Which of the following type of twins share as much genetic material with each other as they do with their other siblings?

Pascalis et al., (2005) used a longitudinal design to show that 9 month old infants who had looked at pictures of monkey faces at home between 6- and 9 months could discriminate between different monkeys, but infants who had not looked at pictures at home, could not.  This suggests that ____________ may be the mechanism that is driving the perceptual narrowing effect.  

In relation to pre-term birth, we say that the limit of viability is currently 24 weeks gestation. This is because....

 ___________ effects are seen when the results of a study might not be able to be generalised simply because of how long the longitundinal design took to run

Generational effects are a problem for _______ designs

1. ___________effects are seen when participants of different ages might differ in how they perform on a test, because of some other variable, other than age.