Iago manipulated almost everybody in the play. He manipulated his Wife, Othello, Cassio, Roderigo, and more.  
"Manipulation is getting what you want by ignoring or harming the desires of others. Manipulators use charm, persuasion, trickery, and misdirection."(SetFree)

Throughout Shakespeare's famous play, Othello, Roderigo is used as a puppet, for many of Iago's evil plans to destroy Othello. The real issue that bring curiosity to the reader is:

Why was it so easy for Iago to

manipulate Roderigo?

"Roderigo is obviously not a very confident man nor is he very smart.   Roderigo’s character would have to be somewhat unattractive and portray a self-conscious and pitiful man." (Scott)


The answer is, Desdemona. Iago tricks Roderigo into giving him money to win him Desdemona. Roderigo is a very innocent, generous, and nice gentleman who happens to be in love with the wife of "The Moor", Desdemona. Iago took advantage of Roderigo's feelings for Desdemona in order to fulfill his own desires.

Iago uses many ways of manipulation throughout the play to convince Roderigo to help get rid of Othello. One of the quotes is in the first act of the Play. Iago tells Roderigo,

"Thou art sure of me. Go make money. I have told thee often, and I re-tell thee again and again, I hate the Moor. My cause is hearted: thine hath no less reason. Let us be conjunctive in our revenge against him."(A.1,S.3,P.14)

 Here Iago is trying to convince Roderigo to help him bring down Othello. Roderigo is not a fan of Othello, considering the fact that he's married to Desdemona, and Roderigo wants Desdemona. One of the main reasons why it was so easy for Iago to psychologically manipulate him, is by convincing him that he only wants to get rid of Othello in order to help him Roderigo with winning over Desdemona, and that if he goes out and makes money, in exchange  Iago will get Desdemona to fall for him. (He's telling Roderigo to pay him for helping him get Desdemona to fall in love with him). 

In the real world, many people get manipulated by their so-called "friends" and lied to in order for their friends to fulfill their own desires. When someone is so in love like Roderigo, they don't really think about what they're doing. If someone tells them that this will help them win the girl, they'll do it. This also includes peer pressure (wanting to be accepted by a specific someone or a specific group of people, and sacrificing a lot to do so). In the novel, Roderigo thinks Iago is smart and important, and takes all the advice he is given from him and acts upon it thinking Iago is always right.

Another reason why it was so easy for Iago to manipulate Roderigo is because Roderigo is very gullible. In Act 4, Iago tells Roderigo,

"I grant indeed it hath not appeared; and your suspicion is not without wit and judgement. But, Roderigo, if thou hast that in thee indeed, which I have greater reason to believe now than ever-I mean purpose, courage, and valor this night show it. If thou the next night following enjoy not Desdemona, take me from this world with treachery, and devise engines for my life"(A.4,S.2,P.220)

At the moment, Roderigo is so convinced that he'll have Desdemona if he listens to Iago because Iago tells him that his judgement and suspicion shows how serious and willing he is in order to get what he wants, and he basically promises him that Desdemona will be his by tomorrow night. Roderigo, being gullible as he is, believes that he can actually win Desdemona tomorrow night after getting rid of Othello. Roderigo would have to be very gullible to believe that, because Desdemona is so in love with Othello that she ran away with him behind her fathers back, and Roderigo still believes that she'll react completely normally to Othello being gone and will run into his arms. Many times in the real world, someone is taken advantage of because of their lack of intelligence.

Roderigo helps start a fight with a drunken Cassio, stabs Cassio, loses all his money and sells his land thinking all this will bring him Desdemona but it doesn't and he STILL trusts Iago and keeps falling into his traps. You'd have to be very gullible and stupid to keep sacrificing so much for so little then realizing you're not getting anywhere, yet still repeating the same mistakes.

Roderigo is a very self-conscious guy especially after being rejected by Brabantio every time he asks to marry Desdemona. Roderigo has been hopelessly in love with Desdemona for a very long time, and he showers her with expenses gifts, hoping to get her attention, ending up empty handed because money cannot buy love.

Roderigo being self-conscious came to Iago's advantage. In the play, every man in Othello basically has a lady companion besides Roderigo. This hurts Roderigo's pride because everyone who is considered important isn't alone. Like a King has to have a Queen, a man must have a wife or a companion. 



Roderigo is very self-conscious because nobody treats him with respect (e.g. Brabantio, Iago...). Roderigo is also self-conscious because he tried so hard to win over Desdemona and Othello didn't try at all, and she fell hopelessly in love with him; this made Roderigo feel so self-conscious. Iago made Roderigo feel like if he listened to Iago, a smart, married man, he will end up like him and Iago thought that bringing down Roderigo's self-esteem will help him get Roderigo to obey him. In the real world,"The manipulator will try to wear down your self esteem so that you will become dependent on him/her."(SetFree)

In court, Othello said to the Duke, Brabantio, and the Senate:

"Her father loved me, oft invited me, still questioned me the story of my life from year to year.--These things to hear would Desdemona seriously incline. But still the house affairs would draw her hence, she’d come again, and with a greedy ear devour up my discourse, which I, observing, took once a pliant hour and found good means to draw from her a prayer of earnest heart --she had something heard but not intentively. I did consent, and often did beguile her of her tears--She gave me for my pains a world of sighs. She swore, in faith,--She wished she had not heard it, yet she wished that heaven had made her such a man. She thanked me and bade me, if I had a friend that loved her, I should but teach him how to tell my story and that would woo her. Upon this hint I spake. She loved me for the dangers I had passed,

And I loved her that she did pity them. This only is the witchcraft I have used. Here comes the lady. Let her witness it." (A.1,S.3,P.38-40)

Here Othello is explaining to the "jury" that he did not use any witchcraft on Desdemona, and she fell for him from listening to the stories he used to tell her Father. She'd tell Othello how if one of his friends loved her and were to tell her a story like his, that wouldwin her over. Desdemona then confirms Othello's story by saying:

"My noble father, I do perceive here a divided duty. To you I am bound for life and education. My life and education both do learn me how to respect you. You are the lord of duty. I am hitherto your daughter. But here’s my husband. And so much duty as my mother showed to you, preferring you before her father, so much I challenge that I may profess due to the Moor my lord."(A.1,S.3,P.40)

If I were to be deeply in love with somebody who doesn't pay any attention to me, and keeps rejecting me, I would be self-conscious and furious at the fact that they fell in love with someone else. Also, Othello didn't even try to win Desdemona's heart yet she fell for him. Roderigo, on the other hand, tried so hard to win her heart. This must have made Roderigo feel like he was never good enough for her, and that Othello is way better than him, making him want to get rid of Othello, and drown himself. 

In the real world, suicide rates, eating disorders, and self harm have increased rapidly because some people don't feel like they live up to peoples expectations, and feel very self conscious about themselves because of past experience with people who did not accept them the way they are (making them feel not good enough).

In conclusion, it was so easy for Iago to manipulate Roderigo because of his strong love for Desdemona and continuous rejection, his lack of intelligence causing him to make the same mistakes constantly after each other not knowing why nor understanding why, and his self-consciousness and jealousy of Othello feeling like he is way better than him because Desdemona chose him.

References

Shakespeare, William. Othello. Thomas Walkley, 1622. Print.

Markham, Samantha, Character Analysis of Iago. 01/02/09
    Suite101, <http://suite101.com/article/character-analysis-of-iago-a157049>

Scott. Othello Scene Play. StudyMode.com. 02/12
    <http://www.studymode.com/essays/Othello-Scene-Play-91682.html>

Deepak, Chopra, What is Manipulation and How do I Recognize it?
     <http://www.sharecare.com/user/deepak-chopra>

Set Free, The Manipulator's Behavior Being Defined. 09/16/09
     <http://setfree0408.blogspot.ca/2009/09/manipulators-behavior-defined.html>