Webquiz Emotional Behaviour

Psychologists typically define emotion in terms of the following three components: a. feelings, actions, and emotions. b. actions, cognitions, and emotions. c. cognitions, feelings, and actions. d. cognitions, actions, and emotions. Which evidence is most detrimental to the James-Lange theory? a. Patients with pure autonomic failure experience emotions. 2 b. Some people feel stronger emotions than others do. c. Sometimes people have trouble reporting what they are feeling. d. Changes in arousal are reported as changes in emotions. Which of the following is characterized by extreme sympathetic nervous system arousal? a. pure autonomic failure 3 b. panic disorder c. prosopagnosia d. locked-in syndrome 4 The Behavioral Activation System is associated with: a. maximum arousal, increased fear, and negative mood. b. low to moderate arousal, tendency to approach new objects, and pleasant mood. c. increased attention and arousal, decreased action, and fear or disgust. d. lack of arousal, decreased action, and pleasant mood. Impulsive behavior and poor decisions are common symptoms of: a. temporal damage. 5 b. occipital damage. c. parietal damage. d. prefrontal damage. A study of conduct disorders and aggressive behavior in adopted children supported the generalization that: a. criminals are made, not born. 6 b. criminals are born, not made. c. behaviors depend on a combination of genes and environment, not on either one alone. d. spankings and other physical punishments increase aggressive behavior rather than decrease it. The concentration of 5-HIAA in the blood, cerebrospinal fluid, or urine provides an estimate of: a. serotonin stores. 7 b. serotonin turnover. c. dopamine turnover. d. dopamine stores. One explanation for why having genes for low serotonin turnover may be beneficial in monkeys is that: a. an intermediate level of aggression prevents them from being too fearful or too violent. 8 b. a low level of aggression is best for survival. c. serotonin causes cancer. d. most highly aggressive monkeys get everything they want. Suppose you want to DECREASE the aggressive behavior of an animal, and all you are allowed to use is a nutritional supplement. Which might be a good choice? a. decrease lecithin 9 b. decrease thiamine c. increase phenylalanine d. increase tryptophan A startle reflex occurs in response to: a. depression. 10 b. anxiety. c. grief. d. an unexpected loud noise. 11 The ________ receives axons from the amygdala and sends axons to the pons to control the startle response. a. caudate nucleus b. midbrain c. cingulate gyrus d. pineal gland The enhanced startle reflex in the presence of a feared stimulus would be reduced by all of the following methods EXCEPT: a. opening chloride channels. 12 b. damaging the amygdala. c. stimulating CCK receptors in the amygdala. d. stimulating GABA-A receptors. A combination of benzodiazepines and alcohol should be avoided because: a. they react with each other chemically to form a new compound. 13 b. each magnifies the effects of the other. c. the combination produces excessive anxiety. d. each cancels the effects of the other. 14 Stress activates two systems. One is the: a. autonomic nervous system which secretes the hormone ACTH. b. HPA axis, which becomes increasingly important with prolonged stressors. c. autonomic nervous system which secretes the hormone cortisol. d. HPA axis, which reacts more quickly than the other. Which type of leukocyte attaches to an intruder and produces a specific antibody to attack the intruder's antigen? a. B cell 15 b. macrophage c. A cell d. T cell One of the main differences between natural killer cells and T cells is that natural killer cells: a. are cancer cells. 16 b. attack normal tissue. c. attack several kinds of intruders. d. are more specific in their targets. The classical illness behaviors such as fever, sleepiness, and lack of appetite are caused by: a. decreased brain activity. 17 b. toxins released by pathogens. c. antibody production. d. the immune system's production of cytokines. Aged people with the highest cortisol levels tend to be those with the: a. greatest memory problems. 18 b. largest hippocampus. c. greatest amount of social support. d. most cellulose in the diet. Among identical twins, if one of them has PTSD, then the other is also likely to have a: a. large hippocampus. 19 b. small hippocampus. c. small adrenal gland. d. large adrenal gland. The ________, which is so important for emotional processing, is essential for the extreme emotional impact that produces PTSD. a. hippocampus 20 b. cingulate c. amygdala d. fornix 1. The parasympathetic nervous system is most active during which of the following? A. Fight-or-flight activities B. Digesting food C. Intense emotions D. Conversations 2. According to the James-Lange theory, feedback from the body’s actions is responsible for which aspect of emotion? A. Appraisal B. Feeling C. Coping D. Compassion 3. When researchers looked for brain areas associated with particular emotions, what did they find? A. Each emotion is centered in a different brain area. B. Anger is easy to localize in one brain area, but other emotions are not. C. Happiness depends on one brain area, but other emotions do not. D. No brain area is responsible for one and only one emotion. 4. Several lines of evidence argue against the idea that facial expressions demonstrate the existence of six basic emotions. Which of the following is NOT one of those lines of evidence? A. Asking people to match six faces to six labels interferes with accuracy. B. People’s guesses about someone’s emotion do not always match what the person reported. C. Depending on someone’s posture, a given facial expression can have several meanings. D. People can recognize expressions from their own culture better than those of others. 5. Which brain area is associated with the behavioral activation system and a tendency to approach? A. The right hemisphere B. The left hemisphere C. The amygdala D. The hippocampus 6. Damage to the ventromedial prefrontal cortex increases which tendency in making decisions? A. Greater conformity to the majority opinion B. Longer delays in making decisions C. More choices based on emotional feelings D. More utilitarian choices 1. Heritability of a tendency toward antisocial behavior is lowest for which of the following? A. Males B. Females C. People in impoverished neighborhoods D. People in middle-class neighborhoods 2. How does the gene for the less active form of the enzyme MAOA affect the probability for aggressive behavior? A. Increased probability, regardless of environment B. Decreased probability, regardless of environment C. Increased probability for someone who was abused in childhood D. Increased probability for someone who lived in a middle-class neighbourhood 3. Aggressive behavior correlates with low turnover of which neurotransmitter? A. Serotonin B. Norepinephrine C. Dopamine D. Glutamate 4. Which of the following hormones tends to inhibit aggressive behavior? A. Cortisol B. Testosterone C. Estradiol D. Insulin 5. Why do we know more about the brain mechanisms of fear and anxiety than we do about other emotions? A. Clinical psychologists have greater interest in anxiety than in other emotions. B. Anxiety depends on brain areas that are easier to reach surgically. C. Unlike other emotions, anxiety depends on only a single neurotransmitter. D. Researchers can more satisfactorily measure anxiety than other emotions in laboratory animals. 6. After damage to the amygdala, what happens to the startle reflex? A. It becomes stronger than before. B. It becomes weaker than before. C. It disappears altogether. D. It becomes more consistent from one time or situation to another. 7. Suppose a researcher wants to determine whether someone is afraid of cats. Of the following, which would be the most reasonable approach? A. Present a photo of a cat and see whether it elicits a startle reflex. B. Present a photo of a cat and then a loud sound. See whether the photo enhances the usual startle reflex. C. Present a loud sound and then show a photo of a cat. See whether the photo calms the person after the startle reflex. D. Present a loud sound to both a person and a cat and see which one shows the greater startle reflex. 8. Research on the amygdala supports which of these psychological conclusions? A. People who experience great fear also tend to experience a great amount of anger. B. Sigmund Freud’s insights provide the best method for treating anxiety disorders. C. What we call fear is a combination of several components, not an indivisible entity. D. People have six basic types of emotion. 9. What role does the bed nucleus of the stria terminalis play in fear or anxiety? A. It affects fear of the environment in general. B. It mediates reappraisal that reduces the response of the amygdala. C. It relays information from the amygdala to the midbrain. D. It is responsible for the extinction of learned fears. 10. The amygdala responds most strongly to which type of facial expressions? A. Expressions by infants and children B. Expressions that require some effort to understand C. Expressions that are directed away from the viewer D. Expressions of sadness 11. What, if anything, can we predict from measuring the strength of amygdala response to frightening stimuli or faces showing fear? A. We can predict changes in personality, as measured by questionnaires. B. We can predict probability of criminal behavior. C. We can predict probability of strong emotional responses to stressful experiences. D. We cannot predict anything. 12. After Urbach-Wiethe disease damaged their amygdala, two people showed no fear under most circumstances. Which of the following did, nevertheless, evoke fear? A. Breathing concentrated carbon dioxide B. Holding a snake C. Standing too close to a stranger D. Watching a horror movie 13. Which of the following types of people would be more likely than average to develop PTSD? A. People who have suffered damage to the amygdala B. People with higher than average levels of serotonin turnover C. People with lower than average levels of cortisol D. People with a smaller than average hippocampus 14. What do benzodiazepines do? A. They decrease cortisol secretion. B. They increase secretion of orexin. C. They facilitate GABA synapses. D. They inhibit serotonin synapses. 1. Which hormone does the alarm stage release, but the resistance stage does not? A. Cortisol B. ACTH C. Epinephrine D. Testosterone 2. How do the functions of the HPA axis compare to those of the sympathetic nervous system? A. The sympathetic nervous system readies the body for brief, vigorous action, and the HPA axis controls digestion and other vegetative activities. B. The sympathetic nervous system activates the brain, and the HPA axis activates the rest of the body. C. The sympathetic nervous system readies the body for brief, vigorous action, and the HPA axis prepares the body for prolonged coping with a persistent stressor. D. The sympathetic nervous system is active during a stressful situation, and the HPA axis becomes active at the end of the stressful situation. 3. How does McEwen’s definition of stress differ from Selye’s? A. Selye’s definition applied only to severe stress. B. Selye’s definition applied equally to favorable or unfavourable events. C. Selye’s definition applied only to laboratory animals. D. Selye’s definition applied only to humans. 4. Which cells of the immune system secrete antibodies? A. Natural killer cells only B. T cells only C. B cells only D. Natural killer cells, T cells, and B cells equally 5. Why do nearly all infections produce similar symptoms, such as fever, sleepiness, and loss of energy? A. Every infection damages the body’s ability to maintain body temperature and overall activity. B. “Sickness behaviors” are an effective way for a sick person to gain sympathy and help. C. Infectious particles clog the arteries, making it difficult for other chemicals to reach their targets. D. The immune system sends prostaglandins to the brain, where they stimulate the hypothalamus to produce these effects. 6. What are the effects of stress on the immune system? A. All stressful experiences impair the immune system. B. Brief stress activates the immune system, but prolonged stress weakens it. C. Brief stress weakens the immune system, but prolonged stress strengthens it. D. All stressful experiences strengthen the immune system. 7. Prolonged stress is known to damage which brain area? A. The visual cortex B. The hippocampus C. The cerebellum D. The corpus callosum 8. Which of these increases resilience? A. Unpredictability of events B. Social support C. Previous severely stressful experiences D. Breathing carbon dioxide People with pure autonomic failure do not react to events with changes in heart rate or other automatic functions. They report still having emotional experiences but they do not feel them as strongly. What is the relevance of pure autonomic failure to the study of emotions? They got people to smile by telling them to hold a pen between their teeth. They got people to frown by attaching golf tees to their eyebrows and then telling them to keep the two tees touching each other. How did reserchers get people to smile or frown without using those words? Emotion is a socially constructed category that people find useful, but it does not correspond to any category that exists in nature. According to Lisa Barrett Feldman, why is it difficult to develop a scientific consensus about any theory of emotions? Given a photo of a spontaneous facial expression, people usually see more than one emotion and often don't see the emotion described by the person whose face was shown. Also, in everyday life we identify someone's emotion by a combination of cues, including posture, context, gestures, and tone of voice. What evidence challenges the idea that we identify people's emotions by their facial expressions? After brain damage that impairs emotion, people make impulsive decisions, evidently because they do not quickly imagine how bad a poor decision might make them feel. If brain damage impairs someone's emotions, what happens to the person's decision making? Aggression depends on the ratio of testosterone to cortisol, not to testosterone alone. What is one reason why testosterone levels correlate only weakly with human aggression levels? We can measure the concentration of 5-HIAA, a serotonin metabolite, in the cerebrospinal fluid or other body fluid. The more 5-HIAA, the more serotonin has been released and presumably resynthesized. If we want to know how much serotonin the brain has been releasing, what should we measure ? Although most monkeys with low serotonin turnover die young, many of the survivors achieve a dominant status that enables them to get more of the food and to reproduce more frequently. Monkeys with high serotonin turnover survive, but at the cost of accepting a low status. Given that monkeys with low serotonin turnover pick many fights and in most cases die young, what keeps natural selection from eliminating the genes for low serotonin turnover? Overall people with genes for high or low production of MAOa, do not differ significantly in their probability of antisocial behaviour. However, among those who suffered serious maltreatment during childhood, people with lower levels of the enzyme showed higher rates of antisocial behaviour. What relationship did Casio Ethan al. (2002) report between the enzyme MAOa and antisocial behaviour? Loud noises activate a path from the cochlea to cells in the pond that trigger a tending of neck muscles. What brain mechanism enables the startle reflex to be so fast? Present the stimulus before giving a loud noise. If the stimulus increases the startle reflex beyond its usual level, then the stimulus producedfear. How could a researcher use the startle reflex to determine whether some stimulus caused fear? The amygdala responds more strongly to a fearful face directed at the viewer, rather than a similar face looking to the side. People usually find it easier to understand a fearful face looking to the side. What evidence indicates the amygdala activity corresponds to the effort needed for interpreting emotional information? People with a highly reactive amygdala are likely to report many negative emotional experiences during a day, to show strong responses to stressful experiences, and to favour strong reliance on military and police power. What can we predict about someone if we know the strength of that person's amygdala responses to upsetting pictures or loud noises? They focus their vision on the nose and mouth. Expressions of fear depend almost entirely on the eyes. Why do people with Amygdala damage have trouble recognising expressions of fear? One the average, PTSD victims have a smaller than average hippocampus . For those who have a monozygotic twin, the twin also has a smaller than average hippocampus , even if he or she does not have PTSD. What evidence indicates that a smaller than average hippocampus makes people more vulnerable to post traumatic stress disorder (PTSD). Benzodiazepines facilitate the effects of GABA, so a person without GABA would have no response to benzodiazepine. What would be the effect of benzodiazepines on someone who had no GABA? The reminding brings the representation of the learning into a labile state from which it can be reconsolidated or extinguished. Why is extinction more effective a few minutes after a brief reminder of the original learning? cholecystokinin, orexin A variety of studies indicate that anxiety is increased by the transmitters ____ and ____. the startle response. The common measure of fear or anxiety that is popular because it can be used with non-humans as well as humans is: Change where they focus their eyes People with amygdala damage have trouble identifying fear expressions. How could we improve their ability to recognize fear? sympathetic; parasympathetic The autonomic nervous system is divided into two parts; the ____ nervous system (which prepares the body for emergency action), and the ____ nervous system (which calms the body). low; low Depression is linked to ____ serotonin and aggressive behavior is linked to ____ serotonin. emotional The limbic system consists of structures that are believed to be important for which kind of responses? PTSD Experiencing nightmares about a traumatic event, avoiding reminders of it, and exaggerated startle response are symptoms of: True According to the James-Lange theory of emotion, we experience physiological changes first and then label these changes as an emotion. True The right hemisphere seems to be more responsive to emotional stimuli than the left hemisphere. amygdala Looking at a picture of people showing emotional expressions causes the greatest activity in the: increased attention and arousal, decreased action, and fear or disgust. The Behavioral Inhibition System is associated with: True Emotions are important for decision making. we could not predict how and when your behavior would change. If a treatment suddenly lowered your serotonin level: emergencies; relaxation The sympathetic nervous system is to ____ as the parasympathetic nervous system is to ____. True Brief activation of the sympathetic nervous system can enhance activity of the immune system. boost the activity of the immune system. Occasional brief periods of stress: blocking CCK One could reduce anxiety by: anxious Startle responses are greater when a person is: limbic system. A group of forebrain structures that appear to be critical for emotion are known as the: brain areas associated with particular emotions vary considerably. A search for the happiness center in the brain is unlikely to be successful because: measures of sympathetic nervous system responses A scientist would be most likely to use which of the following when attempting to obtain an objective measure of emotion? benzodiazepines A person who has developed a tolerance to alcohol is likely to show a cross-tolerance to: chloride The GABA-A receptor complex controls the flow of which ion across the membrane? toward you, to the side Recognition of an angry expression is faster when the face is directed ____, and a fearful expression is faster if it is directed ____. funnier than if they were not forced to smile When people were forced to smile, by clenching a pen between their teeth, how did they rate a cartoon they were reading? Möbius syndrome Children with a rare condition called ____ are unable to move their facial muscles to make a smile. True People with damage to either the prefrontal cortex or the amygdala show difficulties processing emotional information. often make bad decisions Investigators have found that individuals who suffer prefrontal cortex damage: low serotonin turnover According to a number of animal studies, under which of the following conditions is the probability of violent behavior greatest? a. CCK; GABA Increased fear, anxiety, or panic is related to increased activity of ____ and decreased activity of ____. low to moderate arousal, tendency to approach new objects, and pleasant mood. The Behavioral Activation System is associated with: True The most commonly used anti-anxiety drugs are the benzodiazepines. prefrontal cortex Output from the amygdala to the ____ modifies approach and avoidance responses. True Psychologists typically define emotion in terms of three components. decreases anxiety A drug that facilitates transmission at GABA-A synapses has what effect on behavior? each magnifies the effects of the other. A combination of benzodiazepines and alcohol should be avoided because: sympathetic nervous system. The branch of the autonomic nervous system that is responsible for preparing the body for intense, vigorous, emergency activity is the: Emotions People are given moral dilemmas, such as whether it is all right to kill one person in order to save five others. The people most likely to make the "cold, calculating" decision that these acts are okay are people who have suffered brain damage that impairs which of these? focusing attention on emotional stimuli. Across studies involving amygdala damage, the general conclusion seems to be that the amygdala is important for: when emotional interpretation is unclear. Amygdala activation to angry and fearful expressions suggests that the amygdala responds most strongly: Epinephrine, cortisol, and aldosterone. Name three hormones that the adrenal glands release in the alarm stage of the body's response to stress? Leukocytes, which are part of the immune system, release cytokines. What kind of cell releases cytokines? Prostaglandins stimulate the hypothalamus to produce fever, decreased hunger, decreased sex drive, and increased sleepiness. What changes do prostaglandins stimulate? Stress increases release of cytokines, which communicates with the hypothalamus via the vagus nerve and prostaglandins. The hypothalamus reacts with the same responses it uses to combat illness, such as inactivity and loss of appetite. How do the effects of stress mimic the effects of illness? Stress increases the release of cortisol, which enhances metabolic activity throughout the body. When neurons in the hippocampus have high metabolic activity, they become more vulnerable to damage by toxins or overstimulation. How does prolonged stress damage the hippocampus? When people consider a moral dilemma such as whether to push someone off a bridge to save five other people, which of the following correlates with a stronger tendency to agree to push the person? Weaker autonomic arousal What brain area is associated with the behavioral activation system and a tendency to approach? The left hemisphere. Why do nearly all infections produce similar symptoms, such as fever, sleepiness and loss of energy? The immune system sends prostaglandins to the brain, where they stimulate the hypothalamus to produce these effects. What brain mechanism enables the startle reflex to be so fast? Loud noises activate a path from the cochlea to cells in the pons that trigger a tensing of neck muscles. If brain damage impairs someone's emotions, what happens to the person's decision making? After brain damage that impairs emotions, people make impulsive decisions, evidently because they do not quickly imagine how bad a poor decision might make them feel. How does alcohol decrease anxiety? By facilitating the effects of GABA on certain receptors. True or False: Emotion is a socially constructed category that people find useful, but it does not correspond to any category that exists in nature True Which brain area most strongly inhibits or modifies the response of the amygdala to a potential threatening stimulus? The prefrontal cortex. Researchers had people smile by having them hold a pen between their teeth. They were also able to get people to frown by attaching golf tees to their eyebrows and then telling them to keep the two tees touching each other. What was the purpose of this activity? To demonstrate that engaging the facial muscles can induce the onset of certain types of emotions like happiness or anger. True or False: Aggressive behavior relates to both genetic and environmental influences. Several studies indicate that a gene decreasing the activity of monoamine oxidase A increases aggressive behavior mainly among people who had abusive experiences in childhood. True What evidence indicates that a smaller than average hippocampus makes people more vulnerable to PTSD? On average, PTSD victims have a smaller than average hippocampus. For those who have a monozygotic twin, the twin also has a smaller than average hippocampus, even if he or she does not have PTSD. People with amygdala damage have trouble recognizing expressions of fear. If you wanted to help such people recognize fear, which of the following should you ask them to change? The direction they focus their eyes. 00:00 01:27 This Day in History Upgrade to remove adverts Only US$2.99/month True or False: People with damage to the amygdala have trouble recognizing expressions of fear from others around them. True If we wanted to know how much serotonin the brain has been releasing, what should we measure? We can measure the concentration of 5-HIAA, a serotonin metabolite, in the cerebrospinal fluid or other body fluids. The more 5-HIAA, the more serotonin has been released and presumably resynthesized. How does cortisol help the body deal with stressful events? It increases blood sugar, providing more energy. Which if the following are three hormones that the adrenal glands release in the alarm stage of the body's response to stress? Epinephrine, Cortisol, and Aldosterone. True or False: Activity of the left hemisphere, especially its frontal and temporal lobes relates to the behavioral action system (BAS) which increases attention and arousal, inhibits actions and stimulates emotions such as fear and disgust. False Aggressive behavior correlates with high levels of testosterone and low levels of what? Cortisol True or False: Stress activates the sympathetic nervous system and more slowly activates the hypothalamus-pituitary-adrenal cortex axis. The adrenal cortex releases cortisol, which increases metabolism. True Prolonged stress is known to damage which brain area? The hippocampus. Why is the study of emotions related to our understanding of pure autonomic failure? Because people with pure autonomic failure do not react to events with changes in heart rate or other autonomic functions. They report having emotional experiences but they do not feel emotions as strongly. What is the contribution of the sympathetic nervous system to emotions? Sympathetic nervous system arousal is neither necessary nor sufficient for an emotional experience but it contributes to the feeling aspect of an emotion. The less active form of the enzyme MAOA correlates with an increased probability of antisocial behavior for what type of people, if any? Those with a history of childhood maltreatment What can we predict about someone if we know the strength of that person's amygdala response to upsetting pictures or loud noises? People with a highly reactive amygdala are likely to report many negative emotional experiences during a day, to show strong response to stressful experiences, and to favor strong reliance on military and police power. Suppose a researcher wants to determine whether someone is afraid of cats. Which of the following would be the most reasonable approach? Present a photo of a cat and then a loud sound. See whether the photo enhances the usual startle reflex. After damage to the amygdala, what happens to the startle reflex? It becomes more consistent from one time or situation to another. Which of the following causes a panic attack? Intense, unexplained arousal of the sympathetic nervous system. Researchers have found that activity in which part of the brain corresponds to the effort needed for interpreting emotional information? The amygdala tends to respond more strongly to a fearful face directed at the viewer, rather than a similar face looking to the side. Why do we know more about the brain mechanisms of fear and anxiety than we do about other emotions? Researchers can more satisfactorily measure anxiety than other emotions in laboratory animals. How do the functions of the HPA axis compare to those of the sympathetic nervous system? The sympathetic nervous system readies the body for brief, vigorous action, and the HPA axis prepares the body for prolonged coping with a persistent stressor. True or False: Stress increases release of cytokines, which communicate with the hypothalamus via the vagus nerve and prostaglandins. The hypothalamus reacts with the same responses it uses during a panic attack by activating the fight or flight response causing the body to become increasingly hyperactive. False Research on the amygdala supports which of these psychological conclusions? What we call fear is a combination of several components, not an indivisible entity. When researchers looked for brain areas associated with particular emotions, what did they find? No brain area is responsible for one and only one emotion. The amygdala responds more strongly to a fearful face looking toward you than a similar face looking to the side. What is the likely interpretation? Amygdala's response indicates the effort needed to interpret emotional information. True or False: The amygdala is important for increasing or decreasing the startle reflex on the basis of learned information. True True or False: Panic disorder is associated with increased adrenaline release and decreased glucagon release in the amygdala. False True or False: Activity of the frontal and temporal lobes of the right hemisphere is associated with the behavioral inhibition system (BIS), which is marked by low to moderate autonomic arousal and a tendency to approach, which could characterize happiness or anger. False How do the functions of the sympathetic nervous system differ from those of the parasympathetic nervous system? The sympathetic system readies the body for emergency activities and the parasympathetic activates digestive and other less urgent responses. Of the people who endure traumatic experiences, which of the following are the most likely to develop PTSD? People with a smaller than average hippocampus. True or False: Emotion is a socially constructed category that people find useful, but it does not correspond to any category that exists in nature. True Researchers have found that monkeys with low serotonin turnover pick many fights and in most cases die young. However, what keeps natural selection from eliminating the genes for low serotonin turnover? Monkeys with low serotonin turnover die young but many of the survivors achieve a dominant status that enables them to get more food and to reproduce more frequently. Monkeys with high serotonin turnover survive, but at the cost of accepting a low status. What are the effects of stress on the immune system? Brief stress activates the immune system, but prolonged stress weakens it.