The Happiness Formula
Wednesday, 7 June
1900 BST on BBC Two
Is it possible that we can find friendship, fulfilment and contentment on the internet?
Almost two-thirds of all adults now log on to the web. We spend more and more of our time staring at computer screens.
The question is whether this behaviour is driving human beings apart or bringing us together.
Will the internet make the world a happier or less happy place?
The social scientist Robert Putnam is celebrated for his work in measuring the decline in what he calls "social capital" in the United States.
His work has proved that people in America spend more time alone and less time with friends and family. So what does he think of the internet?
"I think the jury is still out on whether the internet is going to be a kind of nifty telephone, that it is some device that we use for making connections with other real people that we know in other contexts, or a nifty television, that is yet one more screen in front of which we sit more or less passively."
Scientists know human contact is critical to happiness, but technology can push it out of our lives.
Television, believes Professor Putnam, is one of the greatest sources of unhappiness in the US because it is essentially a solitary activity which displaces the opportunity for social interaction.
What about cyberspace?
"I'm sceptical of a purely virtual community - that is the idea you can be best friends with someone that you don't even know and you don't even know whether they're the person they pretend to be because they're behind some screen name."
However, all is not lost. Research in the UK has shown that people who log on to the internet tend to have more friends than those who do not.
Professor Putnam says the key is in mixing the real and virtual experience.
"Using the internet to make new connections that you then meet in real life - that's very positive."
Cyberspace is more popular than TV for many teenagers
The huge growth in e-mail, blogs, message boards and messenger services has created a host of new social networks which defy geography.
Teenagers, in particular, increasingly keep in touch with friends and acquaintances every time they log on but they are also forging new relationships with people who may share an interest but live on the other side of the world.
A recent innovation is the creation of virtual worlds which promise an entire social life in cyberspace.
Second Life is an internet community with a population of more than 100,000 real people.
Each resident controls a three-dimensional puppet called an avatar which reflects their personality.
They can then indulge in a wide range of social activities - parties, dancing classes, discussions groups, shows.
The avatars can be programmed to exhibit a range of human responses - sympathy, anger, amusement.
Could this be the answer to social isolation and loneliness in the real world - a thriving social life through the click of a mouse?
The 'real world' online
Aleks Krotoski, a video games expert, says the internet offers new possibilities: "These virtual spaces are capable of creating and engendering happiness between people.
"There's so much socially in these places now that it is no longer just a person sitting in front of the computer zoned out and going off into the nanosphere.
"It's about finding other people and interacting with them. It's very much about a place to go to events, meet people, to hang out, to do ridiculous things and just to chat."
Ms Krotoski argues that these games show how the internet could develop in the future.
"I can imagine that this kind of thing is what the internet is going to be like in the future. Instead of just being simple static pages, it will be like a 3-dimensional space.
"These aren't places that are just swords and sorcery and people wandering around with Orks. These are places that actually look very much like the real world."
You can watch final episode of The Happiness Formula on BBC Two on Wednesday, June 7 at 1900 BST.
Have you found happiness through the internet?
Cyberspace is a pale imitation of real life because it's such a limited interface. Text, voice, maybe cartoony graphics are no match for face to face. But that interface is going to get better every decade. A fully virtual lifestyle as rewarding as real contact is only a matter of time.
David Bofinger, Sydney, Australia (but the whole point is it doesn't matter)
The internet's a wonderfully positive thing, as it allows people with shared interests to connect and is, at least for now, the only remaining bastion of free speech. I love the net and feel almost like it's an extension of my own brain!
Chandra, London, England
My wife's leaving me for someone she met in cyberspace, so I guess it has its downsides as well.
I always prefer to communicate all the people
S Kugananthan, Jaffna, Sri Lanka
Internet is like smoking. Once you get addicted you need to take a puff every now and then. The more addicted the more puffs.
This is probably a decently good addiction. More people are completely addicted to cell phones and that has serious bad effects in several ways.
Mikko Toivonen, Helsinki, Finland
I think the internet is wonderful. Without it I would never have discovered the wonderful sport of cricket. Now I listen to Henry Blofeld and it helps me perfect my English. I have also made many friends on the internet. We meet to discuss cricket and other wonderful English activities.
Micco Tearcino, London, UK
The Internet puts all individuals on an equal footing, and allows us to approach the ideals that we would like to have achieved in our lives. There is the inevitable downside of abuse. Nevertheless, I revel at the reality of not having to commute and to file papers as I had to before I discovered the web!
Dr S Banerji, Mumbai, India
I agree it is a bit tricky to make friends in cyberspace but I have found it most useful to find people I knew in far away places and to stay in touch with my extended family and friends. The internet has taken the "goodbye" away from us since we are always in touch. Our email addresses are universal. You can never lose touch with anyone any longer. That is reason enough to be happy.
Hamid Khawaja, Lahore, Pakistan
It is true that we can get to meet wonderful people on the internet. It is true that one day these people can cease to be virtual entities and materialise into very concrete persons. It is also true that, if you are lucky enough, they can become the dearest friends of all. (Here a very personal thanks to all the scientists and technicians who made this precious tool turn out to be usable.) But what is amazing is that sometimes you can end up having a gripping discussion - or a bitter argument - with somebody you don't know at all; somebody you have never seen in your life; somebody whose name sometimes remains shrouded in mystery.
Siganus Sutor, Mauritius
I have met some wonderful people from all over the world thanks to the internet, all of whom I have had the honour of meeting in person. Long distance relationships certainly can't replace other relationships, but that rule has always applied with or without the internet aspect. The internet is just one of many ways to find likeminded people, and if the relationship develops enough to transform into a "real" friendship, what is wrong with that?
Nina, Brooklyn, NY, USA
I met my boyfriend on the internet and since we met both our lives have changed, we were both single and finding it hard to meet potential partners just by going out, we both have a great social life, have similar interests and love each other dearly, and I can honestly say, since we met I am living my life to the full.
Sharon Adams, West London,
I have been online for about 8 years now, and I must say it is quite addictive. I have been in various online communities, and I have now transformed from meeting people in person to meeting them online. Some of the online people I have spoken to, I have also met in person. It is rather geeky when we meet up, but at least we have the same things in common, so we get on really well. I met my partner on the Internet and we now live together and have a beautiful baby boy. Life is good and I'm so glad my mum let us have 56k dial-up 8 years ago! Of course I have Broadband now.
Gemma Tevendale, Kent, England
I am a cybercynic! Brave New World is almost here. Internet Cyberworlds exist. Children can be cloned. We can shop, work and entertain ourselves on our home computers. I am happy. If people live in their virtual reality, they will they be too unfit to walk in the mountains, and there will be a lot more space for me!
Anthony Lee, Derby
As a player of online games I think the internet is just another medium for meeting new people. I can honestly say that I have met some great friends who I continue to speak with, e-mail and text on a regular basis. It doesn't matter to me that we have never met or that they are in a different part of the country or even the world. Online games, and the internet, just provide us with a different environment to forge these bonds. It doesn't make them any less real or valid.
Sarah, Sheffield, UK
My son, based in Worcestershire, met a girl in South Africa whilst doing some research online. After six months of online dating including endless games of chess and meeting her family and friends during a link up to a party in SA, he finally made the journey to meet her. They married 6 months later in South Africa and she joined him at university in England a few months later. I find it amazing that he found his perfect partner (she shares his love of fishing, camping, travel and sport) thousands of miles away from what started out as an argument in a chat room. We feel so privileged to have such a lovely young woman as part of our family.
Anne Bathurst, Malvern, Worcs
I think that we take advantage of the fact that we are living in the sci-fi future from our parents' comics and television shows. We have SO many ways to communicate with everyone everywhere and almost instantaneously. "Community" is just a word attached to most neighbourhoods to make it sounds friendly when in actuality the most interaction with your neighbour is a simple wave of "hello" as you walk into your home. Community on the internet involves anywhere from 10-10,000 people all networked and ready to be a contributor to that community
Christina, Austin, TX, USA