Free word associations are the words people spontaneously come up with in response to a stimulus word. Such information has been collected from test persons and stored in databases. A well known example is the Edinburgh Associative Thesaurus (EAT). We will show in this paper that this kind of knowledge can be acquired automatically from corpora, enabling the computer to produce similar associative responses as people do. While in the past test sets typically consisted of approximately 100 words, we will use here a large part of the EAT which, in total, comprises 8400 words. Apart from extending the test set, we consider different properties of words: saliency, frequency and part-of-speech. For each feature categorize our test set, and we compare the simulation results to those based on the EAT. It turns out that there are surprising similarities which supports our claim that a corpus-derived co-occurrence network can simulate human associative behavior, i.e. an important part of language acquisition and verbal behavior.