Eye chart smaller symbols until the person cannot identify the symbols. The smallest symbols that can be reliably identified is considered the person's visual acuity. The Snellen chart is the most widely used. Alternative types of eye charts include the logMAR chart, Landolt C, E chart, Lea test, Golovin–Sivtsev table, the Rosenbaum chart, and the Jaeger chart. Charts display several rows of optotypes, which are standardized symbols for testing vision. Optotypes are usually letters, numbers, or geometric symbols. Each row of the chart depicts optotypes of a different size. Typically the largest optotypes are in the top row. The optotypes become progressively
Levels-of-processing effect subject does not explicitly recall the stimulus, but the previous stimulus still affects performance. For example, in a word-completion implicit memory task, if a subject reads a list containing the word "dog", the subject provides this word more readily when asked for three-letter words beginning in "d". The levels-of-processing effect is only found for explicit memory tests. One study found that word completion tasks were unaffected by levels of semantic encodings achieved using three words with various levels of meaning in common. Another found that typical level-of-processing effects are reversed in word completion tasks; subjects recalled pictures pairs more completely