Key points are not available for this paper at this time.
Abstract A one‐year lag was found between the effect of an intervention intended to promote formal operational thinking in students initially 11 or 12 years of age and the appearance of substantial science achievement in the experimental groups. A one‐year lag was also reported on cognitive development: Whereas at the end of the two‐year intervention the experimental groups were up to 0.9σ ahead of the control groups, one year later the differential on Piagetian measures had disappeared, but the experimentals now showed better science achievement of even greater magnitude. Although the control groups showed normal distribution both on science achievement and cognitive development, the experimental groups showed bi‐ or trimodal distribution. Between one‐half and one‐quarter of the students involved in the experiment in different groups showed effects of the order of 2σ both on cognitive development and science achievement; some students appeared unaffected (compared with the controls), and others demonstrated modest effects on science achievement. An age/gender interaction is reported: the most substantial effects were found in boys initially aged 12+ and girls initially 11+. The only group to show no effects was boys initially aged 11+. It is suggested that the intervention methods may have favored the abstract analytical learning style as described by Cohen 1986.
Shayer et al. (Wed,) studied this question.