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Developmental Psychology Studies You Need To Know

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Emily is a PhD student with a BSc in Molecular Biology and Genetics, an MSc in Molecular Medicine, and a passion for science communication.


If you haven't already, I would recommend reading the following articles to fully prepare yourself for your unit 1 exam!

This article will outline some of the key studies and theories that you must know for the developmental psychology (attachment) aspect of the exam, with their strengths and weaknesses and what they support and oppose.


The Learning Theory

The learning theory basically stated that the attachment between an infant and their caregiver is a behaviour that is learned rather than something that is innate or inborn. There are two aspects to the learning theory and these are:

  • Classical Conditioning
  • Operant Conditioning

Classical conditioning is essentially where an unconditioned stimulus produces an unconditioned response (such as a baby being given food which is an unconditioned stimulus and becomes happy which is an unconditioned response to this). The person that is responsible for feeding the baby will be associated with this pleasant feeling. If the person then feeds the baby over and over again they will become the stimulus that causes the happiness of the baby. This association between the caregiver and pleasure is the basis for the attachment between the caregiver and infant.

Operant conditioning occurs when someone is either punished or rewarded for a behaviour that they displayed. When the person is rewarded for their behaviour then this behaviour will be positively reinforced and the person will be much more likely to repeat it. In terms of attachment, operant conditioning says that when an infant is uncomfortable (say because they are hungry), feeding them replaces this uncomfortable feeling is with pleasure. The food then becomes the primary reinforcer and the the person feeding the infant will be associated with the pleasant feeling and become the secondary reinforcer.

Strengths and Weaknesses of the Learning Theory as an Explanation of Attachment

It has been shown that we do learn through association and reinforcement, and the learning theory does provide an adequate explanation of how attachments between caregivers and infants can form; however, it states that the main reinforcer is food, which may not be the case.

Harlow's monkey study was conducted to see if food is in fact the primary reinforcer or if there are other aspects that contribute to the forming of attachments. Harlow got a baby monkey and gave it the option of either food (portrayed by a wire 'monkey' with an attached food bottle) or comfort (portrayed by a wire 'monkey' covered in cloth).

If the learning theory was completely accurate then the baby monkey would have gone to the food 'monkey' most of the time, whereas it was actually the opposite that was true. The baby monkey spent most of his time on the comfort 'monkey,' which suggests that other things are involved in the formation of attachment.

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Ainsworth's Uganda Study

In 1954 a psychologist called Mary Ainsworth conducted a observation study into mother and infant interactions in Uganda. She chose Uganda as the place to conduct her study because as an American she wanted to see what the differences were between infant-caregiver attachment in two completely different cultures.

The participants of the study were 26 mothers and their infants. Some of the observations that she made were that mothers that were more sensitive to their child's needs tended to have children who were more securely attached and were more independent. This observation could not be explained by the learning theory; however it could be explained by the 'secure base' aspect of Bowlby's theory of attachment.

The findings showed that in both the USA and in Uganda there were similar attachment types (such as secure attachment).

Strengths and Weaknesses of Ainsworth's Uganda study

That the Uganda study evaluated attachment types by the means of natural observation means that the study is high in ecological validity and can therefore be generalised to other similar situations. Neverthless, there are some weaknesses to using natural observation research techniques. Some studies, like the Uganda study, have been shown to have something called 'investigator bias.' This is where the person observing and conducting the experiment may see what they want to see. Bias may mean that if more than one person observes there may be very different observations, which in turn leads to low inter-observer reliability.

The Strange Situation

The strange situation was a study that was conducted by Ainsworth and Wittig in 1969 in order to test the nature of attachment. The study involved putting infants into situations that would either be anxiety-provoking or that the infant had probably never witnessed before. There are 8 episodes involved in the strange situation some of which include:

  • Parent sits whilst the infant plays: the behaviour of the infant is assessed to see if they use their parent as a secure base.
  • A stranger is introduced to the infant and the mother leaves: assesses stranger and separation anxiety.
  • The parent comes back into the room: assesses the behaviour that the child shows upon reunion.

This study was conducted by many psychologists on many infants and the results collected by Ainsworth. She deduced that four main attachment types that were observed in all of the 106 middle-class infants. These are:

  • Secure attachment
  • Insecure-avoidant attachment
  • Insecure-resistant attachment
  • Insecure-disorganized attachment

Strengths and Weaknesses of the 'Strange Situation' Experiment

The 'strange situation' was devised in order to try and measure the types of attachment infants have with their caregivers; however it has been argued that maybe the experiment actually measures the quality of the attachment rather than the type of attachment. A study that supports this criticism of the strange situation is that of Main and Weston. The study found that infants behaved differently around each one of their parents, which suggests that it is actually the relationship being measured rather than the attachment that the infant possesses.

Test Yourself!

For each question, choose the best answer. The answer key is below.

  1. Which of the following is not a type of attachment between an infant and caregiver?
    • Secure
    • Secure-avoidant
    • Insecure-resistant
    • Insecure-disorganised
  2. Classical conditioning suggests that?
    • An infants attachment to it's caregiver is innate
    • Infants learn attachment through association
  3. A weakness of the strange situation study is?
    • It is the quality of the relationship being assessed rather than attachment type
    • It wasn't repeated enough times so conclusions cannot be made
    • The people in the study didn't know they were being observed therefore the study is unethical
  4. The conclusions of Ainsworth's Uganda study were?
    • Attachment type differs depending on what culture you're assessing it in
    • There wasn't much variation between cultures in that infants and caregivers displayed the same types of attachment
    • The most common form of attachment obseved was insecure-resistant

Answer Key

  1. Secure-avoidant
  2. Infants learn attachment through association
  3. It is the quality of the relationship being assessed rather than attachment type
  4. There wasn't much variation between cultures in that infants and caregivers displayed the same types of attachment

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