Table 3.

Evaluation criteria for possible threats that limit the conclusions that could be drawn from individual studies to the present hypotheses.

Threat	Validity type
No or inadequate statistical testsa	Statistical conclusion
Heterogeneous stimuli	Statistical conclusion
No manipulation check for human-likenessa	Internal
Image morphing artifacts	Internal
Categorical perception not testedb	Construct
Irrelevant affinity measuresa	Construct
Familiarity evaluations misunderstood	Construct
Outlier stimuli (e.g., morbid characters)	Construct
Alternative explanations	Construct
Narrow human-likeness range	Construct
Narrow set of manipulated stimuli	Construct
Narrow participant sample	External

Validity types refer to Shadish et al. (2002).

^aUsed as article inclusion criteria.

^bApplies only to the hypotheses H3c and H3e.