Strategies for verifying false autobiographical memories

This study examined the types of strategies people use to verify putative childhood memories and the degree to which their preferred strategies are restricted in typical memory implantation studies. We asked subjects to describe a situation in which they recalled a false childhood experience and a hypothetical situation in which they pretended to have developed a false memory after taking part in a memory implantation study. We also asked them how they did (or would) determine the source of the event. We found that subjects relied primarily on other people and cognitive strategies to verify their experiences. These results suggest that laboratory situations cultivate false memories in part because they prevent people from talking to others about the false event, which causes them to rely on less optimal strategies.     

Stroop interference in naming and verifying spatial locations

Two experiments are reported that were designed to assess effects of semantic similarity on naming and verification of spatial locations. In Experiment I, the wordsabove, below, left, andright occurred as distractors when Ss named the location of the word relative to a dot, or the location of a dot relative to the word. In Experiment II. the same dot-word displays were used, but Ss reported whether or not the word correctly specified its own location relative to the dot or the location of the dot relative to itself. The naming task showed some within-dimension facilitation and interference effects, most notably when Ss named the location occupied by the distractor word. The verification tasks showed quite substantial retardation of “no” responses when the word and location represented different values on either the horizontal or the vertical dimension.     

Electrophysiological evidence for the time-course of verifying text ideas

We examined how verb factivity influences the ability of readers to detect and resolve the mismatch of receiving false referents in relation to true referents in discourse contexts. Factive verbs (e.g., know), but not nonfactive verbs (believe), entail the truth of their complements. Recent research by Singer [Singer, M. (2006). Verification of text ideas during reading. Journal of Memory and Language, 54, 574-591] suggests that there are pragmatic costs associated with knowing something that is clearly false and only believing something that is clearly true. However, because Singer measured reading times for full sentences, it could not be determined whether these costs were initiated upon the appearance of the critical target word (i.e., the word that validated or invalidated previous text ideas) or at a later point in the sentences. In the present research we recorded event-related brain potentials while people read the same passages for comprehension and analyzed potentials evoked to the critical target words. Our results demonstrate that the brain distinguishes between true and false target words by at least 200ms after their onset, and that the pragmatic costs identified by Singer lead to interactions between verb factivity and truth in both early (P2) and later occurring brain components (late phase of N400 and late frontal positivity). In general, the results suggest readers had greater difficulty integrating false nouns than true nouns following factive than nonfactive verbs, and that detection of this mismatch also occurred earlier following factive verbs. Our results provide insight into the time-course of the processes that underlie the verification of text ideas, and extend neurocognitive research on anaphoric resolution.     

A logic for describing, not verifying, software

An important perquisite for verification of the correctness of software is the ability to write mathematically precise documents that can be read by practitioners and advanced users. Without such documents, we won't know what properties we should verify. Tabular expressions, in which predicate expressions may appear, have been found useful for this purpose. We frequently use partial functions in our tabular documentation. Conventional interpretations of expressions that describe predicates are not appropriate for our application because they do not deal with partial functions. Experience with this documentation has led us to choose a logic in which predicates are total but functions remain partial. We have found that this particular interpretation results in simpler expressions and is easily understood by practitioners.     

The process of verifying affirmative and negative sentences against pictures

Experiments 1 and 2 investigated sentence context effects on picture encoding in a sentence-picture verification and a picture naming task, respectively. The results showed that a picture following a sentence was encoded faster when the two were congruent than when they were incongruent. Experiment 3 compared two conditions: Under one condition, true affirmatives, false affirmatives, true negatives, and false negatives were mixed in each block of presentation. Under the other condition, different sentence types were presented in different blocks. The results showed (l) that errors committed in verification were largely negation errors, but seldom falsification errors, and (2) that there was a decrease of falsification time, but a resistance to change in negation time from the mixed to the blocked presentation. These results were interpreted to mean that falsification time results from a longer time to encode the picture and to confirm or disconfirm the truth index value by the polarity of the sentence in false affirmatives and true negatives than in true affirmatives and false negatives, whereas negation time and negation errors result from a response-suppression operation.     

On verifying and engineering the wellgradedness of a union-closed family

Current techniques for generating a knowledge space, such as QUERY, guarantee that the resulting structure is closed under union, but not that it satisfies wellgradedness, which is one of the defining conditions for a learning space. We give necessary and sufficient conditions on the base of a union-closed set family that ensures that the family is well-graded. We consider two cases, depending on whether or not the family contains the empty set. We also provide algorithms for efficiently testing these conditions, and for augmenting a set family in a minimal way, to one that satisfies these conditions.     

People consider reliability and cost when verifying their autobiographical memories

Because memories are not always accurate, people rely on a variety of strategies to verify whether the events that they remember really did occur. Several studies have examined which strategies people tend to use, but none to date has asked why people opt for certain strategies over others. Here we examined the extent to which people's beliefs about the reliability and the cost of different strategies would determine their strategy selection. Subjects described a childhood memory and then suggested strategies they might use to verify the accuracy of that memory. Next, they rated the reliability and cost of each strategy, and the likelihood that they might use it. Reliability and cost each predicted strategy selection, but a combination of the two ratings provided even greater predictive value. Cost was significantly more influential than reliability, which suggests that a tendency to seek and to value “cheap” information more than reliable information could underlie many real-world memory errors.     

Stronger effects of self-generated than cue-induced expectations when verifying predictions in data graphs

Expectations can come in different forms when analyzing and presenting data. Prior studies have documented stronger effects (behavioral and electrophysiological) of self-generated predictions as compared to cues. While participants presumably cannot help but use their own predictions, they might sometimes ignore cues (of low validity). In two experiments we compared the impact of cues (verbal and visual) and self-generated predictions on the performance of participants checking their current prediction against a presented data graph (linear upward or downward trend). Different from prior studies, the setup allowed for within-experiment comparison of different cue formats and ensured that cues could not be ignored. Nevertheless we found that self-generated predictions had a stronger impact than cues. Verbal cues had a stronger effect than visual cues without verbalization. Responses to graphs with a linear upward trend were faster and were influenced more strongly by predictions, than the response to graphs with a downward trend.     

Decision processes in verifying category membership statements: Implications for models of semantic memory

Current models of semantic memory assume that natural categories are well-defined. Specific predictions of two such models, the Smith, Shoben, and Rips (1974a) two-stage feature comparison model and the Glass and Holyoak (1974/75) ordered search model, were tested and disconfirmed in Experiment I. We propose an alternative model postulating fuzzy categories represented as sets of characteristic properties. This model, combined with a Bayesian decision process, accounts for the results of three additional experiments, as well as for the major findings in the semantic memory literature. We argue that people verify category membership statements by assessing similarity relations between concepts rather than by using information which logically specifies the truth value of the sentence. Our data also imply that natural categories are fuzzy rather than well-defined.     

The roles of typicality, instance dominance, and category dominance in verifying category membership

Four experiments examined the relationships between category verification reaction time (RT), exemplar typicality, instance dominance, category selection time (an RT measure of category dominance), and three production measures of category dominance. The category dominance measures were obtained in two experiments for use in two nearly identical category verification experiments. In one category verification experiment, the category name was presented 800 ms before the exemplar name; in the other, the exemplar name preceded the category name by 800 ms. Multiple regression analyses of the yes and no category verification RTs indicated that category dominance produced large and highly significant effects in all conditions, whereas instance dominance produced marginally significant and selective effects. Typicality had no effect beyond its shared effect with the dominance measures except as a possible suppressor variable. Category selection time was the best predictor, although all of the category dominance measures were better predictors than typicality or instance dominance. It is concluded that typicality may be an inappropriate independent variable for RT tasks studying the memory representation of natural-world knowledge.     

Responses to verifying and enhancing appraisals from romantic partners: the role of trait importance and trait visibility

An experiment assessed when people respond more positively to verifying and enhancing appraisals from romantic partners. Two‐hundred and fifty‐eight individuals comprising 129 dating couples participated in this research. Couples privately rated their self‐concept on traits that were either high or low on trait visibility, rated how important each trait was to them, and rated their partners. A computer program ostensibly compared their self‐ratings with appraisals from their partners on traits they selected as being high or low in personal importance, and participants received either verifying or enhancing feedback. Confirming predictions, people believed their partners understood them more when they received verifying feedback, but felt their partners saw the best in them when they received enhancing feedback. Additionally, people responded more positively to verifying appraisals on important, less visible traits, and enhancing appraisals on important, highly visible traits. Results are discussed in terms of preferences for enhancing and verifying feedback in romantic relationships. Copyright © 2005 John Wiley & Sons, Ltd.