I need to make a confessionat the outset here. A little over 20 years ago,I did something that I regret, something that I'm notparticularly proud of. Something that, in many ways,I wish no one would ever know, but here I feel kind of obliged to reveal. (Laughter) In the late 1980s, in a moment of youthful indiscretion,
I went to law school. (Laughter) In America, law is a professional degree: after your university degree,you go on to law school. When I got to law school, I didn't do very well. To put it mildly, I didn't do very well. I, in fact, graduated in the partof my law school class
that made the top 90% possible. (Laughter) Thank you. I never practiced law a day in my life; I pretty much wasn't allowed to. (Laughter) But today, against my better judgment, against the advice of my own wife,
I want to try to dust offsome of those legal skills what's left of those legal skills. I don't want to tell you a story. I want to make a case. I want to make a hardheaded, evidencebased, dare I say lawyerly case, for rethinking how we run our businesses.
So, ladies and gentlemen of the jury, take a look at this. This is called the candle problem. Some of you might know it. It's created in 1945 by a psychologist named Karl Duncker. He created this experiment that is used in many other experimentsin behavioral science.
And here's how it works.Suppose I'm the experimenter. I bring you into a room. I give you a candle,some thumbtacks and some matches. And I say to you, quot;Your job is to attachthe candle to the wall so the wax doesn't drip onto the table.quot; Now what would you doé Many people begin tryingto thumbtack the candle to the wall.
The menstrual cycle and your bodys natural signal of fertility cervical mucus
Your reproductive system is wonderfully complex,yet the signals it gives you can be quite simple, helping you identify the fertile andinfertile times in your cycle. You may have noticed different types of discharge throughoutyour menstrual cycle. The sensation that this discharge produces at the vaginal opening,called the vulva, also changes. This is because your cervix produces different types of mucusin response to changing hormone levels. Your cycle begins with menstrual bleeding,when the lining of your uterus, called the endometrium, is shed.Following menstruation your cervix becomes blocked by a thick plug of mucus that preventssperm from entering the uterus. This means
that you are infertile. Many women feel dryat the vulva during this time. Other women notice a pattern of discharge that feels andlooks the same day after day. The number of days that you experience this unchanging patternwill determine the length of your cycle. In an average cycle this pattern of infertilitylasts for a few days. If your cycle is short you may not experience any days of this infertilepattern. In a longer cycle you will have more. Early in your cycle the pituitary gland inyour brain begins to secrete a hormone called Follicle Stimulating Hormone, or FSH. FSHstimulates the growth of a group of follicles in your ovaries. Each follicle contains anegg and a bundle of surrounding cells that
secrete the hormone oestrogen.Oestrogen activates the cervix to produce the mucus essential for fertility. This isthe start of the fertile phase. The fertile phase, shown here using a baby symbol, beginsa few days before ovulation. One type of mucus produced by the cervix dissolves the plug,which means sperm can now enter the uterus. Another type of mucus filters out damagedsperm cells. Yet another type nourishes the sperm so they can live for up to five daysin your reproductive system. It forms channels which help the sperm travel through your reproductivesystem to meet and fertilise the egg. You become aware of your developing fertilityby the changes in the mucus that you feel
and see at the vulva. You will notice thatyou feel increasingly wet and then slippery, and you may see mucus that becomes thinnerand clearer. The last day of the slippery feeling is called the Peak of fertility. Itis very close to the time of ovulation. As one follicle nears maturity, the pituitarygland is stimulated to release a surge of another hormone, called Luteinizing Hormone,or LH. LH triggers ovulation: the release of the egg from its follicle. The egg is sweptup into the fallopian tube, ready to begin its journey towards the uterus. If fertilisationdoesn't occur the egg will die within a day of ovulation. But if the egg meets any spermalong the way, fertilisation can take place.
After ovulation the empty follicle is transformedinto the Corpus Luteum. The Corpus Luteum produces a hormone called progesterone. Progesteroneprepares the endometrium in case there's a fertilised egg ready to implant. It also causesthe mucus to thicken, and the plug to begin forming in the cervix again. The day followingthe Peak you'll no longer feel wet or slippery at the vulva. By the end of three days afterthe Peak your fertility for this cycle is over. About 2 weeks after ovulation a newcycle begins. We can now see how essential cervical mucusis for fertility. Once you're familiar with your patterns you'll be able to identify yourfertile and infertile times. This knowledge
can help you to achieve or avoid pregnancy.It can also help you to safeguard your reproductive health, as you'll be able to recognise changeswhich might need medical investigation. This is knowledge that every woman ought to have.