Effects of positive and negative verbal reinforcement on performance as a function of extraversion-introversion: Some tests of Gray's theory

Abstract Matched groups of extraverts and introverts performed under positive or negative verbal reinforcement in: (1) a computer game involving initiation of cursor movements on a VDU to find a hidden target; (2) a task involving recoding of decimal numbers into, and performing calculations in, a base-6 arithmetic with the letters A–F representing the decimal digits 1–6. In both tasks, consistent with the predictions from Gray's theory, there was a complete absence of main effects distinguishing between either type of personality or type of reinforcement. However, there was a highly significant interaction between these variables; extraverts performed better under positive than negative reinforcement, whilst introverts performed better under negative than positive reinforcement. Whilst the results appear to support Gray's theory that extraverts are differentiated from introverts by a reversal in the balance between the sensitivities of the behavioural activation (BAS) and behavioural inhibition systems (BIS), the covert nature of cognitive operations carried out in the experimental tasks precludes unequivocal attribution of superior task performance in negatively reinforced introverts to the accentuated excitation of the BIS.