The American Journal of Psychology was the first English-language journal devoted primarily to experimental psychology

Experimental psychology

Experimental psychology is a methodological approach, rather than a subject, and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...

 (though Mind

Mind (journal)

Mind is a British journal, currently published by Oxford University Press on behalf of the Mind Association, which deals with philosophy in the analytic tradition...

, founded in 1876, published some experimental psychology earlier). AJP was founded by the Johns Hopkins University

Johns Hopkins University

The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...

 psychologist Granville Stanley Hall in 1887. The journal has distributed some of the greatest groundbreaking and informative papers in psychology. The ‘AGP’ investigates the science of behavior and the mind, releasing reports of original research based on experimental psychology, theoretical presentations, combined theoretical and experimental analyses, historical commentaries along with detailed reviews of well known books.The Journal has published some of the most innovative and formative papers in psychology throughout its history. AJP explores the science of the mind and behavior, publishing reports of original research in experimental psychology, theoretical presentations, combined theoretical and experimental analyses, historical commentaries, and in-depth reviews of significant books.
References

http://www.press.uillinois.edu/journals/ajp.html