AO3

• A strength of studies into care-giver infant interactions is they used infants at such a young age (two-three weeks old) meaning that the babies were unaware they are being recorded and so their behaviour will not change in response to this and they were simply being babies. Therefore the studies have high ecological validity and external validity.
• However, Tronick's Still Face Experiment was a laboratory procedure. This means that it is likely to lack ecological validity and so findings of the experiment may not give an accurate prediction of what would be seen in the real world in infants interactions.
• A limitation is using infants and babies in research can make it difficult to test their behaviours objectively without interpretation. Infants lack coordinated movements and tend to move their limbs randomly. Therefore, it is difficult to distinguish between their general behaviours and specific actions in response to an adult meaning the results may lack internal validity.