In this longitudinal study, we assessed the frequency of birth dates for boys selected for the Football Association National School. Birthdays were divided into three periods of the year: January to April, May to August and September to December. We compared data over a 5 year period and concluded that there is indeed a bias towards selecting older children. Furthermore, analysis of separate data revealed a shift of bias when comparing two different start dates, namely September and January. Our findings show that the youngest children from the January start date (born September to December) are selected significantly more often than the youngest children from the September start date (born May to August). Interestingly, even when the influence of body mass was reduced, the selection bias towards the older players remained.

It has been suggested that individuals may use heuristic methods of reasoning and rely on schemata when a quick decision is necessary. Accordingly, it is possible that decisions made by sport officials may be influenced by prior knowledge they have about teams they are officiating. The aim of the present study was to determine whether sport officials are more likely to penalize individuals who participate in a team with an aggressive reputation. In a balanced design, 38 football referees were randomly assigned to either an experimental or control group and were presented with the same 50 video clips of incidents from football games, all involving a team in a blue strip ('blue team'). The incidents were categorized before the study by five experienced referees into fouls committed both by, and against, the blue team, where all participants agreed that a foul had been committed (certain incidents), disagreed it was a foul (uncertain incidents) or agreed that there was no foul (innocuous incidents). Both groups received written instructions before the task; in addition, the experimental group was informed that the blue team present in all of the clips had a reputation for foul and aggressive play. For each incident, the participants were required to indicate what action they would engage in if refereeing the game. Although there was no difference in the number of decisions made, the experimental group awarded significantly more red and yellow cards against the blue team both overall and for the 'certain' incidents. It is suggested that prior knowledge may impact referees' behaviour in a laboratory setting, although future research should explore whether a similar effect is observed in the behaviour of referees during football matches.

Researchers examining skilled performance in the laboratory must establish contextual relevance to the usual performance environment to ensure that the obtained data truly reflect expertise in the skill under investigation. Interactive video simulation is a viable method for providing such ecological validity. This paper describes the development to date of such a simulator and outlines two sportsperformance studies which demonstrate the validity and reliability of the configuration in competitive situations. Further development of the simulator is possible through new technologies and through the assembly of specific interfaces for other motor skills. The paradigm also has potential as a training resource for teaching the specific knowledge necessary for expert levels of performance.