Placebo Effect 2 Flashcards
Benedetti et al (2003) - Conscious Pain, conditioning cues reducing pain
Control - 12 minutes of pain
Verbal placebo increases and decreases pain respectively
Conditioning before:
On test, pain sensitivity was i the direction of suggestion, even when prior conditioning was in the opposite direction
INSTRUCTIONS OVERPOWER CONDITIONING IN THIS CASE
Benedetti et al (2003) p Hormones (non-conscious)
Less idea of growths for consciousness as unaware what base level of hormones are.
Conditioned increase as expected
However conditioned placebo effect in this case overpowers instruction placebo
On test, hormone levels only changed in those given conditioning, there was no effect of suggestion
In non-conscious it is all about conditioning
Length of placebo effect according to expectancy theory
Response expectancies are self‐reinforcing- No extinction
According to expectancy theory why is there no extinction of placebo effect?
Placebo effects should not extinguish because the occurrence of a placebo effect reinforces the expectancy which it is based
Length of placebo effect according to conditioning
Placebo effects will extinguish because presentation of the CS alone will weaken the CS-US association on which the placebo is based
Colloca et al (2005): length of placebo using placebo electrode
Get a shock and tell you it reduces pain (placebo)
When screen goes red, electrode inactive, green active
Tested pain intensity during red and green light (actual same intensity) - immediate and 1 week later
Results of Colloca et al (2005)
Rate pain less with green due to placebo
Also no within session extinction
1 week later placebo effect is reduced, some extinction, but not much within session
Au yeung et al (2014): length of placebo with electrode placebo
Placebo effect diminishes overtime - more consistent with conditioning account
Placebo vs nocebo on extinction
Looking at nocebo effect with identical design you don’t see any extinguishing of effect
May be due to anxiety and fear that interferes with extinction
Almost all research of PE involves what reinforcement?
continuous reinforcement
Why may partial reinforcement be more ecologically valid? (2)
- Outside the lab you may have variability in your experiences, not like real treatments are always the same - more like real life
- Partial Reinforcement Extinction Effect may
meant that placebo effects established under partial reinforcement are more durable - longer lasting as it is slower to extinguish
Au Yeung et al (2005): PE during partial reinforcement
Produces weaker but maintains over test phases and ends up the same
Partial reinforcement extinction effect
Ader et al (2010)
Tested whether partial reinforcement could be used to boost the effect of a corticosteroid for psoriasisvia the placebo effect
Take steroid everyday in phases one and two or phase one everyday then partial during phase 2 (1 every for days)
Results of Ader et al (2010)
The improvement in psoriasis in the PRF group was equivalent to that of CRF group…even though the PRF group received 25% of the active treatment
Colaguiri: Nocebo with partial reinforcement
Both partial and continuous maintained
Partial reinforcement is lower