Recent Publications

Eisler, A. D., & Eisler, H. (2001). Subjective time in a patient with neurological impairment. Psychologica, 28, 193-206.

Abstract

Subjective time is the feeling of how time is now passing, or how much time has passed. The human capacity to estimate clock time seems to be a highly stable function, varying only with severe disorders or in brain pathology. Subjective time estimation is the human ability to estimate objective (physical) time without cues from external clocks. An important aspect of studies of time perception concerns the effect of brain surgery with neurological impairment. Richards (1973) carried out a time reproduction experiment with the renowned individual H.M., who underwent a bilateral medial temporal lobe resection that included the hippocampus, entailing a severe memory loss. H.M. was required to reproduce durations ranging between 1 and 300 s. The present study attempts to highlight the functioning of time perception in H.M.'s data. With this model, the parameters of the psychophysical power function can be determined from duration reproduction data. One of the remarkable features of time perception revealed by this model is that the psychophysical function shows a break, dividing the function into a lower and an upper segment. The most conspicuous deviations from healthy subjects, which H.M. showed, are: 1) the high value of the experienced starting point of the upper segment, 2) the large overlap at the break, and 3) the position of the break at an extremely long duration. On the basis of the present evidence, H.M. placed the start of long durations more than 50 s before their actual start, which, together with a decelerating psychophysical function, entailed a very slow increase of subjective with clock duration. The results indicate that H.M. had a tendency to forget more and more what he was supposed to be doing, but is reminded again and again. Our findings favor the view that the damage to the hippocampus critically concerns the permanent encoding and subsequent retrieval of the task given in the instruction. We conclude that the impaired memory results in increasingly fewer time units being accumulated because H.M. intermittently forgets his task, but that once accumulated, time units are kept.

Keywords: brain, memory, neurological impairment, psychophysical function, subjective time.