Debriefing
The results from all three different types of experimental trials are shown together: accuracy, speed, and a balance of speed and accuracy. The only differences between these blocks were the instructions and, presumably, participants’ compliance with those instructions. Trials where the letter was easy to spot (e.g when ‘OX’ was presented) were coded as ‘easy’, and trials where the letter was harder to spot (e.g. when ‘OQ’ was presented) were coded as ‘hard’. The response time data is shown in one graph, the accuracy in another. The speed-accuracy trade-offs can be observed by looking at the response time data and the accuracy data at the same time. First consider the speed pressure blocks. The speed-accuracy trade-off is demonstrated by looking at the fast response times and poor accuracy. Next consider the accuracy pressure data. The speed-accuracy trade-off is demonstrated by looking at the slower response times and higher accuracy. The balance condition shows response times and accuracy that fall in between speed pressure and accuracy pressure trials. The plausible impact of instructions and the speed-accuracy trade-offs that result is demonstrated by comparing the hard and easy conditions in speed pressure and accuracy pressure trials. In the speed pressure trials, there is no significant difference, but in the accuracy pressure trials there is. Thus an experimenter who wanted to know if there was a difference in processing time needed for easy and hard trials would get a different answer to their question depending on whether their participants emphasized speed or accuracy. Whenever response time data is considered by a researcher, accuracy data must also always be looked at. Fast trials that are accompanied by significant increases in error rates signify a speed-accuracy trade-off.