Each participant played in each of the three conditions: no sound, constant sound, and increasing sound. The order of the three conditions was counter-balanced across participants to control for learning and fatigue effects. Participants were randomly allocated an order of conditions. Regardless of the order, each participant received one minute of practice time in each condition before playing that condition competitively for 15 minutes. These 15 minutes were further divided into three blocks of five minutes each.
As each condition began, the participant was presented with the game rules. These rules emphasized the importance of both accuracy and speed in the task. At the end of each individual trial, the player received feedback for 500 milliseconds regarding their choice of buckets. A green tick was displayed below the target square if the decision was correct. This was accompanied by a cash-register sound. If the player chose incorrectly, a red cross was displayed below the target, accompanied by a sigh-of-disappointment sound. If the player timed out, an alarm clock was displayed, and a typical alarm clock sound was played.
Both the player’s response time or timeout status for each attempt were recorded for later analysis. Data regarding the correct target bucket (1-4) and the player’s actual selected bucket (1-4) for each attempt were also saved. At the completion of each of the five-minute blocks, participants received summary information about their performance, namely, the number of correct and incorrect responses. At the end of each sound condition, the subject was allowed a two-minute break before commencing the next assigned condition. Generally speaking, subjects completed the experiment in about 60 minutes.
The experiment was conducted within a computer laboratory. Upon arrival, each participant was assigned a workstation that displayed the Buckets game. All data was collected using an Apple Mac Pro running OS X 10.8 Mountain Lion. The game was played online using the Mozilla Firefox (Version 22) web browser and Flash Player (version 11.4). Each participant wore a full-sized headphone (AKG K44) during the whole experiment, even during the “no sound” condition. During the experiment, the volume level on the operating system was set to the lowest possible volume (1 out of 16 bars) for all players.