Introduction
Primary motives, or
drives, are generated by innate biological needs that must be met for survival. These motives include hunger, thirst, and sleep. Hunger has been studied extensively, yet there is still uncertainty as to exactly how this drive works. A large body of research about the physiological analysis of hunger has led to the identification of important differences between physical hunger and psychological hunger.
Physical hunger theories assume that the body’s physiological mechanisms and systems produce hunger as a need and that when this need is satisfied, the hunger drive is, for the time being, reduced. Psychologists have developed models and theories of hunger by analyzing its boundaries and restraint or regulation. The early findings on hunger-regulation mechanisms emphasized the biological state of the individual and his or her control over the hunger drive. If a person experiences hunger, consumption of food will continue until it is terminated by internal cues. This is referred to as regulation.
The individual learns to avoid hunger by reacting to the internal cues of satiety or fullness. The satiety boundary is characterized by feelings of fullness ranging from satisfaction to uncomfortable bloating. The normal eater learns to avoid transgressing far or often into the latter zone. Beyond the reaction to internal cues is a zone of indifference, in which the body is not subject to biological cues. Instead, hunger is influenced by social, cognitive, and psychological cues. These cues may be external or internalized and do not rely on satiety cues for restraint.
Eating past the point of satiety is referred to as counterregulation or, more commonly, as binge eating or compulsive eating. Because the inhibitors of hunger restraint are not physiological in this zone, the restraint and dietary boundaries are cognitively determined. The physical hunger mechanisms may send signals, but quite ordinary ideas such as “being hungry” and “not being hungry” must be interpreted or received by the individual. The person must learn to distinguish between bodily sensations that indicate the need for food and the feelings that accompany this need, such as anxiety, boredom, loneliness, or depression.
Thus, there are both internal cues and external cues that define hunger and lead an individual to know when and how much to eat. External cues as a motive for eating have been studied extensively, particularly in research on obesity and eating disorders such as binge behavior and compulsive overeating. External cues include enticing smells, locations such as restaurants or other kinds of social settings, and the social environment—what other people are doing. When external cues prevail, a person does not have to be hungry to feel hungry.
Children’s Hunger The awareness of hunger begins very early in life. Those infants who are fed on demand, whose cries of hunger determine the times at which they are fed, are taught soon after they can feed themselves that their eating must conform to family rules about when, what, and how much to eat to satisfy their hunger. Infants fed on a schedule learn even earlier to conform to external constraints and regulations regarding hunger. Throughout life, responding to hunger by feeding oneself is nourishing both physiologically and psychologically. Beginning in infancy, the sequences of getting hungry and being fed establish the foundations of the relationship between the physiological need or drive and the psychological components of feelings such as affiliation, interaction, calm, and security when hunger is satisfied.
In preschool and early school years, when children are integrating themselves into their social world, food acceptance and cultural practices are learned. Prior to the peer group and school environment, the family and media are usually the main vehicles of cultural socialization of the hunger drive. According to social learning theory, these agents will play an important role in the child’s learning to interpret his or her level of hunger and in subsequent eating patterns, both directly and indirectly. The modeling behavior of children is also related to hunger learning.
Experiences of hunger and satiety play a central role in a person’s relationship to hunger awareness, eating, and food. Some dispositions that influence hunger and eating behavior are long term (fairly stable and enduring), while other habits and attitudes may fluctuate. There are numerous theories about the relation between the hunger drive and other factors, such as genetic inheritance and activity level.
Hunger and the Brain A strictly physiological analysis claims that an individual’s responses to hunger are caused by the brain’s regulation of body weight. If the body goes below its predetermined “set point,” internal hunger cues are initiated to signal the need for food consumption. External restraints, such as attempts to live up to ideal cultural thinness standards, also affect behavior and may result in restrained eating to maintain a body weight below the body’s defined set point.
The idea of a body set point is rooted in the work of physiologist Claude Bernard
, a pioneer in research based on the concept of homeostasis, or system balance in the body. Homeostasis has played a fundamental role in many subsequent investigations regarding the physiology of hunger and the regulatory systems involved in hunger satisfaction. Inherent in theset point theory is the concept of motivation, meaning that an organism is driven physiologically and behaviorally toward maintenance of homeostasis and the body’s set point and will adapt to accommodate the systems involved in maintenance.
In addition, there appear to be two anatomically and behaviorally distinct centers located in the hypothalamus, one regulating hunger and the other regulating satiety. The area of the hypothalamus responsible for stimulating eating behavior is the lateral hypothalamus. The ventromedial hypothalamus is the area responsible for signaling the organism to stop eating. The lateral hypothalamus is responsible for establishing a set point for body weight.
In comparing hunger and satiety sensation differences, increased hunger and disturbed satiety appear to be two different and quite separate mechanisms. Imbalance or dysfunction of either the hunger mechanism or the satiety sensation can lead to obesity, overeating, binge eating, and other eating disorders. It appears that the way hunger is experienced accounts in part for its recognition. Whether hunger is experienced in context with other drives or becomes a compulsive force that dominates all other drives in life is a complex issue. The prevalence of eating disorders and the multitude of variables associated with hunger drives and regulation have provided psychologists with an opportunity to examine the ways in which hunger might take on different meanings. To a person who is anorexic, for example, hunger may be a positive feeling—a state of being “high” and thus a goal to seek. To others, hunger may produce feelings of anxiety, insecurity, or anger. In this case, a person might eat before feeling hunger to prevent the feelings from arising. People’s ability to experience hunger in different ways provides psychologists with two types of hunger, which are commonly referred to as hunger and appetite.
Hunger and appetite are not the same. Actual physical need is the basis of true hunger, while appetite can be triggered by thought, feeling, or sensation. Physical need can be separate from psychological need, although they may feel the same to a person who is not conscious of the difference. Compulsive eaters are often unable to recognize the difference between “real” hunger and psychological hunger, or appetite. Although psychological hunger can be equally as motivating a need as stomach hunger, appetite (or mouth hunger) is emotionally, cognitively, and psychologically based and thus cannot be fed in the same way. Stomach hunger can be satisfied by eating, whereas “feeding” mouth hunger must involve other activities and behaviors, since food does not ultimately seem to satisfy the mouth type of hunger.
The Cultural Context of Hunger One approach to increasing understanding of hunger and its psychological components is to examine hunger in its cultural context. In American culture, the experience of hunger is inextricably tied to weight, eating, body image, self-concept, social definitions of fatness and thinness, and other factors that take the issue of hunger far beyond the physiological facts. Historian Hillel Schwartz has traced the American cultural preoccupation with hunger, eating, and diet by examining the cultural fit between shared fictions about the body and their psychological, social, and cultural consequences. Hunger becomes a broader social issue when viewed in the context of the culture’s history of obsession with diet, weight control, and body image. The personal experience of hunger is affected by the social and historical context.
Eating disorders such as anorexia, bulimia, and compulsive overeating provide evidence of the complex relationship between the physiological and psychological components of hunger. Obesity has also been examined using medical and psychological models. The etiology of hunger’s relationship to eating disorders has provided insight, if not consensus, by investigating the roles of hereditary factors, social learning, family systems, and multigenerational transmission in hunger as well as the socially learned eating patterns, food preferences, and cultural ideals that can mediate the hunger drive. Body image, eating restraint, and eating attitudes have been assessed by various methods. The focus of much of the research on hunger beyond the early animal experiments has been on eating disorders. The findings confirm that hunger is more than a physiological need and is affected by a multitude of variables.
Hunger Regulation The desire to regulate hunger has resulted in a wide variety of approaches and techniques, including professional diet centers, programs, and clinics; self-help books and magazines; diet clubs and support groups; self-help classes; and “diet doctors.” Many people have benefited from psychotherapy in an effort to understand and control their hunger-regulation mechanisms. Group therapy is one of the most successful forms of psychotherapy for food abusers. Types of group therapy vary greatly and include leaderless support groups, nonprofessional self-help groups such as Overeaters Anonymous, and groups led by professional therapists.
Advantages of group support for hunger regulation include the realization that one is not alone. An often-heard expression in group therapy is “I always thought I was the only person who ever felt this way.” Other advantages include group support for risk taking, feedback from different perspectives, and a group laboratory for experimenting with new social behaviors. Witnessing others struggling to resolve life issues can provide powerful motivation to change. Self-help and therapy groups also offer friendship and acceptance. Creative-arts therapies are other forms of psychotherapy used by persons seeking to understand and control their hunger-regulation mechanisms. Creative therapy may involve art, music, dance, poetry, dreams, and other creative processes. These are experiential activities, and the process is sometimes nonverbal.
A more common experience for those who have faced the issue of hunger regulation is
dieting. Despite the high failure rate of diets and weight-loss programs, the “diet mentality” is often associated with hunger regulation. Robert Schwartz studied the elements of the diet mentality, which is based on the assumption that being fat is bad and being thin is good. Dieting often sets up a vicious cycle of failure, which deflates self-esteem, thus contributing to shame and guilt and to another diet. The diet mentality is self-defeating. Another key element to the diet mentality is the mechanism of self-deprivation that comes from not being allowed to indulge in certain foods and the accompanying social restrictions and isolation that dieting creates. Dieting treats the symptom rather than the cause of overeating.
Numerous approaches to hunger regulation share a condemnation of the diet mentality. Overcoming overeating; understanding, controlling, and recovering from addictive eating; and being “thin-within” are approaches based on addressing hunger regulation from a psychological perspective rather than a physiological one. These approaches share an emphasis on the emotional and feeling components of hunger regulation. They encourage the development of skills to differentiate between stomach hunger and mind hunger—that is, between hunger and appetite—and thereby to learn to recognize satiety as well as the reasons for hunger.
Behavior modification consists of a variety of techniques that attempt to apply the findings and methods of experimental psychology to human behavior. Interest in applying behavioral modification to hunger regulation developed as a result of the research on external cues and environmental factors that control the food intake of individuals. By emphasizing specific training in “ stimulus control,” behavior modification helps the individual to manage the environmental determinants of eating.
The first step in most behavior modification programs is to help the patient identify and monitor activities that are contributing to the specific behavior. In the case of an individual who overeats, this could involve identifying such behaviors as frequent eating of sweets, late-evening snacking, eating huge meals, or eating in response to social demands. Because most people have more than one stimulus for eating behavior, the individual then observes situational stimuli: those that arise from the environment in which eating usually takes place. Once the stimuli are identified, new behaviors can be substituted—in effect, behavior can be modified.
Models of Hunger Early scientific interest in hunger research was dominated by medical models, which identified the physiological mechanisms and systems involved. One of the earliest attempts to understand the sensation of hunger was an experiment conducted in 1912, in which a subject swallowed a balloon and then inflated it in his stomach. His stomach contractions and subjective reports of hunger feelings could then be simultaneously recorded. When the recordings were compared to the voluntary key presses that the subject made each time he experienced the feeling of hunger, the researchers concluded that it was the stomach movements that caused the sensation of hunger. It was later found, however, that an empty stomach is relatively inactive and that the stomach contractions experienced by the subject were an experimental artifact caused by the mere presence of the balloon in the stomach. Further evidence for the lack of connection between stomach stimuli and feelings of hunger was provided in animal experiments that resulted in differentiating the two areas of the hypothalamus responsible for stimulating eating behavior and signaling satiety—the “start eating” and “stop eating” centers.
Psychologist Stanley Schachter and his colleagues began to explore the psychological issues involved in hunger by emphasizing the external, nonphysiological factors involved. In a series of experiments in which normal-weight and overweight individuals were provided with a variety of external eating cues, Schachter found that overweight subjects were more attentive to the passage of time in determining when to eat and were more excited by the taste and sight of food than were normal-weight persons. More recently, the growth of the field of social psychology has provided yet another perspective on hunger, one that accounts for the situational and environment factors that influence the physiological and psychological states. For example, psychologists have examined extreme hunger and deprivation in case studies from historical episodes such as war, concentration camps, and famine in the light of the more recent interest in the identification and treatment of eating disorders.
There does not appear to be a consistent or ongoing effort to develop an interdisciplinary approach to the study of hunger. Because hunger is such a complex drive, isolating the factors associated with it poses a challenge to the standard research methodologies of psychology, such as the case study, experiment, observation, and survey. Each methodology has its shortcomings, but together the methodologies have produced findings that clearly demonstrate that hunger is a physiological drive embedded in a psychological, social, and cultural context.
Viewing hunger as a multidimensional behavior has led to an awareness of hunger and its implications in a broader context. Changing dysfunctional attitudes, feelings, thoughts, and behaviors concerning hunger has not always been seen as a choice. Through continued psychological research into the topic of hunger—and increasing individual and group participation in efforts to understand, control, and change behaviors associated with hunger—new insights continue to emerge that will no doubt cast new light on this important and not yet completely understood topic.
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