:16.360 --> 00:13:19.340 thumb and index finger. Precision. Wow. They 00:13:19.340 --> 00:13:22.200 can also put objects into a container. That's 00:13:22.200 --> 00:13:25.409 a skill, putting things in a box. It is. It requires 00:13:25.409 --> 00:13:28.610 releasing the grasp voluntarily. Before this, 00:13:28.730 --> 00:13:31.350 letting go was hard. The reflex to hold on was 00:13:31.350 --> 00:13:33.769 stronger than the command to let go. Now they 00:13:33.769 --> 00:13:36.250 can drop a block into a bucket. It demonstrates 00:13:36.250 --> 00:13:38.649 high -level motor planning. Okay, so we have 00:13:38.649 --> 00:13:41.889 a physical roadmap. Head up, roll over, sit, 00:13:42.049 --> 00:13:44.210 crawl, walk. But I want to switch gears to the 00:13:44.210 --> 00:13:46.409 brain because you can't separate the body from 00:13:46.409 --> 00:13:48.370 the mind. How are they thinking during all of 00:13:48.370 --> 00:13:50.250 this? This is where we bring in Jean Piaget. 00:13:50.460 --> 00:13:52.860 For the first two years of life, the infant is 00:13:52.860 --> 00:13:55.279 in the sensorimotor stage. Sensorimotor. The 00:13:55.279 --> 00:13:57.539 name kind of gives it away. It does. They learn 00:13:57.539 --> 00:13:59.460 through senses and motor movement. They are not 00:13:59.460 --> 00:14:01.519 logical beings. They are experimental beings. 00:14:01.679 --> 00:14:03.559 They don't think, if I push this button, the 00:14:03.559 --> 00:14:05.659 light goes on. They just mash the button and 00:14:05.659 --> 00:14:07.679 see what happens. So there's no abstract thought 00:14:07.679 --> 00:14:11.200 yet. No planning. Not really. They are reacting 00:14:11.200 --> 00:14:15.139 to stimuli, but there are two massive cognitive 00:14:15.139 --> 00:14:19.000 aha. moments in this year. The first one is cause 00:14:19.000 --> 00:14:22.000 and effect. Like shaking a rattle. Exactly. Piaget 00:14:22.000 --> 00:14:25.259 calls these secondary circular reactions. Around 00:14:25.259 --> 00:14:27.240 four to eight months the baby shakes a rattle 00:14:27.240 --> 00:14:30.240 and hears a noise. Their brain goes, wait. I 00:14:30.240 --> 00:14:32.799 did that. If I do this motion, that sound happens, 00:14:32.980 --> 00:14:35.919 and they do it again. And again. And again! They 00:14:35.919 --> 00:14:38.139 are realizing they have agency in the world. 00:14:38.299 --> 00:14:40.220 That's pretty powerful. The first step toward 00:14:40.220 --> 00:14:42.320 tool use, really. What's the second concept? 00:14:42.500 --> 00:14:45.399 The big one. Object permanence. The ghost concept. 00:14:45.539 --> 00:14:48.620 This is huge! Imagine for the first roughly six 00:14:48.620 --> 00:14:51.019 to eight months of your life, out of sight literally 00:14:51.019 --> 00:14:54.090 means out of mind. If I show you a toy and then 00:14:54.090 --> 00:14:56.309 put it behind my back, to you it didn't just 00:14:56.309 --> 00:14:59.190 disappear, it ceased to exist. The universe deleted 00:14:59.190 --> 00:15:02.110 it. It's gone. So when mom walks out of the room... 00:15:02.110 --> 00:15:04.929 She dissolves. She's gone forever. That is the 00:15:04.929 --> 00:15:07.250 infant's reality. But around nine months, this 00:15:07.250 --> 00:15:09.750 changes. They realize that objects and people 00:15:09.750 --> 00:15:12.070 continue to exist even when they can't be seen. 00:15:12.309 --> 00:15:14.669 In the notes say, this explains why peekaboo 00:15:14.669 --> 00:15:17.529 becomes funny. Yes. Before object permanence, 00:15:17.669 --> 00:15:19.870 peekaboo is just confusing. Mom's gone. Oh, she's 00:15:19.870 --> 00:15:23.570 back. It's startling. Right. But once they have 00:15:23.570 --> 00:15:26.629 object permanence, there is tension. I know she's 00:15:26.629 --> 00:15:29.269 behind those hands. I'm waiting. There she is. 00:15:29.769 --> 00:15:32.490 It's a game of confirmation. They are testing 00:15:32.490 --> 00:15:34.909 their hypothesis that you still exist. That leads 00:15:34.909 --> 00:15:37.129 us perfectly into the emotional side. Because 00:15:37.129 --> 00:15:40.149 if I know mom exists, but I can't see her, that 00:15:40.149 --> 00:15:42.690 feels like a recipe for anxiety. And that is 00:15:42.690 --> 00:15:45.009 exactly where Piaget meets Erickson. This is 00:15:45.009 --> 00:15:47.409 the integration we talked about. You cannot separate 00:15:47.409 --> 00:15:49.769 the cognitive development from the emotional 00:15:49.769 --> 00:15:52.649 crisis. So Erickson's stage for this year is 00:15:52.649 --> 00:15:55.350 trust versus mistrust. Correct. The fundamental 00:15:55.350 --> 00:15:57.730 goal of the first year of life is to answer one 00:15:57.730 --> 00:16:00.929 question. Is the world a safe place? And how 00:16:00.929 --> 00:16:03.169 do they decide that? By whether their needs are 00:16:03.169 --> 00:16:06.909 met. When they cry, does someone come? When they 00:16:06.909 --> 00:16:08.850 are hungry, are they fed? When they are wet, 00:16:08.909 --> 00:16:12.450 are they changed? If the answer is consistently 00:16:12.450 --> 00:16:16.029 yes, they develop trust. If it's inconsistent 00:16:16.029 --> 00:16:19.409 or neglectful, they develop mistrust. There's 00:16:19.409 --> 00:16:21.730 a really interesting nuance in the source material 00:16:21.730 --> 00:16:25.830 about spoiling. I feel like grandmothers everywhere 00:16:25.830 --> 00:16:28.529 are always saying, don't hold that baby too much, 00:16:28.529 --> 00:16:30.889 you'll spoil him. The clinical evidence says 00:16:30.889 --> 00:16:33.720 the exact opposite. You cannot spoil an infant 00:16:33.720 --> 00:16:36.879 in the early months. In fact, meeting those needs, 00:16:37.139 --> 00:16:39.820 immediately responding to the cry, is what creates 00:16:39.820 --> 00:16:41.759 the foundation of trust. So by holding them now, 00:16:41.879 --> 00:16:43.460 you're actually making them more independent 00:16:43.460 --> 00:16:46.279 later. Yes. It's counterintuitive, but think 00:16:46.279 --> 00:16:48.779 about it. If they have that solid foundation 00:16:48.779 --> 00:16:51.440 of trust, they can tolerate small delays later 00:16:51.440 --> 00:16:53.740 on. They learn delayed gratification because 00:16:53.740 --> 00:16:55.620 they know you will come back. Right. If they 00:16:55.620 --> 00:16:57.440 don't trust you'll come back, they scream the 00:16:57.440 --> 00:16:59.549 second you leave. Okay, so let's connect this 00:16:59.549 --> 00:17:02.389 to the anxiety. We have object permanence kicking 00:17:02.389 --> 00:17:05.869 in around nine months. We have trust versus mistrust. 00:17:06.750 --> 00:17:09.869 Why does separation anxiety hit so hard between 00:17:09.869 --> 00:17:12.369 four and eight months? It's the perfect storm. 00:17:12.470 --> 00:17:15.210 Think about the formula. I now have the cognitive 00:17:15.210 --> 00:17:18.009 ability to know you exist when you leave. That's 00:17:18.009 --> 00:17:20.490 object permanence. Right. But I am completely 00:17:20.490 --> 00:17:23.009 dependent on you and I don't have a perfect sense 00:17:23.009 --> 00:17:25.190 of time. That's the mistrust dependence part. 00:17:25.329 --> 00:17:28.049 So when you leave, I know you're somewhere. But 00:17:28.049 --> 00:17:29.710 I don't know if you're coming back. Exactly. 00:17:29.829 --> 00:17:33.869 Mom exists, but she isn't here. That gap creates 00:17:33.869 --> 00:17:36.349 the anxiety. It's actually a sign of healthy 00:17:36.349 --> 00:17:38.950 attachment and cognitive growth. It means they 00:17:38.950 --> 00:17:41.150 remember you. That's a good point. If a 10 -month 00:17:41.150 --> 00:17:42.890 -old doesn't care when the primary caregiver 00:17:42.890 --> 00:17:45.089 leaves, that can actually be a sign of attachment 00:17:45.089 --> 00:17:48.190 issues. And stranger fear. That hits around six 00:17:48.190 --> 00:17:50.549 to eight months, too. That's linked to the ability 00:17:50.549 --> 00:17:53.450 to discriminate. Earlier, a baby might smile 00:17:53.450 --> 00:17:56.390 at anyone, but by six months, they can clearly 00:17:56.390 --> 00:17:59.230 distinguish between familiar and unfamiliar faces. 00:17:59.349 --> 00:18:01.190 So they know you're not their person. They realize 00:18:01.190 --> 00:18:04.289 you are not my person, and they protest. So if 00:18:04.289 --> 00:18:06.210 you're a nurse walking into a room to examine 00:18:06.210 --> 00:18:08.789 a nine -month -old, don't expect them to be thrilled 00:18:08.789 --> 00:18:12.150 to see you. No, you are a threat. The best strategy 00:18:12.150 --> 00:18:14.990 is to talk to the parent first. Ignore the baby 00:18:14.990 --> 00:18:17.750 for a minute. Let the baby see the parent trusting 00:18:17.750 --> 00:18:21.190 you. Don't swoop in. That stranger anxiety is 00:18:21.190 --> 00:18:23.470 a protective mechanism. This brings us to the 00:18:23.470 --> 00:18:26.230 most practical part of the episode, safety. And 00:18:26.230 --> 00:18:29.109 I love how the outline puts this. Safety risks 00:18:29.109 --> 00:18:32.450 are not random. They are the result of the milestones. 00:18:32.829 --> 00:18:35.490 This is the core of the 80 -20 approach. If you 00:18:35.490 --> 00:18:37.609 know the milestone, you know the risk. You don't 00:18:37.609 --> 00:18:39.910 need to memorize a safety checklist. You just 00:18:39.910 --> 00:18:42.269 look at the baby's capabilities. Let's play cause 00:18:42.269 --> 00:18:44.490 and effect. I'll give you the risk. You give 00:18:44.490 --> 00:18:47.509 me the developmental why. First up, aspiration 00:18:47.509 --> 00:18:50.880 and choking. The developmental cause is the pincer 00:18:50.880 --> 00:18:54.000 grasp at nine months plus the oral fixation. 00:18:54.079 --> 00:18:56.960 Remember, Freud? The oral stage. Oh, yeah. They 00:18:56.960 --> 00:18:59.259 explore the world with their mouths. So they 00:18:59.259 --> 00:19:01.559 can pick up tiny things now, and their instinct 00:19:01.559 --> 00:19:03.500 is to put everything in their mouth to understand 00:19:03.500 --> 00:19:06.279 it. Correct. Before nine months, they couldn't 00:19:06.279 --> 00:19:08.920 pick up a coin or a button. Now they can. So 00:19:08.920 --> 00:19:12.900 the safety rule is no grapes, no coins, check 00:19:12.900 --> 00:19:15.259 the buttons on clothing. If it fits in a toilet 00:19:15.259 --> 00:19:18.240 paper roll, it's a choking hazard. Next risk. 00:19:18.410 --> 00:19:21.630 False. This links to gross motor skills. Rolling 00:19:21.630 --> 00:19:23.910 over happens suddenly around four to six months. 00:19:24.130 --> 00:19:26.230 Pulling to a stand happens around nine to twelve 00:19:26.230 --> 00:19:28.630 months. And the problem is, parents don't know 00:19:28.630 --> 00:19:30.930 the baby can do it until they do it. Exactly. 00:19:31.029 --> 00:19:33.230 The baby has never rolled over until the second 00:19:33.230 --> 00:19:36.069 you turn your back to grab a diaper. Ugh. That's 00:19:36.069 --> 00:19:38.730 why the rule is never leave a baby alone on a 00:19:38.730 --> 00:19:40.849 changing table, even for a second. Keep a hand 00:19:40.849 --> 00:19:43.789 on them. And for cribs, the mattress must be 00:19:43.789 --> 00:19:45.730 in the lowest position by the time they can pull 00:19:45.730 --> 00:19:48.450 up to stand or they will vault out of it. Burns. 00:19:48.950 --> 00:19:51.970 That seems broad. This is cognitive. They have 00:19:51.970 --> 00:19:54.170 no cause and effect reasoning for danger yet, 00:19:54.390 --> 00:19:57.069 and they have sensory curiosity. They want to 00:19:57.069 --> 00:19:59.470 touch the hot cup of coffee because it has steam. 00:19:59.910 --> 00:20:01.829 They want to turn the faucet handle because it's 00:20:01.829 --> 00:20:04.390 shiny. So the environment has to be passive protection. 00:20:04.539 --> 00:20:07.380 Right. You can't lecture them. Turn the pot handles 00:20:07.380 --> 00:20:10.500 toward the back of the stove. Set the water heater 00:20:10.500 --> 00:20:13.980 to below 49 degrees Celsius or 120 Fahrenheit. 00:20:14.079 --> 00:20:16.900 That's a big one. You cannot teach a nine -month 00:20:16.900 --> 00:20:19.420 -old not to touch hot things. You have to remove 00:20:19.420 --> 00:20:21.970 the hot things. Motor vehicle safety. This is 00:20:21.970 --> 00:20:24.650 a big one for parent education. Rear -facing 00:20:24.650 --> 00:20:27.269 car seats. Why are we so strict about this? The 00:20:27.269 --> 00:20:31.450 rule is rear -facing until age two or until they 00:20:31.450 --> 00:20:33.769 max out the height and weight limits. But the 00:20:33.769 --> 00:20:37.380 why is anatomy. Is it the big head? It's the 00:20:37.380 --> 00:20:39.920 big head. An infant has a disproportionately 00:20:39.920 --> 00:20:43.000 large heavy head and very weak neck muscles. 00:20:43.039 --> 00:20:45.460 Right. In a frontal crash, which is the most 00:20:45.460 --> 00:20:48.240 common type, if they are forward facing, the 00:20:48.240 --> 00:20:50.799 momentum throws that heavy head forward. It's 00:20:50.799 --> 00:20:52.839 whiplash on steroids. It can literally sever 00:20:52.839 --> 00:20:55.039 the spinal cord. That is a terrifying image. 00:20:55.259 --> 00:20:57.720 It is. But if they are rear facing, the back 00:20:57.720 --> 00:21:00.000 of the car seat acts like a catcher's mitt. It 00:21:00.000 --> 00:21:02.039 cradles the head, neck, and spine, distributing 00:21:02.039 --> 00:21:04.680 the force along the entire back. It's just physics. 00:21:05.119 --> 00:21:08.430 Laz safety point. SID, sudden infant death syndrome. 00:21:08.789 --> 00:21:10.849 The back to sleep campaign, we put babies on 00:21:10.849 --> 00:21:13.150 their backs, and the rationale goes back to that 00:21:13.150 --> 00:21:15.990 two month milestone, head control. Meaning they 00:21:15.990 --> 00:21:18.609 don't have it yet. Exactly. In the early months, 00:21:18.849 --> 00:21:21.750 if a baby is face down on a soft pillow or blanket, 00:21:22.150 --> 00:21:24.630 and their airway gets blocked, they physically 00:21:24.630 --> 00:21:26.849 cannot lift their head or turn it to breathe, 00:21:26.910 --> 00:21:31.230 they suffocate. So, no pillows, no bumpers, no 00:21:31.230 --> 00:21:34.539 stuffed animals, firm mattress. Back to sleep. 00:21:34.799 --> 00:21:36.859 Until they can roll over independently. Once 00:21:36.859 --> 00:21:38.519 they can roll, they can find their own position, 00:21:38.539 --> 00:21:41.039 but you always start them on their back. Let's 00:21:41.039 --> 00:21:43.779 shift to something more fun. Play. How do we 00:21:43.779 --> 00:21:46.319 play with these tiny humans? Well, socially, 00:21:46.539 --> 00:21:49.079 they are solitary players. They don't play with 00:21:49.079 --> 00:21:50.920 other kids. If you put two eight -month -olds 00:21:50.920 --> 00:21:52.759 together, they will ignore each other or maybe 00:21:52.759 --> 00:21:55.039 poke each other like objects. Right. They play 00:21:55.039 --> 00:21:57.400 near others, but focused on their own toy. And 00:21:57.400 --> 00:21:59.200 picking the toy is just matching the developmental 00:21:59.200 --> 00:22:01.480 skill, right? Let's run through the ages. Birth 00:22:01.480 --> 00:22:04.069 to three months. They can't grasp well? and their 00:22:04.069 --> 00:22:06.490 vision is still developing. They love high contrast. 00:22:07.289 --> 00:22:11.509 So mobiles, mirrors, music boxes, it's all about 00:22:11.509 --> 00:22:14.410 auditory and visual stimulation. Three to six 00:22:14.410 --> 00:22:17.150 months. Now they are batting at things and the 00:22:17.150 --> 00:22:20.789 grasp reflex is fading, being replaced by voluntary 00:22:20.789 --> 00:22:23.630 holding. Rattles are perfect because they're 00:22:23.630 --> 00:22:26.490 easy to hold and bonus cause and effect. Shake 00:22:26.490 --> 00:22:29.349 it makes noise. Exactly. Soft stuff toys are 00:22:29.349 --> 00:22:32.009 good too. Six to nine months. This is the teething 00:22:32.009 --> 00:22:35.130 phase and the social interaction phase. So teething 00:22:35.130 --> 00:22:37.950 toys are essential. Fabric books they can chew 00:22:37.950 --> 00:22:40.630 on. And games like pat -a -cake because they 00:22:40.630 --> 00:22:43.109 love that rhythm and interaction. And finally, 00:22:43.369 --> 00:22:46.049 nine to twelve months, the mobile explorer. They 00:22:46.049 --> 00:22:49.049 are working on that pincer grass and object permanence. 00:22:49.630 --> 00:22:52.990 So nesting toys like cups inside of cups are 00:22:52.990 --> 00:22:55.329 amazing for teaching things go inside other things. 00:22:55.670 --> 00:22:58.549 Large blocks, push pull toys to encourage that 00:22:58.549 --> 00:23:00.869 walking skill. It's cool to see how the toy aisle 00:23:00.869 --> 00:23:03.089 is basically just a developmental psychology 00:23:03.089 --> 00:23:06.349 lab. A nesting cup is an object permanence lesson. 00:23:06.490 --> 00:23:08.789 It really is. Every toy serves a neurological 00:23:08.789 --> 00:23:11.230 purpose. OK, we're heading into the final stretch. 00:23:11.650 --> 00:23:14.150 This is the exam writer's perspective. We want 00:23:14.150 --> 00:23:16.150 to give our listeners the edge on those tricky 00:23:16.150 --> 00:23:18.869 clinical application questions. Let's talk nutrition 00:23:18.869 --> 00:23:22.309 first. The classic trap question is about cow's 00:23:22.309 --> 00:23:25.109 milk. Can I give my 10 -month -old regular milk? 00:23:25.410 --> 00:23:28.609 The answer is a hard no. Not until 12 months. 00:23:29.169 --> 00:23:32.269 Three reasons. One, it's hard to digest and can 00:23:32.269 --> 00:23:35.910 cause microscopic GI bleeding. Two, it has a 00:23:35.910 --> 00:23:38.109 high renal salute load. It's hard on the kidneys. 00:23:38.670 --> 00:23:40.710 But three is the big one. It interferes with 00:23:40.710 --> 00:23:43.369 iron absorption. It puts the baby at risk for 00:23:43.369 --> 00:23:45.789 anemia. Speaking of iron, that's also why we 00:23:45.789 --> 00:23:47.829 start solids at six months, right? It's not just 00:23:47.829 --> 00:23:49.809 because they're hungry. Correct. A full term 00:23:49.809 --> 00:23:52.089 infant is born with iron stores that last about 00:23:52.089 --> 00:23:54.470 four to six months. By six months, the tank is 00:23:54.470 --> 00:23:57.140 empty. Breast milk is amazing, but it's naturally 00:23:57.140 --> 00:23:59.700 low in iron. So we introduce iron -fortified 00:23:59.700 --> 00:24:02.519 cereal first to replenish those stores. And for 00:24:02.519 --> 00:24:04.619 allergies. Introduce one new food every three 00:24:04.619 --> 00:24:07.200 to five days. Don't give them peas, carrots, 00:24:07.359 --> 00:24:09.519 and pears all on the same day. If they break 00:24:09.519 --> 00:24:11.680 out in a rash, you need to know which one caused 00:24:11.680 --> 00:24:15.460 it. Next topic, pain assessment. This is tough 00:24:15.460 --> 00:24:18.029 because babies can't tell you it hurts. Self 00:24:18.029 --> 00:24:20.470 -report is impossible, so we have to use observational 00:24:20.470 --> 00:24:23.650 scales. The gold standard for infants, so two 00:24:23.650 --> 00:24:26.470 months to seven years, is the F .L .A .C .C. 00:24:26.849 --> 00:24:30.529 scale. F .L .A .C .C. Face, legs, activity, cry, 00:24:30.750 --> 00:24:33.730 consolability. You score each category 0 to 2? 00:24:34.230 --> 00:24:36.849 Are their legs kicking or relaxed? Are they arching 00:24:36.849 --> 00:24:39.230 their back? Are they crying steadily or just 00:24:39.230 --> 00:24:42.069 whimpering? Are they inconsolable? That gives 00:24:42.069 --> 00:24:44.470 you a number out of 10. But what about a neonate? 00:24:44.809 --> 00:24:47.599 A brand new baby? For them, we often use the 00:24:47.599 --> 00:24:50.660 cry scale. Crying requires oxygen, increased 00:24:50.660 --> 00:24:53.519 vital signs, expression, sleeplessness. It's 00:24:53.519 --> 00:24:55.759 more physiological because newborns respond to 00:24:55.759 --> 00:24:57.900 pain with heart rate spikes, and oxygen drops 00:24:57.900 --> 00:25:00.099 more than behavioral acting out. Okay, here's 00:25:00.099 --> 00:25:02.579 the one that stumps everyone. The math question 00:25:02.579 --> 00:25:05.609 regarding prematurity. Adjusted age. This is 00:25:05.609 --> 00:25:07.630 so critical. If you are assessing a baby who 00:25:07.630 --> 00:25:10.309 was born premature, you cannot hold them to the 00:25:10.309 --> 00:25:12.150 standard milestones based on their birthdate. 00:25:12.190 --> 00:25:14.329 Right. You have to adjust for the time they missed 00:25:14.329 --> 00:25:16.069 in the womb. Walk us through the calculation. 00:25:16.210 --> 00:25:18.029 Let's say we have a six -month -old baby girl, 00:25:18.309 --> 00:25:20.730 but she was born two months early at 32 weeks 00:25:20.730 --> 00:25:24.369 gestation. OK. Chronologically, she has been 00:25:24.369 --> 00:25:26.609 out of the womb for six months. That's her birthday 00:25:26.609 --> 00:25:29.630 age. OK. But she missed two months of development 00:25:29.630 --> 00:25:33.130 inside. So we subtract. Six months minus two 00:25:33.130 --> 00:25:36.269 months equals four months. So her adjusted age 00:25:36.269 --> 00:25:39.829 is four months. Right. And here is the exam trap. 00:25:40.289 --> 00:25:43.410 The question will ask, what developmental milestone 00:25:43.410 --> 00:25:45.690 should this child be performing? And if you use 00:25:45.690 --> 00:25:48.970 her chronological age, six months, you'd expect 00:25:48.970 --> 00:25:51.480 her to sit unsupported. Which she probably can't 00:25:51.480 --> 00:25:54.200 do yet. She is developmentally a four month old. 00:25:54.500 --> 00:25:56.940 So you should be evaluating her for four month 00:25:56.940 --> 00:26:00.420 milestones. Head control, rolling over, maybe 00:26:00.420 --> 00:26:02.740 grasping a rattle. That is such a key distinction. 00:26:03.059 --> 00:26:04.859 You catch up eventually, right? Usually by age 00:26:04.859 --> 00:26:06.759 two. Yeah. But for that first year, you have 00:26:06.759 --> 00:26:08.779 to do the math. Always do the math. We have covered 00:26:08.779 --> 00:26:11.720 a massive amount of ground, from fontanels to 00:26:11.720 --> 00:26:15.420 object permanence, from pincer grasps to car 00:26:15.420 --> 00:26:17.680 seats. Let's try to wrap this up with our 80 00:26:17.680 --> 00:26:19.700 -20 summary box. What are the core takeaways? 00:26:19.960 --> 00:26:21.920 OK, if you remember nothing else, remember this 00:26:21.920 --> 00:26:24.900 logical flow. Right. One. If they can't move, 00:26:25.059 --> 00:26:27.299 they can suffocate. That's the S -I -D -S risk 00:26:27.299 --> 00:26:29.660 in the first few months. Two, if they can move, 00:26:29.839 --> 00:26:32.559 they can fall or aspirate. That's the safety 00:26:32.559 --> 00:26:35.339 risk once rolling and pincer grasp kick in. Makes 00:26:35.339 --> 00:26:37.799 sense. And three, if they know you exist but 00:26:37.799 --> 00:26:41.039 can't see you, they panic. That explains separation 00:26:41.039 --> 00:26:43.539 anxiety. And the growth rules? Weight doubles 00:26:43.539 --> 00:26:47.220 by six months, triples by a year. And head growth 00:26:47.220 --> 00:26:50.019 reflects brain growth. So check those continents. 00:26:50.619 --> 00:26:53.339 And finally, the underlying philosophy. Trust 00:26:53.339 --> 00:26:56.740 versus mistrust. Everything you do as a nurse 00:26:56.740 --> 00:27:00.259 or parent feeding, holding, comforting, is building 00:27:00.259 --> 00:27:03.259 the neurological hardware for trust. It really 00:27:03.259 --> 00:27:05.119 changes how you look at a baby. They aren't just 00:27:05.119 --> 00:27:07.559 sitting there. They are running complex experiments 00:27:07.559 --> 00:27:10.059 on reality. They are the ultimate learning machines. 00:27:10.299 --> 00:27:12.000 I want to leave you with one final thought to 00:27:12.000 --> 00:27:14.390 chew on. We talk about how vulnerable these infants 00:27:14.390 --> 00:27:16.650 are born with almost no instincts other than 00:27:16.650 --> 00:27:19.509 sucking and rooting. They are completely helpless. 00:27:19.690 --> 00:27:21.769 It is unique in the animal kingdom. Most mammals 00:27:21.769 --> 00:27:24.369 can walk within hours. Humans take a year. Exactly. 00:27:24.509 --> 00:27:26.869 And that extreme vulnerability forces a deep 00:27:26.869 --> 00:27:29.529 connection with the caregiver. It makes me think 00:27:29.529 --> 00:27:32.789 maybe that helplessness is actually a feature, 00:27:33.150 --> 00:27:37.009 not a bug. It forces that trust bond to be the 00:27:37.009 --> 00:27:39.349 absolute strongest force in human development. 00:27:39.480 --> 00:27:42.640 Without that initial total dependence, maybe 00:27:42.640 --> 00:27:44.960 we wouldn't form the deep social bonds that make 00:27:44.960 --> 00:27:47.420 us human. That is a profound way to look at it. 00:27:47.579 --> 00:27:50.220 The dependency creates the humanity. Something 00:27:50.220 --> 00:27:51.839 to think about next time you're checking a diaper 00:27:51.839 --> 00:27:54.420 or plotting a growth chart. Thank you for joining 00:27:54.420 --> 00:27:57.000 us on this deep dive into the infant year. Keep 00:27:57.000 --> 00:27:58.319 learning. We'll see you next time.