Extraversion‐introversion and Improvement in an Auditory Vigilance Task*

The study deals with the effect of a secondary signal‐detection task on performance in a primary signal‐detection task in an auditory vigilance situation. Forty subjects were tested under two conditions. In one condition they listened to an 80‐min. recording of a sequence of digits in order to detect the occurrence of primary signals defined as three successive odd digits which are all different. In another condition they listened for primary signals as described above, but in addition they also had to detect secondary signals defined as the occurrence of the digit 68. The primary signals occurred ten times every 16 min.; there were about ten times as many secondary signals (digit 6) as there were primary signals (odd‐odd‐odd). The over‐all detection of primary signals was better when subjects were listening for both primary and secondary signals than when they listened for primary signals alone. Extraverts benefited more by the secondary task than introverts. No significant relationship was found between either neuroticism or intelligence and vigilance performance. A theoretical account of the events in a vigil is proposed and the difference between introverts and extraverts is considered in terms of this account.