What are brains for?

Why did we grow brains?

The evolutionary explanation for brains

Natural Selection

Principles

Cellular instincts

Rock paintings

Commitment

Darwin’s view on emotions

What are emotions?

Who do emotions benefit?

Overlapping disciplines

The Traditional Social Science Model of the Mind

The Massive Modularity Hypothesis

The Swiss-army knife model of cognition

A Social Module?

Theory-of-mind module dysfunction

Archetypal propensities

Archetypes

Biosocial goals

Archetypal Systems

Situations evoking anxiety as a defense

Startle may activate the Fight or Flight Program

Introducing a two-edge sword

The Smoke-Detector Principle

Situations Causing Depressed Mood

Is Depression an Adaptation?

Loss of rank & resources

Brain mechanism connecting mood & status

Causes of mental disorders?

My evolutionary classification!

1. Disorders of Malfunction

Schizophrenia

Bipolar Disorder

2. Disorders of Dysfunction (Environmental trauma or uniqueness)

Psychopathology due to Archetype Disorders

Stages in loss of attachment

Why do archetypes fail?

3. Disorders of Sociability

Disorders of Memes

What determines human behaviour?

Mimetic Lexicon 

Any evidence that memes cause harm?

Vast prevalence

Huge comorbidity

Onset at age of peak health

Huge fitness costs

Waxing & waning courses

Focus on physical diseases

Descriptive classifications (Kraeplin, Bleuler, Maudsley)

Psychoanalytic model

Behavioural model

Descriptive non-aetiological classifications (DSM)

Biomedical model: biological reductionism

Essential in allowing researchers to study comparable groups

Widely criticised for:

	Lacking a foundation in theory
	Encouraging simplistic thinking of psychiatric syndromes as discrete diseases  (Kendell, 1984)
	Neglecting maladaptive psychological processes

This is an evolutionary question requiring evolutionary explanations

"No biological problem is solved until both the proximate & evolutionary causation has been elucidated. The study of evolutionary causes is as legitimate a part of biology as is the study of the usually physico-chemical proximate causes."

E Mayr, 1982 (The Growth of Biological Thought)

Most research attempts to explain “what” & “how”

Evolutionary approaches examine “why” we are susceptible by considering the design characteristics

Proximate & Evolutionary explanations are not competitors, but two halves of a whole 

Causal hypotheses

Integration of prevailing models into a framework

A theory of environment-behaviour-gene interactions

A theory of behaviour, motivations & function 

An evolutionary classification?

A non-judgmental, normalising, humanising explanatory model for patients

…all the corporeal & mental organs …have been developed through natural selection, or the survival of the fittest, together with use or habit...

Charles Darwin, 1876

We are built as gene (replication) machines …

Richard Dawkins, 1978 (The Selfish Gene)

…our brains have evolved to make decisions that enhance reproductive success
Michael Gazzaniga, cognitive neuroscientist

Refers to differential survival of traits

Genetic variations in traits affect reproductive success 

An individual may acquire a propensity that makes him better adapted than his peers in surviving & passing on genes

Over generations, that attribute will become established as a standard component in the species genome

NS shapes bodies to maximise reproduction at the expense of health

NS shapes traits to ensure transmission of genes – too bad for the species

Genetic disease results mainly from quirks that were harmless in the Paleolithic

NS continues after menopause via kin selection

Food acquisition

Cooperation

Inclusive fitness

Inclusive fitness

Tribal bonding

Reciprocal altruism

Conflict over resources

Self defence

Pleasurable sensations … stimulate the whole system to increased action. 

Hence it has come to pass that most or all sentient beings have been developed in such a manner, through natural selection, that pleasurable sensations serve as their habitual guides. 

But pain or suffering… lessens the power of action, yet is well adapted to make a creature guard itself against any great or sudden evil. 

…if long continued, causes depression

(Darwin Francis (ed.), The Life and Letters of Charles Darwin, 1887)

“Adaptations” shaped by Natural Selection

Each emotion is a specialised state that adjusts cognition, physiology, subjective experience & behaviour so that the organism can respond effectively in a particular kind of situation

Positive & negative emotions are derived from the two types of basic arousal

Our ancestors faced many more kinds of threats than opportunities, as reflected by the fact that twice as many words describe negative as positive emotions!

The emotions were “designed not to promote the happiness & survival of the individual, but to favour maximum transmission of the controlling genes.”

(EO Wilson)

"People, like all other organisms, are not evolved to maximise health, wealth, happiness or any other trait – but to have descendants, which is the continuation of life."  

(Chisholm, 1999)

Sociobiology/Behavioural Ecology

Ethological Models

Evo Psych (Cognitive) Models

Psychiatric Models

Neuroscientific models 

Archaeological Models

Anthropological Models Philosophical Models

Blank slate / “Cupboard love” theory  = Behaviour is the result of  classical conditioning

General purpose computer

Learning

Culture

In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation." 

(Darwin: Origin of Species, 1859)

The view of the mind as containing a whole suite of modular psychological adaptations
corresponding to functional components of the CNS solving particular past reproductive problems 

Each blade represents pre-programmed algorithms sensitise the organism to monitor specific situations 

biases to learn certain behavioural responses

(Leda Cosmides & John Tooby, 1997)

Social cognition: information processing that contributes to the correct perception of dispositions & intentions of other individuals

Theory-of-Mind: inferring mental states of others 

(Martin Brune, 2001)

Group cooperation (reciprocal altruism) requires cheater detection algorithms 

(Trivers, 1971)

The Social Brain Hypothesis: Vol. of non-visual neocortex correlates with group size & length of juvenile period 

(Dunbar, 1998)

All perform worse on ToM tasks:

	Autism
	Aspergers
	SCZ (acute episodes) Pathological mind-reading inferences Intentions of others perceived as negatively related to self Pathological egocentrism

Natural selection has equipped us with lifespan-specific, context-sensitive archetypal propensities to navigate biosocial imperatives that facilitate inclusive fitness.

Genes are conveyers of potential for species-characteristic behaviours, rather than rigid determinants of social behaviour.

(Stevens & Price, 2000)

Human “instinct” 

(William James, Principles of Psychology, 1890)

“Collective unconscious” 

(CG Jung)

Mother-infant instinct 

(Bowlby, 1958)

(Gardiner, 1988)

(Stevens & Price, 2000)

Harm from strange humans --> Stranger anxiety 

Separation from carer --> Separation anxiety 

Threats to status/group membership --> Social anxiety 

Socially unaccepted impulses --> Obsessive self-doubt

Lack of food or other resources --> Obsessive hoarding

Getting sick --> Hypochondriasis/Obsessive cleanliness

Dangerous small animals --> Small animal phobias 

Potential attack to family members --> General anxiety 

Imminent attack by predator --> Panic

Environment in which attack is likely --> Agoraphobia 

(Adapted from Nesse, 1990)

… to motivate to urgent action

for survival

…to respond to Danger…

…with Fight …

… Or Flight …

(Walter Cannon, 1929)

Anxiety is a useful defence

…but it uses extra calories, makes us less fit for everyday activities & damages tissues

So why is it so readily triggered?

Because the cost of getting killed even once is enormously higher than the cost of responding to 100 false alarms

Loss of attachment – carer, mate (Bowlby, 1969)

Loss of rank – social status (Stevens & Price, 2000)

Loss of resources  (Nesse, 2000)

	Internal  Trauma Bodily damage
	External Bad decisions e.g. wasted effort pursuing risky goals  Disruption to major life goals and enterprises

Communicate (Darwin, 1872) need for help

Signal yielding in hierarchy conflict

Disengage from unreachable goals

Regulate patterns of investment

Social Competition Hypothesis of Depression

	Agonistic behaviour was principal form of social competition underlying sexual selection
	Involuntary subordinate strategy functions to: Inhibit aggression towards rivals Acceptance of outcome through yielding preserves the loser Signal submission: ‘no threat’ to rivals as ‘out of action”

Loss of resource holding potential (self esteem) can cause depression

(Price, Sloman, Gardner, Gilbert, Rohde, BJP, 1994)

Serotonin (5HT) in a-male (highest ranking) vervet monkeys 2x other males

When lost their position: appeared depressed (huddled, rocked, refused food) & dropped 5HT levels

Depressed behaviour prevented by Prozac, which raised 5HT

If removed a-male & gave Prozac to random male, that male became a every time

(Raleigh & McGuire, )

Differentiation - Mental disorders that result from localised (modular) brain malfunction due to genetic vulnerability or injuries of the developing central nervous system 

Integration - Mental disorders that result from NON-localised brain malfunction due to genetic vulnerability or injuries of the developing central nervous system 

Environmental uniqueness 

Maladaptive memes