ations of measures. If stability were found only when the GZTS was
used, we would begin to suspect that GZTS scores, not personality dis -
positions, were stable, and we would then try to determine what pecu -
liarity about the GZTS accounted for its constancy . But highly similar
results have been seen with the l6PF and the NEO-PI; in fact, almost ev -
ery personality inventory that has been longitudinally examined has
shown exceptional levels of stability .
And so the attack shifts ground. If it is not a specific personality
test that accounts for stability , perhaps it is the nature of personalitytests themselves. All of the instruments examined in Chapter 6 in Ta -
bles 11–13 are self-report inventories, in which we base our assessment
of the individual on the ways in which he or she responds to a series ofmore or less straightforward questions. It has been known for sometime that the scores we obtain in this way are not pure indicators of per -
sonality . Instead, any of several response sets may be operating, and
these are likely to cloud the issue (Jackson & Messick, 1961). Some in-dividuals agree to almost any characterization of them you offer; somereject them all. The former are called yea-sayers , or acquiescers; the lat-
ter,nay-sayers . Some people are extreme responders: They tend to ex-
press their beliefs about themselves and other things strongly . Otherpeople are more noncommittal and frequently use the “neutral” or“don’t know” response category . Social desirability has been the bane ofmany test constructors: How do we know that individuals are not lyingin order to make themselves look good? How do we know that respon-dents are not fooling themselves as well as us?
Other response sets have also been noted: tendencies to respond
carelessly , to try to make a bad impression (out of a kind of test-takingperverseness), to answer consistently . Study after study has documentedthe potential threat that each of these may pose to a straightforward in -
terpretation of data, and scales have been incorporated into many prom -
inent personality inventories in order to screen out the worst offenders.
From time to time critics have alleged that paper-and-pencil tests maybe explainable completely in terms of these stylistic (and substantivelyinsignificant) sets (Berg, 1959), but careful analyses have consistentlyshown that this “nothing but” interpretation is far too extreme. Still, itis possible that the very high levels of stability in Tables 11 and 13 areinflated by response sets.
Consider first the possibility that subjects are motivated to respond
consistently from administration to administration: They recall howQualifications and Rival Hypotheses 117