3) Theories of Gambling

evidence for genetics (4)

• looking at twin studies, MZ who share 100% of genes of DZ who share 50% in the same shared environment

• sklutske’s 2000 study in a vietnam vet database found that heritability estimated at 40- 50% and genetic risk overlaps with alcohol addiction

• sklutske’s 2010 autralian twin registry found that genetic influence was 49.2% and genetic contribution was similar in men and women

• shared environment contributed to no difference but difference seen in nonshared environment

environmental risk factors for gambling (2)

• exposure to parental/ family gambling in childhood and adolescence

• childhood adversity

effects of parental gambling on child

study found that parental gambling problems but not parental gambling predicted child gambling problems when child reaches 18+

how does childhood adversity lead to gambling (2)

• in an adult sample, 61% reported childhood maltreatment

• in youth pathological gamblers, 20% reported physical abuse and 18% sexual abuse

genetics vs environment on gambling

many researchers argue the likely role of gene x environment interactions

testing the addictive personality with a prospective design (4)

• dunedin birth cohort received the multidimensional personality questionnaire aged 18

• looked at 3 factors of negative emotionality (neurotisim), positive emotionality, constraint (the opposite of impulsivity)

• their drug use and gambling was assessed 3 years later at age 21

• found that 10% had alcohol dependence, 9% had cannabis dependence, 18% had nicotine dependence and 6% had gambling problems

what was found regarding the personality profile for development of alcohol dependence, cannabis dependence and gambling problems (2)

• risk for all was all predicted by low constraint so high impulsivity 3 years later

• but for alcohol dependence and cannabis dependence also included high negative emotionality but less clear for gambling problems

fMRI of reward in problem gambling (2)

• found that in healthy group, we see stronger ventral striatum in winning outcomes compared to those with problem gambling where it is weaker

• more severe the symptoms of problem gambling, the lower the brain activity

fMRI to natural rewards (5)

• tasks requires making a fast responses to earn monetary rewards vs erotic images, sexual rewards

• found that in heterosexual men with gambling disorder showed an imbalance between the 2 reward types

• they were more motivated by money cues, responded faster to monetary rewards and slower to erotic rewards

• in healthy controls, ventral striatum is activated in both monetary and sexual cue while in gamblers, ventral striatum is only activated with money cue and dampened to erotic cues

• mechanisms argued for could be reward deficiency and learning based accounts, hyperlearning

dopamine PET in gambling disorder (4)

• dopamine PET scan in men

• found no differences at an overall group level comparing controls and gamblers

• cannot confirm the same effect seen in drug addictions

• but did find that in the group with gambling disorder, higher impulsivity is related to lower D2 receptor binding

using PET to measure dopamine release (3)

• participant received 2 dopamine PET scans, before and after low dose amphetamine

• amphetamine releases natural dopamine that competes with the PET tracer, so tracer binding is lower at scan 2

• the group with pathological gambling show increased dopamine release

study on gambling cues and craving in the brain (7)

• looked at 19 men with gambling disorder vs 19 healthy men

• participants viewed gambling photos and neutral images during an fMRI scan and gave craving ratings after each block of images

• the photos were tailored to the participants preferred forms of gambling

• all participants saw betting shopfronts + roulette machines, slot machines, sport betting

• found that in participants with gambling disorder, there is increased craving ratings overall and especially after blocks of gambling images

• the brain area that responded more to gambling images in the group with gambling disorder is the insula and the medial pre frontal cortex

• the brain area where activity to gambling images is correlated with higher craving ratings is the insula

insula and smoking cravings (2)

• tying insula to drug cravings, smoking cravings

• found that in smokers who suffered a stroke, and if the stroke affected the insula, they were more likely to spontaneously quit

what else does the insula do (3)

• the insula holds the brain’s representation of the state of the body

• e.g. sensing heart beats or subjective heat or coolness

• links cravings, risk taking and loss aversion

behavioural theory of gambling (2)

• argues gambling is an operant response that sometimes results in a win, reward feels good

• there is positive reinforcement as we are more likely to repeat the behaviour because it led to a good outcome before

skinner’s schedules of reinforcement (7)

• argues we have of fixed interval, variable interval and fixed ratio

• interval depends on a passage of time

• ratio depends on number of responses

• fixed internal is when a reward becomes available every certain amount of time (e.g. paychecks)

• variable interval is having unpredictable interval time (e.g. self employed)

• fixed ratio is gaining a prize after a certain number of response (e.g. loyaly card)

• gambling is a variable ratio example where you don’t know which bet is going to win

what do we know about variable ratio schedules (4)

• ratio schedules yield higher rates of responding than interval schedules

• on interval schedules, rat’s slack off after they receive rewards

• variable ratio schedule in particular are highly resistant to extinction, stopping the reward where the behavior keeps happening for a long time even if you completely stop giving the reward

• although variable ratio are not easy to establish in rat or pigeon, many people with gambling problems report a “big win” early in their gambling careers which may be a key conditioning event

relationship of dopamine release and unpredictable rewards (6)

• using raclopride tracer

• in variable ratio, don’t know when they will win $1 in every 4 trial

• in fixed ratio, they win $1 every 4 trial on the 4th trial

• variable ratio minus control show higher levels of dopamine in left striatum

• fixed ratio minus control show no significant dopamine release

• show that there is a dopamine release to reward uncertainty as only variable ratio condition show dopamine drive

what is seen every time in between when a bet is placed and outcome is revealed (2)

• there is a pause, gap seen in every gambling situation

• where a bet is placed, then a gap, then outcome is revealed (e.g. pull the lever, wait 4-5 secs then slot machine outcome)

what are the 2 elements of reward uncertainty

• resolution

• anticipation

resolution (2)

• when the bet is revealed

• information is valuable even for unrewarded outcomes, you know more than you did before

anticipation (2)

• are we getting extra utility from the sheer experience of reward uncertainty and the wait

• some circumstances where we want to wait

what was found to invert delay discounting

savouring

how does savouring invert delay discounting (5)

• in economics, we discount future reward and value immediate reward

• but found that when asked how much participants would pay to receive a kiss from a movie star, of choice now 3 days later or 10 years later

• found that participants will pay more to receive a kiss from a movie star of choice in 3 days, rather than immediately, savouring their reward, inverting classical economic theory

• they will also pay more to avoid and anticipate electric shocks in the future, anticipatory is called dread

• so there is savouring for positive outcomes and dread of negative outcomes

reward anticipation and consumption study (3)

• in the reward uncertain group, they are shown a dice shaker and told that they will cover it and will roll the dice and uncover the shaker, if one dice is a 5 or 6, they will get a 21 pounds bonus

• in the control group, they get no shaker and have a fixed 7 pound bonus

• then they are told to try different snack foods or beverages and rate how much you like them, researcher measuring how much they try during the wait

what was found in the study (4)

• reward uncertainty had its effect during the anticipatory group

• monetary reward uncertainty increased consumption of foods and drinks

• higher consumption of alcohol and pub snacks in reward uncertainty group than control group

• they also rated flavours as more intense than control group

its all about the pause, the effect of the pause (4)

• physiological arousal during gambling play

• the excitement is a commodity that the gambler is prepared to pay for

• fully recognise that there is a negative expected value but willing to pay as it offers them positive expected utility

• gambling may also serve to relief stress, low mood, boredom regardless of winning money, negative reinforcement

how does uncertainty affect dopamine cell signals (3)

• schultz original study we see dopmaine cell activity during appetitive pavlovian conditioning for fruit juice, but it was only with purple picture

• now they included 5 visual stimuli (5 different picture) with different probabilities of reward

• at peak uncertainty of 0.5, there is a cue response of the picture plus anticipatory activity in the pause between the cue response and the juice

gambling and hyper learning (2)

• important that gambling cues should evoke dopamine activity

• with uncertain rewards, there is also anticipatory activity, creating a potential dopamine double hit

psychophysiology of blackjack (4)

• looking at heart rate of when first card is dealt, second card is dealt and result of deal

• compared simulation of hypothetical not playing with real money and real casino setting

• substantial heart rate increases mostly in the real casino setting

• there is a need for ecological validity as incentives of lab setting is different than in real life

study looking at if monetary bet/ prize is a pre- requisite for increased heart rate (5)

• in most of the studies, participants in the lab conditions were playing for a prize, not money

• question of if a monetary bet/ prize is a pre- requisite for this increased heart rate

• in phase 1, they played 50 trials on slot machine with money available and found that heart rate is similar in both groups

• in phase 2, they were then assigned to either play for real money or play for credits, not money

• found major difference in arousal levels where those playing with real money had higher heart rates than

physiological responses and experience of excitement (3)

• lots of gambling research in 1990s- 2000s measured the SIGNAL but with inconsistent findings

• only a couple of studies have looked at interoception or cognitive appraisal

• when there is physiological changes, increase in heart rate, it can lead to a detection of change, interoception but there are alot of individual differences, also a key question of how do you make sense of this experience, cognitive appraisal of physiological state where individual differences also exists

the capilano bridge of gambling (3)

• slot machine gamblers visited an australian crocodile sanctuary played a slot machine in the entry foyer or after holding a baby crocodile

• measured betting on slot machine games

• participants who are rated as having low negative emotionality thought the crocodile was exciting and found that they placed higher bets on the slot machine task vs those who had high negative emotions