Image copyright Other Image caption The third in the trilogy is a comedy, but in a bittersweet way

Many men like to think themselves impervious to Hollywood's traditional tearjerkers, but is the newly-released Toy Story 3 a sign that moviemakers are gaining new powers to make them weep?

Middle-aged men are not "supposed" to cry during movies.

But there's a been a groundswell of admissions that Toy Story 3 is having just such an effect, and that it might be part of a growing trend of more subtle emotion inducing on the silver screen.

Hardy film critics in the US have admitted feeling weepy after watching the film and when it opens in the UK on Friday the same effect will be easily observed.

Jeff Zegas, 56, is typical of the responses to the film in the US.

"I had tears in my eyes. It was so touching about Andy, when he was saying goodbye."

From a very young age, males are taught that it is inappropriate to cry Prof Mary Beth Oliver

The third film in the trilogy shows Andy, the owner of the toys, as a 17-year-old about to leave for university. He has to decide what to do with the toys.

Critics have identified the themes of growing-up, leaving home and loyalty. Particularly powerful is the bittersweet idea - to a parent - of a child leaving home.

Parents can be filled with nostalgia for their own youth, sadness at the distance from their offspring, but happiness that they are going out into the world, eventually to reproduce the cycle.

There have always been tearjerkers, playing on the fact that some audiences' idea of a good time is to have a good cry.

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Over the years misty eyes have been generated by the death of Bambi's mother, the killing of the kestrel in Kes, the ending of Titanic, or Jenny's death in Love Story.

And yet men, if they have felt weepy during these films, have often tried to be surreptitious about it.

That's because there are expectations about their behaviour, says Prof Mary Beth Oliver, of Penn State University, co-author of the academic paper An Examination of Factors Related to Sex Differences In Enjoyment of Sad Films".

"For many men, there is a great deal of pressure to avoid expression of 'female' emotions like sadness and fear. From a very young age, males are taught that it is inappropriate to cry, and these lessons are often accompanied by a great deal of ridicule when the lessons aren't followed."

Media playback is unsupported on your device Media caption Director of Toy Story 3 Lee Unkrich and producer Darla Anderson explain why the film is particularly emotional. Film clips courtesy of Disney/Pixar

It's probably not that grown men are pilloried for crying during films, rather that they are the victims of subtle gestures. Raised eyebrows might be the response to over-effusive expression of emotion.

"There are certain 'arenas' where male crying is deemed appropriate like the loss of a favourite sporting team, the death of a parent, or war," says Prof Oliver. "We can see many of these sorts of arenas reflected in 'male' tearjerkers like Field of Dreams or Brian's Song."

Indeed, some men who might sneer at the idea of crying during Titanic will readily admit to becoming choked up during Saving Private Ryan or Platoon. The idea of sacrifice for a "brother" is a more suitable source of emotion.

And not only is crying in movies not seen as a "male" thing, it also has an age bias.

"In general, there's some research to support the idea that going to the movies to 'have a good cry' is a young person's game - probably part of the developmental task of exploring intense feelings as well as a way to bond with your peers," says Prof Marie-Louise Mares, of the communication arts department at the University of Wisconsin-Madison.

ANALYSIS - WHAT MAKES US CRY? Image copyright Other Prof Mary Beth Oliver is an expert on the effects of the media. I used to think of tearjerkers as sad films. Now, however, I am beginning to think that when we watch "sad" films, we're really watching something that is helping us search for meaning - what is the purpose of life? What is valuable? How can I grapple with questions of the human condition? And in many respects, these questions necessarily are about life's joys, but also its tragedies, too. When we reflect on meanings, we reflect on life (and death), time passing, our place in it, etc. This is meaningfulness, and I believe that many films help us grapple with these types of questions. 10 things that make blokes cry

"Adults generally report less of this as they grow older - there are plenty of other things to make one feel blue and there's often less time and energy to spend on making oneself sob."

The significance of Toy Story 3 is perhaps that it induces male weepiness despite nothing archetypally "sad" happening. No-one dies, no-one gives their life for another, there is no life-changing tragedy - all's well that ends well.

It perhaps is the inheritor of films like It's a Wonderful Life, with it's unrelentingly happy and yet extremely tear-inducing ending.

Another Pixar animation, last year's Up, also had segments which had a wide range of the audience weepy.

And critics have identified a hefty dose of pathos in recent complex family-relations films Cyrus and The Kids Are Alright.

These family dynamics and rites of passage may be what can get the emotions going of an otherwise sobre adult filmgoer.

"Young children will have very little sense of the poignancy of the story," says Prof Mares. "Research suggests that actions rather than emotions are most salient and vivid for young viewers, unless the emotion is writ very large.

"On the other hand, it makes perfect sense that the story would resonate with adults - for them, it can prompt memories of their own moments when everything was in flux and adulthood stands ahead with endless options. That's a very bittersweet thing to look back on, given that the options soon start closing."

Death of youth

And the emotions in films like Toy Story 3 are enhanced by the presence of children at one's side.

"I wonder whether part of the tug of the heart strings also comes from the anticipation that your own kid, who's cheerfully munching popcorn next to you, will soon be growing up and moving on out," says Prof Mares.

"As a parent myself, I'm constantly torn between wishing that my kids would hurry up and grow up already and wanting them to stay my kids."

Any parents who cried during ET will identify with all of this.

For the most part tearjerkers may still mostly come in the form of cutie animals and photogenic young people dying.

But there certainly seem to be signs that Hollywood's emotional range is expanding.