Basic process for development in social animals

  • Process that occurs early in infancy
  • An instinct-based response towards the infant and their mother.
  • If the mother is not there, they will respond to a surrogate mother (Harlowe’s)
  • Evolves from a reciprocal response of the mother to the infant

 Basic to the attachment of the infant to the mother, and the later social/cognitive development of the infant

Also has a role to the mother’s attachment to the infant

There are differences – evolutionary psychologists say there is a difference.

Imprinting was studied first by Lorenz and Tinberg

  • The first behavioural scientists to win the nobel prize for behaviour
  • Studied imprinting in ducks and geese  first social response to their mother is to follow the mother

2 important observations: wild ducks and geese, and ducks and geese in the laboratory.

Imprinting occurs in the critical period: period in which some genetically based physical structure/process is emerging in development, and is most susceptible to environmental affects

Ex. Effects of German measles to mothers-to-be. Pregnant women would develop German measles more frequent than the norm with babies who were defective in some way.

  • Depended on which structure/function in utero, and if it was the critical period or not.

Critical period for all development  physical abilities (climbing, swimming, etc) you acquire this during a younger age, and though you can acquire it later on, you will never reach full potential.

  • Critical period for intelligence (Piaget) and development/capacity to solve more and more complex problems.
  • Critical period for personality characteristics (Freudian stages) and Ericson’s 8 stages of human development

Timing of environmental events is more important than overall quantity.

For ducks the critical period is 4-16 hrs after birth. The duck will follow and imprint to that object –     Mallard ducks will imprint on any moving object.

Qualification of critical period – experiments that were conducted

      Restrained ducks during the critical period, but were allowed to watch other ducks imprinting, and they emerged as imprinted.

–       Just have to go through the physical process and look at the object at the same time.

      Imprinting is essential to later social development. Ducks who did not imprint, never socially matured. Did not flock, feed, mate, etc like other ducks.

  • Applies to dogs as well. Dogs have the capacity to imprint to owners and other dogs.
  • If he does not imprint, he will not make a good pet, never be subservient

Imprinting operates with humans as well

  • Within the 30s and 40s, there was not much done after the original work during this time
  • Why? Political reasons  Lorenz was in Germany during the Nazi regime, and though he was not a Nazi, he used his theory to support Nazi race laws.
  • Isolation of non-Aryan groups
  • Lorenz put a spin on his theory  individuals are genetically programmed to their own race, and interbreeding will cause ‘mongrolization’ of the Aryan race  Produced the hiatus of research about imprinting.

Does have some positive social implications (Harlowe’s) and were implemented with humans – Led to the reform of orphanages.

  • Infants did not get the opportunity to imprint, and were taken care of multiple people and were not cuddled 

Revived by Harlowe. A behaviourist in the 60s, and ethological type.

  • Doing learning set studies with monkeys
  • Monkeys were caged and separated from mothers to keep consistent environments
  • Zimmerman noticed that the monkeys were clinging to towels, like a monkey would cling to their mother.

 ‘Mother love’ was seen as a conditioned, secondary drive. Attachment to mother is because she is around when the child’s primary drives are there. Develops through reinforcement.

Zimmerman’s observation showed a new primary drive  A need for contact.

  • Did their studies with wire and cloth mothers
  • 2 forms of surrogate mothers
  • One was just a metallic mother
  • The other was the same, but covered with terry cloth The monkeys lived alone in cages containing both the surrogates. – In one group, the surrogate provided food and water
  • In the other, it was the cloth which provided food and water

Predictions were that the surrogates would cling to the wire one for primary drives

Results: No exceptions  general observations. Monkeys would cling to cloth mothers even if they did not provide food

Monkey’s raised with the cloth mothers, when exposed to unknown environments, would explore and then go back to the mother for comfort.

  • Return to the monkey colony and have a good life.
  • Monkeys who were deprived of this first stage of imprinting didn’t progress to the other stages  became withdrawn, or aggressive

Zimmerman made the connection that clinging is an imprinting process.

2 monkeys who were not imprinted (withdrawn), put them into a colony, with male monkeys, both had offspring, and both rejected their offspring. Did not have the mothering/nurturing instinct. –        Had a second child, and this one behaved relatively normally

Replicated the Harlow study, and impregnated the monkeys

  • Observed the rejection of the offspring, and then tried drugs to make them accept – The most useful drug to induce the mother instinct was a tranquilizer drug

Imprinting with people: more complex and specific

  • With people, it would include aspects of infant/mother affectionate interaction
  • Specific responses that are early in the infant’s development
  1. Gazing/eye contact: infants gaze, and they gaze hours after birth. Gaze at a full figure of a human face, which is usually the mother’s face. This was demonstrated by Fancz (sp?)  Take infants who were several weeks old.
  • Showed images that were oval (outline of the human face)
  • First drawing had lines that resembled the human face, and the other had randomized drawings

The infant spent 99% of the time gazing at the image that reflected human features the most.

Attributed it to behaviorism, until Wu tested this minutes/hours after birth  Proved it was not exposure or conditioning which accounted for this effect.

Gazing elicits a flow of estrogen in mother, and this is how imprinting and bonding work together

  1. Second response: 3rd or 4th week. Smiling
  • The frontal view of the human face elicits the smile, and then it generalizes.

Effects of the lack of opportunity to imprint

  • Followups of children raised in family homes and orphanages in infancy, little contact other than physical care.
  • Were not picked up carried, etc.
  • Number of studies that found that the later in infancy the child was adopted, the greater the risk of adjustment problems later in life
  • No experience of imprinting during the critical period (8 months)

A dozen major studies which came out with the same findings  all descriptive rather than experimental studies.

  • 2 variables that normally occurred, rather than manipulating variables. Cannot infer causation with a descriptive study.
  • Ethically impossible to do deprivation experiments

1 experiment on this by Lyngo

  • Even though you cannot deprive infants, you can provide maternal care.
  • Worked at a nursery home in an orphanage  mother to 8 infants, and 4 other infants were used as control.
  • Did it 2 shifts: mothered 4 infants for the critical period. And tested them on the EQ quotioent  eye contact, tracking, their responses to her, and the responses to strangers.
  • The control group was raised by the same procedures used in the orphanage.
  • The ones she did not raise were lower on EQ

After they were adopted out, she tested them again. Social responses to her and strangers  All the differences were wiped out.

  • May get early effects, but they don’t seem to carry out long-term

Why? Later in time than other orphanage studies, and these babies got more attention than babies in the earlier studies

Naturalistic data: involved Romanian babies who were adopted out in the 1990s.

  • Tens of thousands of infants ended up in orphanages following the revolution in that time
  • Unusually high amount of adjustment problems in these kids

Social imprinting does occur in most animals, and the data for humans is less conclusive. Human studies are severely restricted by ethical restrictions

Process by which imprinting is established Proximate rather than ultimate

  • Erikson: basic trust  this is essential for all social/cognitive development in later stages. This is once again descriptive.
  • Imprinting is a physical rather than social instinct. All things the mother does during this critical period in terms of contact with the infant is providing nurturance it affects the neurological patterns of the infant  demonstrated in rats.

Rats who are licked and groomed more by mothers during early development show an increase in endorphin.

Moltz:  the low – fear theory

  • Based on the observation that all animals go through a period of low-fear of the unfamiliar – Infants become wary of strangers at around 8 months, but before that they have low-fear.
  • This, according to Moltz IS the critical period.
  • Revolved around classical conditioning

Conceptualize the state of low-fear, but also correlates to the nervous system (measurable physical aspects)

  • Says that if the mother figure is around during low-fear, these physiological responses are conditioned to her.
  • Whenever she appears, the high heart rate goes down to low, muscle tension lowers etc.
  • Cannot be in low fear and high fear at the same time. Mother’s presence has a calming effect on the infant.
  • As long as she is around, the infant can explore the world and deal with unfamiliar things.
  • Explains the nature of the critical period, and the nature of love. – Shows how animals become attached to humans.

Hess  – direct test of this theory using ducks

  • Keep the ducklings in the critical longer by using tranquilizers. Keep the infant in the low-fear period longer, past the critical period.
  • Found that these infants imprinted up to 48 hours.
  • Tranquilized beyond the critical period  they will imprint up to 48 hours later.

Do you need a single caretaker, or is it just a conspecific?

  • Harlow approached this first: separate infant from mother, but have another species. The monkeys would clutch each other.

They came out a little delayed in their progression, but they were within the normal range.

Reserapkin (sp?) Studied communes in Israel.

  • Children raised by a group of people, and peers – Not imprinted to a single person, but adults in general –       A little delayed but then came out normal.

Personal report: do not need to be imprinted to a single adult, but have the same exposure of caretaking and affection.