The discovery of d-lysergic acid diethylamide (LSD)* and its impact upon the human organism has stimulated a considerable amount of research activity, largely concerned with the psychological symptoms which are produced by LSD. These symptoms bear a striking resemblance to those appearing in the psychoses, which undoubtedly constitutes the major source of interest in LSD. Thus Rinkel et al report: "The psychotic phenomena were predominantly schizophrenic-like symptoms that were manifested in disturbances of thought and speech; changes in affect and mood; perception; production of hallucinations and delusions; depersonalization and changes in behavior" (reference 7, p 277). In addition, the sheer extent of its symptom-producing potential, as suggested by a recent study,5 adds greatly to its experimental utility.
The present study is an exploratorattempt to determine the effect of this particular type of stress upon interactive behavior in small