Most studies of the TOT state focus on either the characteristics of the information pertaining to the not-yet-retrieved items—such as the first letter, the number of syllables, the gender of the word in certain languages, or incorrect words called ‘blockers’ (Brown, 1991, 2012; Gollan & Brown, 2006; Kornell & Metcalfe, 2006a; Miozzo & Caramazza, 1997)—or they focus on the compelling phenomenology of the state (Cleary & Claxton, 2015; Schwartz & Cleary, 2016). With respect to the latter, researchers often include William James’ (1890, p. 251) description “The state of our consciousness is peculiar. There is a gap therein; but no mere gap. It is a gap that is intensely active. A sort of wraith of the name is in it, beckoning us in a given direction, making us at moments tingle with the sense of our closeness and then letting us sink back without the longed-for term,” R. Brown and McNeill’s (1966, p. 326) comment that people who are “seized by a TOT state … would appear to be in mild torment, something like the brink of a sneeze,” or A. Brown’s (1991) acknowledgment of “personal introspections of inner turmoil when grappling for an elusive word.” Normally, when individuals are engaged in nonpathological cool cognition, they are not seized by ‘inner turmoil,’ or by any kind of ‘torment.’ But TOT states are different. They arise into consciousness as a distinct emotional configuration that appears to be universally recognizable (Schwartz, 1999). The question that underlies the research in the present article is why this particular metacognitive feeling state surfaces into consciousness as a distinctive and emotional state: what is its function?
Schwartz and Cleary (2016; and see Metcalfe & Schwartz, 2015; Schwartz & Metcalfe, 2011) have suggested that the TOT state may have an adaptive, evolutionary purpose. They have focused on the finding that people persevere in their efforts at recall when they are in a TOT state: the metacognitive feeling appears to prompt people to continue trying. Furthermore, most TOT states are eventually successfully resolved, although with obvious difficulty. Even so, the difficulty of the retrieval itself is thought to play a role in enhancing later memory (see, e.g., Bjork & Linn, 2006)—a consequence that has beneficial effects for the individual’s later performance. The present study takes this idea a step further in suggesting that the TOT state prompts curiosity, which could entail more than just a retrieval attempt—the feeling state may entail general information seeking behavior.
Weiner (2006), in describing the tenants of his attribution theory, argued that consciously experienced feelings (i.e., emotions) are ‘goads to action.’ Consistent with this view, we propose that the conscious emotional instantiation of the TOT state has a function of inducing the experiencer to the action of trying and persisting in efforts to gain the sought-for information. It induces an eager desire to know: curiosity.
Several precursors in the literature provide convergent support for the idea that the TOT state may be related to curiosity and information seeking. First, going back as far as Berlyne’s (1954) theory of epistemic curiosity, theorists have proposed that people’s need to know is ignited by materials that are neither completely unknown nor completely known, but are, instead, in an intermediate zone (Atkinson, 1972; Kornell & Metcalfe, 2006b; Litman, 2009; Loewenstein, 1994; Metcalfe, 2002). These theories indicate that people are best off, as far as learning goes, if they study items that are at an intermediate state of learning. For example, Atkinson (1972) employed an early computerized learning program which sorted items into those that were reliably remembered, intermediate items that were somewhat learned but not permanently (which he called ‘T’ or transitional items), and those that were unlearned. He found that the most effective learning algorithm involved having people selectively study the ‘T’ items. Metcalfe and Kornell (2003, 2005) called T items those in the Region of Proximal Learning (RPL). In addition, they found that college students selectively chose these particular items for further study. Loewenstein (1994), like Berlyne (1954), also zeroed in on such items in his theory of curiosity, pointing to them as being the items people found particularly interesting and deserving of attention.
The items that one finds on the tip of one’s tongue fit the characterization of ‘T’ items or ‘RPL’ items very well. They are not so easy that they can be readily recalled, but they are not so difficult that they are completely unknown and have no resonance. Indeed, some partial and semantic information appears to be retrievable for these items, making them ideal candidates for optimal learning. It is possible that the feeling associated with being in a TOT state is a marker of these special items and has a function of provoking curiosity and inducing the person to epistemic action.
The action involved in information seeking varies from situation to situation. A person may just keep trying to retrieve rather than giving up, may look up an answer in a dictionary, or may ask a friend or teacher. Often Google is the option of choice. To investigate whether the TOT state is perceived as having some special role in inducing such action, we asked 127 participants (61 male, 66 female; mean age = 40.6, SD = 11.6) on MTurk, the following question:
“You have the strongest urge to Google the answer to a question that has been posed to you when:
you are sure you know the answer, and can produce it,
you are sure you don’t know the answer and can’t produce it,
you have a ‘feeling of knowing,’ that is, you think you could probably recognize the answer if it were shown to you.
you are in a ‘tip-of-the-tongue’ state, that is, you are unable to think of the answer, now, but feel sure that you know it and that it is on the verge of coming back to you.”
Only 25% of our respondents chose the TOT option ‘d’; 39% chose ‘b’ and 31% chose ‘c’. Very few people (5%) wanted to know the answer when they thought they already knew it. Not knowing was associated with information seeking. But people did not appear to prioritize among ‘not known’ states. They said they had the urge to Google when they did not know at all and when they had a feeling of knowing, as frequently as when they were in a TOT state. The mTurk survey, of course, may or may not reflect what people choose to do when actually in such states.
The only empirical investigation that we were able to find of the relation between people’s curiosity and their TOT states was that by Litman, Hutchins, and Russon (2005). They gave participants 12 general-information questions to answer in a self-paced manner, and had them indicate for each whether they knew the answer, they did not know the answer, or they were in a TOT state. They then asked for intensity or confidence ratings. Personality questionnaires were administered, allowing examination of trait curiosity. For some participants a forced-choice recognition test was given. At the end of the experiment, the participants were provided with sealed envelopes with the 12 questions written on the outside and the answers enclosed. The researchers invited participants to open any envelopes they wished. They reported that people were more likely to open the envelopes of questions to which they had been in a TOT state.
Although the results of this experiment are supportive of a link between TOT states and curiosity, by the time the choices were made many, if not most, TOT experiences would probably already have subsided (see Brown & Croft, 2014). To overcome this problem, in the experiment that follows we asked participants whether they wanted to see the answer to the questions the moment after they gave their TOT judgments for each question, while they were still in the state. Furthermore, TOT states are rare—occurring in the natural flow of life (see Brown, 2012) only about once per week, and in a laboratory setting about 10–20% of the time for omission errors. With only 12 questions, there probably were not many TOT experiences per person in Litman et al.’s (2005) study. The frequency was not reported. To accumulate enough TOT experiences to allow more detailed analyses, we used 82 questions rather than just 12. We also speeded responding to each question. TOT experiences often exist in the first few seconds of attempted retrieval, but then, upon successful retrieval, they dissipate. Instead of waiting for this to happen, we pushed people to give a TOT judgment quickly, while they were still in the unresolved state. This meant that the experimenter had to run each participant in person, and enforce timing of the responses. He or she read each question aloud and then allowed only 5 s before the participant had to say whether or not he or she was in a TOT state. Our procedure resulted in a considerably higher proportion of TOT states than is typically observed in self-paced experiments. In addition, we used a load manipulation on half of the questions because working memory load, in some but not all experiments (e.g., Schwartz’s, 2008, Experiments 1, 2 and 3 showed the effect whereas Experiment 4 did not), has been shown to influence the probability of TOT experiences. We wanted to see whether curiosity was evoked by TOT states regardless of whether their overall probability was low or high. The materials were also divided into two sets, because some questions are more likely to evince TOT states than others.
Finally, we asked participants to report TOT states for all responses, even those that were correct. Although most studies look only at TOT experiences when the person has made an omission error, TOT states sometimes occur even when people have made a commission error (they may be in what is sometimes called a ‘blocked’ state, and retrieve the blocker as an error) or even when they were correct (presumably if they had low confidence about their answer). We were interested in all of these TOT states. Our primary question, throughout, was the relation of TOT states to curiosity: did people want to see the answers more when they were in a TOT state than when they were not?