AO3

• Strength

  Filmed observations used and lab study. Activity that could distract the baby can be controlled. Filming means it can be analysed later which prevents missing key behaviours. More than one observer establishes inter-rater reliability of observations. Babies are also unaware of observations. Good reliability and validity.
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  Limitation

  Difficult to observe babies. Lack co-ordination and most of their bodies are immobile. Observations made are subtle changes expression and small hand movements. Can’t be certain behaviours have any significant meaning.
• Limitation 

  Doesn’t tell us about developmental importance. Feldman points out ideas like synchrony simply give names to patterns of observable behaviour. Not useful in understanding links to development. Can’t be certain that they are important.

  However, evidence for Isabella et al found that achievement of interactional synchrony predicted the development of good quality attachment.