Feeling-of-knowing and tip-of-the-tongue phenomena in patients with schizophrenia

Introduction: Research on the metacognitive processes of persons with schizophrenia focuses on the analysis of the condition of the memory and the control-monitoring processes, deficits in which can become a cause of disturbances of consciousness of their own cognitive limitations. Disturbances of episodic memory are discussed here, and also deficits in access to the content of semantic memory as well as its disintegration, and deficits of the control-monitoring processes. The analysis of the feeling-of-knowing (FOK) phenomenon and tip-of-the-tongue phenomenon (TOT), and also of feeling of remembering (I remember), allows one to define the essence of the nature of these metacognitive problems and to make a conclusion about disturbances of the neuronal basis of these processes. These are the aims of this research: a comparison of the effect of reminders of semantic information on persons with schizophrenia and on persons in good mental condition, including the analysis of the FOR, FOK and TOT phenomena, which are considered as pointers for the condition of the memory and processes of cognitive regulation; a definition of the factors which modify the results of patients with schizophrenia and the control group.
Material and methods: Thirty ill people with paranoid schizophrenia in the phase of remission, and thirty people as a control group participated in the research. A technique of remembering 15 words in answer to 3 different signals (cues) of remembering was used. The answers were recorded as: I remember, I don’t know (it), and also FOK and TOT. In the case of occurrences of FOK or TOT a technique for their further recognition was used. The correct identifications were marked as FOK+ or TOT+; the wrong ones as FOK– or TOT–.
Results: Those suffering from schizophrenia gave fewer correct answers, but more often showed a lack of ability to actualize information, and used TOT less frequently. Among people who were ill longer and were older, the illusion of knowing increased, and the number of answers I don’t know decreased. They were more sure of their replies.
Conclusions: The data show the deficit of semantic memory of patients with schizophrenia. The pattern of results in this case is different from the results of people suffering from Alzheimer’s disease or with pathology of the frontal lobes.