Contemporary Biological and Integrated Perspectives

by Diana Fishbein  

There are many competing and “integrated” theories within the field of criminology. It is important to distinguish the literature and findings discussed in this lecture, however, from the theories of any particular discipline. While these findings are an extension of certain models and perspectives proposed in the behavioral sciences, they should not be considered theories that are competitive with others in criminology. Instead, research that is described has been generated from a broad range of scientific inquiries and methodologies into the generators of human behavior that are highly relevant to the inquiries of criminologists. Findings from the behavioral sciences should, therefore, be viewed as having the potential to fill existing gaps in our knowledge pertaining to the development of antisocial behavior, and to eventually be understood in the context of social forces that we have identified as significant players in this dynamic equation.  

Q1: Why is it important that criminological inquiry include the perspectives, findings, and methods of the behavioral sciences (e.g., behavioral genetics, psychophysiology, neuroscience, biochemistry, psychology, and developmental biology)?

A1: There are many subdisciplines within the behavioral sciences that have been intensively studying various dimensions of antisocial behavior that are relevant to the field of criminology. They include molecular and behavioral genetics, neurobiology, physiology, psychology, cognitive neuroscience, endocrinology, and forensic psychiatry, among many others. To date, their findings have provided substantial evidence to suggest that individuals are different in the extent to which they are vulnerable to both antisocial behavior and drug abuse. Researchers in these fields are studying the tendency to engage in criminal behavior by attempting to identify genetic and biological mechanisms that underlie or contribute to these problem behaviors. The antecedents or conditions that underlie some types of criminal behavior are psychological traits and behaviors that highly correlate with the development of antisocial behavior and occur early in a child’s life; thus, they are believed to be important in a developmental sense. For example, hyperactivity, attention and other cognitive deficits, conduct disorder (CD), aggressiveness, and negative affect all tend to co-occur with and predict criminal behavior. Each of these so-called antecedents, among others, has been associated with various disturbances or irregularities in brain function, physiological and neuropsychological processes, and biochemical balance. In interaction with certain conditions in the physical and social environment, these disturbances are thought to increase the likelihood for an antisocial outcome.

The vast array of reported studies on vulnerability to Antisocial Personality Disorder  (ASPD), violence, and drug abuse may seem unintelligible at first, but several consistencies across studies reveal a pattern that may characterize vulnerable individuals. Findings indicate that vulnerability to antisocial behavior is partially a function of genetic and biological make-up that manifests during childhood as particular behavioral, cognitive, and psychological traits (e.g., impulsivity, attention deficits, conduct disorder (CD) and are measurable in physiological and biochemical responses (such as heart rate, hormone levels, or EEG recordings) to environmental inputs. Instead of viewing evidence from these various disciplines as independent indicators of biological and social dysfunction, these sources of evidence should be seen as a continuous, developmental sequence of interacting factors; i.e., basic genetic or acquired biological traits contribute to measurable biochemical and physiological conditions that predispose individuals to a constellation of particular behavioral and temperamental outcomes.

The resulting integration of research findings from various disciplines has direct relevance to criminological inquiry, informing ideology with science, which should appeal to social scientists who hold widely divergent views and beliefs but are in search of reliable scientific answers. This research is persuasive in that it compels the reader to acknowledge several decades of serious scientific criminological research in psychology, psychiatry, and the bio-behavioral sciences. Findings account for both intra-psychic (from within) and extra-psychic (from external sources) variables in their emphasis on the recent explosion of genetic and biological evidence that neurobiological conditions often underlie violent and impulsive behaviors by sensitizing the actor to adverse social stimuli. Behavioral sciences research should, therefore, be viewed as having the potential to fill existing gaps in our knowledge pertaining to the development of antisocial behavior, and to eventually be understood in the context of social forces that we have identified as significant players in this dynamic equation.

See Fishbein (1990); Reiss and Roth (1993).

Q2: In studying genetic and biological factors in the field of criminology, why should there be a concentration on various dimensions of “antisocial” behavior as opposed to “criminal” behavior?

A2: The development of a framework for incorporating biological perspectives into criminological theory requires that we first identify behaviors of interest. This exercise is essential given that not all “illegal” behaviors are dysfunctional or antisocial and not all “legitimate” behaviors are moral, acceptable, or adaptive. The term “criminality” includes behaviors that do not necessarily offend all members of society, such as certain “victimless” acts, and also behaviors that may be considered adaptive or rational given the social conditions and circumstances. Also, the concept of criminality excludes behaviors that may be antisocial or illegal but that are not detected by the criminal justice system. Antisocial behaviors, on the other hand, are costly to citizens and society overall. Such behaviors do not necessarily violate legal norms or come to official attention, however. Antisocial individuals have a high probability of being labeled as delinquent or criminal, but being so labeled is not a sufficient criterion to be identified as antisocial. For example, schizophrenics’ behavior is poorly regulated, detrimental to their own well‑being, and considered “deviant,” but they rarely engage in crime. Individuals identified as psychopathic, conversely, are at high risk for crime by virtue of their behavior. Yet, there are psychopathic individuals who find legal, albeit not always ethical, avenues for channeling their behavioral tendencies (e.g., a subgroup of those involved in competitive sports, high‑risk activities, corporate life, and politics). The focus of this lecture is on antisocial behaviors, including both criminal and undetected behaviors, that are detrimental to the individuals affected and/or their milieu; in other words, behaviors that increase risk for criminal stigmatization, for example, violence or drug abuse.

In addition, studies generated from this perspective in criminology should focus on the dimensions of antisocial behavior that can be reliably and precisely measured. This way, investigators are able to replicate studies to identify consistencies in findings and eventually base conclusions on rigorous and reliable methods of measuring behavior. Thus, it is important that researchers isolate the behavioral phenotypes of interest that correlate or co-occur with criminal behavior. A phenotype is the measurable outcome of genetic factors that interact dynamically with the environment. For example, even something as simple as eye color is a result of both genetic influence and the gestational environment. Behavioral phenotypes are much more complex than appearance, but are still amenable to observation, measurement, and manipulation. Thus, they are imminently better candidates for investigation than criminality, which is a socially constructed concept. Phenotypes of interest to the criminologist, which correlate or co-occur with criminal behavior, include aggressiveness, impulsivity, attention and other cognitive deficits, hyperactivity, and negative affect. Each of these behavioral phenotypes is influenced by both genetic and environmental conditions.

Q3: Why are chronic patterns of antisocial behavior more strongly influenced by genetics and biology than single acts?

A3: Phenomenologically, “antisocial behavior” is a complex concept defined variably in different disciplines and arising from widely diverging origins. No single mental disorder is uniquely associated with antisocial behavior, nor are particular behavioral patterns, childhood experiences, or social circumstances. From the various ways of characterizing individuals, however, emerges a subgroup who persistently engage in impulsive (not instrumental) antisocial behavior, potentially violent (resulting in physical injury), typified not simply by the behavioral outcome, but by relatively stable personality and temperamental traits, including impulsivity, negative affect, and cognitive deficits. Displays of impulsive antisocial behavior are, thus, an outgrowth of these traits in interaction with crime-prone situations in the social environment. Conversely, individuals who exhibit only isolated displays of antisocial behavior may be more influenced by social and situational factors and probably do not possess the requisite conditions to produce a true “vulnerability” to a destructive behavioral pattern. This depiction corresponds with the pattern described by Moffitt (1993), who characterizes a subgroup of chronic offenders by “life-course persistent antisocial behavior culminating in a pathologic personality.”   Individuals possessing these features also appear to be unusually susceptible to the abuse of alcohol or drugs.

Due to the nature of the phenomenon of antisocial behavior, studies of the underpinnings of criminal behavior should focus on the measurable dimensions of antisocial behavior that may increase the risk for criminal activity rather than crime, per se, which is an abstract legal and social construct, not a measurable behavioral construct. Criminal acts that occur only once or rarely in an individual may be more a result of a situation than an ongoing predisposition. But a longstanding or recurrent pattern of antisocial behavior is more likely due to the cumulative, developmental influence of interacting biological and environmental factors.

Q4: What is the Diathesis-Stress Model of behavior, and how does it apply to the study of antisocial behavior?

A4: The theoretical framework for biological perspectives in criminology is consistent with the diathesis‑stress model constructed to explain many forms of antisocial behavior. According to this model, individuals vary considerably with respect to their biological strengths and weaknesses. Biological weaknesses, referred to as a "vulnerability," influence the degree to which the individual is at risk for antisocial behavior. Rather than acting alone, however, these biological features operate by setting the stage for how adaptively an individual will respond to personal stressors. In other words, a stressful environment is more likely to contribute to some form of psychopathology when it is received by a biological system that is somehow compromised. Learning disability, brain damage or functional irregularity, drug exposure, genetic predisposition to temperamental disturbances, and other biological disadvantages lay the groundwork for a pathological response to stress. Prior learning experiences contribute further by either increasing or decreasing the risk.

 Although the probability of a pathological response is a function of the number of these risk factors present, the probability is even greater in the presence of an adverse environment with severe stressors (e.g., poverty, unemployment, crime and drug infestation, poor parenting, lack of education, abuse/neglect, social immobility). For example, hyperactive children may function well given appropriate intervention. In the presence of family instability, alcoholism, absence of educational programs, and a delinquent peer group, however, the child may be more prone to antisocial behavior, possibly resulting in criminal acts. Thus, environmental factors play a facilitating role in determining an antisocial outcome in vulnerable persons. Environmental factors may be even more potent determinants of antisocial outcomes than strictly biological vulnerabilities when the environment is unusually harsh or conducive to such behavior, as we may readily observe in our inner cities. Once again, however, not all inner-city residents engage in antisocial behavior; that outcome remains somewhat dependent on individual vulnerability. The reverse may be also apply—even in the presence of a protective environment, a biological disadvantage may be so severe as to overwhelm the positive environmental influence. An example of that particular outcome may be seen in fetal alcohol syndrome, when the biological odds frequently outweigh prosocial influences.

Q5: What are some examples of the interaction between biology and the environment in human behavior?

A5:  The neurotransmitter serotonin is of particular interest for its role in impulsivity and aggressiveness. An individual’s range for synthesis and metabolism of serotonin is largely determined by his genes, although its activity is exquisitely sensitive to changes in the environment. Animal studies show that, when the social hierarchy is altered, the loss in status by dominant monkeys results in decreases in serotonin activity and vice versa, and they become more impulsive and subordinate. Human studies consistently report lower levels of serotonin in individuals exposed to high and chronic amounts of stress (e.g., Post-Traumatic Stress Disorder [PTSD]) than individuals not exposed to high levels of stress. There are indications that poor parenting is also associated with low-serotonin levels in the child and good parenting techniques can raise serotonin activity levels, subsequently minimizing the impact of other risk factors for negative behavioral outcomes.

Temperament, the second example, is known to be largely heritable (i.e., a significant amount of variation in the trait is genetic) and stable across the life span. Nevertheless, the behavioral expression of any given temperament is strongly contingent upon environmental circumstances, such as stressors, situational factors, opportunities, and learning experiences. Shyness is one form of temperament with biological and genetic origins that can be environmentally altered to influence its behavioral manifestations. Overactivity of the autonomic nervous system (ANS) (peripheral to the central nervous system  [CNS]) is, in part, responsible for behavioral withdrawal in social situations in susceptible individuals. Strategies to combat shyness in a child may result in more extroverted behavior and less nervousness in social situations by lowering levels of reactivity of the  ANS.

Third, alcoholism, known to be significantly heritable and associated with several genetic markers contributing to its expression, is also susceptible to environmental influence. While alcoholism is considered to be in large part a genetic disease state, its expression is significantly dependent upon family stability factors. The same may also be true for other forms of drug abuse and addiction in which genetics plays a role, but the environment and learning experiences help to determine their actual expression.

A significant population of children chronically exposed to cocaine prenatally have been characterized as difficult to manage, temperamental, hyper-responsive to environmental stimuli (e.g., lights and noises), developmentally delayed, learning disabled, impulsive, and sometimes aggressive. Cocaine can dramatically alter the developing nervous system to increase the likelihood of these behaviors in predictable ways. Because the brain continues to develop for twelve months after birth, however, the provision of supportive therapies and interventions can substantially alter these negative outcomes. Children raised by the “crack mothers” who gave birth to them exhibit significantly worse behavioral and cognitive outcomes than cocaine-exposed children raised in more supportive and nurturing environments, suggesting that, although prenatal cocaine exposure is a highly preventable cause of behavioral and cognitive disorders, environmental enrichment during the formative years can substantially improve the outcome.

Illustration by Susan Gilbert

One final example is that of cognitive differences between males and females. Similar to other parts of the anatomy, the structure of the developing fetal brain is influenced after the seventh week of pregnancy by the introduction of testosterone, a male hormone, in the presence of a Y chromosome. Subsequent changes in neuroanatomy differentiate the male from the female brain, in addition to promoting the development of external genitalia, a larger musculature and, eventually, facial hair in the male. One result of these differences is distinctive cognitive styles, with males and females performing somewhat differently in various cognitive tasks. Interestingly, however, the gender gap in these cognitive differences has been narrowing in recent decades. Can the environment produce such significant changes in a trait known to be largely genetic? Researchers believe that differences in the way parents treat their children may contribute to cognitive styles and actually alter brain development in the early years. A few decades ago, psychological studies found that parents were more likely to encourage exploration of the environment and active play in baby boys, while little girls were coddled, comforted and “kept safe” from their environment. In contrast, parents in more recent years tend to treat male and female babies more equally, a practice that can, theoretically, lead to a smaller magnitude of gender differences in cognitive abilities by increasing activity levels in baby girls.

 
 
The male and female brain differ in some important ways in their structure
and function.  For the most part, differences are due to the introduction of
relatively large amounts of testosterone to the male fetus during pregnancy.
They help to explain some statistical gender-group differences in brain
function, from verbal and motor skills to the incidence of certain disorders
and learning disabilities.

Q6: What is “Developmental Criminology” and how does it help us to understand how antisocial behaviors develop over time, are influenced by both biology and environment, and change in response to changing conditions?

A6: Research into the multiple determinants of the liability to antisocial behavior requires a developmental perspective to place in context the fluid interaction between environmental and biological factors described in this lecture. The age of onset for antisocial behaviors is not equally distributed throughout the life span among the population of individuals who exhibit these behaviors. This variability is a direct function of changes over time in biological and behavioral processes that result from ongoing interactions with many different environments. For example, family situations, peer interactions, school settings, and work environments are typically not static in an individual’s lifetime, and produce measurable changes in biological systems and behavioral outcomes as the individual ages. Epidemiological data provides support for the notion that some external conditions are more important influences at certain points in the life span than others; for example, maternal influences during childhood, peer influences during adolescence, and perhaps the use of drugs with analgesic (pain relieving) or euphorigenic (pleasurable or euphoric) properties later in life when stress or pain becomes more prevalent. Thus, there is an essential feedback loop between extant traits, phenotypic behaviors, and environmental influences that fluctuate throughout the life span and contribute to varying degrees of “risk” or liability for antisocial behavior at any given stage of life.

Tarter has employed a developmental approach for understanding the etiology of substance abuse disorder. His developmental model can readily be applied to an understanding of antisocial behaviors in general:

This perspective emphasizes the influence of cumulative prior experience as the major determinant of the emergence of each successive phenotype. This epigenetic process allows understanding of the etiology of drug abuse in the context of an orderly process in which the outcome is the culmination of an ongoing developmental trajectory concomitant to person-environment interactions. It is important to note, however, that other outcomes (e.g., AIDS, criminality, dementia) can likewise be investigated through continued monitoring of the trajectory across the life span. Thus, drug abuse is not necessarily the only or final outcome of interest but instead is commonly intermediary to other negative outcomes. The epigenetic approach enables, therefore, the integration and sequencing of adverse outcomes associated with drug abuse as well as quantitative analysis of the patterning of other outcomes.

Although Tarter’s model addresses the development of drug abuse specifically, the implications are relevant to all complex human behavior. Healthy, normal development is characterized by the mastery of particular developmental tasks, such as cognitive and verbal skills, honesty, understanding rights of possession, respect for authority, independence, and basic trust. Maturing or developing successfully is defined by the mastery of these tasks, and is conducive to prosocial behavior and incompatible with antisocial behavior, generally resulting in a well-adjusted social behavioral repertoire. And while there are bases in evidence for the tendency of resultant behavioral patterns to wax and wane over time (contingent upon both physical and experiential stages of development), most assume a predictable trajectory (or life course), absent intervention or drastic socio-environmental change.

Antisocial behavior tends to have an early onset and often persists into adolescence and adulthood, suggesting that it is (1) a developmental trait, and (2) somewhat a function of the inability to assimilate the above developmental tasks. Early manifestations may include difficult temperament, impulsivity, social adjustment problems, poor academic achievement, distractibility and, oftentimes, depressed or negative affect. Attention deficit hyperactivity disorder (ADHD) is especially prevalent in early onsetters who progress to more serious criminal offending. These early signs commonly originate in genetic, congenital, and prenatal processes that subsequently interact with contextual factors to further condition the relationship between biology and behavior. A few of the contextual variables that exacerbate this developmental process, constituting a negative feedback loop, include parental rejection, ineffective parenting practices or severe disciplinary responses, child abuse, negative peer influences, poverty, and negative feedback from teachers. In short, the child’s responses to environmental input stimulate predictable reactions from the social environment, reinforcing or counteracting the child’s reactions, contributing to further changes in reactions from both the social environment and the child. Each step in this action-reaction sequence puts the antisocial child more at risk for long-term social maladjustment and criminal behavior. Rather than replacing one behavior with another in response to changing socio-environmental conditions, however, behaviors diversify and either strengthen, weaken, or reverse the developmental path over time.

See Loeber and Le Blanc (1990).

Q7: How do antisocial behavior and drug abuse relate to one another and what are the common antecedents?

A7: Susceptibility to chronic, excessive use of an abusable drug, increasing risk for dependency and related behavioral and lifestyle complications, is both biologically and socially constructed. Research reveals that a subgroup of the population is especially vulnerable to drug abuse and addiction, that its population exhibits early onset of drug use, finds drugs unusually rewarding, and more quickly develops a pattern of dependency and behavioral dysfunction than less vulnerable populations. This subgroup also exhibits a greater incidence of chronic maladaptive behaviors and demonstrates a tendency to be antisocial and at times violent irrespective of social conditions. Several investigators have proposed that drug abuse and antisociality may share common antecedents in susceptible individuals. These unusually vulnerable drug users are likely responsible for a major portion of drug-related offenses, particularly serious, chronic, violent crimes.

Certain parts of the brain govern specific functions. Areas including the sensory (orange), motor (blue) and visual cortex (yellow) highlight their specific functions. The cerebellum (pink) is involved in coordination and the hippocampus (green) regulates memory. Nerve cells or neurons connect one area to another via pathways to send and integrate information. The distances that neurons extend can be short or long. For example; the reward pathway (orange). This pathway is activated when a person receives positive reinforcement for certain behaviors ("reward"). This occurs when a person takes an addictive drug. As another example, the thalamus (magenta) receives information about pain coming from the body (magenta line within the spinal cord), and passes the information up to the cortex.

Given the commonalities in personality and temperament among populations considered vulnerable to drug abuse and antisocial behavior, it is plausible that underlying mechanisms in addictive behaviors may be interrelated with the specific proclivity to become antisocial under certain social and biological (e.g., drug- or stress-related) conditions. Antisocial behavior is self-stimulating, provides an outlet for frustration, is empowering, and is frequently a result of poor coping skills—properties that resemble those of drug abuse. Simply that these two behavioral outcomes are reinforced by their stimulating effects, however, does not sufficiently explain why only a subgroup of drug users respond with antisocial behavior while the overwhelming majority of users does not. We do not yet fully understand why only some individuals are attracted to and rewarded by these properties.

Individual differences, or unique characteristics, significantly determine both vulnerability to abuse drugs and various antisocial behaviors when sober or under the influence. The presence of conditions conducive to drug taking does not, however, necessitate that result; if drugs are unavailable or if other protective forces are strongly in place (e.g., family stability, strong religious affiliations, or high I.Q.), then drug misuse may not occur. Nevertheless, those “at risk” but who do not partake, may suffer from other chronic problems, for example, violence, depression, compulsive gambling, overeating, overmedicating, or unusual religiosity. Drug abuse may, therefore, be only one form of compulsive or excessive behavior resulting from existing psychopathology. Antisocial behavior may be another outcome. Findings that both antisocial behavior and drug abuse often coexist with other forms of psychopathology are consistent with the idea that both behavioral patterns are symptoms rather than syndromes in and of themselves.  For example, the abuse of psychoactive drugs would, therefore, likely lead to an intensification of underlying traits or psychopathology that predated and perhaps contributed to the onset of drug use, such as violence or another antisocial outcome. And similarly, the presence of antisocial tendencies may increase the likelihood that drug abuse would be one manifestation.

See Web site: www.nida.nih.gov

The co-occurrence of certain forms of psychopathology and cocaine use exemplifies the relationship between propensity to drug abuse and childhood behavioral disorders that antedate antisocial behavior, e.g., ADHD and CD. Alterations in the neurotransmitters serotonin and dopamine appear to be involved in both. There is evidence that individuals with ADHD are particularly vulnerable to cocaine dependence; they progress more quickly from casual use to dependence and experience a greater “crash” upon withdrawal. ADHD is often treated with medications that affect dopamine systems, as does cocaine. Cocaine addicts have also demonstrated a genetic susceptibility to dependence, found as a defect in the metabolism of the neurotransmitter dopamine. Subjects have a high incidence of early deviant behaviors, including CD. Although violence among cocaine users occurs more often in those with a history of violence, chronic use increases the likelihood irrespective of a predisposition as a result of neurotransmitter disruptions. In either event, characterizing users according to an underlying symptomatology may increase the effectiveness of treatment efforts; drug abusers with co-occurring psychiatric disorders, for example, drug abuse and depression, respond more favorably to treatment efforts that incorporate therapies—both pharmacologic and behavioral—appropriate for the underlying disorder.

The relationship between ASPD and alcoholism is also illustrative of neurobiological mechanisms that may underlie propensity to drug abuse and aggressiveness by virtue of common psychosocial traits. Alcoholics diagnosed as having ASPD tend to begin drinking at an earlier age, progress to alcohol dependence more rapidly, evidence greater impairment in social and occupational functioning, and have an increased number of arrests associated with their drinking. The genetic, biological, and psychological conditions discussed herein characterize those at risk for both ASPD and alcoholism: 1) higher levels of ANS activity during alcohol intake, suggesting unusual reward value of alcohol; 2) sensation-seeking which increases displays of impulsivity or aggression when sober and under alcohol's influence; 3) aberrations in serotonin and dopamine activity levels; 4) relatives with alcoholism and ASPD; and 5) a history of childhood hyperactivity among adults with alcoholism,  ASPD, and aggressive behavior. Co-occurring behavioral disorders are purportedly due to impaired impulse control functions that characterize each of them.