Heroine addict: Can a good book actually change our personalities?

Samantha Ellis considers the science – and her own extreme relationships with her favourite female characters

It was Jo March, rebellious heroine of Louisa May Alcott's tearjerker, Little Women, who taught me the best way to read – she likes perching in an apple tree, or curling up on a broken sofa, wrapped in a blanket, eating russet apples, ready to "weep a little weep". As a child, I liked reading in bed on sunny mornings, or in a hot bath on a cold night. At university, when I was either ripping poems apart or gazing into the void beyond language, as every good post-structuralist should, I did my reading in a stiff-backed chair in a chilly library. But after I graduated, I went straight back to reading as I always had.

Then, a couple of summers ago, I started to wonder if this was wise. I was on the Yorkshire moors, arguing (over the wuthering) with my best friend about whether we'd rather be Jane Eyre or Cathy Earnshaw. I thought Cathy. Obviously Cathy. The point of this walk (this pilgrimage) was to see the ruins of the farmhouse that inspired Wuthering Heights, which loomed at us promisingly from the top. I was just about managing to stop myself yelling out to Heathcliff that it was me, Cathy, coming home. So stoic, virtuous, plain Jane was very much not on my mind. But my friend argued that Jane was independent, clever and principled, while Cathy was, scaldingly, "silly". As we got to the top of the hill, I realised that my whole life, I'd been trying to be Cathy, when I should have been trying to be Jane. I started wondering how far Cathy had led me astray.

A recently published study suggests she might actually have made me a different person. Neuroscientist Professor Gregory Berns, of Emory University in Atlanta, Georgia, found that, as we read, we believe we are experiencing what is happening to the characters. (So I really have been in love with Heathcliff!) He found that when people were asked to read books, they created a "muscle memory" for events they had experienced vicariously, and their brains actually changed. After the volunteers had had a reading session, researchers observed heightened connectivity in the left temporal cortex (me neither), which is, they say, an area of the brain linked to receptivity for language. "We already know," Berns said when the research came out, "that good stories can put you in someone else's shoes in a figurative sense. Now we're seeing that something may also be happening biologically."

It's no surprise to me that my literary heroines have got under my skin, but it's startling to think that they might also have got into my left temporal cortex, and permanently, biologically, changed me.

After my epiphany on the moors, I decided to go back and read Wuthering Heights and Jane Eyre again, to see how I'd feel about them now. And I didn't stop there. I met all my heroines again and thought about what they meant to me when I was growing up and what they mean to me now that I'm in my thirties, a playwright and writing heroines of my own. In my book, How to be a Heroine, I chart my journey to realising that Cathy got into my bloodstream somehow, in a way that wasn't always entirely healthy. I've come to hold her partly responsible for my somewhat quixotic love life, my attraction to dark, brooding, complicated men, and my conviction that tempestuous tornado love is the best kind. But did she change me biologically? I'm not sure.

In the Emory University study, all the participants read the same book: Robert Harris's Pompeii. They were all, apparently, changed. But I'm not sure that reading any good book can change you. After I discovered Wuthering Heights at 12, I also read Jane Eyre. But Jane didn't influence me like Cathy did. She didn't get into my head at all, let alone my heart.

And I wonder if the neuroscientists considered how people read. When I went back to the books that had meant so much to me, I wanted to read them with more scrutiny and less sentiment. And I was terrified. I kept thinking of the cringe-making moment in Jane Austen's Northanger Abbey, where Catherine Morland, intoxicated by her beloved Gothic novels, becomes convinced that General Tilney has done something unspeakable to his wife. The general's son – droll, charming Henry Tilney – pours cold water on Catherine's lurid suspicions and she nearly dies of shame at how her reading has misled her. She vows to keep fact and fiction strictly separate.

Joan Fontaine as Jane Eyre in the 1943 film (Rex)

After I met my heroines again, would I end up making a similar vow? Would I end up hating them, or thinking they'd ruined my life? Would I never be able to abandon myself to a book?

When I returned to Wuthering Heights, I was still moved by the tenderness between nine-year-old orphan Heathcliff and eight-year-old hoyden Cathy, but, as I read on, I started to find Cathy petulant and solipsistic. I wish that after Heathcliff runs away, she had the courage to refuse Edgar's proposal. When Heathcliff returns and asks: "Why did you betray your own heart?" I'm wondering the same thing. Worse, the reason she gives is that Edgar is "rich and I shall like to be the greatest woman of the neighbourhood". She's a snob. She won't marry Heathcliff after he has been denied education and "brought low", but later, when her daughter Catherine falls for illiterate Hareton, she finds a way out of the dilemma; instead of rejecting Hareton, she teaches him to read.

As for Heathcliff, it pains me to admit that he's more villain than hero – a wife-beating, grave-disturbing, dog-hanging psychopath. By the end of the book, I feel weepy. Not pleasurable-weepy but very sad. Because Cathy feels remote and I feel like I'm saying goodbye to a book that meant so much to me. I wonder if Jane Eyre will make me feel better.

At first, she does. Jane is so present, addressing the reader directly, questioning authority; in her opening scene, she speaks her mind and gets a book thrown at her head for it. I used to think she was annoyingly placid, but now I think she's cool under pressure. She's never hysterical, whether dealing with a house fire, a stranger with blood pouring out of his arm, or the arguably greater crisis of realising she's in love with her foxy employer Rochester.

When he asks if she finds him handsome, she bluntly says no; she's more interested in his mind. And when she thinks he's going to marry someone else, she refuses to stay and watch, demanding: "Do you think, because I am poor, obscure, plain and little, I am soulless and heartless?" Her anger is dazzling. No wonder Rochester proposes. She does leave him when she finds out he already has a wife. I used to find this cowardly and prudish. But now it feels unbelievably bold. In the horror of discovering her dreams are dust, Jane finds compassion for Rochester's mad wife, finds both pity and forgiveness for Rochester, fights him off as he threatens to crush and tear her, fights her own feelings (she frankly admits it would be "rapture" to stay) and refuses to become his mistress. No one would care if she lost her reputation, but her heart sings out: "I care for myself. The more solitary, the more friendless, the more unsustained I am, the more I will respect myself." It's pretty fearless, and what's even better is that Jane isn't smug – she knows she's hurting Rochester and she hates herself for it. Compared with this strong decision, Cathy's decision to marry Edgar feels ignoble.

So I'm relieved when Jane gets her happy ending – a marriage that Jane sums up by saying: "We talk, I believe, all day long." It's a charming picture of companionship. And it's a million miles from Cathy and Heathcliff's love, which may be transcendent and operatic, but also obliterates them – as Cathy says, "I am Heathcliff." Their love is also impossible. Even if miscommunication and heinousness and bad luck hadn't kept them apart, the idea of Heathcliff and Cathy getting married, settling down and growing old together, does not compute. Their love is too raw and rarefied to exist in the real world, and they know it; they can only be together as restless ghosts. When I tried to use their love as a template for my own romantic life, like Cathy, I lost myself.

But I don't know if Jane Eyre would have given me the answers, either. The more I think about Jane and Rochester's love, the less I like it. Rochester's twice Jane's age, he's domineering, he's lied and he's flirted with another woman. And there's something very troubling about equality coming because he's lost a hand and one of his eyes. Can a woman not be equal to her husband unless he's wounded? And while Wuthering Heights doesn't shrink from the horrible truth that Cathy is dead and Heathcliff has to struggle on alone (until he dies and their ghosts can wander the moors together), Charlotte Brontë has to bring on the gothic in a big way to give Jane her happy ending – with all the fire, madness and supernatural voices, is the ending of Jane Eyre really more realistic than the ending of Wuthering Heights?

Even Jane, lovely Jane, can't entirely hold my affections. She's a heroine who does everything right – but what's interesting about a heroine who never makes mistakes? There's a perverse pleasure in loving Cathy. The more holes I pick in Wuthering Heights, the more my stubborn heart clings to it. And of course this struggle is a pleasure in itself.

I wonder if the participants in the Emory University study struggled. I wonder if, hooked up to their MRI scanners, they let themselves get lost in Harris's page-turner, or whether they read more critically. Because if Professor Berns had scanned my brain as I read Wuthering Heights at 12, I imagine he'd have been amazed (and possibly alarmed) at how fervently I experienced Cathy's life along with her. But if I were to be scanned again now, I think he'd find me immersed, but not overwhelmed.

Because, contrary to my fears, I haven't stopped reading passionately. And I don't think this kind of reading is dangerous. Because when I went back to Northanger Abbey, I found that Austen wasn't warning against intense reading. Instead, she stays firmly on her heroine's side, and backs up her wild claims. General Tilney's no murderer, but he is a villain. Catherine was right to read life like a book – it's just that she thought she was in a Gothic melodrama when in fact she was in a domestic comedy. By the end, she is happily reading fiction again, but with a little more wisdom, a little more discernment. I'm still reading, too. I'm still sharing my heroines' hopes and dreams; still letting myself be changed by them, but I'm also taking them with a pinch of salt. And this doesn't spoil my reading pleasure, not a bit.

Because after all, isn't it the pinch of salt that makes the sweetest cake zing? µ

'How To Be A Heroine: Or, What I've Learned From Reading Too Much' by Samantha Ellis (£16.99, Chatto & Windus) is out now