Perhaps the most famous illustration of the Bystander Effect is the story of New Yorker Kitty Genovese who was brutally killed in Kew Gardens, Queens. She screamed through the attack for more than half an hour and no one came to her aid or called the police. Later investigations showed that 38 of her neighbours had watched the episode from their windows and did nothing.
Social psychologists offer 3 explanations for the bystander effect:
1) Ambiguity: Witnesses reports revealed some were not sure what was happening.
2) Pluralisitc Ignorance: Everyone was uncertain whether there really was an emergency and looked to others for clues as to how they should react, but all felt the same way, so nobody took action.
3) Diffusion of responsibility: Each observer knew that others could respond to the emergency, and that he/she need not be the one to do something.
In Games of Strategy (2nd ed.), Dixit and Skeath offer a game-theoretic explanation for the bystander effect that is remarkably similar to the diffusion of responsibility. They make a reasonable assumption that everyone would gain personal pleasure if Kitty Genovese was rescued, but each must balance that pleasure against the cost of getting involved. That is, each would like to free-ride on another's effort.
Their explanation is as follows:
There are N pple in the group, action brings each of them benefit B, and the person who take action has to bear the cost C. It is assumed that B>C.
So we can see that the person who takes action gets (B-C) while those who don't get B payoff.
If N=1, we don't have a problem since B-C > 0 and therefore he will help.
But if N>1, there is no pure strategy Nash equilibrium of everyone helping or no one helping bcos each would do better to free-ride or help respectively.
Instead, they propose that there is a mixed strategy equilibrium:
Let P be the prob that any one person will not act. To mix strategies, the person must be indifferent between helping or not helping.
Ok, now it will get really messy if i carry on to write the equations. Basically, find the expected payoff of the one person when he does not act and equate that to the payoff when he does act i.e. B-C (known as indifference principle). Next make P the subject of the formula, and by increasing N from 2 to infinity, P increases from C/B to 1. The probability that any one person will act (1-P) therefore falls from (1- C/B) to 0.
Next find the probablity that not even one person helps, which is P power N. Plugging in the previous result for P, and doing same thing again, we can see that the probablity that at least one person helps decreases as N increases.
Whew, this is really tiring, but I think this is a good example of how economics or more specifically game theory, helps to sharpen the social psychological theory of the bystander effect.
I think of this method as a mathematical proof of the diffusion of responsiblity!
I've tried my best to make this as simple as possible. For a much more succint and neater version, pls refer to Games of Strategy 2nd ed. pp 414-418.
Wednesday, January 9, 2008
Tuesday, January 8, 2008
Picture-based cigarette warnings effective?
Singapore passed a legislation sometime back for all cigarette packs to display a picture showing the possible physical consequences of smoking. In 2006 , the Health Ministry commissioned a new set of pictures to replace the ones used since 2004. Compared to the first set of pics, I felt that the 2nd set was significantly more grotesque. See here for comparison.
In passing this legislation, I believe the govt is following in the footsteps of Canada, which if i recall correctly, is the first country to impose picture-based health warnings on cigarette packs. I'm pretty confident that having these picture-based warnings increase the salience of the health warnings. A study by Hammond and colleagues (2003) found such pictures to serve as an effective cessation intervention, was associated with increased cognitive processing of warnings, attempts to quit, and reduction in smoking. A 4-country study published in 2007 by the same author revealed that countries with the least prominent health warnings were associated with the lowest levels of effectiveness. With these results, you can be pretty sure that picture-based warnings do work.
But it's probably not as simple as that. A brief review of the literature on fear appeals show 3 major variables that moderate the effectiveness of such messages. They are the 1) intensity of fear appeal, 2) presence of instructions on how to overcome the fear, and 3) the level of personal relevance of the message to the intended audience.
1) Intensity of fear: Fear arousing communications are unlikely to work if they trigger so much fear that pple shut down and become unable to think rationally about the issue. In one study, a scary ad about AIDS actually led to riskier behaviour in a sample of gay men (Rosser, 1991).
2) Presence of instructions: This will teach the subject how to reduce their fear. This variable may in turn be moderated by an individual's coping appraisal. Say if the subject were to find recommended instructions to be ineffective or impossible, the fear arousal will then bring forth fear control processes, resulting in denial and avoidance (Witte, 1992).
3) Level of personal relevance: Highly relevant info can sometimes result in defensive systematic processing of the threatening message. In an experiment by Liberman and Chaiken (1992), women coffee drinkers were less persuaded of the link between caffeine and fibrocystic breast disease than women non-coffee drinkers and they seemed to process the message in a defensive, biased manner. This runs counter to the Elaboration Likelihood Model which predicts people pay more attention to messages when it is more relevant to them.
Given the variables above, i think it becomes harder to judge whether these picture-based warnings are effective in Singapore. Compared to other countries with the same legislation, I find Singapore's warnings to be bloodier, more grotesque and hence more likely to be considered high in fear intensity. You can compare the pictures across various countries here (just follow the link to the various countries).
So are our picture-based warnings effective? (Effectiveness may be measured by cessation, attitude change, reduction etc depending on your operational definition) I'm not sure but at least anecdotally, I don't see it working but we won't know until someone does a study to find out.
Just a random thought, I'm a bit sad that I won't get to light up in a French cafe when I'm on exchange. Sounds crazy, but I've always pictured myself having a good conversation in a quaint French cafe, over a cup of hot coffee and cigarettes.
In passing this legislation, I believe the govt is following in the footsteps of Canada, which if i recall correctly, is the first country to impose picture-based health warnings on cigarette packs. I'm pretty confident that having these picture-based warnings increase the salience of the health warnings. A study by Hammond and colleagues (2003) found such pictures to serve as an effective cessation intervention, was associated with increased cognitive processing of warnings, attempts to quit, and reduction in smoking. A 4-country study published in 2007 by the same author revealed that countries with the least prominent health warnings were associated with the lowest levels of effectiveness. With these results, you can be pretty sure that picture-based warnings do work.
But it's probably not as simple as that. A brief review of the literature on fear appeals show 3 major variables that moderate the effectiveness of such messages. They are the 1) intensity of fear appeal, 2) presence of instructions on how to overcome the fear, and 3) the level of personal relevance of the message to the intended audience.
1) Intensity of fear: Fear arousing communications are unlikely to work if they trigger so much fear that pple shut down and become unable to think rationally about the issue. In one study, a scary ad about AIDS actually led to riskier behaviour in a sample of gay men (Rosser, 1991).
2) Presence of instructions: This will teach the subject how to reduce their fear. This variable may in turn be moderated by an individual's coping appraisal. Say if the subject were to find recommended instructions to be ineffective or impossible, the fear arousal will then bring forth fear control processes, resulting in denial and avoidance (Witte, 1992).
3) Level of personal relevance: Highly relevant info can sometimes result in defensive systematic processing of the threatening message. In an experiment by Liberman and Chaiken (1992), women coffee drinkers were less persuaded of the link between caffeine and fibrocystic breast disease than women non-coffee drinkers and they seemed to process the message in a defensive, biased manner. This runs counter to the Elaboration Likelihood Model which predicts people pay more attention to messages when it is more relevant to them.
Given the variables above, i think it becomes harder to judge whether these picture-based warnings are effective in Singapore. Compared to other countries with the same legislation, I find Singapore's warnings to be bloodier, more grotesque and hence more likely to be considered high in fear intensity. You can compare the pictures across various countries here (just follow the link to the various countries).
So are our picture-based warnings effective? (Effectiveness may be measured by cessation, attitude change, reduction etc depending on your operational definition) I'm not sure but at least anecdotally, I don't see it working but we won't know until someone does a study to find out.
Just a random thought, I'm a bit sad that I won't get to light up in a French cafe when I'm on exchange. Sounds crazy, but I've always pictured myself having a good conversation in a quaint French cafe, over a cup of hot coffee and cigarettes.
Saturday, January 5, 2008
Tissue pack here, tissue pack there, tissue pack everywhere...
This is a summary of a project that I did with my friends Kenneth, Kenvia, James, Grace, and Geri for our Game Theory Class taken in Fall 2007.
By now, I think many of us are pretty familiar with the phenomenon of using tissue packs to reserve seats at crowded food centres during lunch hours. This phenomeon sprung up only recently and is especially pervasive in the central business district. I'm also pretty sure it's unique to us Singaporeans. In fact, my friend Kenneth notified me that the Coxford Singlish Dictionary has listed this behaviour as one of the things that make us uniquely Singaporean.
At the start of the term when we first got together as a group, we were not sure if this topic was worth exploring, but what made up our minds was a group of office workers (presumably from nearby NTUC) who dropped by our basement Kopitiam for lunch. They came to the table next to ours, and all 6 of them each dropped a pack a tissue paper on the table, forming a beautiful formation of tissue packs, and then proceeded to order their food. When we saw that, that was it for us! We were gonna try and explain this uniquely Singaporean behaviour using a game-theoretic approach.
My group and I thought that this social behaviour can be explained by what ethologists call the Hawk-Dove game. This is a variation of the game of chicken in game theory. Hawks are aggresive individuals who will always fight for a valuable resource and Doves will never fight but display itself in a conflict. A Hawk meeting another Hawk will fight for the resource and the winner will get the resource, whereas a Hawk meeting a Dove will always win the resource. A Dove meeting another Dove will have a one-half probability of getting the resource.
One important assumption must be highlighted here, i.e.
1) The value of the resource is less than the cost of fighting
This means that it will be much better to give up the resource than to fight and risk injury.
Back to our tissue pack scenario, imagine an instance whereby 2 strangers in a crowded food centre, who happen to arrive at an empty table at the same time. Each believes the she has a right to the table. Ignoring altruism, how do we decide who gets the table? If both individuals are Hawks, we will have a fight on our hands. In the absence of a social mechanism to assign property rights to individuals, this is exactly what happens.
In any population, we cannot have a single type of individual i.e. only Hawk or Dove. Dixit and Skeath (2004) explains this rather amusingly with their example. If a population were to be populated with Wimps (Doves) only, then a Macho (Hawk) newcomer will successfully invade bcos he can impress the girls. On the other hand, if a population were to consist only of Machos (Hawks), then they are gonna be in the hospital all the time and the girls will as a result have to go for the healthy Wimps (Doves). Therefore we should expect to see a mixture of both types in the population with each playing a pure strategy Hawk or Dove. This mixture is known as an evolutionary stable strategy (ESS).
Problem is, despite being stable, this outcome is not exactly efficient, because instances of conflicts still arise when Hawks meet Hawks or when Hawks meet Doves. But consider if someone starts to use something (in this case a tissue pack) as a symbol of territory ownership and others slowly start to acknowledge this symbol. Then we have what is called a labelling asymmetry where individuals can be seen as possessor or non-possessor of a resource. The person who puts a tissue pack at the table is marking her territory! With this labelling asymmetry, possessors will gravitate towards playing Hawk invariably and non-possessors will gravitate towards playing Dove invariably. It makes intuitive sense, since if you believe you are the possessor, you will more likely play Hawk to defend your resource. We now have a different game where people tell themselves "If possessor, play Hawk; if non-possessor play Dove" This new strategy now becomes the ESS. According to economist Robert Sugden, this is also called a spontaneous order/convention.
Interested readers on related topics of social evolution can check out Sugden's book: "The Economics of Rights, Cooperation and Welfare". I got most of the material from there.
By now, I think many of us are pretty familiar with the phenomenon of using tissue packs to reserve seats at crowded food centres during lunch hours. This phenomeon sprung up only recently and is especially pervasive in the central business district. I'm also pretty sure it's unique to us Singaporeans. In fact, my friend Kenneth notified me that the Coxford Singlish Dictionary has listed this behaviour as one of the things that make us uniquely Singaporean.
At the start of the term when we first got together as a group, we were not sure if this topic was worth exploring, but what made up our minds was a group of office workers (presumably from nearby NTUC) who dropped by our basement Kopitiam for lunch. They came to the table next to ours, and all 6 of them each dropped a pack a tissue paper on the table, forming a beautiful formation of tissue packs, and then proceeded to order their food. When we saw that, that was it for us! We were gonna try and explain this uniquely Singaporean behaviour using a game-theoretic approach.
My group and I thought that this social behaviour can be explained by what ethologists call the Hawk-Dove game. This is a variation of the game of chicken in game theory. Hawks are aggresive individuals who will always fight for a valuable resource and Doves will never fight but display itself in a conflict. A Hawk meeting another Hawk will fight for the resource and the winner will get the resource, whereas a Hawk meeting a Dove will always win the resource. A Dove meeting another Dove will have a one-half probability of getting the resource.
One important assumption must be highlighted here, i.e.
1) The value of the resource is less than the cost of fighting
This means that it will be much better to give up the resource than to fight and risk injury.
Back to our tissue pack scenario, imagine an instance whereby 2 strangers in a crowded food centre, who happen to arrive at an empty table at the same time. Each believes the she has a right to the table. Ignoring altruism, how do we decide who gets the table? If both individuals are Hawks, we will have a fight on our hands. In the absence of a social mechanism to assign property rights to individuals, this is exactly what happens.
In any population, we cannot have a single type of individual i.e. only Hawk or Dove. Dixit and Skeath (2004) explains this rather amusingly with their example. If a population were to be populated with Wimps (Doves) only, then a Macho (Hawk) newcomer will successfully invade bcos he can impress the girls. On the other hand, if a population were to consist only of Machos (Hawks), then they are gonna be in the hospital all the time and the girls will as a result have to go for the healthy Wimps (Doves). Therefore we should expect to see a mixture of both types in the population with each playing a pure strategy Hawk or Dove. This mixture is known as an evolutionary stable strategy (ESS).
Problem is, despite being stable, this outcome is not exactly efficient, because instances of conflicts still arise when Hawks meet Hawks or when Hawks meet Doves. But consider if someone starts to use something (in this case a tissue pack) as a symbol of territory ownership and others slowly start to acknowledge this symbol. Then we have what is called a labelling asymmetry where individuals can be seen as possessor or non-possessor of a resource. The person who puts a tissue pack at the table is marking her territory! With this labelling asymmetry, possessors will gravitate towards playing Hawk invariably and non-possessors will gravitate towards playing Dove invariably. It makes intuitive sense, since if you believe you are the possessor, you will more likely play Hawk to defend your resource. We now have a different game where people tell themselves "If possessor, play Hawk; if non-possessor play Dove" This new strategy now becomes the ESS. According to economist Robert Sugden, this is also called a spontaneous order/convention.
Interested readers on related topics of social evolution can check out Sugden's book: "The Economics of Rights, Cooperation and Welfare". I got most of the material from there.
Friday, January 4, 2008
Seeking elegant explanations for everyday social behaviour
While I was reading economist Tyler Cowen's new book "Discover Your Inner Economist", I suddenly had this crazy idea of starting a blog. I wanted to write about the things that I learned in school and try to apply to them to what we see in everyday social behaviour. As a student of Economics and Psychology, I'm quite fond of putting the two disciplines together whenever I can. I think many of my friends and fellow students at SMU agree with me that Economics assumes too much, especially the idea of rationality in human beings. Psychology can perhaps better reconcile theory and practice in this aspect. At the same time, I think the mathematical rigour of Economics can sometimes help to reinforce certain theories in Psychology (I will try to give examples later on).
Another reason why I wanted to start this is because I have developed a sceptical eye of what I read in the newspapers, especially the forum section where people give their views and opinions on things like parenting, sex, education etc. Not that I disagree with what is expressed, but I would just like to see a bit more scientific rigour to back up those arguments, as opposed to expression of mere feelings and attitudes.
Just a disclaimer to those who might take an interest in what I write. Although I might cite research articles and diligently ensure the accuracy of what is written, I am still just an undergraduate trying to make sense of what's happening around me. You should never take what I write at face value, but do your own research and form your own attitudes and values.
Lastly, I will appreciate all constructive criticisms and comments from anyone. If you feel that my arguments are not robust enough, or simply not accurate, please point them out. It will be a great learning experience for me.
Another reason why I wanted to start this is because I have developed a sceptical eye of what I read in the newspapers, especially the forum section where people give their views and opinions on things like parenting, sex, education etc. Not that I disagree with what is expressed, but I would just like to see a bit more scientific rigour to back up those arguments, as opposed to expression of mere feelings and attitudes.
Just a disclaimer to those who might take an interest in what I write. Although I might cite research articles and diligently ensure the accuracy of what is written, I am still just an undergraduate trying to make sense of what's happening around me. You should never take what I write at face value, but do your own research and form your own attitudes and values.
Lastly, I will appreciate all constructive criticisms and comments from anyone. If you feel that my arguments are not robust enough, or simply not accurate, please point them out. It will be a great learning experience for me.
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