Individual differences in response to a stranger: social impulsivity as a dimension of temperament in vervet monkeys (Cercopithecus aethiops sabaeus)

Social impulsivity in response to a stranger was assessed in male vervet monkeys (Cercopithecus aethiops sabaeus) using the Intruder Challenge Test. Vervets (N = 128, ages 3-18 years) were presented with an unfamiliar adult male at the periphery of the home enclosure. An index of impulsivity reflecting variation in the tendency to rapidly approach, engage, and challenge the intruder was derived from factor analysis of behavioral responses. Scale reliability (alpha = .84) and test-retest consistency (intraclass correlation = .83) were high, indicating that this index reliably and efficiently measures a stable aspect of temperament from impulsive to inhibited. Impulsivity scores peaked at age 4, when vervet males typically emigrate from the natal group. The highest ranking males in each group were more likely to score in the moderate range, whereas lower ranking males were more likely to score in the highest (impulsive) or lowest (inhibited) quartiles.     

The Ubiquity of Self-Deception

My paper is a discussion of Bas van Fraassen’s important, but neglected, paper on self-deception, “The Peculiar Effects of Love and Desire.” Paradoxes of self-deception are widely thought to follow from the ease with which we know ourselves. For example, if self-deception were intentional, how could we fail to know as target of our own deception just those things necessary to undermine the deception? Van Fraassen stands that reasoning on its head, arguing that is the ease with which we accuse ourselves of self-deception that undermines our confidence in our claims to know ourselves. I unpack and modify his argument, attempting to show that it makes a powerful case for scepticism about self-knowledge. I argue, contra van Fraassen, that local scepticism about self-knowledge threatens our claims to know ourselves in a way that global scepticism does not threaten our claims about the external world. I support this claim by showing that the Wittgensteinian response to the sceptic in On Certainty—that we don’t know what to do with the sceptic’s doubts, that we don’t know how to incorporate those doubts into our practices—does not succeed in deflecting scepticism about self-knowledge because the local sceptic’s doubts—about whether we can distinguish genuine claims to know ourselves from self-deceived claims—are integral to language game of self-knowledge. The local sceptic’s doubts are our doubts because it is natural to ask whether we are deceiving ourselves when we claim to know ourselves. However, because, we have no way of distinguishing genuine claims to know ourselves from self-deceived claims, our claims to self-knowledge are systematically undermined.     

How school-aged students define stuttering and stammering

Fifty students from each of the grades 2, 4, 6, 8, 10, and 12 were asked to complete a questionnaire containing the following three questions: 1) What is stuttering? 2) What is stammering? 3) How did you know that? Analysis of their responses indicated students were more familiar with stuttering as opposed to the term stammering. From grade 6 onward, we can expect at least three-fourths of the students to define stuttering as a disruption of speech consisting chiefly of sound or syllable repetitions. Only about one-fourth of students in grade 6 and above defined stammering as a speech disruption. This disruption was characterized chiefly by repetitions, injections, and pauses. Most of the students were unable to specify how they learned the definitions. The few who did identified family and friends as their chief source of knowledge.