A possible genetic basis of accuracy in personality perception

An analysis was conducted to assess whether individuals are more accurate in perceiving those personality characteristics of other' that have a larger genetic component. Adult monozygotic (MZ) twins (63 pairs) and same-sex dizygotic (DZ) twins (35 pairs) completed the Personality Research Form-E (PRF) and the Sibling Evaluation of Personality Characteristics (SEPC) which consists of 20 sets of adjectives corresponding to the 20 trait scales of the PRF. Subjects also evaluated their co-twin with the SEPC. Self-other agreement correlations were then correlated with the heritability estimates of the PRF traits calculated on the same twin sample. The results suggest that accuracy in perceiving the co-twin's personality does increase with the heritability component of the personality dimension.     

Book reviews

Scientific Discovery A. Kantorovich 1993 New York, State University of New York Press $17.95

A Model of the Universe Storrs McCall, 1994 Clarendon Press, Oxford 288pp. plus 15pp. appendices, plus 14pp. references plus index 0198240538 £30.00

Explanation David Hillel Ruben (ed. 1993) Oxford University Press pp vi + 365 ISBN 019875129X. Pb £9.95, Hb £27.50     

ENTRUSTING THE LIFE THAT HAS EVOLVED: A RESPONSE TO MICHAEL RUSE'S RUSE

Abstract. This piece challenges Michael Ruse on three points: (1) The charge that Christian myth and doctrine are incredible fails to take into account the scholarship that has clarified the genre to which myth belongs and its function. (2) Naturalistic explanations, like Ruse's, have fully as much difficulty dealing with questions of purpose and evil as religion does. (3) The concept of "deception" has a number of inherent problems that Ruse fails to consider, of which the chief is that it requires a certainty about truth and falsity that Ruse cannot and does not claim to possess.     

Accountability amplifies the status quo effect when change creates victims

This study assesses the impact of accountability, the status quo, and anticipated costs and benefits on judgement of the acceptability of a drug in the US pharmaceuticals market. Several effects are documented: (1) subjects were more accepting of a drug, the lower the anticipated risks of side effects and the greater the anticipated benefits; (2) subjects were especially unwilling to accept risk when the drug was not yet on the market and when they felt accountable for their decisions; (3) accountable subjects confronted by an off-the-market drug that posed moderate or high risk were also especially likely to procrastinate, to buckpass, and to think in integratively complex ways about the problem, notwithstanding the fact that many more lives would be saved than lost. We explain these results by positing that perceptual-cognitive processes (loss aversion) and political processes (blame avoidance) mutually reinforce each other when decision makers are accountable for choices that raise the possibility of changing the status quo in ways that impose losses on identifiable constituencies. We conclude by commenting on the complex normative issues that arise in labelling response tendencies as biases. Choices that look irrational within one ethical or political framework sometimes appear quite reasonable with another.     

Mental models and probabilistic thinking

This paper outlines the theory of reasoning based on mental models, and then shows how this theory might be extended to deal with probabilistic thinking. The same explanatory framework accommodates deduction and induction: there are both deductive and inductive inferences that yield probabilistic conclusions. The framework yields a theoretical conception of strength of inference, that is, a theory of what the strength of an inference is objectively: it equals the proportion of possible states of affairs consistent with the premises in which the conclusion is true, that is, the probability that the conclusion is true given that the premises are true. Since there are infinitely many possible states of affairs consistent with any set of premises, the paper then characterizes how individuals estimate the strength of an argument. They construct mental models, which each correspond to an infinite set of possibilities (or, in some cases, a finite set of infinite sets of possibilities). The construction of models is guided by knowledge and beliefs, including lay conceptions of such matters as the “law of large numbers”. The paper illustrates how this theory can account for phenomena of probabilistic reasoning.     

Prepulse effects on magnitude estimation of startle-eliciting stimuli and startle responses

The present studies investigated the relationship between prepulse effects on the modification of the brainstem startle reflex and magnitude estimates of startle-eliciting stimuli. In Experiment 1, startle eyeblink responses were elicited in 24 students, half of whom were instructed to estimate the loudness of the startle stimulus (actual intensities of 80, 90, and 100 dB) and half of whom were instructed to estimate the magnitude of their eyeblink. When weak acoustic prepulses preceded the startle-eliciting stimulus, eyeblink amplitude was inhibited, and estimates of response magnitude decreased, but estimates of startle stimulus magnitude decreased only when 100-dB startle stimuli were presented. In Experiment 2, the same startle stimuli were preceded on some trials by a vibrotactile prepulse to the hand. In conditions in which startle amplitude was inhibited, startle stimulus magnitude estimates were not affected. This suggests that the effect of acoustic prepulses on 100-dB startle stimuli in Experiment 1 may have been due to loudness assimilation, an effect independent of the prepulse inhibition of startle responding.