Missing the dog that failed to bark in the nighttime: on the overestimation of occurrences over non-occurrences in hypothesis testing

Group meaningfulness and the causal direction of influence between the ingroup and the self or another individual: Evidence from the Induction-Deduction Paradigm

The goal of the present study was to investigate the causal direction of influence between the ingroup as a whole and the self or another ingroup member considering a key feature of groups, i.e., their perceived meaningfulness. To this goal, in Study 1, 2, and 3 we predicted a preference for self-stereotyping and ingroup-stereotyping in the meaningful social categories of sorority women, left-handed people and psychology students. In Study 4 we further expect that the meaningfulness attributed to a group moderates the direction of causality between individual and ingroup perception. Thus, we used one’s Zodiac sign as the ingroup whose degree of meaningfulness varies across participants and we hypothesized higher levels of meaningfulness attributed to the ingroup to be associated with higher self- and ingroup-stereotyping. Using the methodologically stringent Induction Deduction Paradigm, participants were given information on unfamiliar dimensions, about either the ingroup or an individual (self or other ingroup member) and asked to make inferences on those same attributes about the ingroup (induction condition) or the individual (deduction condition). As predicted, a preference for deduction to the self (i.e., self-stereotyping) and deduction to another ingroup member (i.e., ingroup-stereotyping) were found for the meaningful groups of sorority women, left-handed people, and Psychology students (Studies 1, 2, and 3). In Study 4, consistent with predictions, the higher the level of attributed meaningfulness to the Zodiac system the higher the degree of deduction both to the self (self-stereotyping) and to another Zodiac ingroup member (ingroup-stereotyping). Several implications of these results are discussed, for example in relation to the possibility of educational interventions aimed at invalidating intergroup differences.

Imagined Intergroup Physical Contact Improves Attitudes Toward Immigrants

In this set of research, we investigated the effects of intergroup physical contact on intergroup attitudes by relying on indirect contact strategies, namely the imagined contact paradigm. We implemented the imagined contact paradigm by leading participants to shape the mental imagery upon pictorial information. Specifically, in Study 1 participants saw a picture of a white hand touching a black hand [i.e., intergroup physical contact condition (InterPC)] or a picture of an outdoor scene (i.e., control condition), and were asked to imagine being either the toucher or in the outdoor scene, respectively. Results demonstrated that InterPC compared to control condition reduced intergroup bias. In Study 2 we compared the InterPC condition to a condition in which participants saw a white hand touching another white hand [i.e., intragroup physical contact (IntraPC)], and imagined to be the toucher. Again, we found that participants in the InterPC condition showed reduced intergroup bias compared to the IntraPC. Study 3 replicated results of Studies 1 and 2 by using an implicit measure of prejudice. Also, Study 3 further showed that asking participants to merely look at the picture of a white hand touching a black hand, without imagining being the toucher was not effective in reducing implicit prejudice. Results were discussed with respect to the literature on physical contact and prejudice reduction processes.

The acquisition of SV order in unaccusatives: manipulating the definiteness of the NP argument

In two sentence repetition experiments, we investigated whether four- and five-year-olds master distinct representations for intransitive verb classes by testing two syntactic analyses of unaccusatives (Burzio, 1986; Belletti, 1988). Under the assumption that, with unaccusatives, the partitive case of the postverbal argument is realized only on indefinites (Belletti, 1988), we tested whether children used indefiniteness as a feature to assign the partitive case to the verb's argument. In the sentences, we manipulated whether the subject preceded or followed the (unaccusative or unergative) verb and whether the subject was expressed by means of a definite or indefinite NP. With unaccusatives, children tended to place the subject in the postverbal position when the subject NP was indefinite, whereas, when the sentence presented a definite postverbal subject, children preferred to place the definite subject in the preverbal position. Definiteness exerted an effect only with unaccusatives, suggesting that children treated unergatives and unaccusatives differently.

Reducing the feature positive effect by alerting people to its existence

The feature-positive effect (FPE) is the phenomenon that learning organisms are better at detecting the association between two present stimuli than between the absence of one stimulus and the presence of the other. Although the FPE was first described 40 years ago, it remains an ill-studied and ill-understood bias. The aim of the present study was to test whether the FPE can be remedied by simply alerting individuals to the possibility that the solution to a given problem may lie in the diagnosticity of a stimulus being absent. The results indicated that the instructions given to participants can indeed reduce the FPE.

Insensitivity and Oversensitivity to Answer Diagnosticity in Hypothesis Testing

Two experiments examined how people perceive the diagnosticity of different answers (“yes” and “no”) to the same question. We manipulated whether the “yes” and the “no” answers conveyed the same amount of information or not, as well as the presentation format of the probabilities of the features inquired about. In Experiment 1, participants were presented with only the percentages of occurrence of the features, which most straightforwardly apply to the diagnosticity of “yes” answers. In Experiment 2, participants received in addition the percentages of the absence of features, which serve to assess the diagnosticity of “no” answers. Consistent with previous studies, we found that participants underestimated the difference in the diagnosticity conveyed by different answers to the same question. However, participants' insensitivity was greater when the normative (Bayesian) diagnosticity of the “no” answer was higher than that of the “yes” answer. We also found oversensitivity to answer diagnosticity, whereby participants valued as differentially diagnostic two answers that were normatively equal in terms of their diagnosticity. Presenting to participants the percentages of occurrence of the features inquired about together with their complements increased their sensitivity to the diagnosticity of answers. We discuss the implications of these findings for confirmation bias in hypothesis testing.