Early Screening for Developmental Language Disorder: Predictive Validity of German Parent Reports.

I completed a PhD thesis early in 1988. This thesis was about the discrimination of brief empty time intervals. In this thesis, findings were explained in terms of the properties of an internal clock (pacemaker‐accumulator system), with the help of some cognitive interpretations. There was no reference to Peter R. Killeen's work in this thesis. Circulation of knowledge was not as easy as it is nowadays! And when you begin to review the existing literature on time perception in the mid 80s, you already have a century of publications on the subject to catch up on, starting with a review by Fraisse () and the edited book by Gibbon and Allan (). During the summer of 1989, having to prepare a first grant proposal for a Canadian agency, I had to refresh and upgrade my knowledge about time perception. My search led me to Killeen and Weiss (), a remarkable and comprehensive article, and I was almost tempted to quit the field because the standard of excellence was suddenly set too high! Obviously, I didn't quit but had to work for a while with the impression that I would never be able to contribute, even modestly, to this research field. That 1987 article was such a fine theoretical integration of the main pieces of information in the field of temporal discrimination, providing an integrative view that would indeed apply to any neural counting mechanism. For those needing additional explanations, after Killeen and Weiss, about the models that could be derived from a pacemaker‐accumulator system, it was possible to refer to the appendix of another article (Killeen & Fetterman, ) where a timing theory, based on animal behaviors (rate of reinforcement), could also be applied to duration discrimination and other tasks or phenomena. And for those who had not yet realized that errors in temporal tasks may not only be caused by the properties of the pacemaker but also by the fallibility of the counter, an even more comprehensive description of its role, also published in , was soon to follow (Killeen & Taylor, ). So far, so good. I prepared the grant proposal and talked with a colleague on the English side of the department that was also preparing a grant proposal for the same agency. We discussed, and, although we were not at all in the same research field (his training was on eating‐related behavior of … pigeons maybe), I noted that among the few references in our proposals, we referred to a likely common author, but his references were from the 70s. Could there be more than one Killeen in experimental psychology? Maybe a common name; after all, there is more than one person who crossed the Atlantic from Ireland. But several P. R. Killeen in experimental psychology? No! Thinking back on it, it makes sense that this was the same person, given the content of Killeen and Fetterman and given convergence of the animal and human timing literature that followed the 1983 meeting of the New York Academy of Sciences (Gibbon & Allan, ).