Table 1.

Classifying Innovation

	Criteria (whether innovation by invention or modification)
Levels
1: Low	Unlearned “chance” innovation not repeated by the individual
2: Mid	Individually learned innovation repeated by the individual
3: High	Individually learned innovation that is acquired by others
Types (from animal behavior)
Cognitively simple/complex (Whiten & van Schaik, 2007)	Simple: An innovation that could arise by individual discovery. Complex: An innovation that requires causal inference and deliberate action; not likely to arise by accident.
Weak innovation/invention (Ramsey et al., 2007)	Weak innovation: An innovation in which social learning or environmental induction is implicated Invention: An innovation that is rarer, more novel, and involves more cognition.
Passive/active (Rendell et al., 2007)	Passive: An innovation that is more likely to rely on chance events. Active: An innovation that is more likely to reflect cognitive abilities of the innovator.
Type I/Type II (Burkart et al., 2009)	Type I: An innovation that is goal directed and problem induced. Type II: An innovation that is more incidental.

By presenting our “levels” and earlier literature's “types,” this table intends to highlight the increased clarity afforded by the former classification. Transition from mid‐ to high‐level innovation does not necessarily directly link to the “usefulness” of the innovation but may be a function of other social and contextual factors, such as the dependency of transmission on the identity of the innovator, due to directed social learning or transmission biases. Owing to its cultural transmission ramifications, learning is a key, and ideal, component of our levels criteria. However, it is not at this stage essential to demonstrate in child research given the difficulties of observing repetitions of innovative behavior.