The Simbari people are from Papua New Guinea. According to anthropologist Gilbert Herdt -- who has written several books about this group & -- war was historically an integral part of their culture. Conflict between neighbouring tribes was regular, which included bow fighting where arrows were shot at their neighbours until a wrong was perceived to be righted. There were injuries; there was death. In this hostile environment, boys needed to become courageous warriors to protect their village, which involved the boys undergoing a series of rituals to initiate them into warriorhood -- to become men, as the Simbari see it. Yet in this climate, prearranged marriages between groups occurred, where the bride would go to a hostile area. There was no kissing between the couple (there was no concept of kissing in the culture), and there was distrust and suspicion about these brides. Perhaps it is little surprise then that becoming a warrior was a secret journey for boys and men.

Women weren''t allowed to know about it -- they couldn''t be trusted -- and warrior rituals were done in secret. Becoming a warrior was a multistage process that was full of secretive rituals. To be kept a secret, boys needed to leave the female realm, which included living solely among men where the secrets of their manhood were safe. It also included having their noses pierced in such a manner as to draw blood and cause pain. The pain might toughen them, while the blood was symbolically similar to how females go through menstruation and become women. Boys, however, bleed through their noses to become men. Becoming a man was more than just this, as semen was thought to be an essential ingredient of manhood, so it was considered a precious resource that needed to be sought after. According to the Simbari, boys don''t have any semen, so to get it, they needed to perform oral sex on older boys and ingest semen, as without it, they couldn''t become full men.

Then as they developed their own reservoir of semen, they could start to provide it to younger boys. Eventually they would also get into sexual relationships with women, but this semen exchange only ended after the man was married and had children. From boys to married men, Simbari males were first homosexual, then bisexual, and finally heterosexual. Yet semen was still a finite resource for the heterosexual married man, so after losing some of the precious substance by having sex with his wife, a married man would ingest white tree sap to replenish his reserves, which was a sufficient substitute for semen. This tree sap ingestion was reserved for the married. There are a few points I want to make about this example. First, there can be little doubt that the Simbari''s beliefs greatly affected who they are. Their views of manhood, being a warrior, sexual orientation, distrust and secrecy -- that is, their culture -- have all greatly affected them in ways that likely seem peculiar to many readers.

It actually goes much deeper than this, as culture can even affect things like how much sleep is needed, whether a baby crawls or not, and someone''s DNA. Culture has an incredibly broad influence on us, affecting our identity and personalities, how we cope with death, the ways in which we solve problems, the diseases we experience, whether we like to drink coffee, and much more. This book is about how culture deeply and profoundly influences us -- how it creates us. The second point I want to make is that cultures change. The Simbari practices I mention are no longer present today. Governments have put a stop to the warfare. Men have left their tribes in search of work and were thus exposed to other cultural practices. Boys no longer live with men and ingest semen.

Marriages are no longer prearranged, and romantic couples now kiss. There has been significant cultural change in a relatively short period of time. In this way, cultures are not static, but dynamic and change regularly as we are influenced by others. We learn about culture from others. Simbari boys learned about their secretive rituals from other men, and I first learned about the Simbari from my mentor in graduate school, Steve Heine. A well-known cultural psychologist, he taught me about the Simbari and uses this example to illustrate the profound influence of culture in his textbook: Cultural Psychology. This is how culture spreads -- from others. We essentially learn from others and copy them.

Steve didn''t create that knowledge but rather learned about it from an anthropologist named Gilbert Herdt who has written extensively about it. From Herdt to Heine to me to you, cultural information gets passed onto others. This book is about how culture deeply and profoundly influences us. I will be covering a wide variety of cultures and topics in this book. However, as is the case with most books, I have to be selective in what to include. I tried to select examples that are informative, interesting, and demonstrate a broad range of influence. Although I focus on how culture affects people, this shouldn''t be interpreted as me claiming that culture is the only factor that affects us. Culture can explain a lot of really interesting things, as we will see, but culture is one factor -- though an important one.

I''ll also be trying to present information in a fair, respectful manner. This isn''t always as easy as it might first seem since topics can be sensitive and even mentioning differences can sometimes be enough to upset people. I''m sure some readers likely found the opening example disturbing. Culture is often controversial. We tend to be taught our culture''s way is the right way, and other ways are wrong. When I teach cultural psychology at the university level, I always have to be careful about how I discuss things, as it is quite easy for people to get offended. I try to avoid moral judgments and instead focus on the differences and cultural explanations for why they exist. I''ve tried to take care to avoid offending, but cultures and people are very diverse, so I surely missed something.

I hope that reading this introduction will help limit any offense taken. Let''s unravel the variety of ways that culture creates all of us. Imagine that you just found out that your mother hid her cultural heritage from everyone. It turns out she is from Badoria. The people of Badoria have historically been persecuted, so your mother hid her past, and her culture, from you. You are 50% Badorian. How do you feel? Do you want to find out more about the culture? Are you starting to feel more Badorian? Do you suddenly like Badorian food? Even though this is just an imagination task, when I ask my students these types of questions, the majority tend to feel a bit more Badorian after imagining that this scenario really happened (it doesn''t seem to matter whether it is their mother or father who hid their past, but learning that both are Badorian has a larger impact than any one alone). It seems we are pretty good at associating with our culture, but if we learn new information about our ancestry, our preferences can also change.

These are just imagination exercises, but people have experienced very similar situations in real life. A prominent case is Csanád Szegedi. Szegedi was a member of the Hungarian political party Jobbik, which has been accused of being antisemitic. It is pretty safe to say that Szegedi had fairly strong antisemitic views. However, at some point he became aware that he has Jewish roots, and under Jewish law, is considered Jewish. What would most people do in his place? Would they continue with their antisemitic views, or would they abandon them and embrace their Jewish heritage? Someone in this position would likely feel some conflicting views. Szegedi adopted a Jewish identity, rejected Jobbik, and even got circumcised. Links to our past can affect us today, and stories like this one are not as rare as we might think.

Mark Halawa was born into a Palestinian Muslim family. They were refugees that found their way to Canada. Born in Kuwait, but also spending time in Jordon, Halawa was taught that Jewish people are evil. It was part of his upbringing. Antisemitism was on the news, in schools, and his father held strong anti-Israel sentiments. While living in Canada, he had a conversation with a Jewish man, and Halawa told the man that he believed his grandmother was Jewish. The Jewish man informed him that according to Jewish law, he was Jewish too. What did Halawa do upon hearing this news? He learned about the holocaust and moved to Israel.

Szegedi and Halawa are dramatic examples of people making significant changes after discovering something new about their past. The realizations about their ancestors changed their perspective and lives. These types of discoveries are likely becoming more common. Technology is contributing to such revelations in a way that wasn''t possible a few decades ago. With DNA tests becoming cheaper and more common, many people are learning that their past is actually something different than what they had expected. DNA tests aren''t perfect and can be misleading, which I touch on at the end of this book, but they have been used to reliably find genetic relatives. A big part of this book is how the past influences us today, so we will be exploring other fascinating stories like those of Szegedi and Halawa. Here is another one.

Kara Rubinstein Deyerin has a white mother and Black father. Although her skin colour didn''t suggest she was Black, she and her family considered her African American. In fact, on.