Gray, like other recent authors, seeks a scientific approach to consciousness, but fails to provide a biologically convincing description, partly because he implicitly bases his model on a computationalist foundation that embeds the contents of thought in irreducible symbolic representations. When patterns of neural activity instantiating conscious thought are shorn of homuncular observers, it appears most likely that these patterns and the circuitry that compares them with memories and plans should be found distributed over large regions of neocortex.

The key questions arising from Mealey's analysis are: Do environmental factors such as early maternal rejection also contribute to the emotional deficits observed in psychopaths? Are there psychophysiological protective factors for antisocial behavior that have clinical implications? Does a disinhibited temperament and low arousal predispose to primary psychopathy? Would primary or secondary psychopaths be most characterized by prefrontal dysfunction?

If sensations were behaviorally conceived, as they should be, as complex functional patterns of interaction between overt behavior and the environment, there would be no point in searching for them as instantaneous psychic elements within the brain or as internal products of the brain.

Recent evidence that psychopathy is a nonarbitrary population, such that the trait may be categorical rather than continuous, is consistent with Mealey's distinction between primary and secondary psychopaths. Thus, there are likely to be at least two routes to criminality, and psychopathic and nonpsychopathic criminals are likely to respond differently to interventions.

Questions are raised about several issues discussed by Mealey: (1) the nature of the distinction between primary and secondary sociopaths, (2) some difficulties with a general arousal theory of criminality, and (3) the possible role of countervailing forces in the development of sociopathy. An important area that calls for attention is the patterning of different specific emotions in the lives of sociopaths as compared to other groups.

Four questions are raised about Mealey's genetic argument: (1) Where is the evidence that secondary sociopathy is less heritable than primary sociopathy? (2) What is the genetic correlation between the two types of sociopathy? (3) How does genotype-environment interaction relate? (4) How strong are the links between our evolutionary past and current heritability?

Heyman s analysis of the relevant complex behavioral variables associated with addiction is evaluated in relation to identifying the appropriate variables in behavior analysis. The model of behavioral allocation and choice known as melioration, discussed by Heyman as a way to understand the complexities of addiction, is examined and contrasted with another model of matching called ratio invariance, which is offered in this commentary as another behavioral account with a significant potential for resolving the contradictions of addiction.

Further understanding at neuroscientific and personality levels should considerably advance our ability to deal with individuals that have strong sociopathic tendencies. An analysis of neurodynamic responses to emotional stimuli will eventually be able to detect sociopathic tendencies of the brain. Such information could be used to enhance the options available to individuals at risk without limiting their personal freedoms.

Heyman's target article seeks to resolve the apparent paradox surrounding the issue of control in relation to addictive behaviour. The present commentary argues that addiction is in fact less paradoxical and more easily understandable than Heyman supposes. A fully satisfactory model of addiction, however, requires a more multifaceted approach than that provided by the type of behavioural choice theory favoured by Heyman.

Gray hypothesizes that the contents of consciousness correspond to the outputs of a subicular (hippocampal/temporal lobe) comparator that compares the current state of the organism's perceptual world with a predicted state. I argue that Gray has identified a key contributing system to conscious awareness, but that his model is inadequate for explaining how conscious contents are generated in the brain. An alternative model is offered.

Heyman's analysis of addiction in terms of matching to local relative value can be supplemented by stimulus-control processes. Stimulus equivalence can broaden the set of situations that occasion addictive behavior, and the situation-reinforcer correlation can enhance its persistence. The joint effects of stimulus-control and reinforcement processes may complicate treatment.

Strengths of Mealey's target article are its implementation of results from game-theoretic analyses and its potential links with other formal developments. In recent dynamic decision/choice models, reduced salience of avoidance tendencies, said to typify primary sociopaths, has quantifiable consequences for response latencies and choices. Also, formal models of stress effects on information processing predict selected effects of hypoarousability.

Gray's neuropsychological model of consciousness uses a hierarchical feedback loop framework that has been extensively discussed by many others in psychology. This commentary therefore urges Gray to integrate with, or at least acknowledge previous models. It also points out flaws in his feedback model and suggests directions for further theoretical work.

We doubt that primary sociopathy is adaptive, for three reasons: First, its prevalence is too low to require an adaptive explanation. Second, a common sequela of damage to the orbito-frontal lobes is Any pattern of behavior that can be produced by brain damage is unlikely to be adaptive. Third, we argue that most human social behavior is not under tight genetic control, but is produced by open-ended calculation of fitness-contingencies.

Heyman's model, paradoxically, predicts that whereas a maximizing approach to drug choice will prevent escalation of drug use it will never yield complete abstinence. We suggest an alternative model that overcomes this difficulty by focusing on changes in drug tolerance. A small modification allows maximization to predict either abstinence or moderation (e.g., social drinking).

The comparator model is insufficient for three reasons. First, consciousness is involved in the process of comparison as well as in the output. Second, we still do not have enough neurophysiological information to match the events of consciousness, although such knowledge is growing. Third, the anatomical localisation proposed can be damaged bilaterally but consciousness will persist.

Knowledge of specific instances of melioration does not imply knowledge of the variables controlling behavior. Drug self-administration has been successfully analyzed in terms of standard variables such as the immediacy and magnitude of the drug reinforcer. An appeal to melioration may not be necessary.

Sociopaths are “outstanding” members of society in two senses: politically, they draw our attention because of the inordinate amount of crime they commit, and psychologically, they hold our fascination because most ofus cannot fathom the cold, detached way they repeatedly harm and manipulate others. Proximate explanations from behavior genetics, child development, personality theory, learning theory, and social psychology describe a complex interaction of genetic and physiological risk factors with demographic and micro environmental variables that predispose a portion of the population (...) to chronic antisocial behavior. More recent, evolutionary and game theoretic models have tried to present an ultimate explanation of sociopathy as the expression of a frequency-dependent life strategy which is selected, in dynamic equilibrium, in response to certain varying environmental circumstances. This paper tries to integrate the proximate, developmental models with the ultimate, evolutionary ones, suggesting that two developmentally different etiologies of sociopathy emerge from two different evolutionary mechanisms. Social strategies for minimizing the incidence of sociopathic behavior in modern society should consider the two different etiologies and the factors that contribute to them. (shrink)

Recent studies lend support to the two-pathway model of the evolution of sociopathy with evidence that: 1) psychopathy (primary sociopathy) is a discrete type and 2) in general, sociopaths have relatively high levels of reproductive success. Hare's Psychopathy Checklist may provide a start for the revision of terminology that will be necessary to distinguish between primary and secondary trajectories.

Addictive behavior has never seemed rational because it persists in spite of drastic aversive consequences. This is a particular problem for models of addiction such as operant psychology which hold that behavior is controlled by its consequences. Inspite of claims to the contrary, Heymans target article illustrates how operant psychology resolves this contradiction. By using the matching law, Heyman suggests a mechanism that explains why delayed aversive events may not control behavior, and a conceptual framework in which we can understand (...) successful therapies. (shrink)

Numerous individual differences determine the effectiveness of the multiple external reinforcement contingencies that control drug seeking behavior. Differences in the capacity to frame reinforcement and also the toxic effects of drugs modulate susceptibility to addiction. As a result, not all individuals are at the same degree of risk for addiction.

Mealey's sociopathy model is an exemplar of popular diathesis-stress models. Although such models, when presented in descriptive language, offer the illusion of integrative explanation, their actual scientific value is very limited because they fail to make specific, quantitative, falsifiable predictions. Conceptual and quantitative weaknesses of such diathesis-stress models are discussed and the requirements for useful models are outlined.

The conflict between drug and conventional rewards leads to a paradox: Sanctions against drug use decrease access to conventional rewards and push drug users toward drug abuse, whereas increased access to the rewards of family, friends, and work may help reduce drug abuse. Lack of control is not specific to drug addiction and is unlikely to yield to a shift in bookkeeping.

A consideration of the genetics of sociopathy suggests the following. The author's Evolutionary Stable Strategy (ESS) types 2 to 4 are more likely than types 1 and 5 in crimes of violence, and there may not be an ESS for crimes of property or for sociopathy. Correlations between sociopathy and crimes of property are also more likely due to environmental than to genetic variants, and correlations between sociopathy and crimes of property are due more to environmental than genetic variants.

Evolutionary analysis suggests that policies based on deterrence may cope effectively with primary sociopathy if the threat of punishment fits the crime in the cost/benefit calculus of the sociopath, not that of the public. On the other hand, policies designed to offset serious disadvantage in social competition may help inhibit the development of secondary sociopathy, rather than deter its expression.

Heyman makes a convincing case that a melioration choice strategy is sufficient to produce addictive behavior. But given a plethora of addiction theories, the question is whether melioration theory is superior to rivals more sophisticated than a simple disease model or operant conditioning account. Heyman offers little direct evidence that melioration actually causes the addictions we observe.

Endorsing Mealey's analysis, it is pointed out that increasing rates of crime and violence are due to increasing proportions of children being reared in circumstances radically different from the extendedfamily environment to which we are evolntionarily adapted, that is, they are reared without fathers.

To avoid teleological interpretations, it is important to make a distinction between functions and uses of consciousness, and to address questions concerning the consequences of consciousness. Assumptions about the phylogenetic distribution of consciousness are examined. It is concluded that there is some value in identifying consciousness an exclusively human attribute.

Choosing the smaller, less delayed reinforcers of drug abuse (including cessation of withdrawal) over the larger, more delayed reinforcers of a healthy life can be described as impulsiveness (the opposite of self-control). Examination of drug abuse using a self-control/impulsiveness framework can help explain many of the puzzles about this behavior, while tying drug abuse into a large research database.

Gray's integration of the different levels of description and explanation in his theory is problematic: The introduction of consciousness into his theorising consists of the mind-brain identity assumption, which tells us nothing new. There need not be correlations between levels of description. Gray's account does not extend beyond “brute” correlation. Integration must be achieved in a principled, mutually constraining way.

Economic models of addiction are choice-based. These models push the choice paradigm too far by modeling addiction as rational, normative behavior. Heyman's target article provides a sensible alternative to this economic approach by emphasizing that addiction is characterized by ambivalence and a perceived loss of self control. However, matching may not be a satisfactory platform on which to build this alternative model. Matching experiments do not provide evidence of ambivalence or perceived loss of self control.

Although Mealey's account provides several interesting hypotheses, her integration across disparate samples renders the value of her explanation for psychopathy ambiguous. Recent evidence on Psychopathy Checklist-identified samples (Hare, 1991) suggests primary emotional and cognitive deficits inconsistent with her model. Whereas high-anxious psychopaths display interpersonal deficits consistent with Mealey's hypotheses, low-anxious psychopaths' deficits appear more sensitive to situational parameters than predicted.

For use in applied settings, the melioration model will need to incorporate changes in the shapes of local value functions over time, treat current value as a continuous function of time since previous choices, and take into account discounting of the effects of current behavior on future value. The policy implications of the model for regulating drugs are limited.

As Gray insists, his comparator model proposes a brute correlation only – of consciousness with septohippocampal output. I suggest that the comparator straddles a feedback loop that boosts the activation ofnovelrepresentations, thus helping them feature in present or recollected experience. Such a role in organizing conscious contents would transcend correlation and help explain how consciousness emerges from brain function.

We consider four mechanisms by which apparent discontinuities in the distribution of antisociality could arise: (1) executive genes or hormonal systems, (2) multiplicative interactions of predisposing factors, (3) environmental tracking into a limited number of social roles, and (4) cross-generational gene—environment interactions. A more explicit consideration of complex self-organizing dynamic systems may help us understand the maintenance of antisocial subpopulations.

To explore the mechanism of sensation correlations between EP component amplitude and signal detection indices were studied. The time of sensation coincided with the peak latency of those EP components that showed a correlation with both indices. The components presumably reflected information synthesis in projection cortical neurons. A mechanism providing the synthesis process is proposed.

Gray takes an information-processing paradigm as his departure point, invoking a comparator as part of the system. He concludes that consciousness is to be found “in” the comparator but is unable to point to how the comparison takes place. Thus, the comparator turns out not to be an entity arising out of brain research per se, but out of the logic of the paradigm. In this way, Gray both reinvents dualism and remains trapped in the language game of his own (...) model – ending up dealing with the unknowable. (shrink)

Heyman's target article is an analytical tour de force, but it makes too hard a distinction between voluntary and driven behavior. It is more fruitful to think about brain and behavior as shifting, interacting “agents,” represented by multiple neural circuits. This has the virtue of better connecting behavioral analysis with wet neuroscience.

Perspective and reflection have each been considered in some way basic to phenomenal consciousness. Each has possible evolutionary value, though neither seems sufficient for consciousness. Consider an account of consciousness in terms of the combination of perspective and reflection, its relationship to the problem of other minds, and its capacity to inherit evolutionary explanation from its components.

Although serotonin, testosterone, and genes contribute to sociopathy, the relationships are probably indirect and subject to modifiers (e.g., present only under certain conditions of rearing and temperament). Age at menarche may be a marker variable as well as a causal factor. Since the genders differ in all four areas, sex differences in sociopathy represent a very complex interaction of these factors.

I discuss various theoretical issues concerning maximizing, matching, and melioration. The model of addiction based on melioration has the key feature that a reduction in drag use increases both the value of drag-taking and the value of conventional activities. I found Heyman's target article stimulating. I don't feel competent to comment on drags but I do have some thoughts, both general and specific, on the theoretical issues.

Mealey's work has several interesting implications: It refutes the charge that sociobiology paints a cynical portrait of human nature and adopts a one-sided reductionism; it exemplifies a general theoretical scheme for constructing evolutionary biopsychosocial models of human behavior; and it has the practical effect of promoting and informing early intervention in children at risk for psychopathic disorder.

Heyman's analysis of addiction suggests that drug taking is irrational. The irrationality of drug taking, however, may depend on the acceptance of mainstream society's view of what is valuable. Consideration of the addict's viewpoint and cultural aspects of drug taking may be useful in trying to fathom the “rationality” of drug taking.

I support the major theme of Heyman's target article that behavioral choice theory can enhance our understanding of drug dependence, but I raise concerns about the critique of the operant model of drug dependence, the underscoring of melioration to the exclusion of other theories of choice, and assertions about the unique effects of drug reinforcement.

The target article emphasizes the relationship between a matching law-based theory of addiction and the disease model of addiction. In contrast, this response emphasizes the relationship between the matching law theory and other behavioral approaches to addiction. The basic difference, I argue, is that the matching law specifies that choice is governed by local reinforcement rates. In contrast, economics says that overall reinforcement rate controls choice, and for other approaches there are other measures or no clear prediction at all. The (...) response also differs from the target article in that there is more emphasis on the finding that stimulus conditions determine whether choice is under local or overall reinforcement rate control. (shrink)

Research findings on addiction are contradictory. According to biographical records and widely used diagnostic manuals, addicts use drugs compulsively, meaning that drug use is out of control and independent of its aversive consequences. This account is supported by studies that show significant heritabilities for alcoholism and other addictions and by laboratory experiments in which repeated administration of addictive drugs caused changes in neural substrates associated with reward. Epidemiological and experimental data, however, show that the consequences of drug consumption can significantly (...) modify drug intake in addicts. The disease model can account for the compulsive features of addiction, but not occasions in which price and punishment reduced drug consumption in addicts. Conversely, learning models of addiction can account for the influence of price and punishment, but not compulsive drug taking. The occasion for this target article is that recent developments in behavioral choice theory resolve the apparent contradictions in the addiction literature. The basic argument includes the following four statements: First, repeated consumption of an addictive drug decreases its future value and the future value of competing activities. Second, the frequency of an activity is a function of its relative (not absolute) value. This implies that an activity that reduces the values of competing behaviors can increase in frequency even if its own value also declines. Third, a recent experiment (Heyman & Tanz 1995) shows that the effective reinforcement contingencies are relative to a frame of reference, and this frame of reference can change so as to favor optimal or suboptimal choice. Fourth, if the frame of reference is local, reinforcement contingencies will favor excessive drug use, but if the frame of reference is global, the reinforcement contingencies will favor controlled drug use. The transition from a global to a local frame of reference explains relapse and other compulsive features of addiction. (shrink)

It is accepted that “primary awareness” may emerge from the integration of two classes of information. It is unclear, however, why this cannot take place within the comparator rather than in conjunction with feedback to the perceptual systems. The model has plausibility in relation to the continuity of conscious experience in the normal waking state and may be extended to encompass certain aspects of the “sense of self” which are frequently disrupted in psychotic patients.

Justification thinking (using excuses to “allow” giving into temptation) has been identified as a potential link between negative affect and self-control failure. We hypothesised that negative affect would prompt greater justification thinking, specifically deservingness thinking (i.e. “I deserve a treat”), and tested this for both inhibitory (temptation is to approach reward; self-control is to inhibit) and initiatory (temptation is to refrain from action, self-control is to initiate action) hypothetical self-control dilemmas. We found that only for inhibitory self-control (Study 1; N (...) = 105) but not initiatory (Study 2; N = 116), negative affect resulted in greater deservingness thinking compared to neutral affect. We also hypothesised that negative mood coupled with justification would prompt greater likelihood of imagined self-control failure. We found that for inhibitory self-control (Study 3; N = 569), participants in negative affect (vs. neutral) and justification (vs. no justification) conditions were independently more likely to report they would fail at self-control. For initiatory self-control (Study 4; N = 321), we found an effect of negative affect on hypothetical self-control failure but no effect of justification. Overall, these studies confirm the role of negative affect in self-control processes and highlight differences between inhibitory and initiatory self-control situations. (shrink)