Chapter 7: The Feeling Mind: Emotion and Motivation

Emotion - brief combination of physical sensations (rapid heartbeat, conscious, subjective feelings etc)

Emotions - spontaneous, automatic responses to our ongoing perceptions and thoughts

Word emotion - derived from the Latin word meaning “to move”

We express emotions through - facial expression, body language, gestures, tone of voice

Psychologists - debate if emotions are discrete stand alone or points on a continuum

Discrete approach - argue there are core universal emotions - each has distinct emotional expressions

Continuum approach - argue emotions as existing along continuous dimensions

Circumplex theory of emotion - argues that all emotions can be placed along two orthogonal dimensions: arousal and valence

Some emotions are closer related to each other than others and might blend together

Motivation - a process that arouses, maintains, and guides behaviour toward a goal

Emotional behaviour - Charles Darwin - concluded that all primates form facial expressions using the same muscles - gained from evolution

Core emotional expressions - anger, sadness, happiness, fear, disgust, etc - identified correctly by most people

A major advantage provided by emotion is the ability to produce arousal

Yerkes-Dodson law - the ideal amount of arousal interacts with the complexity of a task

Simple tasks - greater arousal leads to greater performance

Complex tasks - arousal levels that are too high can begin to interfere with performance

• “Choking” or performing badly because of too much arousal

We can learn more about emotion - studying people whose emotional lives have been affected by brain damage

Antonio Damasio - hypothesized that emotions provide a bridge to past experiences - used to set priorities such as approach and avoidance

Researchers believe emotion expressions evolved through a two stage-process

• Stage 1 - Expressions served an adaptive physiological function

• Stage 2 - Expressions that originally served physiological functions - serve communicative functions

Benefit of having emotions is our ability to enjoy the arts - visual, song, dance etc

Physical sensations and subjective feelings might relate to one another

The James-Lange Theory of Emotion - the individual perceives a stimulus - that person experiences a physiological response

We might be able to influence our subjective feelings by changing our physical sensations

• Ex. modelling happiness can make us happy

Walter Cannon - disagreed with the James-Lange theory and proposed his own theory

Cannon-Bard theory - proposes that physical sensations and subjective feeling occur simultaneously and independently

Ex. Fear would go from the thalamus - amygdala - and occurs at the same time as physiological arousal - generated by fight or flight response

Schachter-Singer Two-Factor Theory - of emotion that adds an intermediate step between physical sensations and subjective feelings

Emotional arousal signals - conscious, cognitive appraisal of our circumstances - then we identify our emotion

Schachter and Singer - 1962 - injected volunteers with epinephrine - caused high level of arousal - told they were getting a vitamin injection - witnessed a second volunteer - an actor for the experiment - act either happy or angry - the participants felt happier or more negative depending on how the actor was behaving

People who have just exercised (producing physiological arousal) more likely to be angry or sexually aroused when exposed to relevant stimuli

Somatovisceral afference model of emotion (SAME) - begins with a recognition that physical responses to a stimulus can range from quite specific to quite general

Ex. Physical sensations associated with disgust can be more precise than the physical sensations associated with pride

The initial degree of specificity of the physical response leads to different cognitive processing

The model - predicts that emotional responses range from immediate to delayed based on the amount of cognitive processing that is required

• Ex. fear occurs quickly, pride occurs slowly

Appraisal Theory - Interpretation is a continuous process rather than a single decision about a stimulus

Ex. Attention may be aroused by some change in the environment - if the appraisal of the stimulus determines it to be of no significance - arousal returns to baseline

Emotional responses - combine bottom-up processing - lower parts of the nervous system send "alerts" to the cerebral cortex

Top-down processing - cortical executive functions such as attention and appraisal modify the activity of the lower structures

The Autonomic Nervous System - controls activities of our glands and organs - participates in the general arousal associated with emotional states

Fight-or-flight response - caused by activity of the sympathetic division of the autonomic nervous system

Autonomic nervous system - under immediate control of the hypothalamus

Negative autonomic responses - stronger then positive autonomic responses

Fear - activates rapid heartbeat and sweaty palms - more dramatic reactions than feelings of happiness

The Hypothalamus - direct management role over the autonomic nervous system

Stimulating the hypothalamus in animals - can elicit behaviours such as sexual behaviours, eating, drinking etc

Renewed interest in the hypothalamus and its role in emotion - resulted from experiments using deep brain stimulation delivered through surgically implanted electrodes

These experiments relieved various conditions from obesity to depression

One patient experienced both the physical and subjective feelings normally associated with a panic attack - physical responses were expected but emotional responses were unexpected

In patients with high levels of aggression - deep brain stimulation of the posterior hypothalamus has led to dramatic decreases in reported aggression and rage

The posterior hypothalamus - believed to serve a central role in activating the subcortical emotional system of the brain

The Amygdala - identifies emotional stimuli and initiates responses to the perception of these stimuli

The amygdala's role - carried out through its participation in a circuit - includes frontal lobes of the cortex, the cingulate cortex, and the insula

The amygdala - forms a bridge between emotional stimuli and the appropriate responses

The amygdala - initiates responses - through its tight connections with the hypothalamus

• This affects autonomic, hormonal, and behavioural processes

When people view facial expressions portraying different emotional expressions - the amygdala - communicates with regions of the brain in response to each emotion

Ex. The perception of sad faces - increases amygdala connectivity with the dorsolateral prefrontal cortex (dIPFC)

Dorsolateral prefrontal cortex (dIPFC) - a region of the brain implicated in the reappraisal of sad events in order to minimize their emotional impact

Dynamic changes in amygdala connectivity in response to distinct emotional expressions - has correlations with cognitive and motor responses

Importance of the amygdala to emotion - resulted from an experiment conducted in 1939 - researchers removed both temporal lobes from rhesus monkeys

• They became tamer and had less intense emotions

• They allowed people to pick them up and stroke them

• They were oblivious to stimuli that would normally scare them

When the amygdala is damaged - animals have inappropriate reactions to danger

Rats - fail to learn to fear a tone or other stimulus that predicts the onset of electric shock

Rhesus monkeys show less restraint around unfamiliar monkeys - this could negatively impact them since they are in a species that enforces strict social hierarchies

Patient S.M. - experienced damage to both amygdalae because of a rare disease

Patient S.M. - can recognize the emotions of happiness, sadness, and disgust portrayed in photographs - she has selective difficulty identifying fear correctly

She has difficulty using information from the eye region of the face in judging emotion - when she was instructed to pay attention to eyes, her performance improved

Autism spectrum disorder - have a reluctance to make eye contact and have difficulty identifying other people's emotions (esp fear)

Consistent biological correlation with autism spectrum disorder - abnormal development of the amygdala

The amygdala participates in both the active exploration of the social environment and the interpretation of the results of that exploration

The Insula - found in the fold between the junction of the temporal lobes with the frontal and parietal lobes

The insula plays an important role in our feelings

Back of the insula - internal sensations - ex. pain and itch, and physical sensations caused by emotional feeligs - ex. blood pressure, breathlessness

Front of the insula - more global feelings - a strong reaction to disgust

The Cingulate Cortex - serves as a major gateway between the amygdala and other subcortical structures and the frontal areas of the cortex

The cingulate cortex processes - the emotional quality of both physical and social pain

The cingulate cortex - forms circuits with the frontal cortex, the amygdala, and other subcortical structures involved with emotional processing

The basal ganglia - part of the brain's voluntary movement systems - help coordinate movement in response to assessments of emotion

The anterior cingulate cortex along and dorsomedial prefrontal cortex - contribute to the more conscious appraisal of threat

Worrying and catastrophizing by anxious people - involves exaggerated appraisals of threat - has unsually high levels of activation

The Basal Ganglia - large, subcortical structures that participate in the generation of voluntary movement in response to emotional stimuli

Nucleus Accumbens - part of the basal ganglia - associated with pleasure and reward

The basal ganglia - show considerable activity in response to facial expressions of disgust

Huntington's disease - a disease that damage the basal ganglia - having difficulty recognizing recognizing facial expressions of disgust

Damage to the frontal lobes produces changes in emotional behaviour - a reduction in fear and anxiety - contributes to impulsive, risky behaviours

Unable to feel "gut feelings" - warnings in threatening situations - would impulsively continue their behaviour

The experience of different emotions produces different patterns of cortical activation

When people are asked to recall a specific event from their past - brain imaging scans identify distinct patterns of activity based on what emotion was felt

However, the same brain regions usually participate in more than one of these states

Humans express emotion with their entire bodies

• Ex. When threatened or scared - they cross their arms and hunch forward

Humans rely most heavily on the face for expressing emotion

Facial expressions - influenced by the way the brain controls the tiny muscles of our faces

Muscles receive input from the motor areas of the cerebral cortex - control voluntary movement - from subcortical areas + basal ganglia

The cortical input - allows us to voluntarily "smile" for the camera

The subcortical input - responsible for more spontaneous expressions of emotion (laughing at a joke)

It is possible to lose one type of input without affecting the other

Ex. A person with issues with their motor cortex - able to smile spontaneously but can’t voluntarily smile

Ex. People with Parkinson's disease - unable to smile spontaneously but can voluntarily smile

Parkinson's disease - damages the subcortical emotional pathways

Darwin - believed that human emotional expression had been shaped through evolution

Supported by - basic emotion expressions appear to be universally recognized, emotional expression is shown by young children

Infants' social smiles - emerge near the same age (around 3 months)

Identical twins are more similar than fraternal twins in the ages at which they first show fear of strangers

Children raised in diverse cultures - similar distress at being separated from their mothers

Developmental timelines for emotional behaviour are also characteristic of nonhuman primate species

Rhesus monkeys - raised in isolation - had typical fear responses to monkeys engaging in threatening behaviours - same as those in normal social conditions

Universality of words for different emotional states - evidence of emotion's common biological source

Words for emotions - similar in a sample of 60 of the world's languages

The Japanese term ijirashi - a feeling that occurs when we see another person overcoming an obstacle

Significant individual differences in emotional expressiveness

• Ex. Children have different reactions to strong odours - ranging from strong to ignoring it

Children who are highly responsive to stimuli - often develop into anxious adults

Children who are oblivious to stimulation - may develop into fearless risk takers

Insensitivity to social signals produced by others - may lead to antisocial behaviour

Psychopaths incarcerated for murder - reduced reactions most situations 

Two major strategies for emotion regulation: suppression and cognitive reappraisal (modifying the meaningfulness of an event)

The ability to suppress emotional expression - can be learned

• Ex. Medical and military personnel

Many cultures have display norms that specify when, where, and how a person should suppress emotion

• Ex. Not common to show strong emotions in Japanese culture
  

Reappraisal as a strategy for regulating emotion involves thinking differently about the stimulus 

People who use the reappraisal strategy more than the suppression strategy experience less depression and higher life satisfaction

Human adults - quite accurate in their ability to read emotions

Twin studies - individual differences in the ability to read emotional expression are heavily influenced by genetics

Emotional intelligence - Our abilities to identify, use, understand, and manage emotions

Individual differences in emotional intelligence - predict the success of work and personal relationships

Multi-Health Systems (MHS) Assessments - numerous scientifically validated measures of emotional assessment

Ex. Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT)

A person's ability to read others' emotional expressions - can be reduced by certain psychological disorders

Individuals with schizophrenia and bipolar disorder - struggle with distinguish among facial expressions

People with Autism and antisocial personality disorder - specific difficulties recognizing expressions of fear

Increase in international students in Canada - many still follow the norms from their home country - this can affect their transition to university 

Juries are made up of human beings - who detect deception in face-to-face - not perfectly accurate 

Research indicates - functional magnetic resonance imaging (fMRI) techniques can be used to distinguish truth-telling from lying - some researchers say that you can beat it using “mental countermeasures”

Guilty Knowledge Test - used to assess deception - participants' brains showed significantly different activation lying (red areas) vs being truthful (blue areas)

Lying can be found out through - inappropriate smiling, nervous laughter, avoiding eye contact, hesitating etc

People telling the truth add 20 to 30 percent more detail to a story 

Reliable way to identify lying - ask people to tell their story backward in time - people conducting a false story struggle since it overwhelms their memory

Animals - limited time and resources - state of arousal is expensive in terms of the energy it requires

Motivational systems allow an animal to be aroused only when necessary - reduce arousal after a solution is found

Preventing the waste of precious energy resources provides a significant survival advantage

Walter Cannon - Motivation is a process that maintains homeostasis

Drive theories of motivation - “push theories” - drive is seen as pushing an organism toward a goal

Psychologists suggest - rewards or incentives have the capacity to pull an organism in a particular direction

Incentive theories - Incentives or rewards may be intrinsic or extrinsic

Intrinsic rewards are internal - Ex. Enjoyment of the task or feelings of accomplishment when a goal is met

Extrinsic rewards are external - Ex. Such as money for completing work or praise from a parent

Extrinsic rewards can have negative effects on intrinsic motivation - shifting motivation

Motives - Some are approached from a mostly biological perspective (hunger) and others are approached from a more sociocultural perspective (affiliation)

People value affiliation - a lack of connection with others can have devastating effects

Solitary confinement - viewed as one of the worst punishments humans inflict on one another

The effects of social isolation - can be as detrimental high blood pressure, lack of exercise, obesity, or smoking - can also cause extreme hostility

Compared to other species - humans require the greatest amount of parenting to survive to adulthood and reproduce

Our ancestors - formed hunter-gatherer groups - the cooperative sharing of responsibilities enhanced the survival of all group members

Individuals differ in the amount of social connection they desire - some people need more, others need less

Twin studies show that this set point is influenced by our genetics

Knowing one identical twin's need for affiliation helps predict the other twin's need

Stanley Schachter - found that people expecting to be given a painful electric shock were more likely to seek the company of others

Achievement motivation - the desire to excel or outperform others - individual motivation to push themselves

A trait - stable characteristic that shows relatively little variation over time - traits interact with situations

A person's trait achievement motivation interacts with the opportunities present in the environment

High-achieving people - prepared to avoid or postpone fun to meet their achievement goals

Low-achieving people - prioritize fun alternatives and inhibited the achievement alternatives

Carol Dweck - argues that achievement motivation is influenced by people's beliefs about their own abilities

Growth mindset - belief that capacities can be developed - able to grow

Fixed mindset - belief that capacities do not change - unable to grow

Higher achievers - thrive on competition

Lower achievers - thrive on fun and relaxing aspects of a task

Hunger is a complex motive - the reduction of hunger through eating is more heavily influenced by emotion, learning, and culture

We respond to combinations of external and internal cues that make us feel hungry

External cues for hunger - time of day, the sights and smells of favourite foods etc - may encourage us to eat when our bodies do not need nutrients or to eat more food than we require

Internal cues for hunger - when our bodies are genuinely short on nutrients

Washburn swallowed a balloon attached to an air pump - since Walter Cannon believed that stomach contractions were an important to detect hunger

The balloon allowed Washburn's stomach contractions to be monitored while Washburn indicated feelings of hunger by pushing a telegraph key

An important hunger cue is a low level of circulating sugars (glucose) concentrations in the blood are highest just following a meal - as the levels drop - person gets hungry again

Glucose levels are intimately connected with levels of the hormone insulin

Insulin - moves circulating glucose from the blood into cells awaiting nutrients

Glucose and insulin levels are positively correlated - high levels after just eating, low levels to signal need for more food

Diabetes - insufficient insulin activity - glucose is unable to move out of the blood into the cells that need nutrients

Hunger results whenever cells are unable to obtain the glucose they require or as a response to low levels of stored facts

If you maintain a healthy weight - carrying sufficient body fat to survive five to six weeks of total starvation

The body monitors fat stores - assessing levels of the hormone leptin

Leptin - Greek word leptos, or "thin," is produced and secreted by fat cells

Fat stores and leptin levels are positively correlated - leptin levels provide a measure for the amount of fat that has been stored

When fat stores and leptin levels are low - brain areas that include the lateral hypothalamus (LH) initiate feeding

Stimulation of the LH typically initiates immediate eating

Low fat stores and leptin levels - activate the parasympathetic division of the autonomic nervous system - enhancing the body's ability to digest and store nutrients

Feeding is stimulated by two additional hormones - Ghrelin and orexins

Ghrelin - released by the pancreas and lining of the stomach - contributes to the rewarding aspects of feeding

Orexins - produced in the LH - contributes to feeding - negatively correlated with blood glucose levels - also participate in sleep - suggesting feeding, activity levels, sleep - linked

We reach satiety (fullness) - long before the nutrients we have eaten can make their way to waiting cells

Ventromedial hypothalamus (VMH) participates in sensing satiety - lesions of the VMH (boosts in insulin production) produce a syndrome of large weight gains

Satiety - releases gut hormone cholecystokinin (CCK) by the digestive system

CCK not only acts in the digestive tract but also serves as a chemical messenger in the brain

CCK limits meals by activating pathways that connect the hindbrain to the digestive system

Our ancestors were much more likely to starve than to be troubled by having too much food - they reproduced to exhibit characteristics for surviving famine

BMI - height-to-weight ratio computed - dividing weight in kilograms by the square of height in metres - 25 - 30 overweight, above 30 - obese

Population-level works well - individual can be inaccurate

Obesity rates have approximately doubled since the 1970s - factors sugary drinks, reduced sleep etc

Genes - influence factors such as set point and rate of metabolism

Genes interact with the bacteria populations in the gut - differ between obese and lean humans

Manipulations of bacteria through antibiotics and probiotics - been used to promote weight gain in livestock for decades

Transplantation of gut bacteria from obese to lean animals led to obesity

The bacteria found in the obese animals appears to be more efficient at harvesting energy from the animal's diet

To avoid starvation - developed strong preferences for calorie-rich foods containing sugars and fats - we have these preferences to this day

Social factors - keeping track of size in social circles

Risks of obesity - Obese spouse raises the risk by 37%, Obese friends raises your risk by 57%

Calorie-reducing diets work - if dieter returns to old habits - weight quickly regained

Surgical methods or liposuction - can still gain weight afterwards

Stomach stapling and gastric bypass procedures - Reduce the amount of nutrients that can be consumed or processed

Eating disorders in Canada is between 2 and 3 percent of the population

Eds - more women have them - there was an increase for men having them as well - many queer men have eating disorder

Anorexia nervosa - characterized by the maintenance of unusually low body weight, an intense fear of gaining weight, and a distorted view of the body as obese

Anorexia - means "loss of appetite"

Anorexia has two patterns of behaviour - restricting type and bingeing-purging type

• In the restricting type - people simply eat little food

In the bingeing-purging type - people combine restricted eating most of the time with behaviours associated with bulimia nervosa

Affects about 0.4 percent of females and perhaps 0.04 percent of males

It is estimated that 10 percent of individuals with anorexia will die within ten years of onset

Bulimia nervosa - characterized by cycles of binge eating - large amounts of food are consumed and purging through the use of vomiting or laxatives

Bingeing - often followed by feelings of depression, disgust, and a sense of lost control

Bulimia affects 1.5 percent of women and between 0.15 percent and 0.5 percent of men

Binge-eating disorder - eating abnormally large amounts of food at one sitting and feeling that eating is out of control

Binge-eating disorder affects 1.6 percent of adult females and 0.8 percent of adult males meet the criteria for this disorder

Cultural attitudes toward beauty - significant role in the development of eating disorders

Becker and her colleagues - observing eating patterns in the Fiji Islands - access to American tv 1995 - dieting was unknown in the culture until they saw American beauty standards

People might have a genetic vulnerability to disordered eating in general - not for a specific type of eating disorder

Once an eating disorder is established - biological factors contribute to maintaining abnormal patterns of eating

Anorexia nervosa regain normal weight - some still show evidence of elevated levels of hormones that typically raise metabolism and inhibit feeding

Treating anorexia nervosa - keeping the person alive (monitoring food intake), cbt can also be effective

The first priority is keeping the person alive, and this effort typically involves hospitalization and careful monitoring of food intake

No known medications are effective in treating anorexia

50% of people with anorexia - full recovery - nearly 20% fail to respond

The binge-purge cycling of bulimia involves processes similar to those of addiction

Treating bulimia and binge-eating disorder - Antidepressant medications (selective serotonin reuptake inhibitors (SSRIs)) - usually effective with cbt

The females of most mammalian species undergo estrus

Estrus - a period of hours or days during which the female is receptive or willing to have sex

Hormone levels and sexual behaviour are tightly linked

The sexual behaviour of estrus and nonestrus species is quite different

Human females show receptivity throughout the menstrual cycle

Women who are not using chemical contraception report feeling more interest in sex around the time of ovulation

Female sexual interest has been viewed as correlated with levels of testosterone

Women typically produce - one-tenth the amount of testosterone that men produce

Women's adrenal glands produce up to half of their male hormones - ovaries produce the rest

Sex hormones released by the ovaries - responsible for female sexual desire

Estrogen - the primary female sex hormone - many types - estradiol being the one that is most important in females of reproductive age

Progesterone is another sex hormone - important role in the menstrual cycle and pregnancy - lower levels - higher levels of general sexual desire

Estrogen levels tend to peak right around ovulation

Progesterone levels rise toward the end of the menstrual cycle

Testosterone is clearly correlated with sexual interest in males

Below-normal levels of testosterone - castration - low sexual desire and activity

Male testosterone levels fluctuate over the course of a day

Numerous studies have shown that competition increases male testosterone levels

Testosterone continues to rise among the winners and temporarily decreases among the losers

Male testosterone levels are also influenced by relationship status

Long-term relationships - lower testosterone levels

These changes might reflect a feedback loop in which reproductive success signals a decrease in testosterone

Higher testosterone levels - increased competitiveness and sexual desire

Reproductive goals are achieved - male testosterone levels drop again

Romantic love - associated with oxytocin and vasopressin

Both hormones are active in the brain - vasopressin is expressed more by males - oxytocin is expressed more by females

In both sexes - oxytocin enhances bonding

Women release oxytocin during breastfeeding

Oxytocin - released at orgasm in both sexes

Since women have higher levels of oxytocin - women are more likely than men to equate sexual desire with feelings of romantic love

Importance of oxytocin and vasopressin to bonding - study of two types of rodents - the prairie vole and the montane vole

Prairie voles are monogamous for life and share parenting duties - prefer to be with their partners (higher levels of hormones)

Montane voles are not monogamous and don’t share parenting duties - prefer to be alone (lower levels of hormones)

Sexual desire and romantic love (typically grouped together) - these two functions represent distinct biological and emotional states

Neurochemical level - sexual desire or lust is driven primarily by levels of testosterone for males and levels of estrogens for females - bonding we associate with romantic love - oxytocin

Activation of the posterior part of the insula - associated with lust

Activation of the anterior part of the insula - associated with love

Humans show wide variations in sexual and emotional satisfaction within relationships

In North America - more committed relationships produce the highest levels of both sexual and emotional satisfaction - one night stands are the opposite

Gay and bisexual men - higher amounts of sexual and emotional satisfaction from casual sex contexts than heterosexual individuals

Individual differences in human sexuality are substantial and normal

A person's sexual orientation can incorporate behaviour, attraction, and identity - often congruent but not always

In 2014 - 1.7 percent of Canadian adults - gay or lesbian - 1.3 percent identified as bisexual

Sexual orientation in males tends to be stable - less fluid

Females experience more fluidity in their sexual attractions over time

Genes appear to influence sexual orientation

Twin reports about sexual orientation - somewhat heritable for both males (0.34 0.39) and females (0.18-0.19)

Women - condition known as congenital adrenal hyperplasia (CAH) - high prenatal levels of male hormones - born with masculinized external genitalia - more likely to engage in lesbian or bisexual behaviour - most women with it are heterosexual

Birth order influences the odds that a man is homosexual - men who have older brothers from the same mother are more likely to be gay - mother’s immune response is stronger after carrying all male fetuses

Small cluster of neurons located in the hypothalamus known as the interstitial nucleus of the anterior hypothalamus - four separate nuclei in INAH

INAH-2 and INAH-3 - larger in males than in females

Simon LeVay asked whether INAH-3 might be different in heterosexual and gay males - concluding that NAH-3 in gay men was two to three times smaller than in heterosexual men

Approach and Avoidance - situations that involve positive outcomes while avoiding them provide negative outcomes

Model for prioritizing motives was contributed by - Abraham Maslow in 1943

Maslow influenced a field of psychology - humanistic psychology

Motivation as a hierarchy of needs - lower levels must be satisfied before the individual can pursue higher-level needs - pyramid

Lowest level of the pyramid - physiological needs, including food, water, and shelter - basic needs must be met daily

Once physiological needs are met - we turn our attention to safety then belongingness

After meeting basic needs - we seek esteem, or respect from others

Self-actualization - desire to fully meet their potential

Emotions involve both physiological changes and subjective feelings - will also result in a prototypical expression

Some emotional reactions occur incredibly rapidly - others may depend on higher level appraisals of the situation

Motivation is more direct in the behaviour that it prompts - sometimes motivations may conflict with one another