The Mental Changes Due to Frontal Lobe Damage

The literature suggests association between arousal, general activation, and anxiety on the one hand, and time judgments on the other hand, implying that reported differences in time judgment between nosological groups may be confounded by group differences in arousal-anxiety.

Self-report measures of anxiety, as well as magnitude estimates and magnitude productions of standards ranging from 500 to 2000 msec in 250 msec steps and presented in 10 randomized blocks, were obtained from 16 male normals and from 16 male hospitalized patients with a tentative diagnosis of chronic undifferentiated schizophrenia. Only 10 of the 16 patients were later found to have the same confirmed diagnosis. Data from nine normals and from seven chronic undifferentiated schizophrenics met a criterion of linearity of response functions for both time judgment methods and were further analyzed.

Magnitude estimates and magnitude productions showed underestimation of elapsed time, both types of judgment exhibited satisfactory reliability, estimates showed “shortening,” and productions showed “lengthening” over blocks of trials.

Intercepts of the response × standards functions were not generally equal to zero, were more negative in estimation than in production, had marginal reliability or were unreliable, did not correlate significantly between methods, and did not show significant trends over blocks of trials.

Following a model by Carlson and Feinberg, slopes of response × standard functions were used as estimates of the rate of the “internal clock.” (In estimation, the rate is equal to the slope; in production, it is equal to the reciprocal of the slope.) Average rates of the internal clock did not differ between methods for normals, but were higher in production than in estimation for the seven patients. Clock rates did not differ significantly between groups, were reliable, and exhibited positive correlation between methods. Clock rates exhibited trends over blocks of trials: arctan equivalents of clock rates were linearly related to ordinal numbers of blocks of trials and showed decreases, or “slowing” of the internal clock, in both methods.

Differences in mean anxiety between groups were not significant. In each group, anxiety scores showed positive average correlations with magnitude estimates and negative average correlations with magnitude productions, failed to correlate significantly with intercepts, but showed positive correlations with clock rates.

The data also suggest that anxiety and intrasubject variability may be interrelated.

To conclude: Reported differences in time judgments between nosological groups may not solely be due to nosological differences per se, but instead may be due to group differences in anxiety.