Background: We introduce a method for quickly determining the rate of implicit
learning.
Methodology: The task involves making a binary prediction for a probabilistic
sequence over 10 minutes; from this it is possible to determine the influence of events
of a different number of trials in the past on the current decision. This profile directly
reflects the learning rate parameter of a large class of learning algorithms including
the delta and Rescorla-Wagner rules. To illustrate the use of the method, we compare
a person with amnesia with normal controls and we compare people with induced
happy and sad moods.
Conclusions: Learning on the task is likely both associative and implicit. We argue
theoretically and demonstrate empirically that both amnesia and also transient
negative moods can be associated with an especially large learning rate: People with
amnesia can learn quickly and happy people slowly
