Table 11. Characteristics of the two cohorts.

	Study 1 (N = 107)	Study 2 (N = 124)	Significant effects
			Study 1	Study 2
Hypothesis	Spatial-temporal analysis provides a bridge between observation of continuous processes and their causal analysis.
Sample characteristics	Middle and high SES	Low and middle SES
Implementation of causal phenomena	A three stage implementation (prediction, description, explanation)	A five stage implementation (observation, prediction, justification, testing, explanation)
Spatial-temporal tasks	Flow of liquid	Flow of liquid	✔	✔
	Speed	Distance, time, velocity	X	✔
Spatial tasks	Monkey mental rotation	Mental rotation (Tick-Tock)	✔ for young children	X
	Paper folding	-	X
Verbal task	WASI vocabulary	WASI vocabulary	X	✔
Nonverbal task	WASI block design	WASI block design	✔	✔