It has been obvious for a while that the way in which the media and entertainment industry are developing increasingly shapes culture, social mores and even institutions across the world. There are those who argue that the impact of the media, and particularly the ''infotainment'' industry, now goes beyond all that, to alter human nature in unexpected ways. It is supposed to result in a whole new category of human beings, whose social integration comes from screens rather than live interaction and whose aspirations are determined by what the purveyors of culture and information through the mass market deem to be desirable.

The most extreme manifestation of this impact on human behaviour and social perception is paradoxically not to be found in the ''new media'' created by the internet, but on television. The basic framework of most television programming in the world today emanates from the United States, and even when particular ideas originate in other countries, it is the development of that idea within the US market, by American broadcasters and media companies, that then has the greatest global spread.

Nowhere is this more evident than in the extraordinary spread of ''reality television'', supposedly based on the depiction of how ordinary people in extraordinary situations behave. As the popularity of this basic idea spread, ever more exotic, weird, wacky or even revolting ideas of what some people can be forced to do in order to be watched by other people were developed especially in the US and Britain, and then taken up internationally, with only minor adaptations to suit local cultural requirements. And as these ideas translate into television programmes that become popular and almost universally known, they can also transform the cultural attributes of the society itself. So, while spectator sport is at least as old as recorded history and probably older, the creation of these newer forms of gladiatorial display that come with very wide media coverage and international spread, are likely to have very significant social implications, even if we do not fully recognise them at present.

One of the implications is in terms of how human behaviour is perceived and categorised and what kinds of behaviour are encouraged. Reality TV promotes some aspects of human personalities over all others, largely because these are more dramatic and more watchable and therefore make for ''better'' television. Thus, almost all successful reality TV shows that are based on performance rely on fostering a highly competitive spirit among the participants. The performance can be related to many different aspects or activities: endurance and physical strength; skills such as designing or cooking; singing or dancing or modelling or just making jokes; the ability to make friends and influence people, and thereby be chosen to join a successful entrepreneur with a job in his company or even to marry a millionaire or another reality TV star; the willingness to expose to wider public view the most intimate and often distressing details of private lives.

Such shows provide constant lures of success and threats of failure, which expose and emphasise the participants' drive to succeed at all costs and also highlight the constant fear of failure and rejection. At every stage there are winners and losers; the winners inevitably exult and the losers turn on themselves and each other. Weaknesses are both despised and exploited. Whatever be the nature of the competition, the various reality shows in different ways also play upon the emotional fragilities of the participants and suck them dry for their dramatic and telegenic content. They encourage mistrust and lack of cooperation among participants for whom competition is always the underlying reality, even when the participants are banded together in temporary teams. They tend to value and reward naked ambition and highly individualistic and often manipulative approaches to both performance and social interaction.

Most of all, they assume and thereby reinforce the perception that everything and everyone have their price: the lure of monetary reward is explicitly seen to drive participants to the most unpleasant, humiliating and even dangerous activities. Pecuniary gratification is therefore plugged as the ultimate driver of human action.

Obviously, therefore, these shows promote and exploit voyeurism at many different levels. But also, in privileging and constantly highlighting these particular personality attributes, they may contribute to making these the more common, defining and socially acceptable features of personalities, even if they are inherently unattractive and even anti-social. This is the result not just of the shows themselves but of the wide publicity they benefit from in the media.

There is another social fallout of the proliferation of reality TV, which could perhaps have been expected but is nonetheless startling when it reaches extreme forms. This is the emergence of a (shifting) category of people whose very existence and public recognition or stature is based on their appearance and possible success in such shows. The phenomenon of ''reality TV star'', celebrities who are famous only for being famous particularly on flat screens, is relatively recent but has nonetheless spread across all countries with amazing rapidity, reflecting the speed and reach of television as a major cultural force. It has also led to the conversion of such activity almost into a professional choice, with several such stars apparently making their living through consecutive serial appearances on various different reality shows.

And now we have evidence that such aspiration to keep appearing on reality TV - for ''glory'' (or at least public recognition) and financial rewards - can drive individuals to the most extraordinary lengths, which would otherwise seem not only irrational but even positively harmful in terms of their own self-interest. So it may even be possible that reality TV is actually changing patterns of psychological health.

Since the US is the original home of reality TV and still remains the foremost source of inspiration for most ideas about programming, it is perhaps fitting that some of the most bizarre recent examples of such affliction have occurred there. Two cases deserve specific mention.

The first relates to a young couple with eight children, a pair of twins and a group of sextuplets. While multiple births are more common now because of the greater use of fertility drugs, survival of all the infants is still comparatively rare. So it is not surprising that this couple attracted some media attention when the sextuplets were born. An enterprising media company then had the idea of tracking the daily lives of this couple, who had to manage eight children as well as carry on with their lives and somehow earn enough to support the large brood.

So, much in the manner of ''The Truman Show'' which describes a life that is continuously lived on camera, this couple consented to have cameras and crew constantly in their home, recording almost every aspect of their lives and even bringing their very young children into constant exposure and media glare. The parents all had periodic face to face interviews with the camera, where they recorded their reactions to daily events, their frustrations and hopes, their changing emotions.

Because of the constant surveillance, intrusion into personal space and human tendency to alter behaviour subtly according to the knowledge of being watched, it is not clear how natural all of this was at any point. In any case, the very process of filming the reality created massive disruptions to it, including the constant presence of many other people and the inevitable need to then recreate what was by then an artificial reality. Also, because the version screened was necessarily a substantially edited version of what had been taped, the producers effectively determined what was finally shown and therefore projected as reality. So, like all ''reality'' shows, this was not reality so much as a complicated construction in which each player had a role in generating that particular illusion of reality.

Nevertheless, the show became a runaway hit, with millions of Americans apparently hooked on to watching what seemed to be the rather boring quotidian activities of this unusual family. (It is now being rerun on cable or satellite television in many countries across the world, including India.) The wife became a major star in her own right, authoring books describing her experience and touring the country offering advice on the rearing of children and the joys and difficulties of maintaining a happy home. The reality moved even further from the manufactured illusion on the show, as the wife's frequent absences and the husband's work moved the care of children to paid professionals and unpaid relatives, who remained invisible on the show.

When the couple's relationship came unstuck, ostensibly through episodes of infidelity and mutual recriminations, it continued to be played out on television. The role of the constant media pressure and abrupt life transformation it brought about in dramatically altering the terms of the relationship were not discussed; instead the marital break-up has become even more of a media obsession, with the couple suffering all the adverse effects of fame including intrusion by paparazzi. The impact of all this on the still very young children can only be imagined.

The other case is possibly even stranger, and more alarming. A few weeks ago, there was a sensational ''accident'' of a boy being left inside a home-engineered air balloon alone as it lifted off into the air and flew for hundreds of miles before finally coming to rest in an open field. While it was going on, it became a national emergency in the US: the news media covered little else; airports were closed and the fate of the little boy became almost a worldwide concern. When the balloon landed, the boy was nowhere to be found, sparking fresh speculation that he may have fallen off at some point in the flight. A few hours later the boy was found hiding in a box in the attic of his home, apparently scared that his father would scold him for playing near the balloon.

The media frenzy this generated can be easily imagined, with the boy, his parents and two brothers appearing for endless interviews (probably paid?). It seemed like a freak accident with a happy ending, until the boy blurted out in one of the interviews that the father had told him to do it ''for the show''. This sparked official suspicion. Further investigation revealed that the entire episode was set up by the father. The entire family, including the children, acted out their roles of terror and despair so well that the authorities and the media were completely fooled. The family had already appeared in one reality show, which involved ''swapping'' wives with another very different kind of family for a few weeks. And this incident was staged to increase the family's chances of being offered another lucrative deal on reality TV!

Now, of course, the family - and the father in particular - is being excoriated by the media and will face penal and possibly legal action. Of course, it is easy to be moralistic and derogatory about such actions, and to deride either the father in this case or the couple who exposed their children to media glare. Indeed, that is precisely what is happening, with these people now receiving possibly even more bad publicity than the public praise that was heaped on them earlier.

But the current high moral tone of the same media that built up the obsession with such supposed reality is misplaced. It is not only that, especially in this period of economic recession, with few job opportunities available, the tendency is much greater to turn to this form of self-publicity in order to earn some income. It is also that the very voyeuristic obsession that has been propagated by reality TV can cause personality and behaviour changes that may not have been anticipated.

In T.S. Eliot's famous poem Burnt Norton (from his Four Quartets), ''the roses had the look of flowers that are looked at''. Unlike the roses, not all human beings can survive such a gaze.