Final answer:
The specific conclusion from Walster et al.'s experiment is not detailed in the provided context. Additional information is needed to accurately describe their findings on the effectiveness of 'overheard' persuasive communications in influencing attitudes or beliefs.
Step-by-step explanation:
The conclusion from Walster et al.'s experiment on the effectiveness of "overheard" persuasive communications is not provided within the context of the information given. To ensure a precise and accurate response, more information about the study's results and specific conclusions is needed. However, in general, the study by Walster and Festinger likely explored how overhearing a conversation or message might impact an individual's attitudes or beliefs, which is a concept related to social psychology and persuasive communication techniques. This specific area of study could provide insight into the mechanisms of how people are influenced indirectly through social interactions in their environment.