Why is recognition easier than recall? The main ways of memory retrieval are recognition and recall. 

Why has it been found that recognition is "easier" to perform, meaning it is usually faster or is more likely to yield an accurate retrieval?
It is not. At least not always: In this famous experiment Tulving and Thomson show that under certain circumstances recall can be better than recognition. 

It seems that the reason why recognition is usually more accurate than recall, is the context. Usually, the context in the recognition test is very similar to the conditions in the learning phase - the subject sees a list of words. In the free recall test, the context is different - the subject is not given any external stimulus. 

Tulving and Thomson changed that in their experiment: the context of learning was more similar to the recall test, which resulted in higher performance in the recall.

This indicates that the encoding in memory has some context specificity. Items that were encoded using a visual stimulus will be easier to recognize or recall if the same or similar stimulus is presented during the test.

Note: I interpreted the word 'easier' in the question as 'more accurate' because typically accuracy is measured, and not the 'ease' of the recall/recognition, which could be defined in many different ways.


  Tulving, E., &amp; Thomson, D. M. (1973). Encoding specificity and retrieval processes in episodic memory. Psychological review, 80(5), 352-373. PDF