The depressed brain: an evolutionary systems theory
Open accessAbstract
Major depression is a debilitating condition characterised by diverse neurocognitive and behavioural deficits. Nevertheless, our species-typical capacity for depressed mood implies that it serves an adaptive function. Here we apply an interdisciplinary theory of brain function to explain depressed mood and its clinical manifestations. Combining insights from the free-energy principle (FEP) with evolutionary theorising in psychology, we argue that depression reflects an adaptive response to perceived threats of aversive social outcomes (e.g., exclusion) that minimises the likelihood of surprising interpersonal exchanges (i.e., those with unpredictable outcomes). We suggest that psychopathology typically arises from ineffectual attempts to alleviate interpersonal difficulties and/or hyper-reactive neurobiological responses to social stress (i.e., uncertainty), which often stems from early experience that social uncertainty is difficult to resolve.
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- Premisecitation
This risk-averse approach increases cognitive sensitivity to sensory cues of social risk.
“This maintains that depressed mood reflects an adaptive, risk-averse approach to social interaction that reduces the likelihood of further aversive outcomes by: (1) increasing our cognitive sensitivity to (sensory) cues of social risk; (2) reducing our (behavioural) propensity for taking social risks; and (3) initiating signalling behaviours that elicit support and defuse conflict [32].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [32] source
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- Interpretationreasoning
Depression is an adaptive response to perceived threats of aversive social outcomes (e.g., exclusion) that reduces the likelihood of surprising interpersonal exchanges.
“we argue that depression reflects an adaptive response to perceived threats of aversive social outcomes (e.g., exclusion) that minimises the likelihood of surprising interpersonal exchanges (i.e., those with unpredictable outcomes).”
- Also stated in: § Concluding Remarks · plain
“normative levels of depressed mood instantiate an adaptive prior that minimises the likelihood of surprising interpersonal interactions when faced with threats of aversive social outcomes that typically compromised ancestral fitness.”
Quote in the paperSubstantial claim- The authors state this as an assumption: The brain is a hierarchical, self-organising system sculpted by evolution.
- The authors state this as an assumption: The brain is situated within the evolutionary dynamics of the brain-body-environment system.
- Also stated in: § Concluding Remarks · plain
- Premisecitation
Exposure to early social stress (e.g., parental loss, abuse, or neglect) is a strong predictor of depressive vulnerability.
“Ontogenetically, exposure to early social stress (e.g., parental loss, abuse, or neglect) is a strong predictor of depressive vulnerability [37]”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [37] source
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- Premisecitation
Social support and belonging are key protective factors against depression.
“social support and belonging are key protective factors [45]”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [45] source
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- Premisecitation
This risk-averse approach reduces behavioural propensity for taking social risks.
“This maintains that depressed mood reflects an adaptive, risk-averse approach to social interaction that reduces the likelihood of further aversive outcomes by: (1) increasing our cognitive sensitivity to (sensory) cues of social risk; (2) reducing our (behavioural) propensity for taking social risks; and (3) initiating signalling behaviours that elicit support and defuse conflict [32].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [32] source
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- Premisecitation
Depressed mood reflects an adaptive, risk-averse approach to social interaction that reduces the likelihood of further aversive outcomes.
“This maintains that depressed mood reflects an adaptive, risk-averse approach to social interaction that reduces the likelihood of further aversive outcomes by: (1) increasing our cognitive sensitivity to (sensory) cues of social risk; (2) reducing our (behavioural) propensity for taking social risks; and (3) initiating signalling behaviours that elicit support and defuse conflict [32].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [32] source
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- Premisecitation
Conditional expectations are encoded by deep pyramidal cells (representation units) at each cortical level, which convey predictions downward to suppress errors at the level below.
“Conditional expectations are thought to be encoded by deep pyramidal cells (i.e., representation units) at each level of the cortical hierarchy that convey predictions downward to suppress errors at the level below”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [10] source
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- Premisecitation
Prediction errors are encoded by superficial pyramidal cells (error units) that convey errors forward to revise expectations at the level above.
“while prediction errors are encoded by superficial pyramidal cells (i.e., error units) that convey errors forward to revise expectations at the level above [10].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [10] source
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- Premisereasoning
Predictions are optimised by evolution, development and learning.
“A key corollary of this model is that our predictions are optimised by evolution, development and learning.”
Quote in the paperSubstantial claim - Premisecitation
The risk of depressive onset rises markedly in adolescence because of an increased sensitivity to social threats in this period.
“Behavioural and neuroimaging studies further suggest that the risk of depressive onset rises markedly in adolescence because of an increased sensitivity to social threats in this period [41,42].”
Quote in the paperNot a substantial claim0 of 2 sources checked- cites [41] source
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- cites [42]
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- Premisereasoning
Depression entails impairments in reward-approach systems emerging from deficits in predictive processing of sensory evidence and prior beliefs that negatively bias predictions.
“Taken together, the frameworks considered here suggest that depression entails impairments in reward-approach systems emerging from two neurocognitive processesdeficits in the predictive processing of sensory evidence; and prior beliefs that negatively bias predictions.”
Quote in the paperSubstantial claim - Premisecitation
Early social stress is thought to heighten susceptibility to disorder by leading to hyperactivity of the HPA axis and up-regulating proinflammatory immune responses.
“and is thought to heighten susceptibility to disorder by leading to hyperactivity of the HPA axis [38,39] and up-regulating proinflammatory immune responses [40].”
Quote in the paperNot a substantial claim0 of 3 sources checked - Interpretationreasoning
The species-typical capacity for depressed mood serves an adaptive function.
“our species-typical capacity for depressed mood implies that it serves an adaptive function.”
- Also stated in: § An Evolutionary Systems Approach to Depression · plain
“We propose that our species-typical capacity for depressed mood can be explained as an evolved biobehavioural strategy that responds adaptively to adverse interpersonal conditions by minimising the likelihood of unpredictable social interactions.”
Quote in the paperSubstantial claim - Also stated in: § An Evolutionary Systems Approach to Depression · plain
- Premisecitation
Exposure to social stressors (e.g., low maternal care and social defeat) produces potentially heritable epigenetic changes that confer risk for disorder by heightening stress reactivity.
“studies involving rodents, primates, and humans showing that exposure to social stressors (e.g., low maternal care and social defeat) produces potentially heritable epigenetic changes that confer risk for disorder by heightening stress reactivity [35,36].”
Quote in the paperSubstantial claim0 of 2 sources checked - Premisecitation
The precipitants of depression are typically interpersonal in nature.
“For example, the precipitants of depression are typically interpersonal in nature [44]”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [44] source
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- Interpretationreasoning
The idea that depression reflects an evolved response to adverse social conditions concords with evidence across Tinbergen's remaining levels of inquiry.
“The idea that depression reflects an evolved response to adverse social conditions concords with evidence that extends across Tinbergen's remaining levels of inquiry.”
Quote in the paperNot a substantial claim - Premisecitation
Typical correlates of depression exemplify negative self-other relations (e.g., low self-esteem).
“typical correlates of depression clearly exemplify negative self-other relations (e.g., low self-esteem [46]).”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [46] source
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- Interpretationreasoning
The human capacity for depressed mood can be explained as a risk-averse adaptive prior that minimises uncertainty in the social world when sensory cues indicate high socio-environmental volatility and increased probability of aversive interpersonal outcomes.
“we suggest that the human capacity for depressed mood can be explained in terms of a risk-averse adaptive prior that minimises uncertainty in the social world when sensory cues indicate both a high degree of socio-environmental volatility (i.e., unpredictability) and an increased probability of aversive interpersonal outcomes (e.g., rejection, defeat or loss) (see Figure 1).”
Quote in the paperSubstantial claim - Premisecitation
Natural selection favours a hierarchical organisation of neural structure.
“It is now broadly accepted that a hierarchical neural structure is favoured by selection.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [70] source
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- Interpretationreasoning
The comorbidity of depression and other disorders might arise from a common pathophysiological mechanism, which can be explained in terms of false inference.
“However, perhaps the more intriguing implication is that the comorbidity of depression and other disorders might arise from a common pathophysiological mechanism, which can be explained in terms of false inference.”
Quote in the paperSubstantial claim - Premisecitation
Many features of depression (e.g., anhedonia, negative thinking bias, social withdrawal) reduce exposure to social risks by inhibiting reward-approach behaviours.
“many features of depressionsuch as anhedonia, a negative thinking bias and social withdrawalreduce exposure to social risks by inhibiting rewardapproach behaviours [51]”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [51] source
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- Premisecitation
Signalling behaviours associated with depression (e.g., reassurance-seeking and submissive behaviours) attempt to elicit support and defuse potential conflict.
“while the signalling behaviours associated with depression (e.g., reassurance-seeking and submissive behaviours) explicitly attempt to elicit support and defuse potential conflict [52][53][54].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [52][53][54]
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- Premisecitation
Computer simulations of evolving networks indicate that selection favours hierarchical organisation.
“Computer simulations of evolving networks have also shown that selection favours a hierarchical organisation because it conserves the (spatial, processing and metabolic) cost of neural connections; improves problem-solving by recursively combining solutions to sub-problems; and adapts more rapidly to new environments than non-hierarchical structures [74].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [74]
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- Interpretationcitation
Exacerbation of normative depressed states into severe, dysfunctional forms is likely when depressive changes fail to alleviate social stress, creating a self-perpetuating cycle arising from heightened and prolonged arousal of ineffectual attempts to reduce socio-environmental volatility.
“Notably, the exacerbation of normative depressed states into severe, dysfunctional forms is also likely when depressive changes fail to alleviate social stress, creating a self-perpetuating cycle arising from heightened and prolonged arousal of ineffectual attempts to reduce socio-environmental volatility [32].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [32] source
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- Interpretationcitation
The depressive spiral is engendered by a positive feedback loop between increased precision of social prediction errors and a negative bias affecting social predictions.
“previous applications of the FEP suggest that this depressive spiral is engendered by a positive feedback loop between two neurocognitive mechanismsthe increased precision of social prediction errors, coupled with a negative bias affecting social predictions.”
Quote in the paperSubstantial claim - Interpretationreasoning
An adaptive depressive response suspends sensory attenuation and action so that we can attend to interpersonal prediction errors and revise our posterior beliefs about our relationships with others, via perceptual inference and learning.
“This means that an adaptive depressive response suspends sensory attenuationand actionso that we can attend to interpersonal prediction errors and revise our (posterior) beliefs about our relationships with others, via perceptual inference and learning.”
Quote in the paperSubstantial claim - Interpretationreasoning
Depression can be viewed as an adaptive faculty that underwrites emotional allostasis in an increasingly prosocial and volatile world.
“Ultimately, our basic claim is that depression can be viewed as an adaptive faculty that underwrites emotional allostasis in an increasingly prosocial and volatile world.”
Quote in the paperNot a substantial claim - Premisecitation
The brain exhibits a multiscale hierarchical organisation, with a given node comprising a network of smaller interacting nodes at a lower level.
“imaging studies in network neuroscience have provided direct evidence that the brain exhibits a multiscale hierarchical organisation, with a given node (e.g., network, module or sub-module) itself comprising a network of smaller interacting nodes at a lower level [68,70] (see Figure I).”
Quote in the paperNot a substantial claim0 of 2 sources checked - Interpretationcitation
Depression is not solely attributable to social causes.
“That said, we do not wish to imply that depression is solely attributable to social causes.”
Quote in the paperSubstantial claim - Premisecitation
A hierarchical organisation improves evolvability because damage to one component is unlikely to impair the whole system.
“It enhances evolvability because deleterious changes to a single component of the system are unlikely to affect the system itself, and it allows adaptive novelties to emerge without disrupting global functioning [70].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [70] source
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- Premisecitation
Depression involves dysfunction of the extended visceromotor network, in which the medial PFC regulates affective states by modulating visceromotor output via connections with the amygdala, ventral striatum, hypothalamus, and other subcortical regions.
“evidence gleaned from neuroimaging and animal studies suggests that depression involves dysfunction of the”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [55]
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- Interpretationreasoning
Depression can also arise from depressogenic neuroanatomical abnormalities produced by influences other than unfavourable social conditions.
“and as we have noted, depression can also arise from depressogenic neuroanatomical abnormalities produced by influences other than unfavourable social conditions.”
Quote in the paperSubstantial claim - Premisecitation
Neurodevelopmental changes in these regions throughout adolescence heighten vulnerability to disorder by increasing sensitivity to rapidly changing social contexts.
“Neurodevelopmental changes in these regions throughout adolescence are also thought to heighten vulnerability to disorder by increasing sensitivity to rapidly changing social contexts in this period (see Box 4).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites (see Box 4)
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- Interpretationnone given
This faculty increases sensitivity to interpersonal, affiliative and interoceptive cues.
“Physiologically, this faculty increases sensitivity to interpersonal, affiliative and interoceptive cues.”
Quote in the paperNot a substantial claim - Interpretationreasoning
This depressive response instantiates a 'better safe than sorry' strategy that minimises the likelihood of unpredictable social interactions by causing adaptive changes in cognition and action.
“This depressive response instantiates a”
Quote in the paperSubstantial claim - Premisenone given
Depression appears to have positive selective pressure.
“the positive selective pressure that depression appears to have [see Box 3].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [see Box 3]
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- Interpretationcitation
Clinical manifestations of depression can result from asocial causes that produce neurobiological abnormalities typically associated with dysregulated mood (e.g., proinflammatory immune responses induced by illness and medications).
“Nevertheless, it should also be recognised that clinical manifestations of depression can result from asocial causes that produce neurobiological abnormalities typically associated with dysregulated mood (e.g., proinflammatory immune responses induced by illness and medications; 40).”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [40] source
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- Premisecitation
A hierarchical organisation permits adaptive novelties to appear without disrupting global functioning.
“It enhances evolvability because deleterious changes to a single component of the system are unlikely to affect the system itself, and it allows adaptive novelties to emerge without disrupting global functioning [70].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [70] source
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- Premisecitation
Hierarchical organisation reduces the spatial, processing and metabolic cost of neural connections.
“Computer simulations of evolving networks have also shown that selection favours a hierarchical organisation because it conserves the (spatial, processing and metabolic) cost of neural connections; improves problem-solving by recursively combining solutions to sub-problems; and adapts more rapidly to new environments than non-hierarchical structures [74].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [74]
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- Interpretationcitation
A structure that widens the critical region is probably favoured by natural selection.
“Since systems at criticality have optimal information-processing capacities, a structure that extends this critical region is likely to be naturally selected [76].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [76] source
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- Rests on an assumption: Self-organised criticality improves evolvability because minor external changes can trigger major internal reorganisation.
- Premisecitation
The maturing of subcortical areas and hormonal shifts make adolescents more responsive to affective and self-relevant social signals.
“Maturation of subcortical regions, along with marked hormonal changes [82,84], increase sensitivity to affective and self-relevant social cues.”
Quote in the paperSubstantial claim0 of 2 sources checked - Interpretationreasoning
Natural selection acts as a Bayesian model-selection process that lowers the free energy of phenotypes.
“In other words, natural selection is nature's way of performing Bayesian model selection to minimise the (variational) free energy of phenotypes (i.e., generative models).”
Quote in the paperSubstantial claim - Premisecitation
Hierarchical organisation improves problem-solving by recursively combining solutions to sub-problems.
“Computer simulations of evolving networks have also shown that selection favours a hierarchical organisation because it conserves the (spatial, processing and metabolic) cost of neural connections; improves problem-solving by recursively combining solutions to sub-problems; and adapts more rapidly to new environments than non-hierarchical structures [74].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [74]
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- Premisereasoning
The free-energy principle also covers the brain's form, development and evolutionary history.
“The FEP also applies to the morphology, development and evolution of the brain.”
Quote in the paperNot a substantial claim - Premisecitation
Peer relationships become increasingly important, hierarchical and complex during adolescence.
“Peer relationships become increasingly important, hierarchical and complex, and there is significant socio-environmental volatilityfriendships change frequently, and romantic relationships are typically short-lived [83].”
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The brain undergoes significant maturation in adolescence, beginning with puberty and continuing until the mid-to-late twenties.
“The brain undergoes significant maturation in adolescence, involving processes that begin with puberty and continue until a young person is in their mid-to-late twenties [77].”
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Homeostasis translates into a proximal avoidance of surprise.
“Thus, an organism's distal imperative of maintaining functional states within physiological bounds (i.e., homeostasis) translates into a proximal avoidance of surprise [5].”
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- Premisecitation
Prefrontal maturation also makes individuals more attuned to subtle and complex social relationships.
“Moreover, prefrontal cortical development leads, on the one hand, to improved regulation of affective processes, but on the other, heightens sensitivity to the nuance and complexity of interpersonal relationships [58].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [58] source
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- Premisecitation
Depression most often begins between adolescence and early adulthood.
“It is unsurprising, then, that the period from adolescence to early adulthood is a peak time for the onset of depression [42].”
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Association cortex, including prefrontal regions implicated in social processing, has the most prolonged development.
“Subcortical regions, including the primary components of the reward system, undergo more rapid maturation [79], while the most prolonged development is in association cortex, including prefrontal regions that are implicated in social processing [78,80].”
Quote in the paperSubstantial claim0 of 2 sources checked - Premisecitation
Systems at criticality have optimal information-processing capacities.
“Since systems at criticality have optimal information-processing capacities, a structure that extends this critical region is likely to be naturally selected [76].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [76] source
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- Premisecitation
Hierarchical organisation reaches new environments faster than non-hierarchical structures.
“Computer simulations of evolving networks have also shown that selection favours a hierarchical organisation because it conserves the (spatial, processing and metabolic) cost of neural connections; improves problem-solving by recursively combining solutions to sub-problems; and adapts more rapidly to new environments than non-hierarchical structures [74].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [74]
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- Interpretationcitation
Such changes are thought to raise mood-disorder risk by making adolescents more sensitive to social threats.
“Brain imaging studies show that adolescence is typified by significant alterations in social and affective processing systems, which are thought to increase risk for mood disorder by heightening sensitivity to social threats in this period [41,[80][81][82].”
Quote in the paperNot a substantial claim0 of 3 sources checked - Premisecitation
Alongside these neural developments, the social world of adolescents also changes considerably.
“Coincident with these neurodevelopmental processes, there are also substantial changes in the adolescent social environment.”
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- Interpretationreasoning
Adolescents often face many sources of social uncertainty.
“During adolescence, sources of social uncertainty are frequently encountered.”
Quote in the paperSubstantial claim - Interpretationreasoning
Perception and action work together to improve an organism's model of its environment.
“Thus, action and perception operate synergistically to optimise an organism's model of the environment.”
Quote in the paperSubstantial claim - Premisecitation
Subcortical regions, including primary reward system components, mature more rapidly.
“Subcortical regions, including the primary components of the reward system, undergo more rapid maturation [79], while the most prolonged development is in association cortex, including prefrontal regions that are implicated in social processing [78,80].”
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- Premisecitation
The social risk hypothesis has direct empirical backing.
“Figure: direct empirical support for the social risk hypothesis itself (Badcock & Allen, 2003; Badcock & Allen, 2007; Dunn, Whelton & Sharpe, 2012; Girard, Cohn, Mahoor, Mavadati, & Rosenwald, 2013).”
Quote in the paperNot a substantial claim0 of 3 sources checked- cites Badcock & Allen, 2003
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- cites Badcock & Allen, 2007
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- cites Dunn, Whelton & Sharpe, 2012 source
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Development of the prefrontal cortex enhances control over emotional processes.
“Moreover, prefrontal cortical development leads, on the one hand, to improved regulation of affective processes, but on the other, heightens sensitivity to the nuance and complexity of interpersonal relationships [58].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [58] source
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- Interpretationreasoning
Because an organism's repertoire of states is limited, the probability of those states has low entropy.
“Because the repertoire of states an organism occupies is limited, the probability of these states has low entropy (i.e., surprise).”
Quote in the paperSubstantial claim - Interpretationreasoning
Biological systems can minimise surprise indirectly by minimising free energy, which approximates precision-weighted prediction error.
“Surprise itself cannot be evaluated; however, biological systems can minimise surprise vicariously by minimising their free-energywhich roughly translates to prediction error, weighted by its precision.”
Quote in the paperSubstantial claim - Premisecitation
Imaging research indicates that adolescence involves marked changes in systems for social and affective processing.
“Brain imaging studies show that adolescence is typified by significant alterations in social and affective processing systems, which are thought to increase risk for mood disorder by heightening sensitivity to social threats in this period [41,[80][81][82].”
Quote in the paperSubstantial claim0 of 3 sources checked
- Classified as probably not a substantial claim. 18
- May combine two claims. 20
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InterpretationreasoningIf depression instantiates an adaptive prior, it should minimise surprise in response to specific environmental challenges that threatened inclusive fitness over evolutionary time.
“If depression instantiates an adaptive prior, it should minimise surprise in response to specific environmental challenges that have threatened our inclusive fitness (i.e., free-energy) over evolutionary time.”
Quote in the paperNot a substantial claimClassified as probably not a substantial claim.
PremisecitationThis risk-averse approach initiates signalling behaviours that elicit support and defuse conflict.
“This maintains that depressed mood reflects an adaptive, risk-averse approach to social interaction that reduces the likelihood of further aversive outcomes by: (1) increasing our cognitive sensitivity to (sensory) cues of social risk; (2) reducing our (behavioural) propensity for taking social risks; and (3) initiating signalling behaviours that elicit support and defuse conflict [32].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [32] source
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PremisecitationThe FEP describes the brain as a hierarchical generative model that reduces surprise by minimising discrepancies between incoming sensory inputs and top-down predictions.
“In line with predictive coding, the FEP describes the brain as a hierarchical generative modela hierarchy of hypotheses about the world that enables a reduction of surprise by minimising discrepancies between incoming sensory inputs and top-down predictions [9].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [9] source
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PremisecitationDepressed mood states are elicited by aversive interpersonal outcomes (e.g., exclusion, defeat, or loss) that indicate a critical loss of control over social relationships that were critical to ancestral fitness.
“According to this view, depressed mood states are elicited by aversive interpersonal outcomes (e.g., exclusion, defeat, or loss) that indicate a critical loss of control over social relationships that were critical to ancestral fitness [31].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [31] source
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PremisecitationPerception and action operate synergistically to minimise prediction errors and optimise internal representations of the environment.
“Thus, perception and action operate synergistically to minimise prediction errors and optimise our internal representations of the environment.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [11] source
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InterpretationreasoningPsychopathology typically arises from ineffective attempts to alleviate interpersonal difficulties and/or hyper-reactive neurobiological responses to social stress (uncertainty), often stemming from early experience that social uncertainty is difficult to resolve.
“We suggest that psychopathology typically arises from ineffectual attempts to alleviate interpersonal difficulties and/or hyper-reactive neurobiological responses to social stress (i.e., uncertainty), which often stems from early experience that social uncertainty is difficult to resolve.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S2 (checkable), S4 (based).
Premisenone givenThe literature to date sheds little light on the ecological conditions responsible for the positive selective pressure that depression appears to have.
“Second, the literature to date sheds little light on the ecological conditions responsible for the positive selective pressure that depression appears to have [see Box 3].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [see Box 3]
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PremisecitationThe neural mechanisms responsible for depression can only be understood by considering the broader context of human evolution, enculturation, development, embodiment and behaviour.
“According to this view, the neural mechanisms responsible for depression can only be understood by considering the broader context of human evolution, enculturation, development, embodiment and behaviour.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [6][7][8]
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PremisecitationLow mood reflects an adaptive biobehavioural strategy that conserves or reallocates energy and resources in unpropitious social environments.
“a theme common to many of these is that low mood reflects an adaptive biobehavioural strategy that conserves or reallocates energy and resources in unpropitious social environments [29,30].”
Quote in the paperSubstantial claim0 of 2 sources checkedClassified as probably not a substantial claim.
PremisecitationAdaptive priors are inherited expectations about the world shaped by natural selection to guide action-perception cycles toward adaptive (unsurprising) states.
“Emphasis is placed on adaptive priorsinherited expectations about the way our world unfolds that have been shaped by natural selection to guide action-perception cycles toward adaptive (i.e., unsurprising) states [5,12].”
Quote in the paperSubstantial claim0 of 2 sources checkedClassified as probably not a substantial claim.
PremisereasoningThe literature to date says little about the species-typical capacity for depressed or low mood.
“First, by concentrating on depressive disorders, the models above say little about our speciestypical capacity for depressed or low mood.”
Quote in the paperSubstantial claimMay combine two claims.
PremisecitationA hierarchical architecture is a hallmark of the mammalian brain, progressing from highly segregated sensorimotor hierarchies common to all mammals through to cortical association areas that confer heightened cognitive control among primates.
“Comparative work suggests that a hierarchical architecture is a hallmark of the mammalian brain, progressing from highly segregated sensorimotor hierarchies common to all mammals through to the cortical association areas that confer the adaptive advantage of heightened cognitive control among primates [71,72].”
Quote in the paperNot a substantial claim0 of 2 sources checkedMay combine two claims.
InterpretationcitationThe depressive response is adaptive when changes in mood state and behaviour reduce uncertainty in the face of socio-environmental change, and lead to re-engagement with that environment when volatility abates.
“The depressive response is adaptive when changes in mood state and behaviour reduce uncertainty in the face of socio-environmental change, and lead to re-engagement with that environment when volatility abates (which should, at least in part, be brought about by depressive behaviours; see [32]).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [32] source
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InterpretationcitationOngoing depressive behaviours seek to confirm negative biases, creating a self-fulfilling prophecy born from mutually reinforcing patterns of cognition and behaviour.
“Following active inference, this is likely to engender ongoing depressive behaviours that seek to confirm negative biases, creating a self-fulfilling prophecy (i.e., high predictability) born from mutually reinforcing patterns of cognition and behaviour [16].”
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PremisecitationDepressive cognition is characterised by a specific attentional bias towards socially-threatening stimuli and increased rumination about interpersonal problems.
“Depressive cognition is characterised by a specific, attentional bias towards socially-threatening stimuli [47] and increased rumination about interpersonal problems [48]”
Quote in the paperSubstantial claim0 of 2 sources checkedClassified as probably not a substantial claim.
PremisecitationThe distinction between social and non-social depressive responses is widely recognised.
“In evolutionary psychology, for instance, the distinction between social and non-social depressive responses is widely recognised [Durisko 2015;Gilbert 2006]”
Quote in the paperSubstantial claim0 of 2 sources checkedProbably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationMost theoretical work concentrates on two general brain systems: a ventral affective system (including subcortical regions such as amygdala and ventral striatum) and the prefrontal cortex (PFC), which modulates the reactions of the ventral affective system.
“Most of the theoretical work in this area concentrates on two general brain systems that work in concerta ventral affective system, including subcortical regions such as the amygdala and ventral striatum; and the prefrontal cortex (PFC), which modulates the reactions of the ventral affective system [1].”
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May combine two claims.
InterpretationreasoningDepression often stems from the need to adapt to complex social contexts, and manifests through the bidirectional interplay of hierarchical neuronal processes.
“Collectively, such findings fit well with our proposal that depression often stems from the need to adapt to complex social contexts, and manifests through the bidirectional interplay of hierarchical neuronal processes.”
Quote in the paperSubstantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Premisenone givenA hierarchical neural structure is favoured by selection.
“It is now broadly accepted that a hierarchical neural structure is favoured by selection.”
Quote in the paperNot a substantial claimMay combine two claims.
PremisecitationUnder active inference, sensitivity to stress-related cues corresponds to their precision, implicating neuromodulatory systems associated with reward, action selection and interoceptive inference.
“Under active inference, sensitivity to stress-related cues corresponds to their precision [13,60], implicating neuromodulatory systems associated with reward, action selection and interoceptive inference [61][62][63].”
Quote in the paperSubstantial claim0 of 3 sources checkedMay combine two claims.
PremisecitationThe PFC can potentiate vulnerability to depression by underwriting the formation of distal goals that, when frustrated by rejection or failure, can lead to depression by suppressing the brain's reward system and the confidence in (or precision of) beliefs about behaviour, thereby inhibiting goal-directed behaviours.
“Neurodevelopmentally, the PFC can also potentiate vulnerability to depression by underwriting the formation of distal goals that, when frustrated by rejection or failure, can lead to depression by suppressing the brain's reward system [58] and the confidence in (or precision of) our beliefs about behaviour [59], thereby inhibiting goal-directed behaviours.”
Quote in the paperSubstantial claim0 of 2 sources checkedMay combine two claims.
InterpretationcitationThis self-perpetuating cycle chronically activates neurophysiological stress responses and leads to debilitating sickness behaviours.
“This, in turn, is likely to chronically activate neurophysiological stress responses and leads to debilitating sickness behaviours [13,14].”
Quote in the paperSubstantial claim0 of 2 sources checkedMay combine two claims.
InterpretationreasoningMaladaptive forms of depression reflect a pervasive, self-maintaining failure of sensory attenuation, leading to ruminations, false inference and a concomitant inability to act and test these false beliefs.
“According to this scheme, maladaptive forms of depression reflect a pervasive, self-maintaining failure of sensory attenuation, leading to ruminations, false inference and a concomitant inability to act and test these false beliefs.”
Quote in the paperSubstantial claimMay combine two claims.
PremisecitationBrain regions across the extended visceromotor network regulate motivation and neurobiological responses to stress, and play a central role in social threat and reward processing.
“Brain regions across this network regulate motivation (e.g., anhedonia and dopaminergic function) and neurobiological responses to stress, and play a central role in social threat and reward processing [39,41,56,57].”
Quote in the paperSubstantial claim0 of 4 sources checkedMay combine two claims.
InterpretationcitationDepression can be interpreted as a maladaptive pattern of dysregulated defences: if the depressive response is effective, an individual escapes or avoids the social stressor or adapts to it; if the defence fails, the individual is at risk of entering a self-perpetuating dysregulated state beyond the normal range of adaptive functioning.
“Here, depressed can be interpreted as a maladaptive pattern of dysregulated defencesif this depressive response is effective, an individual either escapes or avoids the social stressor or adapts to it; if the defence fails, the individual is at risk of entering a self-perpetuating dysregulated state, which falls beyond the normal range of adaptive functioning (Allen & Badcock, 2003;Gilbert, 2001).”
Quote in the paperSubstantial claim0 of 2 sources checkedMay combine two claims.
InterpretationreasoningThe depressive response becomes maladaptive when there are failures of precision engineered visceromotor inference (e.g., from sustained social distress), leading to illness behaviours that fail to respond to improvements in interpersonal contexts and can exacerbate socio-environmental stress.
“we suggest that the depressive response becomes maladaptive when there are (neuromodulatory) failures of”
Quote in the paperSubstantial claim0 of 2 sources checkedMay combine two claims.
PremisecitationNormative depressed states increase the accuracy of social inferences (depressive realism) and improve social problem-solving.
“while normative depressed states have been shown to increase the accuracy of social inferences (e.g., depressive realism [49]) and improve social problem-solving [50].”
Quote in the paperSubstantial claim0 of 2 sources checkedClassified as probably not a substantial claim.
Premisenone givenDepression emerges from bidirectional interactions between hierarchically organised neural regions.
“It is widely accepted that depression emerges from bidirectional interactions between hierarchically organised neural regions.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
PremisereasoningThe model embodies inherited prior beliefs that, over evolutionary time, have reduced free energy by leading the organism to seek a limited set of predictable states matching its phenotype and surroundings.
“This model instantiates genetically specified (empirical) prior beliefs that have minimised free-energy (i.e., maximised model evidence) over evolutionary time by ensuring an organism seeks out a small number of unsurprising states that are consistent with its phenotype and environment.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
PremisecitationThe free-energy principle is intended to account for how living systems preserve their integrity by staying within a restricted set of states.
“The FEP seeks to explain how biological systems maintain their integrity by occupying a constricted number of states [5].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [5] source
Not checked in the free run.
May combine two claims.
InterpretationreasoningVulnerability to depression rises from puberty onward and remains elevated past adolescence.
“For this reason, increased vulnerability to depression starts in puberty but is maintained well beyond adolescence.”
Quote in the paperSubstantial claim- Rests on an assumption: Adolescence constitutes a sensitive window for social adaptation.
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisereasoningReducing free energy also requires predicting how precise prediction errors are, which involves attentional gain and neuromodulation.
“Crucially, to minimise free-energy, the precision of prediction errors also has to be predicted, invoking notions of attentional gain (psychologically) and neuromodulation (physiologically).”
Quote in the paperNot a substantial claimMay combine two claims.
PremisecitationAdolescent social environment has significant volatility, with frequent friendship changes and typically short-lived romantic relationships.
“Peer relationships become increasingly important, hierarchical and complex, and there is significant socio-environmental volatilityfriendships change frequently, and romantic relationships are typically short-lived [83].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [83] source
Not checked in the free run.
May combine two claims.
PremisecitationWhen neural networks are hierarchically segregated into distributed neighbourhoods, the range of parameters supporting self-organised criticality widens, permitting subcritical and supercritical dynamics to occur together.
“The hierarchical segregation of neural networks into distributed neighbourhoods has been found to stretch the parameter range for self-organised criticality by allowing subcritical and supercritical dynamics to co-exist simultaneously [75].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [75] source
Not checked in the free run.
Classified as probably not a substantial claim.
Premisenone givenThe free-energy principle treats the brain as a hierarchical inference device that reduces prediction error by aligning incoming sensory data with top-down predictions.
“The FEP appeals to predictive coding by characterising the brain as a hierarchical inference machine that minimises prediction error by seeking to match incoming sensory inputs with top-down predictions [see Figure II].”
Quote in the paperSubstantial claimMay combine two claims.
InterpretationreasoningThe brain does not merely contain a model of the world; it is itself a model, a physical record of environmental regularities shaped by evolution.
“It suggests that instead of just containing a model of the world, the brain is a model of the worlda physical transcription of causal regularities in the environment that is optimised by evolution.”
Quote in the paperSubstantial claimMay combine two claims.
PremisecitationDuring adolescence, white matter progressively increases, alongside synaptic pruning and grey matter loss, which delineate large-scale brain networks.
“Over this period, there is a progressive increase in white matter, alongside synaptic pruning and grey matter loss, which have the effect of delineating more clearly defined large-scale brain networks [78].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [78] source
Not checked in the free run.
Classified as probably not a substantial claim.
PremisecitationEvery organism lowers the disorder of its sensory and bodily states by reducing free energy.
“It suggests that all organisms actively reduce the entropy (i.e.disorder or dispersion) of their sensory and physical states by minimising free-energy.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [5] source
Not checked in the free run.
The authors state this as an assumption.
The brain is a hierarchical, self-organising system sculpted by evolution.
“The first appeals to a consensus among cognitive scientists that the brain is a hierarchical, self-organising system sculpted by evolution [3][4][5].”
The authors state this as an assumption.
The brain is situated within the evolutionary dynamics of the brain-body-environment system.
“The second assumption echoes dynamic systems approaches that situate the brain within the evolutionary dynamics of the brain-body-environment system [6][7][8].”
The authors state this as an assumption.
Risk corresponds to uncertainty and uncertainty is expected surprise or free energy.
“technically, risk corresponds to uncertainty and uncertainty is expected surprise or free energy”
The paper relies on this without support.
Self-organised criticality improves evolvability because minor external changes can trigger major internal reorganisation.
“This is a dynamical state poised between completely ordered, stable cycles of activity and highly complex, chaotic ones that optimises evolvability because it allows small extrinsic changes to elicit large intrinsic reorganisations.”
The paper relies on this without support.
Adolescence constitutes a sensitive window for social adaptation.
“It is now widely accepted that the functional and structural changes that accompany adolescence reflect a particularly sensitive period for adapting to the social world.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The brain's hierarchy ranges from lower-order, highly segregated neurocognitive systems for sensorimotor processing to highly integrated association areas underlying sophisticated cognitive faculties unique to humans.
“This hierarchy ranges from lower-order, highly segregated neurocognitive systems responsible for sensorimotor processing, through to the highly integrated association areas that underlie the sophisticated cognitive faculties unique to humans [70].”
From Answering Schrödinger's question: A free-energy formulation (2018) · cites this paper as [70]
The hierarchically mechanistic mind (HMM) is an interdisciplinary evolutionary systems theory of the embodied brain that synthesises the free-energy principle with major paradigms in psychology.
“To address this need, an interdisciplinary EST of the embodied brain has recently been forwarded called the hierarchically mechanistic mind (HMM).”
From Answering Schrödinger's question: A free-energy formulation (2018) · cites this paper as [70]
The FEP can be equally applied across all four of Tinbergen's research questions, casts new light on the reciprocal interplay of ultimate and proximate processes, stands to benefit both evolutionary and developmental psychologists, and proffers a common transdisciplinary language to unite psychology's sub-disciplines.
“Finally, since it can be equally applied across all four of Tinbergen's research questions, the FEP casts new light on the reciprocal interplay of ultimate and proximate processes; stands to benefit both evolutionary and developmental psychologists; and proffers a common, transdisciplinary language to unite psychology's sub-disciplines [7,70].”
From Answering Schrödinger's question: A free-energy formulation (2018) · cites this paper as [70]
These temporal processes are captured by Tinbergen's four levels of inquiry, which appeal to a dynamic causal hierarchy encapsulated by complementary paradigms in psychology.
“These temporal processes are captured by Tinbergen's four levels of inquiry, which appeal to a dynamic causal hierarchy that is encapsulated by complementary paradigms in psychology: evolutionary psychology; evolutionary developmental approaches; developmental psychology; and the psychological subdisciplines [7,70].”
From Answering Schrödinger's question: A free-energy formulation (2018) · cites this paper as [70]
The HMM can be translated into a multidisciplinary research heuristic that promotes a tripartite approach to scientific inquiry.
“The HMM is not just a second-order theory derived from variational neuroethology; it can also be translated into a multidisciplinary research heuristic that promotes a tripartite approach to scientific inquiry [70].”
From Answering Schrödinger's question: A free-energy formulation (2018) · cites this paper as [70]
The synergistic approach to developing hypotheses has already furnished important new insights into depression.
“Although this synergistic approach to developing hypotheses is undoubtedly complex and remains in its infancy, it has already furnished important new insights into depression [70], and yields distinct implications for neuroscientists and psychologists alike, while creating new avenues for collaborative research.”
From Answering Schrödinger's question: A free-energy formulation (2018) · cites this paper as [70]
The citation lists haven’t been fetched yet
References 107 · Cited by 190
- Authors
- Badcock, P. B., Davey, C. G., Whittle, S., Allen, N. B., & Friston, K. J.
- Affiliations
- The University of Melbourne (AU)
- University of Oregon (US)
- Wellcome Centre for Human Neuroimaging (GB)
- Corresponding author
- Badcock, Paul B.
- Venue
- Trends in Cognitive Sciences
- Publisher
- Elsevier BV
- Published
- 2017-03
- Volume
- 21
- Issue
- 3
- Pages
- 182-194
- ISSN
- 1364-6613 (ISSN-L)
- OpenAlex
- W2584391386
- Semantic Scholar
- 339e703939d58f16b9bc834ce2498f09634a7de9
- Cited by
- 190
- References
- 107
- Citations by year
- 2026: 6 · 2025: 14 · 2024: 22 · 2023: 36 · 2022: 29 · 2021: 31 · 2020: 16 · 2019: 15 · 2018: 13 · 2017: 7
- FWCI
- 1.56
- Type
- journal article
- Language
- en
- Open access
- green
- discovery.ucl.ac.uk
- Locations
- Trends in Cognitive Sciences (publishedVersion)
- PubMed (publishedVersion)
- UCL Discovery (University College London) (submittedVersion)
- Figshare (submittedVersion)
- Funders
- Wellcome Trust
- National Health and Medical Research Council of Australia (NHMRC)
- Topics
- Life Sciences › Neuroscience › Cognitive Neuroscience › Embodied and Extended Cognition
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Anxiety, Depression, Psychometrics, Treatment, Cognitive Processes
- Life Sciences › Neuroscience › Cognitive Neuroscience › Neural and Behavioral Psychology Studies
- Keywords
- major depressive disorder, depressive mood, free energy principle, social exclusion, social uncertainty, interpersonal threat, social stress, psychopathology
- MeSH terms
- Brain, Depression, Depressive Disorder, Major, Major Depressive Disorder, Biological Evolution, Systems Theory
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