- Gibson & Walk: Methodology. (MERVS)
- Method: Lab experiment - Strength = control the variables/ apparatus/ procedures.. easy to replicate. Weakness = artificial setting.. lacks ecological validity.
- Ethics: Strengths = gained informed consent from parents and right to withdraw. Weaknesses = caused distress, future psychological issues, took away some of the animals natural instincts, not all of the animals were generalisable to humans.
- Reliability: Other researchers have used the 'visual cliff' and also found that human infants appear to be able to perceive depth. Some suggest that depth perception can be demonstrated in infants before they are able to move independently = good external reliability.
- Validity: Only tested depth perception in infants able to crawl meaning they had no control over previous learning/ experiences. Infants may have strayed onto the deep side due to lack of co-ordination, but having done so learned that they would not fall. = Reduces internal validity.
- Sample: Variety of species used allowing more general conclusions to be drawn about depth perception being innate or learned = :) Human infants are unable to crawl until several months old = :(