Interviewing Witnesses: Forced Confabulation and Confirmatory Feedback Increase False Memories

In two experiments, adults who witnessed a videotaped event subsequently engaged in face-to-face interviews during which they were forced to confabulate information about the events they had seen. The interviewer selectively reinforced some of the participants' confabulated responses by providing confirmatory feedback (e.g., "Yes, _is the correct answer") and provided neutral (uninformative) feedback for the remaining confabulated responses (e.g., "O.K. _"). One week later, participants developed false memories for the events they had earlier confabulated knowingly. However, confirmatory feedback increased false memory for forcibly confabulated events, increased confidence in those false memories, and increased the likelihood that participants would freely report the confabulated events 1 to 2 months later. The results illustrate the powerful role of social-motivational factors in promoting the development of false memories.     

The effect of causal chain length on counterfactual conditional reasoning

We investigated German and Nichols' finding that 3‐year‐olds could answer counterfactual conditional questions about short causal chains of events, but not long. In four experiments (N =192), we compared 3‐ and 4‐year‐olds' performance on short and long causal chain questions, manipulating whether the child could draw on general knowledge to answer. We failed to replicate German and Nichols' result, finding instead that in two experiments (Experiments 1 and 3) there was no difference in performance on short and long causal chain questions and in two experiments (Experiments 2 and 4) children showed the opposite pattern: short causal chain questions were more difficult than long. These two unexpected patterns of results were replicated in a fifth study (N =97). Children with lower language ability found short causal chains more difficult than long. Performance by children with higher language ability was unaffected by the length of the causal chain they had to consider. We found no evidence that children showed precocious counterfactual thinking when asked about recent events in a causal chain and conclude that counterfactual thinking develops after 4 years of age.     

Amending limb movements to mechanical perturbations under choice reaction time conditions

This paper examines the amendment of limb movements to mechanical perturbations under choice reaction time conditions. The two experiments reported were designed to examine the question of whether amendment latencies increase under choice conditions using two different choice manipulations. In Experiment 1, choice was manipulated by varying the duration of a mechanical perturbation in a known direction, while in Experiment 2 the strategy was to present perturbations of similar duration but unknown direction. Subjects produced discrete timing responses (700 ms-70 degrees) during which perturbations were interjected on random trials. The results reported reflect the outcome accuracy, the kinematics of the responses and latency of response modifications as a function of the various choice manipulations. The data demonstrated no statistically significant increases in reaction time as a function of choice manipulations. Although latencies did not significantly vary, both experiments demonstrated a significant decrease in response accuracy for the choice conditions. Collectively, the results are discussed in relation to the discrepancies between previous proprioceptive choice reaction time studies, which appear to stem from inconsistencies in both experimental methods and data analysis procedures.     

Cognitive specificity and positive-negative affectivity: complementary or contradictory views on anxiety and depression?

A principal factor analysis, conducted on a mixed psychiatric outpatient sample (N = 470), identified both common and specific dimensions underlying anxiety and depression. Although an initial single-factor extraction accounted for a significant proportion of variance in cognitive and symptom measures of anxiety and depression, a two-factor solution, in which anxiety and depression formed separate dimensions, proved to be the better solution. MANOVAS performed on pure depressed, pure anxious, and mixed anxious/depressed subgroups provided evidence of a specific cognitive profile for anxiety and depression. The mixed subsample evidenced greater severity, a mixed cognitive and symptom profile, and character traits that may indicate increased vulnerability to psychological disturbance. Results are discussed in terms of Beck's (1976) cognitive content-specificity hypothesis and the positive-negative affect model (Watson & Tellegen, 1985).     

The conjunction fallacy?

Tversky and Kahneman (1983) showed that when subjects are asked to rate the likelihood of several alternatives, including single and joint events, they often make a "conjunction fallacy." That is, they rate the conjunction of two events as being more likely than one of the constituent events. This, they claim, is a fallacy, since the conjunction of two events can never be more probable than either of the component events. In addition, they found that prior training in probability theory does not decrease the likelihood of making this fallacy. We argue that in some contexts, an alternative that contains the conjunction of two events can be more probable than an alternative that contains only one of the conjunction's constituent events. We carried out four experiments in which we manipulated this context. The frequency of making a conjunction fallacy was affected by the manipulation of context. Furthermore, when the context was clearly specified, prior training in statistics influenced the ratings.     

Tracking a group's focus on normative-organizational or personal exploration issues

Group - This last paper in the series on group development and emergent leaders presents a process analysis variable designed to track the group's focus on either normative and organizational...