Final answer:
Deception in research is deemed acceptable by the APA when necessary for maintaining a study's integrity and not causing harm, with a required full debriefing for participants post-study.
Step-by-step explanation:
According to the American Psychological Association, deception in research is justified and acceptable when necessary to prevent participants' knowledge from affecting the study's results and when it does not cause harm. The researchers must maintain the integrity of the experiment and ensure that the deception is not harmful. Once the study concludes, participants must receive a full debriefing, which includes the purpose of the experiment, how the data collected will be used, the reasons why deception was used, and information on obtaining further details about the study.