Answer:
after many previous trials, people had difficulty recalling the stimuli, even with only a short delay
Step-by-step explanation:
John Brown was an Englishman while Lloyd Peterson and Margaret Peterson were Americans. They all carried out an experiment in determining the duration of short term memory.
They all discovered after after like three trials that people have difficulty in remembering things, even after a short or brief delay.
Lloyd Peterson and Margaret Peterson concluded that it was due to decay of the memory trace.