Final answer:
The provided references do not indicate a study by Howard & Jones from 2000. More detailed citation information is required to identify and summarize the specific study conducted.
Step-by-step explanation:
There appears to be a mix-up as the provided references do not include a specific study by Howard & Jones from the year 2000, nor is one mentioned in the given materials. Without further context or information about the study, it's not possible to provide a precise answer. It is essential to check for the accurate citation to ascertain the correct study. If Howard & Jones did indeed publish a study in 2000, additional information such as the journal name, volume, page numbers, or a study title would be necessary to identify and summarize the study conducted.