Human Ethology As Anthropology: a holistic understanding

(to understand we use four lines of evidence):

abuse and

neglect

Cross-cultural

(range of variability, role of social valaues)

(3) Cross-species

(2)

Evolutionary

Origins,

Function,

Reconstruction

(1) Developmental (socialization)

Sleep

One third of our lives spentdoing it!

human

Sleep

What is it? What Does It Look Like? Do other animals sleep? How does it function? Why did it evolve? What happens when we sleep? Measurement? How does it change with age and with each

culture? What contributions does culture make to how

we think about it, interpret and evaluate sleep? How does sleep develop? Infant sleep vs. adult sleep?

Human Ethology Lines of Evidence

What causes sleep?

How does it develop?

How does it function?

How did it evolve?

What is sleep?

A state of (1) sustained immobility or quiescence in a (2) characteristic posture accompanied by (3) reduced responsivity to external stimuli;

Immobility need not be absolute as dolphins, seals and whales may float or swim while asleep…most sleep with eyes closed but not all;

Cattle may sleep with eyes open..horses and elephants sleep while standing…

Recognizing sleep: behavioral criteria

• Behavioral inactivity;• A characteristic sleep posture• Decreased responsiveness to

stimulation• A rapid return to waking with moderate

stimulation

Why Do We Sleep?

Proximate Explanation:

» Because we begin to “feel” tired..melatonin

» Need to consolidate energy and experiences;

» Need to avoid predators;» Need to restore body cells

and promote protein anabolism;

» Maintain hormonal secretions, immune function

Ultimate Explanation» sustains our

ability to reproduce successfully, by maintaining good health

What happens when falling asleep--transition to

Stage 1

Body temperature drops; Slow rolling eye movements; Alpha rhythm ((8-13 cycles per second) Heart rate slows; Relatively low voltage, mixed frequencies.

(vertex sharp waves) Myoclonus jerk? Sensitive to external stimuli--dreamlike thoughts

Circadian rhythm

Refers to circa=approximately and

dias=day

What’s the Endocrine System?

A collection of glands that secrete hormones in order to regulate functions within the body.

Environmental cues: activity and rest =growth, maintenance, hormonal

fluctuations.too

Earths rotation--light-dark cycle, on 24-hour circadian system. Activity-non-activity (circadian rhythms) can be further subdivided up into smaller time activity-rest units,called, ultradian cycles

As wakefulness (alert), stage 1 sleep, stage 2, stage 3 and stage 4 (Non-Rem) and Rem (rapid eye movement sleep), also called active of paradoxical sleep.

About life, students….

» Its about circles..i.e. cycles…all the way down…we live inside of circular space..

» cycles within cycles within cycles…» as in life cycle..sleep cycles, menstrual

cycles, hormonal cycles..time cycles..midnight

» (when and where morning and night are simultaneously one, a beginning and an end at the same instant.. Where beginning and ending is the same, is it Friday or Saturday

Light cues24 hours

Active vs. Rest

What is “sleep architecture” (Awake/sleep)

drowsy, stage 1,stage 2, stage 3. Stage 4, REM, drowsy

Awake/sleep

Studying The Physiology and Nighttime Behavior of

Breastfeeding Human Mother-Infant Pairs

Conversing with data across discipline

cultures: polysomnography

Why was the first ever

physiological study of

mothers and infants co-sleeping

completed by a biological

anthropologist ?

Polysomnography (tracings)

Sometimes babies sleep in mother-baby sleep laboratories

Sleep Laboratory Sleep Laboratory LoungeLounge

Nighttime Sleep Studied From a New Bio-cultural Perspective

Solitary infant turns prone-face down;

Educated nurse wraps up baby;

Clinically depressed teen;

Breastfeeding moms Increased sensitivity

Environmental cues (zeitgebers) and selective pressures determine how

and when animals sleep

Dolphins, whales, porpoises need brain awake to monitor breathing and to detect danger. Experience “unihemispheric” synchronization--one half of brain exhibits synchronous EEG, the other dysynchronous--that is, one half of the brain is awake the other, asleep.

Reptile Species

Crocodiles an alligators rest-activity brain waves are temperature dependent…

Lizards and snakes--eye tissues reflect some REM-like movement but it remains questionable;

Turtles and tortoises--somewhat likely as EEG spikes correlate with arousal from sleep in some species

Reptiles? Crocodiles, Alligators, Lizards, Snakes, Turtles and

Tortoises

Meet behavioral criteria Different electroencephalographic (EEG)

patterns during behavioral sleep High amplitude spike potential --but,

recall, reptiles lack human neocortex that generates slow- wave sleep..(but is present in mammals in certain subcortical areas)

Sleep Position? Locale?

Bats and sloths sleep upside down, hanging by their feet;

Belly, side, haunches, or back-…all positions?..depending on anatomy and environmental pressures,

“Type” of predator can determine sleep locale cave, crevice, tree, nest, or whether animals sleep together for protection in herds (giraffe,antelope, wildebeast, many primates)

What Co-sleeping Looks Like

Maori, New Zealand

recliner co-sleeping (unsafe)napping desert Aborigine

Koala

Diversity of Co-sleeping

(requires taxonomic distinctions)

Co-bedding twins

(within sensory range)

partial, mixed

bedsharing with Dad

Oh, But let’s not forget the Dads.

Ventral-Ventral mother-infant contact: is not an example of

unsafe sleep

Courtesy of Dr. Helen Ball

…Solitary Sleep

What is REM sleep?

Rapid eye movement..during a sleep period (eyes dart from right to left) stimulates occular muscles;

Called “active sleep” or “paradoxical sleep”; Respiration is irregular, heart rate is generally

faster, blood pressure is higher…brain waves fast and shorter;

Dreaming occurs;

REM (not just a rock group)

REM contributes (makes possible) metabolic homeostasis;

Deprivation experiments on rats reveal:» Deprivation of REM leads to eating

more, but losing weight, loss of control of body temperature

» Death ensued in 30 days

Function of REM?

Exercise brain cells (neurons) for memory consolidation, cognition

Oxygenate and distribute nutrients to body organs and muscles;

Metabolic homeostasis: temperature, cortisol, prolactin, melatonin release, human growth hormone?

During REM, atonia occurs

During REM» Inhibitory neurons release glycine on surface

of motoneurons;» Creates a form of electrical polarization,

preventing the discharge of large muscle sets involved in locomotion, prevents them from discharging;

» Prevents acting out dreams..this is called atonia

Dreams

Real acts performed elsewhere in time and space-deja vu- ?…considered channels of communication; shamans learn how to control events and disease; in some cultures both spaces..”real an imaginary” are distinct but both considered..real..:

Across Cultures the meaning and function of dreams vary:

Dreams….

A dream takes place in a subjective space, different from the space of walking life;

The relationship between these two spaces is not the same from one culture to another…

For Ojibwa Indians..dreams are another way of acting in “life space”..having visited a spot in one’s dream…

BUT..no culture confuses dreams with waking reality, or fails to make a distinction..

Culturally specific..

Content? Direct? Indirect?

Creativity:

Dr.Jeckll and Mr. Hyde (Robert Louis Stevenson)

Samuel Taylor Cooleridge:

Fell asleep in 1797--dreamed 200 lines of one of his finest poems: Kubla Khan

Dreams

Dreams discussed by Greek philosophers…Pythagoras, Plato, Aristotle..sleeping in certain temples provided access to dreams..special cures ..special knowledge..

Aristotle: attributed dreams to “residual sensory impressions”..to a persons past..presented without controlling emotional senses..in present..but not access to power

What kind of genetic trait underlies human

sleep?

Polygenetic--gene complexes? Facultative? Obligative? How “labile” is our need for sleep?

Daily Sleep Quotas of Various Mammalian Species

(in Hours)

Opossum (18) Bat (19) Mole (8.5) Baboon (9.5) Humans (8?) Rabbit (8) Hamster (14) Rat (13)

Giraffe (2) Horse (3) Dog (10) Seal (6) Dolphin (10) Cat (12) Squirrel (16) *70% of all sleep is

NREM..Rem varies from 30 min. for

Giraffe to 5 hours for opossum

Polyphasic Species

Baboons-3 -4 naps? Rabbits-evenly

distributed. light/dark Rodents: Gerbil,

guinea pig (all day, short sleep periods);

Cat (domestic) 12/15 cats nocturnal--2 sleep periods during night, most sleep periods during day;

Dogs--polyphasic--with emphasis of sleep at night;

Horses --polyphasic--3-16 sleep bouts per day;

Goats 0-6 sleep episodes per 12 hour period (polyphasic);

Thompson’s gazelle--mostly night--3-6 during day;

Most vulnerable mammals?

Wake up frequently, must remain vigilant..to predation

Or must be alert to other environmental dangers (dolphins

and sharp rocks and reefs)

Relevance of Napping Across Species

Is napping one variant of “polyphasic sleep”--an evolutionary human relic?

What are the different trade-offs related to survival-for different sleep lengths at different times?

How do naps and sleep patterns vary according to: » Activity patterns

(diurnal, nocturnal, split)?

» Carnivores vs herbivores

» Habitats: secure, insecure, terrestrial, aquatic, avian?

What Kind of Sleep Pattern Do Humans

Exhibit?

Monophasic?

Biphasic

Polyphasic?

The concept of…the “Sleep debt”

“The brain keeps an exact accounting of how much sleep it is

owed!”

William Dement: “The Promise of Sleep”

Sleep Disorders

Restless leg syndrome--about 10% population:

Insomnia--not sleeping; Parasomnias--not staying asleep for

desired length Introduce “die model” (western

societies)..a problem?

Primary or Secondary Enuresis (bedwetting)

Surprisingly common: 25% of four year olds, 10% of 8 year olds, 1% 18 year olds;

Not a disease but a symptom..delayed maturity, insecurities;

rule out: diabetes, cerebral palsy, chronic urinary tract infections; sleep apneas

occurs in any stage of sleep;

Behavior modification (75% cured)

Imipramine and /or demopressin acetate (DDAVP)--as a nasal spray;

patience and tolerance

Sleep disorders Apneas (without breadth) can be divided into two

types » obstructive and central apneas » Obstructive apneas afflict 50 million Americans,

20% of which have serious disorders--increases blood pressure and increases coronary build-up--can induce heart attacks..–snoring heavily is one symptom, but

daytime sleepiness is the single most important clue

Reducing apneas----

“CPAP”

continuous positive airway pressure

Sleep Disorders

Somnambulism…sleepwalking» 40% of children will have an episode,

peaking at between 11-12 years of age;

» Can be induced if arouse children during NREM;» associated with complete amnesia,» Occurs within 2 hours of falling asleep..

EEG..reveals both waking and sleep signals. Considered benign.

Where is the “culture”--in sleep?

on what do we sleep,in what room? why we sleep, where we sleep, with

whom we sleep; When we sleep, what clothing we sleep

in (if anything) .. what we do before we sleep (rituals--prayers? cleaning, grooming,making love, reading, speaking with someone)

Napping and Culture:

The “siesta” is a universal behavior that is de-valued with

industrialization in some western countries..associated with

indolence or laziness..i.e. ”never get caught napping” ?

“Although sleep may be judged a necessary part of sleep,napping has often been considered deviant and an unwanted form of sleep, indicative of laziness, senility,Immaturity, and irresponsibility”. Broughton and Dinges 1989

Development of Sleep; General trends

Infancy--18 hours a day of sleep; fall right into REM sleep--little day-night consolidation/demarcation..Breast feeding vs Bottle, cosleeping vs. solitary?

Toddlers; naps until about 3 years of age--experiencing 11-14 hours of sleep..stage 4 sleep within ten minutes

Slow wave sleep for about an hour--then mixed movement/arousals/ 7-10 REM cycles, about 30-35 % of total sleep..70% non-REM

Birds eye view of developmental changes through the life cycle

(Ontogeny)

From infantile polyphasic pattern---toward increasing consolidation of night sleep with multiple daytime naps…to a single daytime nap (3-4 years of age) to the emergence of the more common monophasic adult sleep pattern……to

Adolescent 8-11 hours--with more Stage 3-4 sleep to..young adult…to….

Older adult--less stage 3-4, less total sleep, more naps/and polyphasic pattern (back to infancy)

Does the human fetus sleep?

6 to 7 month old fetus develops REM/Non-Rem sleep precursors;

By end of 8th month, patterns established; mimick post-natal quiescence and activity;

Active sleep is developmental precursor to REM--Quiet Sleep in newborns represents precursors to Stages 1,2 3,4

Human evolutionary origins of sleep? (Phylogeny)

Consider life style (the paleo-ecology) of Australopithecines 3-5 million years ago) » Lived in a predator rich habitat (social

carnivores);» fossil evidence of hominids being heavily

preyed on by large cats (leopards and saber-tooth cat);

» Hominids were slow, weak, without claws, sharp teeth: What did they have going for them?

The Hominid Dilemma?

Bipedal, free hands, clever brains; Innovative , using and making tools Living and communicating in social

groups, perform “social roles’ dependent on learning; expensive, slow developing, immature

babies, unable to run or cling to mom

Where Did They Sleep 3-5 million to 300,000 Years Ago

Trees? with grasping adaptations..building nests,,sleeping in nests like present chimpanzees...

Caves? Roosting sites? Cliffs?

What changed things--when could hominids come to the ground to sleep

safely?

Felididae: Sabertooth Cats

Felids…(Megantereon)across

three continents

Fire, changed things!(In evidence by

800,000 years ago) with Homo erectus

Fire could be used as a weapon against large cats and other

predators..sleep could be prolonged..and , on the ground!