Generally, in recall and recognition tasks, participants are given a list of to be remembered stimuli and later asked what they remember from the list. Recall tasks ask a participant to relist all the items they remember. Recall tasks may be free or cued. In cued recall, participants are given hints (cues) to help them recall items from the list, unlike a free recall task, where recall is ‘free’ from hints.
Recognition tasks do not require a participant to call up a specific memory of an item or event. Generally, researchers will present a new list of stimuli, some of which overlap with the to-be-remembered list and participants are asked to identify which of the stimuli are from the to-be-remembered list. Additionally, in recognition tasks, researchers can ask a participant whether they remember or know a particular item. To remember refers to items they have a vivid and specific memory(recollection) of being in the list, whereas, knowing refers to having a familiarity with the item, but not being able to pinpoint the exact memory of the item being in the to-be-remembered list.
Participants’ responses to recall and recognition tasks can be analyzed to determine the whether there is a pattern to the way items are remembered. For example, a researcher may be looking for a serial position curve (see Ebbinghaus 'things'), or they may look at what kind of items are remembered versus which are forgotten.
(See, for example, this figure from former GSU psychology faculty member Frank Heist and his advisor Larry Squire, http://whoville.ucsd.edu/PDFs/192_Haist_etal_JEP_1992.pdf .)