The curse of knowledge in reasoning about false beliefs

Assessing what other people know and believe is critical for accurately understanding human action. Young children find it difficult to reason about false beliefs (i.e., beliefs that conflict with reality). The source of this difficulty is a matter of considerable debate. Here we show that if sensitive-enough measures are used, adults show deficits in a false-belief task similar to one used with young children. In particular, we show a curse-of-knowledge bias in false-belief reasoning. That is, adults' own knowledge of an event's outcome can compromise their ability to reason about another person's beliefs about that event. We also found that adults' perception of the plausibility of an event mediates the extent of this bias. These findings shed light on the factors involved in false-belief reasoning and are discussed in light of their implications for both adults' and children's social cognition.     

The origins of cognitive dissonance: evidence from children and monkeys

In a study exploring the origins of cognitive dissonance, preschoolers and capuchins were given a choice between two equally preferred alternatives (two different stickers and two differently colored M&M's, respectively). On the basis of previous research with adults, this choice was thought to cause dissonance because it conflicted with subjects' belief that the two options were equally valuable. We therefore expected subjects to change their attitude toward the unchosen alternative, deeming it less valuable. We then presented subjects with a choice between the unchosen option and an option that was originally as attractive as both options in the first choice. Both groups preferred the novel over the unchosen option in this experimental condition, but not in a control condition in which they did not take part in the first decision. These results provide the first evidence of decision rationalization in children and nonhuman primates. They suggest that the mechanisms underlying cognitive-dissonance reduction in human adults may have originated both developmentally and evolutionarily earlier than previously thought.     

Experiencing Body Worlds: Voyeurism, Education, or Enlightenment?

Until the advent of plastinated cadavers, few outside the medical professions have had firsthand experience with human corpses. Such opportunities are now available at the Body Worlds exhibits of Gunther von Hagens. After an overview of these exhibits, we explore visitor responses as revealed in comment books available upon exiting the exhibit. Cultural, philosophical, and religious issues raised in the comments serve as a microcosm of society at large. The conclusion considers the challenge of such exhibits in introducing the public to science education, notes the image of the body as machine-so prevalent in the West-reflected in visitor comments, and finds hope that the exhibits promote, for many visitors, a sense of community among all humankind.     

Distinguishing between social reinforcement and social elicitation

The theoretical, procedural, analytic, and interpretive components of Poulson's (1983, Journal of Experimental Child Psychology, 36, 471–489) study were considered in an effort to clarify the distinction between social reinforcement and social elicitation. Contrary to Poulson's contention, DRO was not, and cannot by definition be, a control for reinforcement. More importantly, the speciestypical, social nature of the infant probably reflects the collaborative influence of elicitation and reinforcement. By carefully unravelling these two interacting processes, future conditioning studies might specially enhance our knowledge of early social development.     

Comment on 'Measuring Machiavellianism with Mach V: a psychometric investigation'

A recent article (Shea & Beatty, 1983) attacks the reliability, triadic-choice format, and validity of the Mach V. The issues of meaningful versus statistical criteria, differing perspectives of bias, and reliability-validity independence are raised in challenge. Although the Mach V may have some construct validity problems, Shea and Beatty's call for a new measure of Machiavellionism is not supported by their article.     

Selective autonomic blockade of conditioned and unconditioned cardiovascular changes in rhesus monkeys (Macaca mulatta).

Changes in heart rate and in systolic and diastolic blood pressures were examined in eight rhesus monkeys during six sessions of differential classical conditioning. The conditioned stimuli consisted of tones differing in frequency and the unconditioned stimuli consisted of tail shock. Both the conditioned responses (CRS) and unconditioned responses (UCRs) consisted of increases in heart rate and in systolic and diastolic pressures, but blood pressure CRs sometimes occurred in the absence of heart rate CRs. Graded doses of the selective blocking agents propranolol, phentolamine, and atropine methylnitrate were systemically administered to four of the monkeys prior to additional conditioning sessions. The results suggested that the CRs and UCRs were mediated by both sympathetic and parasympathetic influences.     

Social conditioning and its proper control procedures.

In Expt I, eight infants received response-contingent social stimulation, while another eight infants received response-independent social stimulation. Both groups' vocalization rates similarly increased from baseline to stimulation periods and decreased from stimulation to extinction periods. In Expt II, 12 infants were given continuous social stimulation (elicitation treatment) for one period, and, in a second period, stimulation was withheld for 5 sec contingent upon each vocalization (omission treatment). Response rates were similar for both periods, and rates decreased when social stimulation was removed (mobile treatment). In both studies social stimulation increased vocalization rates and rate of responding was insensitive to the programmed contingency. There were, however, fewer “bursts” of responses with the negative and positive contingencies as compared with response-independent stimulation.     

Some theorems on structural consequence operations

Two characterizations are given of those structural consequence operations on a propositional language which can be defined via proofs from a finite number of polynomial rules.