Extensive listening: The Brain with David Eagleman: What Is Reality?

The Brain with David Eagleman is a BBC series in which Dr David Eagleman takes viewers on an extraordinary journey that explores how the brain, locked in silence and darkness without direct access to the world, conjures up the rich and beautiful world we all take for granted.

What Is Reality? begins with the astonishing fact that this technicolour multi-sensory experience we are having is a convincing illusion conjured up for us by our brains. In the outside world there is no colour, no sound, no smell. These are all constructions of the brain. Instead, there is electromagnetic radiation, air compression waves and aromatic molecules, all of which are interpreted by the brain as colour, sound and smell.

We meet a man who is blind despite the fact that he has eyes that can see. His story reveals that it's the brain that sees, not the eyes. A woman with schizophrenia, whose psychotic episodes were her reality, emphasises the fact that whatever our brains tell us is out there, we believe it.
Visual illusions are reminders that what's important to the brain is not being faithful to 'reality', but enabling us to perceive just enough so that we can navigate successfully through it. The brain leaves a lot out of its beautiful rendition of the physical world, a fact that Dr Eagleman reveals using experiments and street demonstrations.

Each one of our brains is different, and so is the reality it produces. What is reality? It's whatever your brain tells you it is.

What makes tattoos permanent

What makes tattoos permanent is a TEd lesson by Claudia Aguirre in which she tries to give a scientific answer to the question 'how do these markings last?'. She also details the different methods, machines and macrophages that go into making tattoos stand the test of time.

Self-study activity:
There's quite a lot of scientific name-dropping in this video, which might make it a bit difficult for learners to understand. Don't be deterred by the jargon and just focus on the task at hand, which is quite general.

Watch the video and say whether the statements below are true or false.



You may also want to go to the original TEd-ed lesson and do the activities suggested there. Remember that you will find more comprehension questions in the Think tag, suggestions to explore the topic further in the Dip deeper tag and some topics for discussion in the Discuss tag.

1 No tattoos have been found in human remains before Christ.
2 Human skin falls off like that of snakes.
3 Thomas Edison invented the electric tattooing machine.
4 The tattooing process is similar to causing a wound to the body.
5 Sun exposure and swimming help tattoos to fix.
6 With time tattoos become paler.
7 In most cases, tattoos stay fixed in a person's skin for life.
8 With the help of a laser, tattoos can easily be erased.

Tattoos have often been presented in popular media as either marks of the dangerous and deviant or trendy youth fads, but while tattoo styles come and go and their meaning has differed greatly across cultures. The practice is as old as civilization itself. Decorative skin markings have been discovered in human remains, all over the world with the oldest found on a Peruvian mummy dating back to 6000 BCE.
But have you ever wondered how tattooing really works? You may know that we shed our skin, losing about 30,000 to 40,000 skin cells per hour, that’s about a million per day. So, how come the tattoo doesn’t gradually flake off along with them. The simple answer is that tattooing involves getting pigment deeper into the skin than the outermost layer, that gets shed. Throughout history different cultures have used various methods to accomplish this, but the first modern tattooing machine was modeled after Thomas Edison’s engraving machine and ran on electricity.
Tattooing machines used today insert tiny needles loaded with dye into the skin at a frequency of 50 to 3,000 times per minute. The needles punch through the epidermis, allowing ink to seep deep into the dermis, which is composed of collagen fibers, nerves, glands, blood vessels, and more. Every time a needle penetrates it causes a wound that alerts the body to begin the inflammatory process, calling immune system cells to the wound site to begin repairing the skin and it is this very process that makes tattoos permanent.
First, specialized cells called macrophages eat the invading material in an attempt to clean up the inflammatory mess as these cells travel through the lymphatic system, some of them are carried back with a belly full of dye into the lymph nodes, while others remain in the dermis, with no way to dispose of the pigment the dyes inside them remain visible through the skin. Some of the ink particles are also suspended in the gel like matrix of the dermis, while others are engulfed by dermal cells, called fibroblasts.
Initially ink is deposited into the epidermis as well, but as the skin heals the damaged epidermal cells are shed and replaced by new dye free cells with the top most layer peeling off like a healing sunburn. Blistering or crusting is not typically seen with professional tattoos and complete epidermal regeneration requires two to four weeks during which excess sun exposure and swimming should be avoided to prevent fading.
Dermal cells, however, remain in place until they die. When they do they are taken up ink and all by younger cells nearby so the ink stays where it is. But with time tattoos do fade naturally as the body reacts to the alien pigment particles, slowly breaking them down to be carried off by the immune system’s macrophages.
Ultra-violet radiation can also contribute to this pigment break-down, though it can be mitigated by the use of sun block. But since the dermal cells are relatively stable much of the ink will remain deep in the skin for a person’s whole life, but if tattoos are embedded in your skin for life is there any way to erase them. Technically, yes.
Today a laser is used to penetrate the epidermis and blast apart underlying pigment colors of various wavelengths. Black being the easiest to target, the laser beam breaks the ink globules into smaller particles that can then cleared away by the macrophages, but some color inks are harder to remove than others, and there could be complications; for this reason removing a tattoo is still more difficult than getting one, but not impossible.
So, a single tattoo may not truly last forever, but tattoos have been around longer than any existing culture, and their continuing popularity means that the art of tattooing is here to stay.

Key:
1F 2T 3F 4T 5F 6T 7T 8F

Why Do We Talk?

Talking is something that is unique to humans, yet it still remains a mystery. Why Do We Talk? meets the scientists beginning to unlock the secrets of speech - including a father who is filming every second of his son's first three years in order to discover how we learn to talk, the autistic savant who can speak more than 20 languages, and the first scientist to identify a gene that makes speech possible.

This BBC's Horizon documentary also hears from the godfather of linguistics, Noam Chomsky, the first to suggest that our ability to talk is innate.

You can read the transcript for the first ten minute of the documentary here.

Reading test: How do we really make decisions?

In this week's reading comprehension activity we are going to practise a different kind of multiple choice activity. Read the article How do we really make decisions? on the BBC's web page and say whether the statements below are true (T), false (F) or the information in the sentence is not mentioned in the article (NM).

1 We always make our decisions using solid reasoning.
2 We are aware of the mistakes we make, but we can’t help making them over and over again.
3 The ‘stranger within’ or ‘hidden autopilot’ is a recent discovery in psychology.
4 Most of the mistakes we make come from decisions taken by our intuitive mind.
5 Our logical mind has nothing to do with our biases.
6 The example of the chocolate box shows how irrational some of our decisions are.
7 Confirmation bias means that negative events are more easily remembered than positive ones.
8 Behavioural economics is the part of psychology that studies the way we respond to economic losses.
9 Loss aversion is very much to blame for the current economic crisis.
10 The evolutionary origins of the logical and intuitive systems have been studied for long.
11 As humans cannot change themselves, they’ll continue making the same mistakes.

Key:
1F; 2F; 3NM; 4T; 5F; 6T; 7F; 8F 9T; 10NM; 11F

Pregnancy explained -Video activity

In early July we published DNA explained, the first short documentary from BBC Knowledge & Learning series , a forthcoming project that aims to explore a large variety of subjects in engaging and accessible ways.

Today we have posted the second episode in the series, Pregnancy.

Self-study activity:
Watch the video and complete the blanks in the transcript with the missing words.

The activity is suitable for Intermedio 1 and Intermedio 2 students.

BBC Knowledge Explainer: Pregnancy from TellyJuice on Vimeo.


Each and every one of us began life as a single cell, no bigger than a full stop. From this we (1) ... into a human being made up of trillions of cells performing countless different functions. But how?

Pregnancy from conception to birth takes an average of forty weeks starting from the beginning of the mother’s last menstruation period. Development begins with fertilization when a sperm (2) ... with an egg to create a single cell called zygote. This cell holds immense potential. It is a shared genetic (3) ... from the mother and the father encoded in the genes of their combined DNA.

Over the next four days the zygote journeys down the fallopian tube to the uterus. On the way, it divides, eventually forming a cluster of cells called a blastocyst which has two distinct parts. One part will form the embryo. The other part will form the placenta, which (4) ... it. The blastocyst arrives in the uterus and within two days the cells sink in and attach to the uterine wall to continue their development.

By four weeks the embryo consists of three (5) ... that will become the baby’s organs and tissues. The ectoderm will become the central nervous system, the brain and spine. The mesoderm gives rise to deep structures, the (6) ... , cartilage and bones, and the endoderm could form blood cells and the intestines.

At around five weeks a heart beat can be detected. (6) ... begin to form, and small swellings called limb buds show where the legs and arms are growing. From eight weeks, the organs, nerves and muscles are all in place. The embryo is now referred to as the foetus.

At around ten weeks the face is taking shape and the foetus is recognizably human. Between eleven and fourteen weeks finger nails, toe nails and unique fingerprints are beginning to form. Between fifteen and twenty-six weeks the foetus  begins to react to loud sounds. It is now possible to tell whether it is a boy or a girl.

Between twenty-six and thirty-six weeks the foetus will begin to react to life and to develop a (7) ... cycle. The lungs and and nerve system have matured to the point where the foetus has a good chance of survival if it is born prematurely. From now the foetus starts to put on weight very rapidly, growing (8) ... deposits under the skin, ready for life outside the womb.

From thirty-seven weeks the baby is full term and maybe be born at any time. By now, the baby is usually head down, so that they can (9) ... into the mother’s pelvis. Eventually the mother’s uterine (6) ... start to contract. The cervix shortens and opened and the baby makes its journey down to the birth canal and into the world. It is the start of its life as a physically separate being, a baby with trillions of specialized cells, and it all began from just one.

Key:
1 developed 2 merges 3 inheritance 4 nourishes 5 layers 6 muscles 7 sleep 8 fat 9 descend