Sakuri (1998)
Eating behaviour is controlled by neural circuits that run through the brain. The lateral hypothalamus may not be the brain's 'eating centre'. This research involved using rats.
Gold (1973)
- Lesions to the VMH alone did not result in hyperphagia in rats and only had effect when PVN was also damaged.
- Subsequent research failed to replicate Gold's findings.
Marie et al (2005)
Genetically modified rats (without NPY) had no change in eating behaviour.
Rolls and Rolls (1973)
Surgically removing the amygdala in rats would cause them to consume familiar and unfamiliar foods.
Zald and Pardo (1997)
The amygdala participates in the emotional processing of olfactory stimuli.
Showing posts with label Studies. Show all posts
Showing posts with label Studies. Show all posts
Wednesday, 4 November 2015
Dieting - Studies
Herman and Mack (1975)
Procedure
- 15 participants in three conditions.
- No preload; one milkshake; two milkshakes.
- Groups 2 and 3 asked to rate the taste qualities of milkshake.
- All participants given 3 tubs of ice cream and 10 minutes to rate the tastes of them.
- Told they could eat as much as they'd like.
- All given a questionnaire on their degree of dietary restraint.
Findings
- Low-restraint participants ate less ice cream in the two milkshake condition than the one or zero (considered to be 'fuller')
- High restraint participants ate more ice cream in the one and two conditions than the zero condition.
- Significant positive correlation across all participants between score on eating restraint questionnaire and amount eaten after two preloads - higher restraint = more eaten.
Wegner et al (1987)
- Asked some participants not to think about a white bear.
- Ring a bell when thinking of bear.
- Told others to think about bear.
- Participants told not to think about bear rang bell more.
Thomas and Stern (1995)
- Modest payments as a reward for weight loss do not enhance initial weight loss.
- Strategies to improve social networks have focused on teaching spouses to provide support during weight loss has had modest success rates.
Jelly Beans Experiment - Redden
Procedure
- Gave 135 people 22 jelly beans each, one at a time.
- As each bean dispensed, information on bean was given.
- One group saw general information, another group saw specific flavour details.
Findings
- Participants got more bored with eating beans if they saw the general information.
- Detailed group enjoyed the experiment.
Lowe et al (2004)
- Weight losses achieved through WeightWatchers were reasonably maintained over a five-year period and that an average of 71.6% of people maintained a loss of 5% of body weight or more.
Bartlett (2003)
- Dieting is most successful when goals are realistic and objectively defined.
- Optimal target levels centre around reducing calorific intake by 500-1000 calories per day for a six month period.
Procedure
- 15 participants in three conditions.
- No preload; one milkshake; two milkshakes.
- Groups 2 and 3 asked to rate the taste qualities of milkshake.
- All participants given 3 tubs of ice cream and 10 minutes to rate the tastes of them.
- Told they could eat as much as they'd like.
- All given a questionnaire on their degree of dietary restraint.
Findings
- Low-restraint participants ate less ice cream in the two milkshake condition than the one or zero (considered to be 'fuller')
- High restraint participants ate more ice cream in the one and two conditions than the zero condition.
- Significant positive correlation across all participants between score on eating restraint questionnaire and amount eaten after two preloads - higher restraint = more eaten.
Wegner et al (1987)
- Asked some participants not to think about a white bear.
- Ring a bell when thinking of bear.
- Told others to think about bear.
- Participants told not to think about bear rang bell more.
Thomas and Stern (1995)
- Modest payments as a reward for weight loss do not enhance initial weight loss.
- Strategies to improve social networks have focused on teaching spouses to provide support during weight loss has had modest success rates.
Jelly Beans Experiment - Redden
Procedure
- Gave 135 people 22 jelly beans each, one at a time.
- As each bean dispensed, information on bean was given.
- One group saw general information, another group saw specific flavour details.
Findings
- Participants got more bored with eating beans if they saw the general information.
- Detailed group enjoyed the experiment.
Lowe et al (2004)
- Weight losses achieved through WeightWatchers were reasonably maintained over a five-year period and that an average of 71.6% of people maintained a loss of 5% of body weight or more.
Bartlett (2003)
- Dieting is most successful when goals are realistic and objectively defined.
- Optimal target levels centre around reducing calorific intake by 500-1000 calories per day for a six month period.
Monday, 2 November 2015
Attitudes to food - Studies
Rapopori (2003)
People are motivated by health in contradictory ways. Existence of healthy foods so health must be a motivation for some. At the same time, people are becoming heavier. More people are eating out and consuming processed foods.
Tuorila & Pangborn (1988)
Obtained questionnaire data about women's intended and actual consumption of milk, cheese, ice cream and high fat and found that actual was based more on liking than on health concerns.
Steptoe et al (1995)
Put into rank order the factors taken into account by participants when choosing food to eat at, top - sensory appeal, health then convenience and price.
Birch & Malin (1982)
- Introduced 2 year olds to new foods over 6 weeks.
- 1 food presented 20 times; 1 ten times; 1 five times; 1 was novel.
- There was a direct relationship between exposure and food preference.
- 8-10 exposures were necessary for a shift in preference.
Brown & Ogden (2004)
- Reported consistent correlations between parents and their children in terms of snack food intake, eating motivations and body dissatisfaction.
People are motivated by health in contradictory ways. Existence of healthy foods so health must be a motivation for some. At the same time, people are becoming heavier. More people are eating out and consuming processed foods.
Tuorila & Pangborn (1988)
Obtained questionnaire data about women's intended and actual consumption of milk, cheese, ice cream and high fat and found that actual was based more on liking than on health concerns.
Steptoe et al (1995)
Put into rank order the factors taken into account by participants when choosing food to eat at, top - sensory appeal, health then convenience and price.
Birch & Malin (1982)
- Introduced 2 year olds to new foods over 6 weeks.
- 1 food presented 20 times; 1 ten times; 1 five times; 1 was novel.
- There was a direct relationship between exposure and food preference.
- 8-10 exposures were necessary for a shift in preference.
Brown & Ogden (2004)
- Reported consistent correlations between parents and their children in terms of snack food intake, eating motivations and body dissatisfaction.
Sunday, 11 October 2015
Mood and Eating Behaviour - Studies
Garg et al (2007)
Procedure
- Observed the food choices of 38 participants who watched either a funny movie or sad one.
- Participants were offered buttered popcorn and seedless grapes.
Findings
- Those watching the sad film consumed 36% more popcorn than those watching the funny film.
- People watching the funny film ate far more grapes than the other group.
- People who feel sad want to 'jolt themselves out of the dumps' and are more likely to want a anck that will give them a sudden rush of euphoria.
- Happy people choose healthy foods.
When people were presented with the nutritional value beforehand, consumption of unhealthy foods dropped dramatically.
Parker et al (2006)
Found that, although chocolate has a slight antidepressant effect, when consumed as an emotional eating strategy, it is more likely to prolong rather than alleviate the negative mood.
Wolff et al (2000)
Procedure
- Investigated differences between 20 female bing eaters and 20 female normal eaters.
- Daily measures of mood, coping and eating behaviour were self-recorded for three weeks.
Findings
- Binge group reported more stress and negative moods but stress levels were similar on their binge and non-binge days.
- Negative mood states are related to abnormal eating practices such as binge eating.
Procedure
- Observed the food choices of 38 participants who watched either a funny movie or sad one.
- Participants were offered buttered popcorn and seedless grapes.
Findings
- Those watching the sad film consumed 36% more popcorn than those watching the funny film.
- People watching the funny film ate far more grapes than the other group.
- People who feel sad want to 'jolt themselves out of the dumps' and are more likely to want a anck that will give them a sudden rush of euphoria.
- Happy people choose healthy foods.
When people were presented with the nutritional value beforehand, consumption of unhealthy foods dropped dramatically.
Parker et al (2006)
Found that, although chocolate has a slight antidepressant effect, when consumed as an emotional eating strategy, it is more likely to prolong rather than alleviate the negative mood.
Wolff et al (2000)
Procedure
- Investigated differences between 20 female bing eaters and 20 female normal eaters.
- Daily measures of mood, coping and eating behaviour were self-recorded for three weeks.
Findings
- Binge group reported more stress and negative moods but stress levels were similar on their binge and non-binge days.
- Negative mood states are related to abnormal eating practices such as binge eating.
Wednesday, 30 September 2015
Warfare - Studies
Lehmann and Feldman (2008)
Men who are stronger and more aggressive will win wars and survive to pass on genes, leading to an increasingly aggressive species. Two traits that have evolved in humans that determine the likelihood of conflict:
- Belligerence
- Bravery
Men with both traits have a higher chance of winning.
Kelly and Dunbar (2001)
Claim that bravery or heroic acts my have evolved owing to a female preference for brave, risk prone men. It is more likely that males that are willing to commit such 'brave' acts will also protect them in times of danger.
Farthing (2005)
Surveyed whether men and women desired physical risk tears as partners. The result was that only when the risks were considered 'brave' there was a significant advantage in mate selection. Physical risks that were not considered 'brave' were not an advantageous mate quality.
Men who are stronger and more aggressive will win wars and survive to pass on genes, leading to an increasingly aggressive species. Two traits that have evolved in humans that determine the likelihood of conflict:
- Belligerence
- Bravery
Men with both traits have a higher chance of winning.
Kelly and Dunbar (2001)
Claim that bravery or heroic acts my have evolved owing to a female preference for brave, risk prone men. It is more likely that males that are willing to commit such 'brave' acts will also protect them in times of danger.
Farthing (2005)
Surveyed whether men and women desired physical risk tears as partners. The result was that only when the risks were considered 'brave' there was a significant advantage in mate selection. Physical risks that were not considered 'brave' were not an advantageous mate quality.
Group display - studies
Marsh (1978)
Football hooliganism is the human equivalent of 'ceremonial conflict' in animals and involves trials of strength over territory.
Cialdini et al (1976)
After a university football team had performed well, students were more likely to wear university scarves and sweaters - 'basking in reflected glory'.
Neave and Wolfson (2003)
Found that football teams playing at home were far more likely to win than the visiting team partly because players have the benefit of a huge surge in testosterone before the match. They believed this could be due to an evolved drive to defend home territory.
Pollard and Pollard (2005)
The relationship with crowd sir is unclear as the advantage had been shown to operate even with very small crowds.
Football hooliganism is the human equivalent of 'ceremonial conflict' in animals and involves trials of strength over territory.
Cialdini et al (1976)
After a university football team had performed well, students were more likely to wear university scarves and sweaters - 'basking in reflected glory'.
Neave and Wolfson (2003)
Found that football teams playing at home were far more likely to win than the visiting team partly because players have the benefit of a huge surge in testosterone before the match. They believed this could be due to an evolved drive to defend home territory.
Pollard and Pollard (2005)
The relationship with crowd sir is unclear as the advantage had been shown to operate even with very small crowds.
Jealousy and Infidelity - studies
Buss et al (1992)
Procedure
- Asked male and female students the question 'what would distress you more?'
'(a) imagining your mate having sexual intercourse with someone else'
or
'(b) imagining your mate forming a deep emotional attachment to someone else'
(a) represents a threat to paternity security
(b) represents a threat to domestic paternity
Findings
- 60% of men said A
- 80% of women said B
- 40 % of males who didn't choose A - most had never experienced a committed sexual relationship and therefore unlikely to experience sexual jealousy.
- Suggests even if there is an underlying evolutionary mechanism behind male sexual aggression, it is modified by experience.
Pipat
Pipat given a decrease sentence for killing his wife dye to his young children and a 'fit of jealousy'.
Procedure
- Asked male and female students the question 'what would distress you more?'
'(a) imagining your mate having sexual intercourse with someone else'
or
'(b) imagining your mate forming a deep emotional attachment to someone else'
(a) represents a threat to paternity security
(b) represents a threat to domestic paternity
Findings
- 60% of men said A
- 80% of women said B
- 40 % of males who didn't choose A - most had never experienced a committed sexual relationship and therefore unlikely to experience sexual jealousy.
- Suggests even if there is an underlying evolutionary mechanism behind male sexual aggression, it is modified by experience.
Pipat
Pipat given a decrease sentence for killing his wife dye to his young children and a 'fit of jealousy'.
Wednesday, 23 September 2015
Adoption - studies
Mednick et al (1975)
From 14,000 adoptions in Denmark, it was found that a significant number of adopted boys with criminal convictions had biological parents with criminal convictions.
Miles and Carey (1997)
Procedure
- Meta-analysis of 24 twin adoption studies.
- Concerned with genetic basis of aggression.
Findings
- A strong genetic influence accounted for as much as 50% variance in aggression.
- Both genes and family environment were influential.
- At later ages, influence of rearing environment decreased and influence of genes increased.
Brennan and Mednick (1993)
A series of adoption studies in which the criminal history of an adopted male was compared with criminal history of both biological and adoptive fathers, found that genetic influences were significant in cases of property crime but not in violent crime.
Adoption studies have shown the highest rates of criminal violence in adopted children occur when both biological and adoptive parents have a history of violent crime - clear evidence of a gene-environment interaction.
From 14,000 adoptions in Denmark, it was found that a significant number of adopted boys with criminal convictions had biological parents with criminal convictions.
Miles and Carey (1997)
Procedure
- Meta-analysis of 24 twin adoption studies.
- Concerned with genetic basis of aggression.
Findings
- A strong genetic influence accounted for as much as 50% variance in aggression.
- Both genes and family environment were influential.
- At later ages, influence of rearing environment decreased and influence of genes increased.
Brennan and Mednick (1993)
A series of adoption studies in which the criminal history of an adopted male was compared with criminal history of both biological and adoptive fathers, found that genetic influences were significant in cases of property crime but not in violent crime.
Adoption studies have shown the highest rates of criminal violence in adopted children occur when both biological and adoptive parents have a history of violent crime - clear evidence of a gene-environment interaction.
Tuesday, 22 September 2015
Twin - Studies
Berkowitz (1993)
Studies from the 1930s found an average concordance rate of 75% for MZ twins and 24% for DZ. Support that genetics do influence levels of aggression.
McGuffin and Gottesman (1985)
Found a concordance rate of 87% for aggressive and antisocial behaviour for MZ twin pairs, compared with DZ twin pairs (72%).
Findings also indicate that family environment, shared across siblings, exerts an important influence.
Studies support the importance of genetic factors in aggression - but also environments that siblings share.
Meta analysis by Mason and Frick (1994)
Procedure
- Analysed 12 twin studies involving 3795 twin pairs.
Findings
- Approximately 50% of the difference between antisocial and non-antisocial behaviours could be attributed to genetic factors.
Coccaro et al (1997)
In one of the twin studies, Coccaro assessed the degree of genetic and environmental influences on aggression in male participants. Data from 182 MZ twin pairs and 188 DZ twin pairs were analysed.
Genes accounted for more than 40% of individual differences in aggression.
Environment accounted for 50% of individual differences in physical aggression and 70% in verbal aggression.
Studies from the 1930s found an average concordance rate of 75% for MZ twins and 24% for DZ. Support that genetics do influence levels of aggression.
McGuffin and Gottesman (1985)
Found a concordance rate of 87% for aggressive and antisocial behaviour for MZ twin pairs, compared with DZ twin pairs (72%).
Findings also indicate that family environment, shared across siblings, exerts an important influence.
Studies support the importance of genetic factors in aggression - but also environments that siblings share.
Meta analysis by Mason and Frick (1994)
Procedure
- Analysed 12 twin studies involving 3795 twin pairs.
Findings
- Approximately 50% of the difference between antisocial and non-antisocial behaviours could be attributed to genetic factors.
Coccaro et al (1997)
In one of the twin studies, Coccaro assessed the degree of genetic and environmental influences on aggression in male participants. Data from 182 MZ twin pairs and 188 DZ twin pairs were analysed.
Genes accounted for more than 40% of individual differences in aggression.
Environment accounted for 50% of individual differences in physical aggression and 70% in verbal aggression.
XYY Studies
Court-Brown (1965-67)
A sample of 314 patients with XYY would be 'best hospitalised due to an increased likelihood of aggressive behaviour'. The request for hospitalisation was based upon common knowledge of traits associated with each of the sexes.
Theilgaard (1984)
Researched the personality traits of a sample of XXY men and compared these to a sample of XY men and men with XXY. Part of the research compared the aggressiveness of the XYY to XY men. Theilgaard's background research showed that about 1 in 1000 males are XYY and that no single characteristic except height has been associated with XYY. Aggression levels fluctuate.
Also used the Rorschach test, in which XYY males gave more aggressive interpretations than XY counterparts.
Saturday, 19 September 2015
Hormonal Mechanisms - Studies
Dabbs et al (1987)
Measured salivary testosterone in violent and non-violent criminals. Violent criminals had higher levels of testosterone.
Lindman et al (1987)
Young males who behaved aggressively when drunk had high testosterone levels.
The challenge hypothesis (Wingfield et al, 1990)
In monogamous species, testosterone levels should only rise above baseline levels in response to social challenges. Males are expected to increase testosterone upon male-male conflict or
reproductive success.
Kouri et al (1995)
Procedure
- Double-blind procedure using young men.
- Given either testosterone or placebo.
- Paired with fictitious participant and told that each member of the pair could reduce the amount of cash the other received by pushing a button.
- Also told that the other participant was reducing the cash that the participant was receiving.
Findings
- Participants who received testosterone rather than the placebo pushed the button significantly more times.
Olweus et al (1980)
Procedure
- Measured blood testosterone levels in 16-year-old boys.
- Assessed aggression using a questionnaire.
Findings
- Higher levels of self-reported physical verbal aggression were associated with higher levels of testosterone.
Baucom et al (1995)
Women with higher testosterone levels has higher occupational status, possibly as a result of assertiveness.
Albert et al (1993)
Despite many studies showing a positive correlation between aggression and testosterone levels, other studies find no such relationship and most studies showing a positive correlation involved small samples of men in prisons using self-reports of judgements on severity of the crime.
Van Goozen (2007)
Measured salivary testosterone in violent and non-violent criminals. Violent criminals had higher levels of testosterone.
Lindman et al (1987)
Young males who behaved aggressively when drunk had high testosterone levels.
The challenge hypothesis (Wingfield et al, 1990)
In monogamous species, testosterone levels should only rise above baseline levels in response to social challenges. Males are expected to increase testosterone upon male-male conflict or
reproductive success.
Kouri et al (1995)
Procedure
- Double-blind procedure using young men.
- Given either testosterone or placebo.
- Paired with fictitious participant and told that each member of the pair could reduce the amount of cash the other received by pushing a button.
- Also told that the other participant was reducing the cash that the participant was receiving.
Findings
- Participants who received testosterone rather than the placebo pushed the button significantly more times.
Olweus et al (1980)
Procedure
- Measured blood testosterone levels in 16-year-old boys.
- Assessed aggression using a questionnaire.
Findings
- Higher levels of self-reported physical verbal aggression were associated with higher levels of testosterone.
Baucom et al (1995)
Women with higher testosterone levels has higher occupational status, possibly as a result of assertiveness.
Albert et al (1993)
Despite many studies showing a positive correlation between aggression and testosterone levels, other studies find no such relationship and most studies showing a positive correlation involved small samples of men in prisons using self-reports of judgements on severity of the crime.
_____________________________
Thers is a link between aggression and cortisol.
Virkkunen (1985)
Low levels of cortisol in habitually violent offenders.
Tennes and Kreve (1985)
There are low levels of cortisol in aggressive schoolchildren.
McBurnett et al (2000)
Procedure
- Evaluated 38 boys aged 7 to 12 for problem behaviour.
- Behaviours evaluated annually for four years.
- Salivary cortisol measurements taken during second and fourth years.
Findings
- Boys with lower cortisol levels exhibited three time the number of aggressive symptoms compared to boys with higher levels of cortisol.
- Boys with low cortisol were also named the most aggressive and 'meanest' by peers.
Gerra et al (1997)
Procedure
- Actually reported high cortisol = higher aggression.
McBurnett et al (2000)
Procedure
- Evaluated 38 boys aged 7 to 12 for problem behaviour.
- Behaviours evaluated annually for four years.
- Salivary cortisol measurements taken during second and fourth years.
Findings
- Boys with lower cortisol levels exhibited three time the number of aggressive symptoms compared to boys with higher levels of cortisol.
- Boys with low cortisol were also named the most aggressive and 'meanest' by peers.
Gerra et al (1997)
Procedure
- Actually reported high cortisol = higher aggression.
Wednesday, 16 September 2015
Brain Structure - Studies
Protegal (1996)
Direct stimulation of an area of the amygdala in hamsters produces aggressive behaviour.
Charles Whitman (1966)
Killed 16 people by gunshot from the top of a building and left a note asking to inspect his brain. A tumour was found pressing on his amygdala.
Siegel & Pott (1988)
The stimulation of the ventromedial hypothalamus results in spontaneous aggression.
Phillip Bard (1930s)
Procedure
- Removed the cortex in cats and made them decorticate.
Findings
- Cats became aggressive and exhibited 'sham rage'.
- Arched backs, hissing, growling and bared teeth.
Phineas Gage
Had his amygdala impaled by a pole working on a railway line and became extremely aggressive.
Direct stimulation of an area of the amygdala in hamsters produces aggressive behaviour.
Charles Whitman (1966)
Killed 16 people by gunshot from the top of a building and left a note asking to inspect his brain. A tumour was found pressing on his amygdala.
Siegel & Pott (1988)
The stimulation of the ventromedial hypothalamus results in spontaneous aggression.
Phillip Bard (1930s)
Procedure
- Removed the cortex in cats and made them decorticate.
Findings
- Cats became aggressive and exhibited 'sham rage'.
- Arched backs, hissing, growling and bared teeth.
Phineas Gage
Had his amygdala impaled by a pole working on a railway line and became extremely aggressive.
Neurotransmitter Studies
Couppis et al (2008)
Some individuals intentionally seek out aggressive encounters because of the rewarding sensations caused by dopamine.
Couppis & Kennedy (2008)
In mice, a reward pathway in the brain is engaged in response to an aggressive event and dopamine is a positive reinforcer.
Ferrari et al (2003)
Procedure
- Rats used.
- Forced to fight at the same time every day for 10 days.
- Not allowed to fight on the 11th day.
- Measured dopamine and serotonin.
Findings
- In anticipation for the fight, the rats; dopamine increased and serotonin decreased.
Linnolia & Virkkunen (1992)
Some individuals intentionally seek out aggressive encounters because of the rewarding sensations caused by dopamine.
Couppis & Kennedy (2008)
In mice, a reward pathway in the brain is engaged in response to an aggressive event and dopamine is a positive reinforcer.
Ferrari et al (2003)
Procedure
- Rats used.
- Forced to fight at the same time every day for 10 days.
- Not allowed to fight on the 11th day.
- Measured dopamine and serotonin.
Findings
- In anticipation for the fight, the rats; dopamine increased and serotonin decreased.
_____________________________
Low levels of serotonin are linked to 'impulsivity and explosive acts of violence'.
Cleare & Bond (1997)
'Serotonin depletion tends to ruffle people's feathers'.
Summers et al (2005)
Observed that globally acting serotonergic drugs do modify aggressive behaviour.
Davidson (2000)
Neurotransmitter research ignores the influence of brain structure.
Wednesday, 9 September 2015
Studies - Institutional Aggression
Mills, Kroner & Weeks (1998)
Procedure
- Surveyed 202 inmates newly admitted to Canadian prison
- Used Alcohol Dependence Scale
Findings
- Higher levels of misconduct were associated with more severe levels of alcohol dependence.
- Employment record, a lower level of education and a more serious criminal record were also linked with a greater likelihood of aggression when imprisoned.
Harer and Steffensmeier (2006)
Procedure
- Collected data from 58 US prisons
Findings
- Black inmates had significantly higher rates of violent behaviour but lower rates of alcohol and drug related misconduct than white inmates.
Delis (2004)
Procedure
- Studied prison records of 831 male inmates from south western USA to explore prison violence records of inmates involved in street and prison gangs.
Findings
- Significant relationship between gang membership and institutional aggression - suggesting subcultural values had been imported into prisons.
Poole and Regale (1983)
They assessed the relative impact of several deprivation and importational variables on inmate violence in four juvenile correction centres. Both sets of variables were shown to exert some effects on inmate aggression but pre-institutional violence emerged as the best predictor of inmate aggression.
_____________________________
Procedure
- Examined assaults in 900 US prisons.
Findings
- Some inmate programmes increased rates of assaults while other decreased them. This suggests it is the characteristics of the prison that accounts for the levels of aggression.
McCorkle (1995)
Found that overcrowding , lack of privacy and lack of meaningful activity all significantly influence peer violence, supporting the deprivation model.
Also looked at individual and group aggression in 370 US prisons. Results demonstrated that the deprivation model didn't fully explain prison violence but there was a link between prison procedures and levels of aggression.
Monday, 29 June 2015
Studies - Deindividuation
Colman (1991)
In some countries, deindividuation has even been accepted as grounds for extenuating circumstances in murder trials.
Hogg and Vaughn (1998)
In some countries, deindividuation has even been accepted as grounds for extenuating circumstances in murder trials.
_____________________________
Hogg and Vaughn define deindividuation as: 'a process whereby people lose their sense of socialised individual identity and engage in unsocialised, often anti-social behaviours'.
_____________________________
Zimbardo (1969)
Procedure
- Groups of 4 female undergraduates.
- Delivered shocks to other student.
- Half in bulky lab coats and hoods in separate cubicles, never referred to by name; half in normal clothes with large name tags and introduced to each other by name.
- Both sets told they could see the person being shocked.
Findings
- Hooded - deindividuated - shocked participant for twice as long as identifiable participants.
_____________________________
Rehm et al (1987)
Procedure
- Randomly assigned German schoolchildren to handball teams of 5.
- Half wore orange shirts; half wore street clothes.
Findings
- Children wearing orange played more aggressively.
_____________________________
Mullen (1986) - The Faceless Crowd
Mullen analysed newspaper cuttings of 60 lynchings in US between 1899 and 1946 and found more people = more savagery.
_____________________________
Milgram (1965)
Found that participants were more likely to give higher levels of shock when they could not see their victim. When the victim was in the same room, participants were more reluctant to deliver high level shocks.
_____________________________
Mann (1981) - The Baiting Crowd
- Analysed 21 suicide leaps from US newspapers in 1960s and 70s.
- 10 out of 21 cases had a large crowds gathered, baiting the jumper.
- Occurred at night when crowd was large and some distance from the person jumping.
- This caused anonymity and deindividualisation.
_____________________________
Malamuth (1981)
Almost 1/3 of male students questioned at an American university admitted there was a likelihood that they would rape if they were certain they would not get caught.
_____________________________
Diener et al (1976)
Procedures
- Observed behaviour of 1,352 children on Halloween trick-or-treating.
- Approached 27 focal homes in Seattle where they were invited to take one candy.
- Half children were asked their names and addresses beforehand - reduced deindividuation.
Findings
- Groups and deindividuated children were more than twice as likely to take extra candy.
- Transgression rate varied from 8% of individuated individuals to 80% of deindividuated groups.
_____________________________
Prentice-Dunn et al (1982)
It is reduced self-awareness, rather than simply anonymity, that leads to deindividuation. If an individual is self-focused, they tend to focus on, and act according to their internalised attitudes and moral standards, thus reducing the likelihood of antisocial behaviour. If an individual submerges themselves in a group, they could lose their focus and less able to regulate their own behaviour.
Johnson and Downing (1979)
Procedure
- Female participants administer shocks to confederates in paired association task.
- Half women wore KKK robe; half in nurse's uniform. Experimenter commented on the explicit resemblance.
- Half wore a large name badge.
Findings
- Deindividuation failed to increase aggression.
- Nurses less aggressive.
- Individuated nurses least aggressive.
- Two important conclusions:
1. Aggression and antisocial behaviour are not automatic and inevitable consequences of anonymity.
2. Normative expectations surrounding situations of deindividuation may influence behaviour.
It is reduced self-awareness, rather than simply anonymity, that leads to deindividuation. If an individual is self-focused, they tend to focus on, and act according to their internalised attitudes and moral standards, thus reducing the likelihood of antisocial behaviour. If an individual submerges themselves in a group, they could lose their focus and less able to regulate their own behaviour.
_____________________________
Johnson and Downing (1979)
Procedure
- Female participants administer shocks to confederates in paired association task.
- Half women wore KKK robe; half in nurse's uniform. Experimenter commented on the explicit resemblance.
- Half wore a large name badge.
Findings
- Deindividuation failed to increase aggression.
- Nurses less aggressive.
- Individuated nurses least aggressive.
- Two important conclusions:
1. Aggression and antisocial behaviour are not automatic and inevitable consequences of anonymity.
2. Normative expectations surrounding situations of deindividuation may influence behaviour.
Studies - Social Learning Theory
Bandura et al (1961)- Bobo Doll
Sample: 72 child participants (36 boys & girls) between 3-5 years old
Procedure
- Condition one : aggressive group - 24 participants
- Condition two : non-aggressive group - 24 participants
- Condition three : control group - 24 participants
- Children rated on aggression
- Enter playroom with role model and experimenter. Played away from role model.
- Adult had bobo doll, mallet and construction set.
- Aggressive model hit doll and non-aggressive model ignored doll.
- Role model and experimenter leave.
- Children go to a room with toys they can't use.
- Then go to a different room with aggressive and non-aggressive toys.
- Observer watches behind one way mirror.
Findings
- Aggressive model = aggressive children
- 1/3 of children following aggressive model made verbal remarks. None of non-aggressive children did this.
- Boys = more physical, girls = more verbal.
Conclusion
Aggression can be learned through observation.
Bandura and Walters (1963)
Children who saw the model being rewarded for aggressive behaviour showed high level of aggression. Reverse if seeing punishment. Learning through vicarious reinforcement.
Bandura (1963)
Sample: 72 child participants (36 boys & girls) between 3-5 years old
Procedure
- Condition one : aggressive group - 24 participants
- Condition two : non-aggressive group - 24 participants
- Condition three : control group - 24 participants
- Children rated on aggression
- Enter playroom with role model and experimenter. Played away from role model.
- Adult had bobo doll, mallet and construction set.
- Aggressive model hit doll and non-aggressive model ignored doll.
- Role model and experimenter leave.
- Children go to a room with toys they can't use.
- Then go to a different room with aggressive and non-aggressive toys.
- Observer watches behind one way mirror.
Findings
- Aggressive model = aggressive children
- 1/3 of children following aggressive model made verbal remarks. None of non-aggressive children did this.
- Boys = more physical, girls = more verbal.
Conclusion
Aggression can be learned through observation.
______________________________________
Bandura and Walters (1963)
Children who saw the model being rewarded for aggressive behaviour showed high level of aggression. Reverse if seeing punishment. Learning through vicarious reinforcement.
______________________________________
Viewing aggression by cartoon characters produces as much aggression as viewing live aggression performed by adults. Entertainment industry has an influential role on the social development of children.
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Patterson (1989)
Demonstrated that role models are important in the development of antisocial behaviour and that parents are the most important ones. Through surveys/questionnaires, they found that aggressive children are raised in homes of high aggression, little affection and little positive feedback.
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Mead (1935)
Found the Arapesh is an example of non-aggressive culture in which aggression is not admired or modelled by adults. The Mundugmor show the opposite pattern. Shows that SLT can be applied universally.
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Flanagan (2000)
Suggests that testosterone had been cited as a primary cause of aggression and other genetic/neuroanatomical structures are involved. SLT is reductionistic.
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Runciman (1966)
Challenged Bandura's explanation; suggested that aggressive behaviour might be due to relative deprivation - the perceived difference between what you have and what you think you should have.
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Dollard et al (1939)
Aggressive behaviour is not due to imitation alone. Aggression is the result of frustration built up (psychoanalysis) and presence of environmental cues (behaviourism) that signal aggression.
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