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The Neurobiological Foundations of Altruism
Abstract
This project advocates an urgent role for neurobiological evidence and models in the study of altruism. I argue for two claims: that neurobiological evidence should be used to constrain candidate scientific accounts of altruistic behavior, and that neurobiological techniques can be used to elucidate component mechanisms of altruistic behavior.
Chapter 1 reviews the historical progression of theories of altruism, and the empirical observations that motivated their development. A distinction is drawn between evolutionary altruism -- any self-sacrificial, fitness-reducing behavior, and psychological altruism -- self-sacrificial behaviors that are caused by psychological states like desire and motivation. Three theories of psychological altruism are described, and it is argued that the crucial difference between these theories is their conceptions of the role of affect in motivation, and how the processes of affect and motivation contribute to psychological altruism.
Chapter 2 describes dominant theories of motivation and the neurobiological and psychological mechanisms that support motivated behavior. Although the evidence is not conclusive, I argue that our best scientific models and neurobiological evidence support affective models of psychological altruism, and that other models are at best incomplete and possibly implausible in light of neurobiological considerations.
Chapter 3 introduces mind reading approaches to altruism, which argue that the capacity for altruistic motivations depends upon the capacity to represent the psychological states or circumstances of others. I conclude that altruism requires at a minimum the ability to attribute affective experiences to others. Further, I argue that the representations produced by mind reading processes provide a means for distinguishing between self-regarding and altruistic motivations. In contrast with the dominant philosophical theory of psychological altruism, the mind reading model I propose is compatible with the affective theory of motivation depicted in Chapter 2. My own empirical work is described as an example of how neurobiological techniques can reveal the differential role of neural systems in producing self-regarding and altruistic behavior.
Chapter 4 departs from the mechanistic approach to altruism discussed in the previous chapters, and presents an overview of how the fields of philosophy, psychology, psychobiology and genetics, have investigated altruism as a stable characteristic or personality trait. Recent technological advances make this a promising approach for investigating the psychological and neurobiological systems supporting altruistic behavior.
Dissertation
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We propose that the crucial difference between human cognition and that of other species is the ability to participate with others in collaborative activities with shared goals and intentions: shared intentionality. Participation in such activities requires not only especially powerful forms of intention reading and cultural learning, but also a unique motivation to share psychological states with others and unique forms of cognitive representation for doing so. The result of participating in these activities is species-unique forms of cultural cognition and evolution, enabling everything from the creation and use of linguistic symbols to the construction of social norms and individual beliefs to the establishment of social institutions. In support of this proposal we argue and present evidence that great apes (and some children with autism) understand the basics of intentional action, but they still do not participate in activities involving joint intentions and attention (shared intentionality). Human children's skills of shared intentionality develop gradually during the first 14 months of life as two ontogenetic pathways intertwine: (1) the general ape line of understanding others as animate, goal-directed, and intentional agents; and (2) a species-unique motivation to share emotions, experience, and activities with other persons. The developmental outcome is children's ability to construct dialogic cognitive representations, which enable them to participate in earnest in the collectivity that is human cognition.
A model is presented to account for the natural selection of what is termed reciprocally altruistic behavior. The model shows how selection can operate against the cheater (non-reciprocator) in the system. Three instances of altruistic behavior are discussed, the evolution of which the model can explain: (1) behavior involved in cleaning symbioses; (2) warning cries in birds; and (3) human reciprocal altruism. Regarding human reciprocal altruism, it is shown that the details of the psychological system that regulates this altruism can be explained by the model. Specifically, friendship, dislike, moralistic aggression, gratitude, sympathy, trust, suspicion, trustworthiness, aspects of guilt, and some forms of dishonesty and hypocrisy can be explained as important adaptations to regulate the altruistic system. Each individual human is seen as possessing altruistic and cheating tendencies, the expression of which is sensitive to developmental variables that were selected to set the tendencies at a balance ap...
Sober and Wilson have recentlyclaimed that evolutionary theory can do whatneither philosophy nor experimental psychologyhave been able to, namely, ``break the deadlock''in the egoism vs. altruism debate with anargument based on the reliability of altruisticmotivation. I analyze both their reliabilityargument and the experimental evidence ofsocial psychology in favor of altruism in termsof the folk-psychological ``laws'' and inferencepatterns underlying them, and conclude thatthey both rely on the same patterns. I exposethe confusions that have led Sober and Wilsonto defend a reliability argument whilerejecting the experimental evidence of socialpsychology.
This study investigated the performance of boys with psychopathic tendencies and comparison boys, aged 9 to 17 years, on two tasks believed to be sensitive to amygdala and orbitofrontal cortex functioning. Fifty-one boys were divided into two groups according to the Psychopathy Screening Device (PSD, P. J. Frick & R. D. Hare, in press) and presented with two tasks. The tasks were the gambling task (A. Bechara, A. R. Damasio, H. Damasio, & S. W. Anderson, 1994) and the Intradimensional/Extradimensional (ID/ED) shift task (R. Dias, T. W. Robbins, & A. C. Roberts, 1996). The boys with psychopathic tendencies showed impaired performance on the gambling task. However, there were no group differences on the ID/ED task either for response reversal or extradimensional set shifting. The implications of these results for models of psychopathy are discussed.
An essential, evolutionarily stable feature of brain function is the detection of animate entities, and one of the main cues to identify them is their movement. We developed a model of a simple interaction between two objects, in which an increase of the correlation between their movements varied the amount of interactivity and animacy observers attributed to them. Functional magnetic resonance imaging revealed that activation in the posterior superior temporal sulcus and gyrus (pSTS/pSTG) increased in relation to the degree of correlated motion between the two objects. This activation increase was not different when subjects performed an explicit or implicit task while observing these interacting objects. These data suggest that the pSTS and pSTG play a role in the automatic identification of animate entities, by responding directly to an objective movement characteristic inducing the percept of animacy, such as the amount of interactivity between two moving objects.
We report a functional neuroimaging study with positron emission tomography (PET) in which six healthy adult volunteers were scanned while watching silent computer-presented animations. The characters in the animations were simple geometrical shapes whose movement patterns selectively evoked mental state attribution or simple action description. Results showed increased activation in association with mental state attribution in four main regions: medial prefrontal cortex, temporoparietal junction (superior temporal sulcus), basal temporal regions (fusiform gyrus and temporal poles adjacent to the amygdala), and extrastriate cortex (occipital gyrus). Previous imaging studies have implicated these regions in self-monitoring, in the perception of biological motion, and in the attribution of mental states using verbal stimuli or visual depictions of the human form. We suggest that these regions form a network for processing information about intentions, and speculate that the ability to make inferences about other people's mental states evolved from the ability to make inferences about other creatures' actions.
Previous functional imaging studies have explored the brain regions activated by tasks requiring 'theory of mind'--the attribution of mental states. Tasks used have been primarily verbal, and it has been unclear to what extent different results have reflected different tasks, scanning techniques, or genuinely distinct regions of activation. Here we report results from a functional magnetic resonance imaging study (fMRI) involving two rather different tasks both designed to tap theory of mind. Brain activation during the theory of mind condition of a story task and a cartoon task showed considerable overlap, specifically in the medial prefrontal cortex (paracingulate cortex). These results are discussed in relation to the cognitive mechanisms underpinning our everyday ability to 'mind-read'.
Thesis--University of Texas at Austin. Vita. Includes bibliographical references (leaves 209-219).
The book offers an original theory of meaning in discourse that combines a dynamic representation of discourse with an intentional explanation of processing. It contains an exposition of a theory of default semantics and its application to a range of language constructions. Default semantics provides cognitive foundations of discourse interpretation and does so in a broadly conceived truth-conditional framework where truth conditions are applied to utterances. The theory combines the subject matter of post-Gricean ‘truth-conditional pragmatics’ with the formalism and semanticization of meaning found in discourse representation theory (DRT). It is assumed that pragmatic information can contribute to the truth-conditional representation of an utterance. This information can have the form of (i) conscious inference, or it can have a form of default interpretation conceived of as (ii) cognitive defaults and (iii) social-cultural defaults. From DRT, it borrows the idea of dynamic semantics as context change implemented in semantic representation and the idea that meaning in discourse will, somehow or other, turn out to be compositional, that is, it will turn out to be a function of the parts and the structure. In short, default semantics combines two seemingly incompatible assumptions that (i) pragmatic input contributes to the truth conditions and (ii) the theory of meaning of utterances and discourses is a compositional, semantic theory. Such semantic representations are called merger representations in that they combine (merge) information from word meaning, sentence structure, pragmatic inference, and various kinds of defaults. Predicating compositionality of such merger representations aided by using an extended and amended language of DRT allows for the semanticization of the account of discourse meaning. The book is divided into two parts. Part I contains theoretical foundations and addresses the questions of the semantics/pragmatics boundary, underspecification, logical form, levels of representation, default meanings, and ‘pragmatic’ compositionality of merger representations. Part II contains some applications of the theory, including definite descriptions, propositional attitude reports, temporality, presupposition, sentential connectives, and number terms.
This chapter focuses on functional magnetic resonance imaging (FMRI). Techniques that can localize functional activity can provide clinically relevant information in cases of distorted or uncertain brain anatomy. Functional imaging is also valuable in the surgical treatment of brain lesions. In many cases, the precise localization of essential functional cortex is required to minimize postoperative neurologic deficit yet allow maximum removal of diseased or dysfunctional tissue. The preoperative identification of essential functional regions allows evaluation of both surgical feasibility and approach. The resulting clinical benefits include improved identification of candidates for successful surgery, improved outcome of those surgeries undertaken, and reduced overall treatment cost. Presurgical localization of critical functional regions is an area where FMRI can be immediately clinically useful. FMRI offers the possibility of performing these localizations routinely and on existing rather than expensive new instrumentation. Image acquisition and processing times are similar to those for structural MRI examinations and allow the ready integration of FMRI into existing radiology practice.
Although clinical evidence of spatial attention deficits, such as neglect and extinction, is typically associated with lesions of the right temporal-parietal junction, recent evidence has suggested an important role for the superior parietal lobe. Two groups of patients, selected for lesions at the temporal-parietal junction including the superior temporal gyrus (TPJ group), or for lesions involving the parietal but not the superior temporal region (PAR group), performed cued-target detection tasks in 2 experiments. An extinction-like response time pattern was found for the TPJ but not the PAR group. In addition, both groups were able to use expectancy information, in the form of cue predictiveness, suggesting that separate mechanisms mediate exogenous and endogenous processes during attention shifts. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Allelic variants at the catechol-O-methyl-transferase (COMT) locus are candidates to contribute to genetic components of interindividual differences in vulnerability to substance abuse. COMT plays a prominent role in dopaminergic circuits important for drug reward, and COMT alleles encode enzymes whose activities vary from three- to four-fold. We compared COMT allele frequencies in control research volunteers reporting insignificant lifetime use of addictive substances with those in volunteers reporting substantial polysubstance use. Homozygosity for the high-activity COMT allele was found in 18% of controls, 31% of volunteers with high lifetime substance use, and 39% meeting DSMIII-R substance abuse criteria [odds ratio (relative risks) 2.0 (control vs. use; 95% confidence interval 1.2-3.5; P < 0.013) and 2.8 (control vs. DSM; 1.3-6.1; P < 0.008)]. Individuals with the high-activity COMT variant may have greater genetic vulnerability to drug abuse. Am. J. Med. Genet. 74:439–442, 1997.
What roles do mesolimbic and neostriatal dopamine systems play in reward? Do they mediate the hedonic impact of rewarding stimuli? Do they mediate hedonic reward learning and associative prediction? Our review of the literature, together with results of a new study of residual reward capacity after dopamine depletion, indicates the answer to both questions is 'no'. Rather, dopamine systems may mediate the incentive salience of rewards, modulating their motivational value in a manner separable from hedonia and reward learning. In a study of the consequences of dopamine loss, rats were depleted of dopamine in the nucleus accumbens and neostriatum by up to 99% using 6-hydroxydopamine. In a series of experiments, we applied the 'taste reactivity' measure of affective reactions (gapes, etc.) to assess the capacity of dopamine-depleted rats for: 1) normal affect (hedonic and aversive reactions), 2) modulation of hedonic affect by associative learning (taste aversion conditioning), and 3) hedonic enhancement of affect by non-dopaminergic pharmacological manipulation of palatability (benzodiazepine administration). We found normal hedonic reaction patterns to sucrose vs. quinine, normal learning of new hedonic stimulus values (a change in palatability based on predictive relations), and normal pharmacological hedonic enhancement of palatability. We discuss these results in the context of hypotheses and data concerning the role of dopamine in reward. We review neurochemical, electrophysiological, and other behavioral evidence. We conclude that dopamine systems are not needed either to mediate the hedonic pleasure of reinforcers or to mediate predictive associations involved in hedonic reward learning. We conclude instead that dopamine may be more important to incentive salience attributions to the neural representations of reward-related stimuli. Incentive salience, we suggest, is a distinct component of motivation and reward. In other words, dopamine systems are necessary for 'wanting' incentives, but not for 'liking' them or for learning new 'likes' and 'dislikes'.
We review evidence for partially segregated networks of brain areas that carry out different attentional functions. One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected. This ventral frontoparietal network works as a 'circuit breaker' for the dorsal system, directing attention to salient events. Both attentional systems interact during normal vision, and both are disrupted in unilateral spatial neglect.
This book argues that recent work in philosophy, neuroscience, and anthropology supports two radical hypotheses about the nature of morality: moral values are based on emotional responses, and these emotional responses are inculcated by culture, not hard-wired through natural selection. In the first half of the book, the hypothesis that morality has an emotional foundation is defended. Evidence from brain imaging, social psychology, and psychopathology suggest that, when we judge something to be right or wrong, we are merely expressing our emotions. The book claims that these emotions do not track objective features of reality; rather, the rightness and wrongness of an act consists in the fact that people are disposed to have certain emotions towards it. In the second half of the book, it turns to a defence of moral relativism. Moral facts depend on emotional responses, and emotional responses vary from culture to culture. The book surveys the anthropological record to establish moral variation, and draws on cultural history to show how attitudes toward practices such as cannibalism and marriage change over time. It also criticizes evidence from animal behaviour and child development that has been taken to support the claim that moral attitudes are hard-wired by natural selection. The book concludes that there is no single true morality, but also argues that some moral values are better than others; moral progress is possible.
This paper is divided into two parts. In the first, the rank order stability of individual differences in altruism across situations is examined and it is found that substantial consistency occurs when due regard is given to the principle of aggregation. In the second, a self-report altruism scale, on which respondents rate the frequency with which they have engaged in some 20 specific behaviors, is found to predict such criteria as peer-ratings of altruism, completing an organ-donor card, and paper-and-pencil measures of prosocial orientation. These data suggest there is a broad-based trait of altruism.
This chapter examines brain mechanisms of reward utility operating at particular decision moments in life—moments such as when one encounters an image, sound, scent, or other cue associated in the past with a particular reward or perhaps just when one vividly imagines that cue. Such a cue can often trigger a sudden motivational urge to pursue its reward and sometimes a decision to do so. Drawing on a utility taxonomy that distinguishes among subtypes of reward utility—predicted utility, decision utility, experienced utility, and remembered utility—it is shown how cue-triggered cravings, such as an addict's surrender to relapse, can hang on special transformations by brain mesolimbic systems of one utility subtype, namely, decision utility. The chapter focuses on a particular form of decision utility called incentive salience, a type of "wanting" for rewards that is amplifi ed by brain mesolimbic systems. Sudden peaks of intensity of incentive salience, caused by neurobiological mechanisms, can elevate the decision utility of a particular reward at the moment its cue occurs. An understanding of what happens at such moments leads to a better understanding of the mechanisms at work in decision making in general.
L'A. applique les resultats et les theories des sciences cognitives au domaine de l'ethique, en particulier au jugement de valeurs, a la question du bien procure par une action, et au mecanisme psychique qui intervient dans le sentiment et le choix moral. Il montre en particulier l'importance de l'empathie dans la determination a agir moralement
In the current resurgence of interest in the biological basis of animal behavior and social organization, the ideas and questions pursued by Charles Darwin remain fresh and insightful. This is especially true of The Descent of Man and Selection in Relation to Sex, Darwin's second most important work. This edition is a facsimile reprint of the first printing of the first edition (1871), not previously available in paperback. The work is divided into two parts. Part One marshals behavioral and morphological evidence to argue that humans evolved from other animals. Darwin shoes that human mental and emotional capacities, far from making human beings unique, are evidence of an animal origin and evolutionary development. Part Two is an extended discussion of the differences between the sexes of many species and how they arose as a result of selection. Here Darwin lays the foundation for much contemporary research by arguing that many characteristics of animals have evolved not in response to the selective pressures exerted by their physical and biological environment, but rather to confer an advantage in sexual competition. These two themes are drawn together in two final chapters on the role of sexual selection in humans. In their Introduction, Professors Bonner and May discuss the place of The Descent in its own time and relation to current work in biology and other disciplines.
Prosocial behavior in 5-8-year-old children was examined in relation to social inferential ability and assertiveness. It was hypothesized that assertiveness would be a significant predictor of prosocial behavior but that the strength of the relation would depend on the child's ability to make inferences about others' behaviors. 39 boys and 40 girls attending a summer day camp were each observed over a 6-week period and their assertive and prosocial behaviors recorded. Inferential ability was assessed by asking the child to interpret a series of videotaped social episodes in which an affective experience brought about an abrupt change in the central character's behavior. Correct interpretation depended on the subject's comprehending the relation between the earlier events in the sequence and the change in behavior. As hypothesized, assertiveness was positively and significantly related to prosocial behavior for high inferential ability subjects while no significant relations were identified in the low inferential ability group.
The purpose of this study was to identify personality characteristics associated with kin altruism and reciprocal altruism, and to relate those characteristics to the Big Five personality dimensions. We hypothesized that traits such as empathy and attachment mainly facilitate kin altruism, and that traits such as forgiveness and non-retaliation mainly facilitate reciprocal altruism. Self-report items that we constructed to measure those kinds of personality traits defined two factors as hypothesized. Those factors correlated significantly with external criterion measures intended to represent kin altruism and reciprocal altruism, respectively. Furthermore, correlations with adjective markers of the Big Five indicated that the Empathy/Attachment factor was related positively to Agreeableness and negatively to Emotional Stability, whereas the Forgiveness/Non-Retaliation factor was related positively to both Agreeableness and Emotional Stability.
Moral theorists often invoke sociopaths and psychopaths as the quintessential example of a morally impaired agent. In the current debate, both moral rationalists, who argue that moral competence consists in the ability to apply a set of moral rules, and moral sentimentalists, who define moral competence as appropriate emotional responding, refer to evidence regarding these pathologies to support their theory. Neither experimental data on antisocial pathologies nor neuroscientific data provide definitive support for either moral theory, but both of these empirical literatures suggest a deep complexity in the mechanisms supporting moral competence, and perhaps an inadequacy of our current conceptions of "emotional" versus "rational" or "cognitive" systems, and how these contribute to psychopathology and influence "moral" capacities.
Explored the relationship between cognitive perspective taking (the ability to infer another person's thoughts, attitudes, or intentions) and teachers' ratings of classroom behavior of 96 1st–4th graders. Good cognitive perspective taking skill was related to classroom behaviors that involved active peer interactions, particularly fighting/quarrelling. This finding supports Piaget's contention that the decline in egocentric reasoning is brought about through peer involvement. It is suggested that although the present evidence suggests that cognitive perspective taking may be a cognitive prerequisite for various social behaviors, the investigation of the link between social cognition and social behavior would proceed more fruitfully if the motivational systems underlying the social behavior of interest were identified and assessed. (24 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Tested the hypothesis that empathy leads to altruistic rather than egoistic motivation to help. 44 female college students watched another female undergraduate receive electric shocks and were then given a chance to help her by taking the remaining shocks themselves. In each of 2 experiments, Ss' empathic emotion (low vs high) and their ease of escape from continuing to watch the victim suffer if they did not help (easy vs difficult) were manipulated in a 2 × 2 design. It was reasoned that if empathy led to altruistic motivation, Ss feeling a high degree of empathy for the victim should be as ready to help when escape without helping was easy as when it was difficult. But if empathy led to egoistic motivation, Ss feeling empathy should be more ready to help when escape was difficult than when it was easy. Results followed the former pattern when empathy was high and the latter pattern when empathy was low, supporting the hypothesis that empathy leads to altruistic rather than egoistic motivation to help. (19 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Investigated the psychophysiological responsiveness of children with autism and comparison groups to distress cues, threatening and neutral stimuli. 20 children (mean age 11.95 yrs) with autism, 20 children (mean age 10.9 yrs) with moderate learning difficulty and 20 normal developing children (mean age 6.27 yrs) were shown slides of these 3 types of stimuli and their electrodermal responses were recorded. The children with autism showed appropriate electrodermal responses to the distress cues. However, and surprisingly, the children with autism were hyporesponsive to the threatening stimuli. The results are interpreted with reference to the violence inhibition mechanism model (R. J. R. Blair, 1995) and possible frontal lobe dysfunction in autism. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The results of research dealing with the effects of noise on intrapersonal behavior suggest a variety of possible consequences for interpersonal functioning. The effects of various levels of noise on simple helping behavior were explored in a laboratory and a field setting for a total of 132 male Ss. In 2 experiments, Ss exposed to 85-db white noise were less likely than those in lower noise conditions to offer assistance to a person in need. Results are interpreted on the basis of prior research suggesting that noise-produced arousal leads to a restriction in attention deployment or cue utilization. Alternative accounts in terms of the effect of noise on mood and on drive level are also considered. (34 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Conducted 4 experiments with a total of 97 male and 98 female newborn infants to determine whether reflexive crying occurs in newborns and to define the parameters that control this behavior. It was found that (a) vocal properties of the newborn's cry were effective in promoting crying in other newborns, and (b) that feedback from the infant's own cry may be instrumental in the development of this behavior. Data were obtained questioning the likelihood of a direct relationship between reflexive crying and the later development of preverbal vocal behavior. Ancillary results pertaining to a seasonal trend, sex differences, and the role of arousal in supporting reflexive crying are provided. (39 ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Reviews the evidence regarding the development of altruism and suggests that various forms of perspective-taking (perceptual, social, empathic, moral) might be the mediators of this development. Previous reviews in this area have generally concluded that the evidence relating perspective-taking and prosocial behavior is equivocal. Using a technique that allows the assignment of an exact probability to the results of a series of studies, the present authors conclude that there are reliable relations between altruism and perceptual, social, and moral perspective-taking. The results concerning empathy and altruism are nonsignificant overall, but it is suggested that a reliable association between empathy and altruism develops over time and is found in adults. The significant effects cannot be attributed to artifactual effects of either age or other measures of perspective-taking, nor can these relations completely account for age-related increases in altruism. The evidence for a causal influence of perspective-taking on altruism is strongest for studies of empathy and altruism among adults, but even there it is not totally conclusive. (64 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
We investigate individual differences in behaviour within an ultimatum game with advance production. It is a simple bargaining game, in which the size of the ‘pie’ to be distributed between two parties depends on both players' monetary investments. One player, the ‘proposer’, has to state a demand, which can be accepted as it is or rejected (with the consequence of zero return for both players) by the second player (‘responder’). We find that global personality measures contribute significantly to the explanation of both demands and rejection decisions. Proposers who score high on independence and tough-mindedness, two global personality dimensions with affinity to selfishness, demand higher return shares than proposers who score low on these dimensions. This is particularly true when the proposer's cost share is low, i.e. when a high demanded return share cannot be justified by a concern for equity. In this situation there is a strong conflict between economic rationality and equity. Regarding rejection decisions we find that reciprocity oriented responders (i.e. persons who are either emotionally unstable and extraverted or emotionally stable and introverted) reject a proposal more often than others. Rejection of an unsatisfying offer is interpreted as an act of angry retaliation (negative reciprocity) against an interaction partner who violates the social norm of equity. Copyright © 2001 John Wiley & Sons, Ltd.
IntroductionProcessing Models and Levels of ExplanationAutomaticity and Executive ControlBeyond the Cognitive Architecture: Bias at the Knowledge LevelIntegrating Levels of Explanation: The S-ref ModelImplications for TherapyConclusion
AcknowledgementReferences
In recent attempts to characterize the cognitive mechanisms underlying altruistic motivation, one central question is the extent to which the capacity for altruism depends on the capacity for understanding other minds, or ‘mindreading’. Some theorists maintain that the capacity for altruism is independent of any capacity for mindreading; others maintain that the capacity for altruism depends on fairly sophisticated mindreading skills. I argue that none of the prevailing accounts is adequate. Rather, I argue that altruistic motivation depends on a basic affective system, a ‘Concern Mechanism’, which requires only a minimal capacity for mindreading.
A critical review of major trends and developments in the study of children's helping behavior is presented, with specific emphasis on demand characteristics of different situations (rescue, donation, assistance) and methodological difficulties inherent in such a study. In general, researchers have been able to isolate certain here-and-now situational influences which have led to mean increases in children's sharing behavior. As yet, however, relatively few studies have attempted to isolate personal characteristics of individual children as a means of examining baseline differences of individuals across different helping behaviors. As a start, this paper calls for a person-situation interactional approach to the study of children's helping behavior, examining such key factors as the child's family style, status in the peer group, and personality style as interactive with the characteristics of the particular helping situation.
The analysis of the behavioural and neural mechanisms of reinforcement and motivation has benefited from the recent application of learning theory and better anatomical knowledge of the connectivity of certain key neural structures, such as the nucleus accumbens. This progress has enabled the dissection of motivational processes into components that can begin to be related to the functioning of specific limbic cortical structures that project to different compartments of the ventral striatum.
What roles do mesolimbic and neostriatal dopamine systems play in reward? Do they mediate the hedonic impact of rewarding stimuli? Do they mediate hedonic reward learning and associative prediction? Our review of the literature, together with results of a new study of residual reward capacity after dopamine depletion, indicates the answer to both questions is `no'. Rather, dopamine systems may mediate the incentive salience of rewards, modulating their motivational value in a manner separable from hedonia and reward learning. In a study of the consequences of dopamine loss, rats were depleted of dopamine in the nucleus accumbens and neostriatum by up to 99% using 6-hydroxydopamine. In a series of experiments, we applied the `taste reactivity' measure of affective reactions (gapes, etc.) to assess the capacity of dopamine-depleted rats for: 1) normal affect (hedonic and aversive reactions), 2) modulation of hedonic affect by associative learning (taste aversion conditioning), and 3) hedonic enhancement of affect by non-dopaminergic pharmacological manipulation of palatability (benzodiazepine administration). We found normal hedonic reaction patterns to sucrose vs. quinine, normal learning of new hedonic stimulus values (a change in palatability based on predictive relations), and normal pharmacological hedonic enhancement of palatability. We discuss these results in the context of hypotheses and data concerning the role of dopamine in reward. We review neurochemical, electrophysiological, and other behavioral evidence. We conclude that dopamine systems are not needed either to mediate the hedonic pleasure of reinforcers or to mediate predictive associations involved in hedonic reward learning. We conclude instead that dopamine may be more important to incentive salience attributions to the neural representations of reward-related stimuli. Incentive salience, we suggest, is a distinct component of motivation and reward. In other words, dopamine systems are necessary for `wanting' incentives, but not for `liking' them or for learning new `likes' and `dislikes'.
Mesencephalic dopamine neurons are believed to facilitate reward-dependent learning by computing errors in reward predictions. We used fMRI to test whether this system was activated as expected in response to errors in predictions about whether a social partner would reciprocate an act of altruism. Nineteen subjects received fMRI scans as they played a series of single-shot Prisoner's Dilemma games with partners who were outside the scanner. In both ventromedial prefrontal cortex and ventral striatum, reciprocated and unreciprocated cooperation were associated with positive and negative BOLD responses, respectively. Our results are consistent with the hypothesis that mesencephalic dopamine projection sites carry information about errors in reward prediction that allow us to learn who can and cannot be trusted to reciprocate favors.