It just happened to me the other day: I was watching Marvel’s Agents of S.H.I.E.L.D. and there was a new guest star; I turned to my husband and said – “Oh I remember her – she was in ‘Angel’ and the new ‘Much Ado About Nothing’…Amy something or other….” And then I drove myself crazy trying to remember her name before giving up and searching it on IMDB (It’s Amy Acker).
We’ve all experienced moments like that before – what scientists call the “tip-of-the-tongue” phenomenon, or TOT – where we remember all sorts of things about something or someone but can’t seem to get the name out. Understanding how and why this happens is more than just a matter of helping us access random celebrity names: TOT opens a window into aphasia, a language disorder caused by stroke and other brain injuries in which people have a hard time remembering words and generating speech.
Alexander Leff of University College London and colleagues are studying TOT in healthy patients in order to help patients with aphasia. In new work published in the Journal of Cognitive Neuroscience, they are challenging parts of the model commonly used to understand TOT. Rather than the brain moving linearly from processing concepts, to a name, to physically generating speech, they found that the parts of brain governing each step activate at overlapping times.
Leff’s team used brain scanning with magnetoencephalography to track the timing and brain regions involved while participants were asked to name celebrities while viewing pictures of their faces. The researchers were able successfully induce TOT in 29% of their trials, comparing the brain data collected there with those from when participants could correctly name a famous face or said that they didn’t know. Leff spoke to CNS about the study’s design and findings, and how it might help with aphasia research moving forward.
CNS: How do you describe the tip-of-the-tongue phenomenon?
Leff: Everyone gets it: It’s when you know that you know the name for something (or somebody) but cannot access it. My favorite description is from William James (1890) this: “Suppose we try to recall a forgotten name. 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.”
CNS: When do we most commonly experience TOT?
Leff: It is most common with proper names (names for people or places), likeforgetting someone’s name, perhaps when you need it most as you are about to introduce them; or the name of a famous person, “you know, the actor who was in that film with Leo DiCaprio”.
CNS: Are certain people more prone to TOT?
Leff: The incidence increases with age. Some patients with brain injury causing aphasia have a severe form called anomia, where they find it difficult to find a high proportion of words they want to use.
CNS: How did you personally become interested in studying TOT?
Leff: I became interested because I am interested in aphasia. I think it gives an important window into what it must be like to have anomia. Most of us experience tip-of-the tongue every few weeks or so, but imagine getting it every time you wanted to say something.
CNS: How did you induce TOT in your study?
Leff: We used pictures of famous people, many of whom had not been in the media recently. We also time-pressured the subjects; they had 3 seconds to respond.
CNS: You were trying to figure out where in language processing TOT occurs — what did you find? Can you walk us through how you think the process works?
Leff: Both healthy controls and stroke patients with aphasia retain knowledge about the person whose name they are trying to find. The person’s name is a somewhat arbitrary fact about them and so it seems that it can become ‘cut adrift’ from the other bits of knowledge you have about them. If you know who John Wayne is, you may still experience tip-of-the-tongue for his name, but you’ll never transiently forget that he was an actor who played cowboys a lot. I think this is why actors sometimes change their name to something more alliterative or interesting to aid recall – Marilyn Monroe, Doris Day, etc.
In terms of brain function, we showed that areas of the brain involved in storing information about the world (semantics: “John Wayne was a cowboy actor”), and those that store knowledge about words and sounds are both active during the TOT state.
CNS: How do your findings compare to past work on modeling TOT?
Leff: There is an influential model that suggests that when moving from thought to expression (Levelt’s model), we pass through stages in a serial way – from concept retrieval, to name retrieval, to motor programming for the act of speech. While this is certainly true to an extent – in TOT you get ‘hung up’ at the name retrieval stage – we found that these stages appear to overlap a lot in successful naming.
We used a novel analysis. First, we looked at the brainwave data at the time after the picture is shown (classical analysis) but then we also analyzed the data looking back in time from when the person spoke. By analyzing our data in this way, we were able to conclude that these processes overlap in time for normal naming.
CNS: Were any celebrities’ pictures associated with more participants experiencing TOT?
Leff: When people get in the TOT state in these sorts of experiments, they can get stuck in it for a series of pictures. It’s as if the naming system gets a bit ‘jammed up’ and has trouble moving on to new tasks while still processing the previous ones. To try and break this, we had a series of 34 universally famous faces that were easier to name, including Elvis Presley, Marilyn Monroe, Winston Churchill, and Margaret Thatcher, and we interspersed these after TOT trials to try and get subjects back in the naming rhythm. This worked, but we always ran out of these easy pictures before getting through the rest of the 300 faces.
CNS: What are the next steps for the research?
Leff: The main aim of the study was to set the scene for what happens in normal subjects in TOT states and then see what happens in patients with aphasia. This requires more funding, and I’m working on getting that now!
-Lisa M.P Munoz
The paper, “Between Thought and Expression, a Magnetoencephalography Study of the “Tip-of-the-Tongue” Phenomenon” by Karmen Resnik, David Bradbury, Gareth R. Barnes, and Alex P. Leff, was published online on March 27, 2014 in the Journal of Cognitive Neuroscience.
Answers to famous faces test (left to right, then top to bottom):