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“TRUTH in the BRAIN” the neuropsychology of belief. Neil Greenberg University of Tennessee Knoxville, TN USA. KNOXVILLE AREA PSYCHOLOGICAL ASSOCIATION 21 May 2007. WHAT is BELIEF?.
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“TRUTH in the BRAIN”the neuropsychology of belief Neil GreenbergUniversity of TennesseeKnoxville, TN USA KNOXVILLE AREA PSYCHOLOGICAL ASSOCIATION21 May 2007
WHAT is BELIEF? Belief is the psychological state in which an individual is more-or-less confident in the validity of a proposition. (confidence can translate into biological fitness) Validity can be more-or-less internal (limited generalizability; eg, individual) or external(broad generalizablity; eg, population)
We derive our beliefs… “…through argument and experience. Argument brings conclusions and compels us to concede them, but does not cause certainty nor remove the doubts in order that the mind may remain at rest in truth, unless this is provided by experience.” Roger Bacon (1268)
HOW IS BELIEF ESTABLISHED? • Empiricism and Reality-Testing • data-based, induction-driven • PERCEPTS CORRESPOND to reality • Rationalism and Story-Telling • theory-based, deduction-driven • PERCEPTS COHERE with each other
evidence and theorycorrespondence and coherence A “sense” of truth??” Biologically, we don’t need the truth except insofar as (1) the search for truth exercises and enlarges our competence(the scientist in the crib)and (2) approximating the truth may provide a biological advantage (better maps)
An Essential Tension Like “fight or flight,” • Correspondence and Coherence, • Empiricism and Rationalism • Reality-testing and Theory-building • Are mediated by different physiological systems in a balance that is easily tipped by (for example) genetic disposition, experience, context, or more-or-less stress
CONFIDENCEis a biologically important quality Much of our behavior is structured by the possession and pursuit of confidence in the validity of our beliefs – their “truth.” The neuroethology of consciousness and its dysfunctions have helped us identify the manner in which correspondence and coherence operate and converge to create a sense of doubt or confidence in the veracity of a belief.
CONFIDENCE affects our ACTIONS which are based on BELIEFS. we seek “TRUTH” because we can never be too confident. It is BIOLOGICALLY ADAPTIVE in that it meets a NEED and enhances FITNESS Such NEEDS range from physiology (health) through fitness (“self actualization”), and meeting them is the principal business of life. CONFIDENCE can be anxiolytic: real or perceived needs that are not met evoke more-or-less of the STRESS RESPONSE, the physiology of which selectively activates brain circuits which also energize MOTIVATION
DEEP ethology of belief • DEVELOPMENT: change within a lifespan -- the scientist in the crib and accumulating experiences • ECOLOGY: meeting needs in the environment -- dynamic balance, and meeting needs, real or perceived • EVOLUTION: Change between generations -- What elements of belief are fixed and which are flexible? • PHYSIOLOGY: Homeostasis, coping with needs; stress, orchestrating the cerebral symphony; dynamic tension of tradition and innovation
DEVELOPMENT Infants are “scientists in the crib,”always developing and testing, accepting or rejecting, hypotheses about the nature of our environments and how best to control them. It is a necessary stage of our cognitive development that makes learning possible . . and it is the beating heart of the scientific method. (if we can hold onto the “freshness” of perceptions)
Our brains are formed by the EPIGENETIC interaction of organism and environment:all percepts are modified by those that came before.
PHYSIOLOGY STRESS RESPONSES are evoked by REAL or PERCEIVED challenges to an organism’s ability to meet its needs SUBCLINCAL STRESSis evoked by modest challenges to homeostasis, including COGNITIVE DISSONANCE, an apparent mismatch between internal perceptions and external reality; challenges to the narrative that confers biologically valuable confidence.
THE POWER OF REALITY- TESTING We confirm and establish confidence in CORRESPONDENCE (the validity of experiences) at every level, from spinal reflexes through thoughtful cognition. Experiences we are confident are real but which challenge theory is the key method of enlarging our worlds. Establishing validity is a key element of learning.
THE POWER OF THEORY We confirm and establish confidence in COHERENCE by assessing the validity of component percepts and their complexity. Expectations exist at many levels, from habituation and sensitization of sensory receptors through the most elaborate flights of philosophy.
We NEED theory La theorie seule peut faire surgir et developper l'esprit d'invention" (Without theory, practice is no more than the routine given by habit. Theory alone can bring forth and develop the spirit of invention) Louis Pasteur
FALSE CONFIDENCE "What a man believes upon grossly insufficient evidence is an index into his desires — desires of which he himself is often unconscious. If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.” --Bertrand Russell ...
BUT IS MYTH SO BAD? “These things never were,” said Sallust, speaking of the Greek myths, “but always are!” “Is there anything truer than truth?” Asked Kazantzakis, “Yes, Legend.”
Are beliefs more important than truth?TRUTH and STRESS SELF-DECEPTION serves a vital function(Daniel Goleman’s use of Ibsen’s term: “Vital Lies” 1985) “You can’t handle the truth!” (Jack Nicholson in In “A Few Good Men,” 1992) DENIAL ---The more-or-less “…willing suspension of disbelief…” (Wordsworth) – is that the function of art?… to provide a safe zone for exploring the otherwise troubling, stress-evoking truth? Or of myth? (“theory used to be an “enchanted circle”)
DISORDERS of BELIEF? Acceptance of experience that doesn’t correspond to external reality:kinds of hallucinations; Bonnet’s Syndrome(filling in scotoma); dismorphic body; pareidolia. (False positive (confident match with memories); Type I Error; gullible, trusting) Denial of experience that corresponds to external reality: agnosias: eg, visual(left occip), associative, anasognosia(denial of dysfunction / right cerebral cortices), prosopagnosia(faces) (False negative (failure to match with memories); Type II Error; skeptical, wary)
PLACEBO EFFECT EXPECTATIONS: the power of coherence: • Acupuncture IS effective in many cases, but application at arbitrary site is comparable (Melchart et al. 2005) • Antidepressant medications can be 80% replicated with placebo (Kirsch et al. 2002) • Parkinson’s patients experience an endogenous dopamine “rush” when nigrostriatal system activated by placebo (expectation of reward – Fuente-Fernandez 2001)
PLACEBO EFFECTnot merely subjective? Extra endorphins were also released from sites not usually engaged in analgesia, including • rostral anterior cingulate (perception of degree of pain)(ACC: autonomic, error-detection, conflict rersolution or management) • insular cortex (receives somatic pain information) • nucleus accumbens (assesses urgency of pain) • dorsolateral prefrontal cortex(involved in decision making, interpretation, and selective attention) BUT, only in those that expected relief. (Zubieta et al. 2005) . . .
Anosognosia • ANOSOGNOSIA: a term derived from the Greek: A + nosos (disease) + gnosis (knowledge) • Ignorance or denial of the presence of disease • Most famously of paralysis in patients with non-dominant (usually right) parietal lobe damage -- patients deny their hemiparesis, & confabulate rationalizations • Right hemisphere, denied input from the reality-testing of the left hemisphere, seems unable to detect discrepancies between internal model and feedback, and left-side function seems “hallucinated.”
Putative Causes of Anosognosia • Freudian denial: avoidance of confrontation with dysfunction, preserve self image. • Phantom function: as with phantom limbs, signals from motor cortex go to parietal monitoring area AND to muscles (that no longer exist). In the absence of feedback (confirming dysfunction) parietal area prevails • Right hemisphere impairmentby muting emotionality, and flattening affect, might create the appearance of indifference
Confabulation • “The production of fictitious stories” • First observed by Korsakoff in alcoholics • Can be provoked (eg., to avoid embarassment) or spontaneous (Schnider 2003) • Involve anterior limbic structures (orbitofrontal) • Impressive when right hemisphere (and its “reality-check” on the left hemisphere) is damaged
Causes of Confabulation • Right hemisphere stroke: denial of left side paralysis. • Korsakoff’s syndrome: inability to form new memories due to temporal lobe dysfunction. • Acting out after a hypnotic suggestion will be rationalized with improvised confabulations • Schizophrenia: confabulations to rationalize hallucinations or to justify paranoia • Capgras syndrome: incomplete sense of who owns a familiar face: alien imposters?
LEFT - RIGHT HEMISPHERE LATERALITY • When separated, EACH hemisphere is UNAWARE of the ipsilateral world • Yet neither is aware of being incomplete • Each functions as best it can with the information available
LEFT HEMISPHERE Coherence: creates a consistent belief system – works to “save appearances” (Ramachandran 1998) Probabilistic reasoning (Osherson et al 1998) Abstract object recognition (Marsolek 1999) Activated by familiar percepts (Goldberg 2001) RIGHT HEMISPHERE Correspondence: “skeptical,” tests reality and if damaged, confabulation runs rampant (Ramachandran 1998) Deductive reasoning (Osherson et al 1998) Specific object recognition (Marsolek 1999) Activated by unfamiliar percepts (Goldberg 2001)
Kant: "The senses cannot think, the understanding cannot see.”
POST-SCRIPT on LEFT HEMISPHERE function in establishing coherence • When the body orientation association area in the left superior parietal lobe is suppressed, physical boundaries between the body and the world become uncertain : can evoke a “spiritual” sense of “being one with everything.”
The Anterior Cingulate Cortex The ACC is a stress-sensitive site that has the potential to affect our confidence in beliefs. Spindle cells project to many sites but especially frontal polar cortex where responses that compensate for “error-detection” are selected and initiated. While often regarded as part of the emotion-processing limbic system, ACC is more likely a specialized neocortical structure that can also deploy mechanisms of the autonomic nervous system by which we express activation of the stress response.
Anterior Cingulate Cortex (ACC) ACC is STRESS sensitive AND appears to generate brain waves manifesting “error-related negativity” (ERN) associated with the detection and correction of errors. Alternatively, the ERN may indicate an affect-laden response to a mismatch between expectancies and outcomes.
"Our life is an apprenticeship to the truth that around every circle another can be drawn; that there is no end in nature, but every end is a beginning, and under every deep a lower deep opens" --Ralph Waldo Emerson