Behaviour Change

PROPAGANDA FOR CHANGE is a project created by the students of Behaviour Change (ps359) and Professor Thomas Hills at the Psychology Department of the University of Warwick. This work was supported by funding from Warwick's Institute for Advanced Teaching and Learning.

Thursday, March 22, 2018

2017 General Election: How Labour Turned it Around

In 2017 Theresa May called a UK General Election and everyone presumed the Conservatives would win by a landslide and further solidify their position in power. However, Corbyn’s Labour Party increased their seats and ran arguably a far better election campaign in the process. While both parties used many of the same techniques, I will focus here on Labour’s use of them and how this successfully influenced their result.

Competition Template

Labour consistently compared their policies with those of their rivals. Their slogan, ‘For the Many, Not the Few’ is a reference to their view on the Conservatives’ policies and aims to demonstrate Labour’s superiority in this. They produced and displayed many posters that were directly referencing the Conservatives and focused on their perceived negative points such as ‘The Tories have held Britain back long enough’. This is one of many advertising templates which have been found to, when utilised well, greatly improve the effectiveness of adverts (Goldenberg, Mazursky, & Solomon, 1999).

Use of both the Central and Peripheral Route

A good campaign needs to appeal to people who are engaged with the content (politics in this case), but also with those who aren’t very engaged. To do this, a campaign must employ both the central and peripheral route to persuasion as outlined in the Elaboration Likelihood Model (Petty & Cacioppo, 1986). Labour’s 2017 election campaign did this. Lots of their campaign was policy focused, such as the content of interviews and the TV debates, so politically engaged people were able to make their decisions based on this. However, they also had a very memorable slogan (‘For the Many, Not the Few’) which was displayed on billboards/posters and on social media, so less engaged people had something easily accessible to remember.

 Direct Targeting of Young People

This was a very vital aspect of Labour’s success in this campaign. As Carnegie states in his book (1936), making someone feel valued is a key way to win their allegiance. By focusing so heavily on young people, Labour made them feel important and this may well have had an impact on how young people voted. They also heavily utilised social media (e.g. twitter) during the campaign. Research has stated that one of the hardest things about involving young people in politics is being able to contact them, and that social media is a far more successful means of doing this than traditional media (Leppӓniemi, Karialuoto, Lehto, & Goman, 2010). Everyday political talk on social media also leads to higher political engagement according to Vromen, Xenos, and Loader (2015). As the Labour party was the most active on social media, this would not only increase general political engagement, but would make young people think specifically about the relevant party. The availability heuristic would suggest that more available information is more easily retrieved (Schwartz et al, 1991), so if the Labour party is the more available one, people may be more inclined to favour it.

Emotional Appeals

This campaign also tried to use emotion to influence voters. By using the competition template heavily, Labour tried to scare voters as to what the consequences of a rival government could be. This is seen in a poster concerning UKIP – ‘What is UKIP Leader Paul Nuttall’s Plan for our NHS?’. Research has shown that anxiety created by fear appeals can change political choice (Marcus, Neuman, & MacKuen, 2000). However, much of Labour’s campaigning was enthusiastic, focusing on the positive ideas Labour had going forward. Increased enthusiasm is linked to more public interest in a campaign, including willingness to vote (Brader, 2005).

The good use of these techniques, along with many others, may well have been a key factor in Labour’s surprise result in the 2017 election which destabilised an apparently ‘Strong and Stable’ government. 


Brader, T. (2005). Striking a responsive chord: How political ads motivate and persuade voters by appealing to emotions. American Journal of Political Science49(2), 388-405.
Carnegie, Dale (1936), How to Win Friends and Influence People, New York: Simon & Schuster.
Goldenberg, J., Mazursky, D., & Solomon, S. (1999). The fundamental templates of quality ads. Marketing science18(3), 333-351.
Leppäniemi, M., Karjaluoto, H., Lehto, H., & Goman, A. (2010). Targeting young voters in a political campaign: Empirical insights into an interactive digital marketing campaign in the 2007 Finnish general election. Journal of Nonprofit & Public Sector Marketing22(1), 14-37.
Marcus, G. E., Neuman, W. R., & MacKuen, M. (2000). Affective intelligence and political judgment. University of Chicago Press.
Petty, R. E., & Cacioppo, J. T. (1986). The elaboration likelihood model of persuasion. In Communication and persuasion (pp. 1-24). Springer New York.Schwarz, N., Bless, H., Strack, F.,
Klumpp, G., Rittenauer-Schatka, H., & Simons, A. (1991). Ease of retrieval as information: Another look at the availability heuristic. Journal of Personality and Social psychology61(2), 195.
Vromen, A., Xenos, M. A., & Loader, B. (2015). Young people, social media and connective action: From organisational maintenance to everyday political talk. Journal of Youth Studies18(1), 80-100.

Wednesday, March 21, 2018

Indeed's 'Search for greatness' advertisement

Indeed is the world's largest job-searching site and aims to tackle the issue of unconscious bias in job recruitment through their new advertisement. Through utilising the method of perspective-taking, Indeed seeks to encourage employers to proactively consider talent they may otherwise have overlooked as a result of stereotyped views of attributes irrelevant to job qualification such as skin colour, age, religious belief and area of residence (to note some of the cues mentioned by the narrator in the campaign).

Research has demonstrated that taking a specific point of view makes information relevant to this perspective salient and accessible and this newly highlighted information then goes on to impact judgement. This was seen in research by Iyengar (1991 in Pratkanis, 2007) who found that the reporting of crime events as either specific disrete happenings or more abstractly, within a broader story affected individuals' subsequent ratings of where responsibility should be located. The individual perpetrator was deemed responsible in more focused reporting while wider social forces were held responsible in more general reports.

Indeed utilises this effect in its method of transporting the viewer into the perspective of the job-seeker, an appeal being made from the individual to prospective employers. This places the viewer into the role of powerful other, utilising the dependency-responsibility altercast identified by Pratkanis (2007). The viewer is placed into the role of recruiter, and the narrator takes the role of the individual dependent on our consciousness to not give in to biases (which would jeopardise their chances of employment).

This message is emphasised by the first and last shots of the advert, where the CV covers and then reveals the narrator's face - driving home the centrality of being assessed as a candidate by his qualifications over any other attribute.

Pratkanis, A. R. (2007). Social influence analysis: An index of tactics. The science of social influence: Advances and future progress, 17-82.

Snapchat, you son of a behavioural psychologist 

Snapchat, the app that took over the social media world in 2011, allows users to send pictures and videos that can vanish forever in seconds (depending on your setting) (Colao, 2012). A research found about 98%  users snap funny things and about 85% snap their faces and their surroundings (Utz, Muscanell & Cameran, 2015). Snapchat boasts a whooping amount of 187 daily active users (Snap Inc, 2018).There may be many reasons for the excess popularity of the app with a few that are relevant to behavioural psychology are highlighted below.

 This principle influences people to repay what they get (Cialdini, 2009). Social interaction on mobile phones is seen as akin to ‘ritualised gift giving’ (Taylor & Harper, 2002). Therefore when you receive a snap, you feel like you are obligated to snap back. What may facilitate the principle of reciprocation is the ease to snap back. When you receive a snap,the simple instruction of ‘double-tap to reply’ may make the instruction easier to follow. Past research shows that more compliance is associated with simple exercise programmes (Becker, 1985). However the rule of reciprocity is not unique to just Snapchat as it’s used in several other social interactions. 

This principle is unique to snapchat. It suggests that people attach more value to things that are scarce (Cialdini, 2009). Messages warning about limited quantity therefore signalling scarcity have been found to influence consumer’s intention of purchasing products (Aggarwal, Jun & Huh, 2011). Snapchat uses this principle as the snap that is sent can be seen for a minimum amount of time and then disappears forever. As it can never been accessed again it’s a scarce therefore valuable. Furthermore the ‘stories’ that people share on snapchat have a time limit on them as well. After 24 hours they will disappear as well. People can stray away from apps like Facebook without the fear of losing out as the pictures shared on it can be accessed at anytime however a snap story will disappear if snapchat isn’t accessed. 

Commitment and Consistency 
This Principle is another reason why people can’t get off Snapchat for more than 24 hours. When you constantly snap a person back and forth each day, a fire emoji appears next their name. We have an innate need to align our behaviour to what we’ve commitment to (Cialdini, 2009). Therefore once we start a fire, we feel rather obligated to finish it. 

Use of Reinforcements

Negative Reinforcement 
Another reason why we stay so true to streaks is because we want to remove the awful ‘ticking hour glass’ that may act as an aversive stimuli increasing our snapping behaviour. 

Positive Reinforcement 
 As we successfully remove the aversive stimuli, the number next to the fire increases which acts as a reward therefore positively reinforcing our snapping behaviour

Variable Reinforcement 
Snapchat can positively reinforce snapping behaviour through rewards or trophies. However they are variability reinforced as the trophies are locked so the users aren’t aware what action to perform. This makes it likely that the users will try to use the app more and more in the hope for a reward.

Aggarwal, P., Jun, S. Y., & Huh, J. H. (2011). Scarcity messages. Journal of Advertising40(3), 19-30.

Becker, M. H. (1985). Patient adherence to prescribed therapies. Medical care23(5), 539-555.

Cialdini, R. B. (2009). Influence: Science and practice (Vol. 4). Boston, MA: Pearson education.

Colao, J. J. (2012). Snapchat: The biggest no-revenue mobile app since Instagram. Forbes. Available at:

Snap Inc. Reports Fourth Quarter and Full Year 2017 Results. (2018). Retrieved 21 March 2018, from

Taylor, A. S., & Harper, R. (2002,). Age-old practices in the'new world': a study of gift-giving between teenage mobile phone users. In Proceedings of the SIGCHI conference on Human factors in computing systems (pp. 439-446). ACM.

Utz, S., Muscanell, N., & Cameran, K. (2015). Snapchat elicits more jealousy than Facebook: a comparison of Snapchat and Facebook use. Cyberpsychology, Behavior, and Social Networking, 18, 1e6

No Frills In Your Prices

Link to Advertisement: 

This commercial for a Canadian grocery store called No Frills, is a short but effective advertisement that catches the viewers’ attention.  It does so by knowing its audience, and appealing to it. For one, it uses humour by playfully mocking other grocery stores, and how they often use excessive or fancy words to describe simple things.  While there is nothing wrong with higher end grocery stores, No Frills knows its target customers, and it is not those whom grocery shop at luxurious places. The advertisement is also very relatable; essentially, it is telling people that they are not paying for fancy wallpaper or a special shopping experience, but instead they are paying for the food, which is the purpose of the grocery store.  The Canadian supermarket chain also uses honesty, a trait which people respect, in the ad. This can be seen towards the end of the commercial, when the pristine, white backdrop is removed and the realistic looking walls of the grocery store are revealed. This relates to Cialdini’s principles of persuasion. One of the principles is liking, meaning people are persuaded by likable people who are cooperative towards mutual goals (2018).  In this case, the advertisement gives the appearance that the grocery store has the same goal as its target audience, being to allow for reasonable, discounted prices and that people are paying for what they get and nothing more.


Cialdini, Robert B. (2018) Principles of Persuasion. Influence at Work.

No Frills (2017). No Frills Aisles Commercial. Loblaw Companies.  

Flyering at the Fringe! Please just see my show!

The effects of a range of flyering techniques and the behaviour change principles behind them on potential audience members.

I have spent the last two Augusts in Edinburgh at the Fringe Festival performing stand-up comedy with the Warwick Comedy Society. It is an incredibly vibrant and thrilling month but needless to say it is also very stressful, with the continuous worry – what if no one comes to the show? There are over 3,000 shows across 300 venues being performed every day. So needless to say your flyer and your flyering technique are very important when it comes to getting an audience. You can barely walk 100m down the Royal Mile without acquiring 20 bits of paper, so what makes flyering effective? This module got me taking a more critical reflective look at my time in Edinburgh, and the flyering techniques I saw.

Mere exposure:  
Those with enough money too, were able to buy big wall and bus stop posters everyone saw every day while walking past. By simply being presented with the same piece of information multiple times you increase the change of a behavior change, specifically an action the information was encouraging you to pursue (Cacioppo & Petty, 1989). Of course here that is to see the show the poster/flyer is advertising. This also enabled repetition of message without any extra effort from the performer. Others plastered their flyer everywhere they could, on bar tables, in windows, on lampposts, on trees. Although an A5 flyer is much smaller than a wall poster this was still very effective. This will have the same cognitive effect of making the viewer ‘like’ the stimulus more each time they see it, each time increasing the likelihood they will be persuaded by it. (Gordon & Holyoak, 1983)
I saw these two posters at least 10 times a day

Foot in the door technique:
The foot in the door technique is where you initially ask for something small with the intention of later securing a larger action (Freedman & Fraser, 1966). I saw the foot in the door technique being used as follows:
1.       Have a catchy opening line to the attention of a passer by (foot in)
2.       Get them to stop and chat to you  to find out more about the show and
3.       Convince them to buy a ticket (bigger action which was ultimate goal from the beginning)
To date the best line anyone trying to get me to see their show has said is ‘excuse me mama do you love free comedy and hate fascism?’
To which I responded ‘yes’ and stopped to find out more. I was interested until he said tickets were £12. As a broke student I was picking my paid shows wisely. But I was seriously considering seeing it because of the conversation. Whereas if I had just been handed the flyer, the price would have put me off.

Looking back the Fringe is really one big negotiation.
Lots of performers who are flyering for themselves swap flyers with other performers, agreeing to go to each other’s show. This way you both gain something/ get what you wanted. Also longer term its good networking!
FREE TICKETS: sometimes a flyer offers you a free ticket if you promise to come of if the show is about to start! Once this method was used on me to trick me into going into an almost empty room to see a piece of theatre I had no intention of seeing. However the opposite also happened I hung around near a venue of a show I wanted to see but couldn’t afford to in the hope of getting a free ticket – and I did!

Celebrity endorsement/ higher authority:
Some less well known but still professional comedians had reviews from more well-known/ TV comedians on their flyers. Some also had reviews from reputable comedy sources such as Chortle and The Skinny as well as newspapers. This influences our cognitive processes and convinces us that the act on the flyer is like or as good as the individual who is endorsing them. This is because we take celebrity opinions to be of greater value (Muda, Musa, Mohamed & Borhan, 2013).

‘last ticket!’    ‘Sold out for the next two days!’      ‘Last date!’
Were also phrases I frequently heard. Lee and Seidle looked at narcissists and their purchasing in scare situations. Now while I can’t assert a percentage of people who are narcissists at the fringe I believe it is fair to say an environment full of comedians and actors looking for their big break will contain a high percentage of narcissists, hence I thought this experiment was relevant. They found that narcissists have a stronger preference for scarce products (Lee & Seidle, 2012). Narcissists assign a higher symbolic value to something when they know it is scares. I saw many individuals who were not paying much attention flyerers be sucked in when they heard ‘last ticket’. Or rush towards the half price hut when they heard only 10 tickets left for tonight’s performance of Hamlet! ( there were actually 7 productions of hamlet on at the fringe last year which I thought was pretty funny)
It also makes you think the show is good, because so many others are going to see it, even though this fact does not in itself guarantee the show is good. This plays into social proofing, which is where we look to others to gage an idea of how we should act. If we see others rushing to see a particular show, it will make us think maybe we should do the same.

It would be a lie if we didn’t admit the attractiveness of the flyerer could affect whether you stopped to talk or not (Till & Busler, 2000). This is due to a cognitive bias known as the Halo Effect, we believe that those who are physically attractive will have other positive traits. In this context we are likely to perceive someone who we see as attractive to be better at stand up or theatre than someone who we don’t perceived as attractive. Even though we know that these two things are not causally related.


Cacioppo, J., & Petty, R. (1989). Effects of message Repetition on Argument Processing, Recall, and Persuasion. Basic And Applied Social Psychology, 10(1), 3-12.

Daneshvary, R., & Schwer, R. (2000). The association endorsement and consumers’ intention to purchase. Journal Of Consumer Marketing, 17(3), 203-213.

Freedman, J., & Fraser, S. (1966). Compliance without pressure: The foot-in-the-door technique. Journal Of Personality And Social Psychology, 4(2), 195-202.

Gordon, P., & Holyoak, K. (1983). Implicit learning and generalization of the "mere exposure" effect. Journal Of Personality And Social Psychology, 45(3), 492-500.

Lee, S., & Seidle, R. (2012). Narcissists as Consumers: The Effects of Perceived Scarcity on Processing of Product Information. Social Behavior And Personality: An International Journal, 40(9), 1485-1499.

Muda, M., Musa, R., Mohamed, R., & Borhan, H. (2013). Celebrity Entrepreneur Endorsement and Advertising Effectiveness. Procedia - Social And Behavioral Sciences, 130, 11-20.

Till, B., & Busler, M. (2000). The Match-Up Hypothesis: Physical Attractiveness, Expertise, and the Role of Fit on Brand Attitude, Purchase Intent and Brand Beliefs. Journal Of Advertising, 29(3), 1-13.

Ul-Abideen, Z., & Saleem, S. (2018). Effective advertising and its influence on consumer buying behavior. European Journal Of Business And Management, 3(3), 55-65. Retrieved from

Wyckham, R., Banting, P., & Wensley, A. (1984). The language of advertising: Who controls quality?. Journal Of Business Ethics, 3(1), 47-53.

Weiden+Kennedy's 'Nothing Beats a Londoner' Nike Advertisement

This advertisement was released early last month and has made waves across social media. It has been reported on extensively by news and marketing outlets such as The Independent, The Metro and, garnering millions of views on Youtube within the first few days of its release.

Humorously communicating the struggles of young people training in different sports across the capital, Nike made use of both celebrities and over 250 members of the public throughout the 3 minute short clip titled ‘Nothing Beats a Londoner'. 

The means of storytelling (Pratkanis, 2007) was employed with characters appearing adamant that the challenges they face are greater than those of any other sport background in the capital. This acts to  engage the audience and creatively increases salience of all of different means of fitness outlets which are available to young people in the capital: a core aim of the campaign. 

The utilisation of celebrities in order to persuade viewers to support Nike in their youth fitness campaign (as well as in purchasing their products) is the basis of the‘high-status admirer altercast’ (Pratkanis, 2007). This makes use of the influence of celebrities who are often viewed as higher status individuals whose lives, actions and appearances are deemed to be desirable and thus imitable. Celebrities specific to the target audience of London youth were used from a wide range of backgrounds spanning from musicians to sports personalities including Skepta, Jorja Smith, J Hus and Mo Farah.


Pratkanis, A. R. (2007). Social influence analysis: An index of tactics. The science of social influence: Advances and future progress, 17-82.

If London were Syria

Most Shocking Second a Day Video
Still the Most Shocking Second a Day
Effectiveness of the Ad
This powerful short clip was created by Don’t Panic London for Save The Children UK, to mark the third anniversary of the Syrian Civil War to improve the lives of children in Syria and around the world. The video went viral and listed as one of the most successful fundraising videos for charity in 2014, reaching nearly 60 million views. This led to a dramatic increase of donations of about 25% in the first week. The goal was to raise public awareness of the suffering of refugees who might otherwise have been ignored.

Why is it so powerful?

Firstly, the title itself is persuasive and catches your eye. ‘Most Shocking Second a Day Video’ is ambiguous and creates a curiosity gap by providing just enough information to make people want to click to know more.

Similarity Altercast
Research has found a message to be more effective if the recipient perceives themselves as similar to the source (Pratkanis, 2007). The mundane, normal activities of an average British person is shown in the girl playing with make-up, learning the recorder and playing in the park, which reflect similar childhood activities in many of the viewers. Research has found even these trivial similarities often encourages liking and prosocial behaviour (Berschield, 1966).
Social Identity Theory
Social Identity Theory is where we see ourselves belonging to an in-group based on shared characteristics compared to out-groups that are perceived as different to us (Tajfel, 1982). Making the child British, encourages us to view Syrian children to be similar. This video allows our in-group to increase in size, by showing that people in Syria are human too and not so different from ourselves. Research has found when a stranger was perceived to be an in-group member, participants are more generous and give more money (Gomez, Kirkman & Shapiro, 2000).

Perspective Taking
The video’s alternative title ‘If London were Syria’ reflects its simple but impactful premise – ‘imagine if we ourselves were the refugees?’. This video brings the war to a familiar ground, making it more relatable to the viewer. Subverting the norm by using a British girl as the protagonist and London as the setting creates a personal connection and relevance to the viewer. This allows us as viewers to easily empathise and see the perspective of the young girl. Pinker (2011) highlights the importance of perspective taking in his book ‘The Better Angels of Our Nature’ as to understand what it is to be a different ethnic group subject to war, makes us more empathetic and compassionate, leading us to be more likely to help. Figure 1 highlights the impact of negative emotions in ads leading to empathic responses and a decision to help (Bagozzi & Moore, 1994). Oswald (1996) found when participants took the perspective of stressed students, they rated themselves higher on empathetic arousal and volunteered more of their time to help. This shows taking the perspective of others increases helping behaviour and is therefore a valuable technique to increase charity donations.

Figure 1. shows the role of negative emotions and empathic responses as mediators of the effects of exposure to anti child abuse ads on decision to help (Bagozzi & Moore, 1994)

Storytelling and Emotion
The ad gives a narrative that provides a causal structure to how one girls life changes dramatically. The story has a strong emotional hook, and an open-ended narrative which leaves you feeling uncomfortable without clear closure. The safety of the girls life is uncertain – much like the safety of Syrian refugees now. We are taken through snippets of the girls journey day by day. Storytelling has been found to be effective in inducing emotion (Banikowski & Mehring, 1999). And emotion has been linked with better recall (Bradley, Greenwalk, Prety & Lang, 1992). We are emotionally invested in this girls story. Emotional see-sawing is a technique used in the ad, where we see the girls experience change quickly from positive to negative. This dramatic change in emotion has been found to increase compliance, and thus donations to the charity (Nawrat & Dolinski, 2007). The story also has a cyclical feel, as it begins and ends on making a wish on her birthday, showing a contrast not only in her emotions, but physically in the candles reducing and lack of family. This repetition effect is another powerful technique, which further enhances the salience of the message (Pratkanis, 2007).
Addressing YOU directly
The ad ends with the girl hauntingly looking directly at the camera, as if she is looking to you for help personally. Eye contact is a powerful technique to connect with the viewer, and creates personal involvement, increasing the likelihood of processing information through the central route (Petty, Cacioppo & Schumann, 1983). At the end of both ads she looks up after blowing out her candle and makes a wish – a wish for you to help her.
Personal Relevance

This video really hit a cord as a lot of my family including my mother were refugees after being forced to flee Iraq due to civil war. They fled to the mountains, living in an abandoned school in a valley for 9 months, before moving on to Iran to seek refuge and escape Saddam Hussains Army. The mountains were filled with hundreds of Kurds fleeing on foot from the savagery of the Government. There was an appeal for international aid and neighbouring countries allowed them to seek refuge.
Yet again, history is repeating itself. The experiences my family went through in Iraq mirrors the situation in Syria now, which is why I can relate to it. But this is why this video is so powerful, it allows people who are so detached, to feel personally connected with the atrocities of war in other countries.

It’s difficult to empathise with the suffering of distant strangers, especially when media exposure has habituated us to becoming desensitised and numb to violence and trauma. The idea of ‘out of sight, out of mind’ is indeed a more comfortable position to take. But it is important, and necessary that we do not ignore those in need of international aid.

Bagozzi, R. P., & Moore, D. J. (1994). Public service advertisements: Emotions and empathy guide prosocial behavior. The Journal of Marketing, 56-70.

Banikowski, A. K., & Mehring, T. A. (1999). Strategies to enhance memory based on brain-research. Focus on Exceptional Children, 32, 1.

Berscheid, E. (1966). Opinion change and communicator-communicatee similarity and dissimilarity. Journal of Personality and Social Psychology, 4, 670.

Bradley, M. M., Greenwald, M. K., Petry, M. C., & Lang, P. J. (1992). Remembering pictures: Pleasure and arousal in memory. Journal of experimental psychology: Learning, Memory, and Cognition, 18, 379.

Gomez, C., Kirkman, B. L., & Shapiro, D. L. (2000). The impact of collectivism and in-group/out-group membership on the evaluation generosity of team members. Academy of management Journal, 43, 1097-1106.

Nawrat, R., & Dolinski, D. (2007). " Seesaw of Emotions" and Compliance: Beyond the Fear-Then-Relief Rule. The Journal of social psychology, 147, 556-571.

Petty, R. E., Cacioppo, J. T., & Schumann, D. (1983). Central and peripheral routes to advertising effectiveness: The moderating role of involvement. Journal of consumer research, 10, 135-146.

Pinker, S. (2011). The better angels of our nature: The decline of violence in history and its causes. London: Penguin UK.

Pratkanis, A. R. (2007). Social influence analysis: An index of tactics. The science of social influence: Advances and future progress, 17-82.

Oswald, P. A. (1996). The effects of cognitive and affective perspective taking on empathic concern and altruistic helping. The Journal of social psychology, 136, 613-623.

Tajfel, H. (1982). Social psychology of intergroup relations. Annual review of psychology, 33, 1-39.