Vasconcelos, M., Urcuioli, P.J. & Lionello-Denolf, K.M. (2007).
When is a failure to replicate not a Type II error?
Journal of the Experimental Analysis of Behavior, 87, 405-407.
Zentall and Singer (2007) challenge our conclusion that the work-ethic effect reported by Clement, Feltus,
Kaiser, and Zentall (2000) may have been a Type I error by arguing that (a) the effect has been extensively
replicated and (b) the amount of overtraining our pigeons received may not have been sufficient to produce it.
We believe that our conclusion is warranted because (a) the original effect has not been replicated despite
multiple attempts to do so and (b) the statement that more extended overtraining may be needed itself suggests
that the original effect is not reliable.
Key words: work-ethic effect, Type I error, Type II error, within-trial contrast, overtraining, replication