What If Humans Only Had A Left Brain? | Unveiled - video Dailymotion

Unveiled

Watch What If Humans Only Had A Left Brain? | Unveiled - Unveiled on Dailymotion

Transcript

00:00 The human brain has been described as the most complex known structure in the entire

00:04 universe.

00:05 It's the hub for everything we do, see, think, feel, experience, learn and remember.

00:10 Although it's held inside the thick bone of our skulls, it's also the only reason

00:14 we're ever able to understand anything that happens to us in the outside world.

00:19 And yet, from some perspectives, it's actually quite a simple entity.

00:22 A near-symmetrical organ with distinct halves that combine to make the whole.

00:26 So, what happens if that basic setup falls apart?

00:30 This is Unveiled, and today we're answering the extraordinary question; what if humans

00:34 only had a left brain?

00:38 Do you need the big questions answered?

00:40 Are you constantly curious?

00:42 Then why not subscribe to Unveiled for more clips like this one?

00:45 And ring the bell for more thought-provoking content!

00:50 Physically speaking, what is the brain actually made of?

00:53 In the past, some have wrongly referred to it as a muscle, which it isn't.

00:57 What it is is mostly fat.

00:59 It weighs about three pounds, and according to John Hopkins Medicine, it's about sixty

01:03 percent fat.

01:05 The remaining forty percent is a combination of water, protein, carbohydrates and salts.

01:10 Based on only that description, however, you might imagine the brain to be something of

01:14 a bland and lifeless blob of nothing much.

01:18 But really, we know that all of that matter is arranged in such a way so as to produce

01:22 something incredible.

01:23 The brain contains enormous amounts of nerves and blood vessels, billions of neurons and

01:29 synapses, along which all of life is processed.

01:32 It has an outer layer of grey matter covering an inner core of white matter.

01:36 What's key for today's question, though, is that it's near perfectly split in two.

01:42 The mysteries of the left and right brain, the two hemispheres of our cerebral organ,

01:47 have been a key focus in neurological study for centuries.

01:50 The fact that there are two halves has been known since as far back as in ancient Rome,

01:54 although many of the greatest strides in our understanding have been made in the last two

01:58 hundred years or so.

01:59 The two halves are connected by a dense bundle of nerve fibres called the corpus callosum,

02:05 although there are some split-brain patients who have had their corpus callosum severed,

02:10 often as a last resort to treat severe epilepsy.

02:13 Much of what we know about each of the brain's hemisphere's function is then derived from

02:17 studies involving split-brain patients.

02:20 The most famous of all were carried out by the American neuroscientist Roger Sperry,

02:25 beginning in the 1960s, with Sperry's work then continued by many of his students, among

02:30 them Michael Gazzaniga and Jerry Levy.

02:33 Such studies have shown that each side of the brain is somewhat specifically responsible

02:38 for certain functions and abilities.

02:40 However, the idea that any one person can be more influenced by one side over the other

02:45 - i.e. that you can be more left-brained than right - is now generally regarded to be a

02:50 myth.

02:51 In the standard set-up of the human brain, with both sides fully linked by the corpus

02:55 callosum, scans show that each side is called upon in essentially equal measure.

03:01 As a result, and in the real world, you really need both sides to survive.

03:06 For this what-if scenario, though, we're imagining that your body does find a way to

03:10 carry on with only the left.

03:12 How different would your life be?

03:14 And how much can that tell us about the way the brain works?

03:17 The left side of the brain is typically referred to as the "logical" side.

03:21 Most language functions are attributed to sections of the left, including fundamental

03:25 vocalization skills.

03:26 The left brain is said to be a communicator, an analyser, a problem-solver.

03:31 It specialises in facts and sequences, but could struggle with more abstract things,

03:36 like emotions.

03:37 While contemporary research has shown that it's not quite so black and white as "left

03:41 equals logic, right equals creativity" - that the relationships are much more nuanced than

03:46 that - we can predict that if we were somehow only left-brain beings, then there'd be

03:51 some things that we'd be great at, and some that we'd find difficult, if not impossible.

03:57 Researchers can demonstrate this via some quite simple visual tests conducted on split-brain

04:02 patients.

04:03 What's important in every test like this is that the left brain controls the right

04:08 side of the body, and vice versa.

04:10 In this way, it's been shown that if a visual cue is presented to the right visual

04:14 field, then a patient is easily able to say what they've seen.

04:19 The left brain, containing key areas for language and speech, does this automatically.

04:23 However, if the same visual cue is presented to the left visual field, and therefore processed

04:28 by the right brain only, then that same patient can't vocalize the image.

04:33 In our particular hypothetical situation, then, perhaps humans would be constantly talking

04:38 if they had only a left brain.

04:41 Writing as well, as this is another ability found to be primarily guided by the workings

04:45 of the left hemisphere.

04:47 For as long as the left brain still only controlled the right side of the body, though, we would

04:51 all inevitably be right-handed.

04:54 More broadly, it would seemingly be a world of unapologetic speech and script.

04:59 However, while that may sound like something of an ultra-expressive utopia, there would

05:03 more than likely be plenty of problems.

05:06 Michael Gazzaniga, a psychologist at the University of California, Santa Barbara, and again, a

05:11 former student of Roger Sperry, has devised what he calls the "left brain interpreter".

05:16 This is a neuropsychological model that might go some way to explaining why humans do some

05:21 of the things they do.

05:23 Studies presided over by Gazzaniga have shown that not only can the left brain vocalize

05:27 what it encounters, but it can also invent an explanation for anything the body is doing

05:32 based on right brain stimulation.

05:35 For example, if the right brain is told to walk, and so the subject gets up and walks

05:40 to the door - all while the left brain is unaware of what's happening - then the subject,

05:45 when questioned, might still provide an explanation for what they're doing.

05:49 For example, they might say "I'm going to check that that door is unlocked" when

05:53 actually they never had any inclination to do that.

05:56 In isolation, this might be seen as bizarre, but as a repeating pattern, it could lead

06:01 to various unwanted effects, including confusion or bias.

06:05 In a revised 2002 article for Scientific American, Gazzaniga concluded "it appears that the

06:11 inventive and interpreting left hemisphere has a conscious experience very different

06:17 from that of the truthful, literal right brain".

06:20 On the one hand, then, the left brain's apparent sureness - achieved via its seemingly

06:24 analytical bent - might instil confidence into a person, leaving them free of such feelings

06:29 as doubt and anxiety.

06:31 On the other hand, however, a solely left interpretation of events could lead to overconfidence,

06:36 to the continued entrenchment of harmful ideas, and to even delusion.

06:40 When both halves of the brain are connected, the right serves to check the left, and vice

06:45 versa.

06:46 But if the left were somehow cast adrift, then its specialisms would know no bounds.

06:51 The apparently more emotionally-driven right brain might seem to offer context to what

06:56 the left brain understands.

06:59 The two combined achieve a greater complexity than any one half could on its own.

07:04 All this to say that it's not as though we should ever really value one half over

07:08 the other.

07:09 On the surface level, we can theorise that anyone with only a left brain would be a talker,

07:13 a writer, and probably quite sure of themselves and their convictions.

07:17 Our hypothetically 100% left brainer would likely excel at calculations, and at memorising

07:22 facts as though they're data.

07:24 However, they probably wouldn't be a very imaginative talker, or a very creative writer,

07:30 without an in-depth appreciation of more abstract concepts.

07:33 Their memory might be great in some ways, but flawed in others - such as in remembering

07:37 how any one experience made them feel.

07:40 Gazzaniga's characterisation of the left brain as more inventive than the truthful

07:44 right, however, then appears to turn all of that on its head.

07:47 But with context, we can see how, in this case, the inventiveness is more of a bid to

07:52 maintain logical control, rather than an exploration of the more unknowable right brain concepts.

07:59 Over the years, however, what Gazzaniga's work - and the work of countless others in

08:03 the field - has done is show just how intricate the inner mechanics of the brain really are.

08:08 The Corpus Callosum, when it is intact - as it is for most people - is like a spectacular

08:13 neural highway, transporting information across and transforming it into the unique lives

08:18 and experiences that every one of us has.

08:21 At the same time, split-brain patients are proof that you can live without it.

08:26 Life is sometimes a little different, but you do at least still have both halves of

08:30 your brain to call upon.

08:32 In contrast, and in reality, living with just one of those halves probably isn't possible…

08:38 but as a thought experiment, it shows exactly what either side contributes.

08:42 Because that's what would happen if humans only had a left brain.

08:46 What do you think?

08:47 Is there anything we missed?

08:48 Let us know in the comments.

08:49 Check out these other clips from Unveiled, and make sure you subscribe and ring the bell

08:54 for our latest content.

What If Humans Only Had A Left Brain? | Unveiled

Category

Transcript

Be the first to comment

Recommended