HUMAN BEHAVIOR PROGRAM 249 



Audiometric Tests — Pre-exposure and postexposure hearing tests were administered to 

 all divers. Hearing levels (re American Standards Association, 1951) at 500, 1000, 2000, 3000, 

 4000, and 6000 cycles per second (cps) were obtained using a Rudmose ARJ-4 Bekesy-Type 

 Audiometer with Otocups. The technique and equipment for all tests were identical, and the 

 equipment was calibrated before and after each series of tests. Hearing levels were derived 

 from the Bekesy-Tape tracings in the usual manner of accepting midpoints of the tracings and 

 recording thresholds in 5-decibel (db) increments. 



Visual Tests — Although several visual tests were planned related to color, form, and light 

 visibility, it was not possible to collect baseline data before submersion on these tests. During 

 a predive briefing, however, the divers were shown the types of targets to be used, and the 

 procedures to be followed. In addition, brightness measurements were made so as to establish 

 the optical characteristics of the targets. 



Mental Ability Test — A test of mental arithmetic was given to estimate the gross level of 

 mental functioning of the divers. This test consisted of multiplying a two-digit number by a 

 one-digit number; zero's, fives, and multiples of eleven were excluded. The task was to com- 

 plete as many items as possible in a two-minute period. Laboratory and chamber studies have 

 shown that mental arithmetic is affected by narcosis. It was desirable, therefore, to ascertain 

 differences between dry-land data and data collected during submersion. 



Data Collected Inside Habitat During Submersion 



1. Mood checklist — A self-report of moods filled out every other day. 



2. Daily activities checklist — A self-report of eating, sleeping, and recreational activities 

 filled out each day. 



3. Sortie reports — Specially designed report forms were provided to the divers on a daily 

 basis to enable them to report in detail on their activities during each sortie into the water. 

 These forms were filled out in the habitat following each dive or during the evening. The forms 

 had three main parts. Part I required the subject to state the plan of his dive and, when he did 

 not complete the plan, the reasons preventing completion. Clothing, equipment, and tools used 

 also were noted. Insofar as feasible, this reporting was done by means of a checklist. Other 

 insertions in this portion of the form included the name of the "buddy," exit and reentry times, 

 diving depth, and conditions encountered in terms of visibility, temperature, and bottom state. 



Part II provided space for reporting the objective results of the various tests the diver 

 performed. Part III required the diver to estimate the difficulty or ease of any task he under- 

 took during the sorties; his personal state in terms of a strong or weak continuum; and whether 

 the task required him to be active or passive. In addition to these scales, the divers were en- 

 couraged to comment in writing on their diving experience. 



4. Arithmetical tests — The arithmetical tests described in the preceding section were ad- 

 ministered three times during the period of submersion; at the beginning, near the middle, and 

 at the end. 



5. Helium speech data — Although a helium atmosphere has long been known to have a 

 marked effect on speech, little systematic data have been collected. With the advent of under- 

 water living, it is imperative that we study this problem from the standpoint of gaining a better 

 understanding of the underlying mechanism, and to provide information for the design of com- 

 munication systems. With this in mind, periodic samples of conversational speech were re- 

 corded in the surface monitoring station, utilizing the open mikes strategically placed inside 

 Sealab. In many instances, the signal-to-noise ratio was extremely low, due to ambient Sealab 

 noise, and/or noise generated by the communication system itself. Therefore, specified sen- 

 tences and word lists were read directly into a tape recorder inside the habitat during the pe- 

 riods of relative quiet. It is planned subsequently to analyze the speech content of these tapes. 

 In addition, subjective data were obtained during interviews and with questionnaires as to 

 speech intelligibility in the habitat. 



