Influence of Lysergic Acid Diethylamide (LSD-25) on Subjective Time

This open-label within-subjects design study (n=24) investigated the effects of LSD (75-150μg) on time perception. Participants were assigned time intervals (15, 60, 120, and 240 minutes) and asked to indicate when the time had elapsed; participants provided shorter times estimates under the influence of LSD, indicating that subjective time elapsed more rapidly compared to the control condition.

Abstract

Introduction:  Various reports have shown that the subjective sense of time can be considerably altered through changes in the external circumstances under which the judgment is made. Somewhat less is known of the influence of the subject’s physical state on his ability to estimate time. This lack may be at least partially due to the fact that most conditions, such as fever or delirium, which have been described as bringing about such changes often simultaneously make it difficult or impossible to collect systematic data. When physical states are experimentally induced, however, the effects can be better controlled and tested. In this way, information has been obtained on the influence of nitrous oxide and mescaline on the sense of time. The very striking effect of lysergic acid diethylamide (LSD-25) on the sense of time has been described in various ways by those who have observed the reaction: “Time sense . . . was characterized by the feeling of being accelerated or retarded” ; “Not only is there impaired ability to estimate the passage of time, but there is also a sense of timelessness.

Methods: Twenty-four subjects were used as their own controls to determine the effect of lysergic acid diethylamide (LSD-25) on the subjective passage of time.

Results: Under the drug the subjects overestimated the stimulus intervals to a significant degree, indicating that the drug has the effect of making time appear to pass more slowly than usual.

Discussion: The results of this study were unlike those reported in an earlier experiment, in which no consistent changes were found under the drug. Differences between experimental procedures were discussed to suggest reasons for the divergent results. The findings were examined for theoretical implications in light of other changes noted as common to the LSD-25 reaction.

Authors: H. Aronson, A. B. Silverstein, G. D. KLee

Summary

Introduction

Various reports have shown that the subjective sense of time can be considerably altered through changes in the external circumstances under which the judgment is made.

Lysergic acid diethylamide (LSD-25) has a striking effect on the sense of time, but a systematic study found only an increase in variability and no change in the direction of the estimate.

Method

24 men were divided into two groups, one of which was given LSD-25 first and then a control, and the other of which was given LSD-25 first and a control later.

Four time intervals were chosen for testing, and each subject was asked to estimate these same intervals twice, once under the drug and once in his normal state.

Under both conditions, the subject was told the length of time to estimate and then given a signal to begin. He was not allowed to use his watch or to see the experiment apparatus, an electric stop watch.

Eight judgments per subject were analyzed using the Mann-Whitney test and Wilcoxon’s matched-pairs signed-ranks test.

Results

The Mann-Whitney test did not show any significant interaction between the effect of the drug and the order in which the conditions were presented. The subjects judged time to have passed more slowly while under the drug than under the control condition.

The results show that the subjects’ time judgments were significantly lower under the drug than under the control condition at each interval.

Comment

The results of this experiment show that time passes more slowly than usual after taking LSD-25, and that this change is consistent throughout the drug’s long span of effect.

The results reported here and those of Boardman and associates may be explained by different mechanisms used to judge time, or by different clues and abilities necessary for judging shorter periods.

The present study uses a different procedure from that reported by Boardman, in that the subjects were presented with stimuli which differed in length by 0.1 minute. This may have introduced a factor of perceptual rigidity, which could explain the increased variability.

The results reported here do reflect a change in temporal perception, but the reason for this change is difficult to ascertain.

A hypothesis is often called upon to explain changes in the subjective passage of time. This hypothesis is consistent with the observation that time appears to pass slowly under the influence of LSD-25.

LSD-25 may disturb temporal judgment by causing a failure to receive cues or a failure to integrate them properly. This may be due to the extensive im pairment of perceptual and conceptual functioning that the drug produces.

Summary

LSD-25 caused subjects to overestimate stimulus intervals, and this resulted in a slower perception of time than usual.

Study details

Compounds studied
LSD

Topics studied
Neuroscience

Study characteristics
Open-Label

Participants
24