Different factors influence how we understand the meaning of words and how we attend and remember them. For example, the relative usage of words in a particular language affects how quickly we can read and process those words, with faster reading times shown for higher-frequency words (word frequency effect). Additionally, the length of the word can affect how memorable a word is (word length effect), and letters are easier to identify if they are included as part of a word than when they are seen in isolation or in a string of letters forming a non-word (word superiority effect). Because of these and many other factors, cognitive researchers must carefully select word stimuli in a task, many times pulling from standardized word banks that have been matched along various dimensions (e.g. concreteness, frequency, word length).