Modern-day psychologists such as Donna J. Dahlgren, an assistant professor of psychology at IU Southeast, continue to analyze tip-of-the-tongue, or TOT, experiences. As a Ph.D. student at Kent State University, Dahlgren was conducting experiments related to other aspects of memory when she noticed that she was eliciting a TOT state in her subjects with many of her questions, which were based on trivia and general knowledge. "What is the most widely used tranquilizer in America?" was one of the questions, says Dahlgren, as was "Which of the seven dwarfs comes first alphabetically?" Knowing that psychologists traditionally have found it difficult to evoke TOT states deliberately, Dahlgren decided to build a pool of such questions and then to embark on her current study, now under way at IUS.
"I am using my general-knowledge questions to determine if there are age differences between elderly (ages 60-80), middle-aged (ages 30-59), and young adults (ages 18-29) that affect frequency and information available during the TOT state," Dahlgren says. (The term "information available" refers to how fully a person in a TOT state can describe the "longed-for term"--what it sounds like, what it means, what its first letter is.) In previous, comparable studies, Dahlgren says, "Elderly people have been found to be less able to retrieve partial information, such as the first letter or a sound-alike word; rather, the experience is described as an 'empty gap' or a state in which 'nothing will come.'" Often, however, subjects in a TOT state "are able to retrieve partial information about the target word, but are unable to fully retrieve the word," Dahlgren says. "They may know exactly what the word is, but can only say that it starts with a particular letter or has a certain sound; or they can retrieve a similar-sounding word, noting that the stated word is not exactly what they are searching for."
These abilities suggest that the human memory stores words and their definitions in a way that resembles a dictionary. But, Dahlgren says, "Our mental dictionaries are much more flexible than the alphabetized version on a bookshelf. Words can be recovered by either their meaning or their sound, and the entries need not be examined in alphabetical order. Psychologists call this search for a desired word 'lexical retrieval.' A TOT state appears to be a breakdown in an intermediate stage of lexical retrieval."
This breakdown demonstrates an essential concept in the study of long-term memory--the difference between accessibility and availability. Dahlgren explains, "It is widely believed that long-term memories are stored somewhere in memory, but the memories may be inaccessible--unable to be retrieved, either temporarily or permanently. Evidence that supports the distinction between availability and accessibility comes from the work on the tip-of-the- tongue phenomenon."
To continue her own work on the phenomenon, Dahlgren plans to expand on the current study. "I want to determine if exposing the subjects to the target words prior to asking the general-knowledge questions will increase or decrease the experimental rate of TOTs among the subjects," she says. "This manipulation will allow me to investigate their implicit memory of the target words and to see if more TOTs are resolved if the subjects have been recently exposed to the target word." It is an interesting query, one of significance to anyone who has ever tried to remember "Valium" or "Bashful" and failed.