In science, replication is key.

If independent scientists can replicate your work using the same methods, it's science.

Using psychology undergraduates from one university for survey data is not going to lend itself to much replication beyond the obvious, like that college students in social sciences are more liberal than students in engineering.

Psychology journals, with their size and cost limitations, don't want to publish replications - trying to do so would mean a lot of retractions when giant numbers of studies couldn't be replicated, but open access, mentioned previously, helps here also. As long as the credit card clears, an open access journal will publish a replication.

Lots of key studies in psychology have been replicated, it's the outrageous 'conservatives are driven by fear, liberals have prettier daughters' nonsense that gets all of the attention and can never be verified.  Instead, psychologists engage in 'conceptual replication', where they do their own work and find, yep, they see it too. That's not replication.

But there are calls to have more actual replication because young psychologists want to get out of the humanities buildings and into the science ones, and they know that adopting the methods of science, rather than the trappings, is the way to do it.

On to: Conclusion