Jan 13 Flashcards
lecture title
mankind’s two sovereign masters: the psychology and neuroscience of pain and pleasure
Jeremy Bentham 1789 quote
“Nature has placed mankind under the governance of two sovereign masters, pain and pleasure. It is for them alone to point out what we ought to do, as well as to determine what we shall do.”
psychological hedonism
perspective arguing that people are motivated to act in ways that INCREASE PLEASURE and DECREASE PAIN
reward
something an animal will WORK TO ACHIEVE
primary and secondary rewards
primary rewards
naturally rewarding & biologically essential
ie. food, water, warmth, sexual gratification
secondary rewards
learned rewards that gain importance through repeated associations with primary rewards
ie. money
pleasure
subjective hedonic value of rewards
what it feels like to get the reward - the sense of enjoyment or gratification
is subjective by definition
punishment
something an animal will work to avoid
primary and secondary punishments
primary punishments
naturally aversive, threaten survival
ie. physical injury & tissue damage
secondary punishments
learned punishments that ACQUIRE aversiveness through repeated associations with primary punishments
ie. financial loss, bad grades
pain
the subjective HEDONIC and MOTIVATIONAL response to punishing stimuli
subjective utility
personal value or satisfaction an individual assigns to an outcome
based on their preferences and circumstances
(rewards don’t always produce pleasure; punishments don’t always cause pain - CONTEXT matters)
what are the sources of pain and pleasure? recall that organisms strive to maintain…
optimal internal equilibrium (homeostasis)
connection between hedonic feelings and homeostasis
hedonic feelings (pleasure and pain) exist to ENCOURAGE BEHAVIOURS that help optimize internal balance
pleasure guides us towards stimuli that help RESTORE/MAINTAIN homeostasis
pain SIGNALS DEVIATION from homeostasis
alliesthesia
subjective hedonic value of stimulus is tied to extent to which a stimulus CONTRIBUTES TO or DISRUPTS homeostasis
ie. food is most pleasurable when it alleviates hunger, but once homeostatic needs are met it becomes less pleasurable
a stimulus will be experienced as pleasurable or painful depending on how it affects the body’s homeostatic balance
______ and ______ contexts determine the hedonic value of a stimulus
internal and external contexts
while traditionally considered opposites, pain and pleasure…
are intertwined and exert reciprocal influences on each other
the statement that we’re motivated solely by desire to avoid pain and attain pleasure doesn’t…
capture the full complexity of human motivation
ie. why do we sometimes seek out painful experiences?
international association for the study of pain definition of pain
“an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”
are nociception and pain the same thing?
no
nociception =/= pain
nociception
neural detection & transmission of information about tissue damage
involves SENSORY RECEPTORS (nociceptors) that respond to THERMAL, MECHANICAL, CHEMICAL stimuli
occurs without conscious awareness
nociceptors respond to what 3 types of stimuli?
thermal, mechanical and chemical
pain
subjective, conscious experience of discomfort or distress
has both a sensory and emotional component
dissociation between nociception and pain
can have pain without nociception
and can have nociception without pain
pain without nociception
phantom limb
neuropathic pain
(no tissue damage involved)
nociception without pain
withdrawal reflex, anesthesia, high-adrenaline situations
things that can alter pain perception
psychological state
context
expectations
ascribed meaning
2 components of pain
- sensory-discriminative component
- affective-motivational component
sensory-discriminative component of pain
provides info about INTENSITY, QUALITY, LOCATION
processed in PRIMARY and SECONDARY SOMATOSENSORY CORTICES and the POSTERIOR INSULA
where is the sensory-discriminative component of pain processed?
primary and secondary somatosensory cortices
posterior insula
affective-motivational component of pain
relates to EMOTIONAL EXPERIENCE of pain
how distressing is it?
drives MOTIVATION to escape/stop painful experience
where is the affective-motivation component of pain processed?
in the DORSAL ANTERIOR CINGULATE CORTEX (dACC)
and the ANTERIOR INSULA (AI)
evidence of dissociation of the 2 components of pain in the brain
lesions to dACC or insula
hypnosis
congenital insensitivity to pain
rare genetic disease characterized by COMPLETE INABILITY to PERCEIVE PAIN
case studies of people with congenital insensitivity to pain
- repeated injuries (ie. fractures, burns, oral wounds due to self-biting)
- infections from untreated wounds
- reduced life expectancy
pain is crucial for…
protecting against injuries
function of pain: neural alarm system
pain is our body’s way of telling us to PAY ATTENTION to something that could cause tissue injury/death
tells us to TAKE APPROPRIATE ACTION
neural alarm system: 4 functions
- captures attention, heightens arousal & awareness
- supersedes other goals
- drives action (avoidance, escape, fight or flight, solicitation of support)
- promotes recuperation & healing
adaptive value of belonging
recall that an ADAPTIVE TRAIT is a characteristic that helps organisms SURVIVE & REPRODUCE
ie. sharp claws, camouflage
in humans, SOCIAL AFFILIATION and group living
group living as a multi-purpose _______ tool
survival
- help hunting large game & foraging
- sharing food
- defensive vigilance and greater strength against predators & hostile outgroups
- help caring for offspring
- access to mates
social pain hypothesis
belonging to a group = matter of LIFE and DEATH
- those who stayed within group were more likely to survive and reproduce
- those who isolated themselves were at greater risk of harm/death
PHYSICAL PAIN MECHANISMS may have been ADAPTED to support affiliation
social pain may have evolved from…
physical pain
in order to promote group cohesion
pain could signal need to stay with the group, encouraging cooperation, reconciliation and survival
cyberball task exclusion neuroimaging evidence
cyberball exclusion related to increased activation in the dACC and AI
MAGNITUDE of neural activation correlates with both SELF-REPORTED FEELINGS of exclusion and OBSERVER-RATED social distress
neuroimaging evidence examples - increased dACC and/or AI activation in response to social pain…
- viewing photo of rejecting ex-partner
- viewing photo of deceased relative
- artwork conveying sense of loneliness & social disconnection
- viewing disapproving facial expressions (for those high in rejection sensitivity)
- negative social evaluations
evidence of shared sensitivity to physical and social pain
greater baseline sensitivity to PHYSICAL PAIN predicts greater sensitivity to SOCIAL EXCLUSION
genetic variant related to greater physical pain sensitivity (OPRM1 118G)
genetic variant related to greater physical pain sensitivity
OPRM1 118G
OPRM1 118G related to…
- greater trait rejection sensitivity
- greater self-reported subjective & neutral reactivity to Cyberball exclusion
- more sensitivity to hurtful partner behaviour (ie. being ignored, criticism)
factors that decrease social pain have what effects on physical pain?
parallel
ie. SOCIAL SUPPORT decreases physical pain (ie. during labour, thermal pain tasks in lab)
reflected in decreased signaling in dACC and AI in response to pain task
factors that increase social pain - this is a bit more ________
complicated
- cyberball exclusion has been shown to lead to pain hypersensitivity, with Ps who feel most excluded reporting highest pain ratings
- intentionally influcted pain hurts more than incidental pain
BUT
- social pain has also been linked to HYPOALGESIA (reduction in pain)
^ may depend on paradigm, context, motivational factors
- importantly, social & pain responses mirror each other (ie. analgesia coincides with emotional numbing)
analgesia coincides with…
emotional numbing
factors that decrease physical pain have parallel effects on social pain: tylenol…
Ps taking tylenol (vs placebo) report lower levels of hurt feelings in daily life
exhibit less dACC and AI activation during Cyberball exclusion
factors that increase physical pain have parallel effects on social pain: inflammatory challenge…
an inflammatory challenge (endotoxin injection) increases:
- interpersonal sensitivity
- neural reactivity
to social exclusion
factors that influence how intensely individuals react to social exclusion
- perceived availability of social support
- rejection sensitivity
- attachment style
all related to the subjective utility of social pain
individuals who spent more time with friends in adolescence and those with greater access to social support show…
less social pain neural activation in response to social exclusion
those high in rejection sensitivity and anxious attachment show…
enhanced reactivity to social exclusion
behavioural consequences of social pain: neuropsychological evidence
- in animals, dACC lesions lead to decreases in separation distress, deficits in social behaviour (maternal behaviour, social interest, proximity seeking)
- less research in humans - but case studies of cingulotomies (ACC lesions) suggest social disinhibition, reduced concerns about opinions of others, decreased self-consciousness
experimental evidence that social pain drives affiliative behaviour examples
- increased desire to work with others on task
- increasing effort on subsequent group task
- more likely to sign up for a “friend matchmaking service”
- provide more positive evaluations & allocate monetary rewards to a novel partner
- pay more attention to social information (social monitoring)
^ ie. selective memory for explicitly social events
behavioural consequences of affiliation behaviours: caveats
- likely to engage in affiliative behaviour only to extent to which we see target as VIABLE SOURCE of social connection
- those who are PARTICULARLY FEARFUL of negative social evaluation are LESS LIKELY to affiliate after rejection
- after rejection, tend to direct affiliative efforts TOWARDS NOVEL PARTNERS but not those responsible for the rejection
^ may DEROGATE rejectors
- like physical pan, social pain has been shown to LEAD TO AGGRESSION (fight) responses
^ aggressive response may be particularly likely when defensive distance is low
to sum up
- pain involves sensory, affective, motivational components
- plays important function in protecting homeostatic balance and ensuring survival
- stimuli/conditions other than physical injury may engage physical pain systems to extent that they threaten homeostasis and survival prospects
ie. pain may be a more general signal that “all is not well”
^ best documented example of this is social loss & rejection
