Table 2.

Experimental designs used to study the spread of traditions. (Criteria for inclusion are that a behaviour pattern is either facilitated (row 1) or explicitly seeded, usually through training of an initial model (rows 2–7), and the spread of such patterns is subsequently documented. Experimental designs are classified according to (i) experimental versus control conditions (condition designs: rows 1–7) and (ii) methods used to examine the spread of any traditions emerging (transmission designs: columns A–C), distinctions fully explained in the text. Studies marked with a single asterisk showed spread within a first group in an open diffusion design (column A) then on to a second or third group, thus demonstrating a chain of transmission (column C). For more information on each study see table 1, and table S1 in the electronic supplementary material.)

	transmission designs (A–C)
condition designs (1–7)	A. open group	B. replacement	C. linear chain
1. one group, presented with novel learning opportunities	Cambefort (1981), Paquette (1992), Tonooka et al. (1997), Biro et al. (2003) and Huffman & Hirata (2004)
2. action explicitly seeded in one group but no baseline	Sumita et al. (1985), Hannah & McGrew (1987), Reader & Laland (2000) and Swaney et al. (2001)
3. one experimental group with one trained, seeded action, following no-model baseline	Gajdon et al. (2004)	Menzel et al. (1972)	Curio et al. (1978a)
4. one experimental condition with one trained, seeded action, versus no-model control condition	Lefebvre (1986) and Cloutier et al. (2002)	Stanley et al. (2008)	Laland & Plotkin (1990, 1992)
5. two experimental conditions, with alternative actions seeded in each	de Waal & Johanowicz (1993), Freeberg (1998) and Freeberg et al. (2001)	Galef & Allen (1995) and Laland & Williams (1997, 1998)	(Freeberg (1998), Freeberg et al. 2001 *see also Col. A)
6. two experimental conditions, with alternative actions seeded in each, after baseline, no-model control period	Fragaszy et al. (2004), Price & Caldwell (2007) and Whiten et al. (2007)		(Whiten et al. (2007), *see also Col. A)
7. two experimental conditions, with alternative actions seeded in each, plus third, no-model control condition	Langan (1996), Brown & Laland (2002), Whiten et al. (2005), Bonnie et al. (2006) and Hopper et al. (2007)		Laland & Plotkin (1993), Horner et al. (2006) and Dindo et al. (2008)