Rather than passively receiving information about the body, individuals perceive physical symptoms through an active and constructive process. Physical symptoms are thought to arise from a process in which changes in the functioning of the body are detected, attended to by the individual, and given meaning through their labeling as symptomatic of a given physical condition. As will be seen, there are numerous points at which this process can be influenced by physical, psychological, and social circumstances. For example, changes in the body can be missed, sensations that are not symptoms of disease can be mislabeled as symptomatic and acted on inappropriately, and actual symptoms of disease can be detected and attended to, but mislabeled as nonsymptomatic, delaying treatment and affecting medical outcomes.
Physical symptoms provide subjective information about the state and well-being of the body. The relationship between physical symptoms and objective measures of health, however, is modest at best. There is ample evidence that even when physical functioning can be measured objectively, many people with conditions such as asthma, hypertension, and diabetes base their daily medical management on their perception of physical symptoms. For example, although blood pressure can be measured easily, and research suggests that people are not very accurate in estimating blood pressure from their symptoms, many people with hypertension use their perception of symptoms to guide the level of their physical activity and the taking of medication.
Symptom Perception Accuracy
When an individual reports that she or he is experiencing a physical symptom, such as headache, she or he is reporting what is essentially a personal and private experience. The experience is observable only to the individual with the headache, and others gain knowledge of it only through observable illness behavior, that is, what the individual says or how she or he behaves. Some physical symptoms can be assessed for how accurately they map onto physical functioning, such as an individual reporting that his or her headaches relate to high blood pressure, which itself can be measured objectively. Most perceptions, however, have no such measurable referent. Regardless of the ability to validate accuracy (e.g., measurement of blood pressure), the sensations that an individual perceives (e.g., headache), and the way in which these perceptions are processed remain unobservable to others. These experiences are subjective and influenced by a number of environmental and psychological factors. Given this, it is not surprising that there is only a modest relationship between the symptoms people report and objective indicators of their physical functioning.
Further complicating this process is evidence not only that individuals differ in the accuracy with which they can identify physical symptoms related to their body’s functioning, but that an individual’s accuracy can change over time, as in James Pennebaker’s study of people with diabetes. In this study, people with poorly controlled diabetes were more accurate in identifying the physical symptoms related to blood glucose fluctuations than people with well-controlled diabetes. This may be understandable, as poorly controlled diabetes results in more changes in glucose level and greater opportunity to learn which physical sensations relate to these changes. Later, when their diabetes was better controlled and changes in glucose level less pronounced, people’s beliefs about which sensations related to glucose level did not change even though the actual symptoms related to glucose did, and they became less accurate. Thus, experience, expectation, and learning affect the perception of physical symptoms as well as physical factors. The main factors influencing the perception of symptoms that have been studied are those related to the symptoms themselves, demographic factors, attentional factors, and personality and mood factors. As will be seen, the distinctions made among these factors are at times arbitrary, and factors often overlap.
Physical symptoms can be characterized along a number of different dimensions, such as duration, frequency, and quality, and these dimensions affect the likelihood that symptoms will be recognized. Sensations that are more intense and appear suddenly, such as pain, are more likely to be noticed and labeled as symptomatic than sensations that are indistinct and longstanding, such as tiredness. Sensations in different parts of the body may also be more likely to be noticed. For example, sensations in the chest may be more likely to be noticed and labeled as symptoms than sensations in the arm. Differences in symptom perception dimensions such as these can present difficulties for individuals, as some very serious conditions (e.g., heart attack) may be experienced along dimensions that are less likely to be noticed (e.g., numbness in arm), delaying identification and treatment.
The ability to detect and report physical symptoms may also be affected by the state of the body itself. An area that has been studied extensively is the ability of individuals to detect and report on their cardiac activity, with the consistent finding that individuals differ in this ability. One factor that may account for differences is an individual’s physical conditioning. Individuals with a lower proportion of body fat are better discriminators of cardiac activity than others, and individuals with larger, more efficient hearts, like athletes, tend to be better at reporting cardiac activity than less conditioned individuals. In these cases, body fat may act as an insulator, dampening the vibrations made by cardiac activity, and decreasing the ability of individuals to perceive cardiac activity.
In other cases, alterations in the functioning of nerves may influence symptom perception. One complication of diabetes, neuropathy, damages nerves, often of the feet and legs. Individuals with this condition may experience symptoms due to the nerve damage (e.g., pain, numbness, tingling, loss of balance). However, they also lose sensation in the extremities, which may lead them to miss physical symptoms associated with minor injuries. This missed perception can lead to delays in treatment and result in serious infection, which sometimes requires amputation.
Older age and lower economic status have been shown to relate to an increase in symptom reporting. It is unclear whether this results from greater variability in health status, cultural factors, or some other cause. A large number of studies have been performed examining gender differences in the reporting of physical symptoms. Whether gender differences exist in symptom reporting is unclear, with some studies demonstrating that women report more physical symptoms than men, and other studies showing no difference between the groups. What is clear is that men and women use different types of information to understand their physical functioning.
Studies that bring people into the laboratory to examine accuracy of symptom reporting suggest that men are more accurate perceivers of cardiovascular, gastrointestinal, and blood glucose activity than women. However, field studies, which occur in natural environments, have suggested that women are equal to and perhaps more accurate than men in this ability. These strikingly different findings appear to result from gender-based differences in the information men and women use to understand their symptom experiences. In making decisions about physical sensations, men tend to relay more heavily on internal, physiological cues, whereas women are more likely to rely on external, environmental cues, such as time since last meal or level of physical activity. Laboratory-based studies usually put great effort into controlling both the environment in which the experiment takes place and the availability of external information by having all participants equated on such things as time of day of the experiment, time since last meal, and level of activity. This places greater emphasis on internal cues and may favor the informational style more common in men. Field studies, which are more naturalistic, allow participants to use both internal and external cues to inform their judgments about their physical state. Thus, differences in accuracy are diminished.
Individuals are limited in the amount of information that they can attend to and process at any given time. Thus, they must strike some balance between attending to internal and external information, and their ability to recognize internal, physical symptoms will depend on the ratio of internal to external information. James Pennebaker has suggested that when the environment is stimulating and exciting, attention tends to focus externally, and there is less capacity to attend to internal information, such as physical sensations. Conversely, an unstimulating and boring environment tends to increase the focus on internal states, which may lead people to notice more physical sensations. This competition-of-cues theory has been repeatedly upheld in research demonstrating that individuals report more physical symptoms in unstimulating environments than in challenging and exciting ones, even when the physical tasks they are performing are equal. It may also help explain why distraction is a useful short-term means of coping with physical discomfort.
Mood And Personality Factors
Personality and mood have also been linked to symptom perception and reporting. Individuals experiencing negative mood states (e.g., sadness) report more physical symptoms than individuals experiencing positive mood states (e.g., happiness). These findings hold for both laboratory studies in which negative mood is manipulated and field studies in which negative mood occurs naturally.
The aspect of personality that has been examined most in relation to symptom perception is neuroticism or negative affectivity (NA). NA is best thought of as a dimension of normal personality that encompasses susceptibility to negative moods, introspection, and a tendency to interpret the world and the self in negative terms. NA has been reliably linked to increased reports of physical symptoms across a wide range of populations and symptoms. However, although high-NA individuals report more physical symptoms than low-NA individuals, they do not appear to differ in objective health status. Thus, NA relates to symptom reporting, but not health.
David Watson and James Pennebaker suggested that the introspection and emotional distress that underlie NA influence the labeling of physical sensations, and may account for differences in symptom reporting. This symptom perception hypothesis suggests that an internal focus of attention coupled with distress leads individuals to scan their bodies more frequently, leading them to notice more physical sensations. Because they are anxious and see things negatively, these sensations are more likely to be labeled as signs of physical pathology, and to be reported as symptoms. This increase in the reporting of symptoms regardless of disease explains the results of studies finding no relationship between NA and illness.
Symptom perception is a constructive process in which individuals make meaning of sensory information by detecting, attending to, labeling, and making attributions about its cause and significance. This process is influenced simultaneously by multiple factors, including psychological, physical, and environmental conditions. Although people vary widely in their ability to accurately perceive and report on physical symptoms, and use symptoms to guide their health care behavior, the relationship between reports of physical symptoms and objective indices of health and disease is modest.