THE EFFECTS OF SECONDARY VERBAL TASKS ON TRACKING PERFORMANCE WERE EXAMINED. IN EXP. I REDUNDANCY WAS VARIED IN BOTH PRIMARY AND SECONDARY TASKS, WITH THE LATTER INTRODUCED AT A RETENTION SESSION. THE SECONDARY TASK RESULTED IN MARKED INTERFERENCE, INDEPENDENT OF EITHER PRIMARY OR SECONDARY TASK REDUNDANCY, PRIMARILY IN THE TIMING ASPECT OF TRACKING. IN EXP. II, STIMULUS AND RESPONSE COMPONENTS OF THE SECONDARY TASK WERE PRESENTED SEPARATELY. THE RESPONSE COMPONENT PRODUCED AS MUCH INTERFERENCE AS THE COGNITIVELY MORE DIFFICULT SECONDARY TASK. EXP. III SHOWED THAT SECONDARY TASK EFFECTS OCCUR INDEPENDENT OF A RETENTION INTERVAL. (PsycINFO Database Record (c) 2006 APA, all rights reserved)