Response-outcome contingency: Behavioral and judgmental effects of appetitive and aversive outcomes with college students

In two experiments, positive, negative, and zero response-outcome contingencies were responded to and rated by college students under a free-operant procedure. In Experiment 1, outcomes were either neutral or were associated with point gain. In Experiment 2, subjects were administered different outcome treatments: neutral outcomes, outcomes associated with money gain, or outcomes associated with money loss. In both experiments, subjects' judgments of response-outcome contingency and their operant responses were each strong linear functions of ΔP, the difference between the probability of an outcome given a response and the probability of an outcome given no response. Appetitive and aversive outcomes produced opposite and symmetrical response patterns. In Experiment 1, no differences in ratings occurred with neutral or appetitive outcomes; however, in Experiment 2, more potent appetitve outcomes led to somewhat more extreme ratings than either neutral or aversive outcomes. Increasing outcome probability produced only a slight bias in ratings of noncontingent problems in Experiment 1 and no bias in Experiment 2. Contrary to predictions derived from an analysis of superstitious behavior, increasing outcome probability in noncontingent problems decreased operant responding when outcomes were appetitive and increased operant responding when outcomes were aversive. Trend analyses revealed that Δ P was superior to several other metrics in predicting subjects' estimates of contingency and the behavioral effects of contingency. Operant responding was in closer accord with matching predictions than with maximizing predictions.     

Action outcome probability influences the size of the head-fake effect in basketball

Both kinematic and contextual information (e.g., action outcome probability) play a significant role in action anticipation. However, few researchers have examined the reciprocal influence of the two types of information and fewer still have investigated this issue for deceptive actions in sports. In the present study, we investigate the impact of action outcome probability on the processing of deceptive kinematic cues for the head fake in basketball. We manipulated the probability of the action outcome to either pass the ball to the left or to the right side (i.e., 75%, 50%, 25%) and examined how this contextual information affected the influence of head orientation on pass direction judgments. Outcome probability information was either provided explicitly (Experiment 1) or implicitly (Experiment 2). Both experiments indicated an increased head-fake effect with increasing outcome probability. Moreover, the bias to respond in line with the player’s head direction increased linearly with outcome probability. Also, discriminability between deceptive and genuine actions was poorer for high outcome probability (75%) associated with head orientation than for the 25% and 50% values. Last, a stronger response bias toward the higher probability side for deceptive trials than for genuine trials was only significant when the outcome probability information was processed implicitly in Experiment 2. The results of this study fit well with recent literature on contextual information in action prediction and are discussed in light of confirmation bias and signal detection theory.     

Linda versus World Cup: Conjunctive Probabilities in Three-event Fictional and Real-life Predictions

Conjunction errors in probability judgments have been explained in terms of representatives, non-normative combination procedures, and linguistic, conversational, or conceptual misunderstandings. In two studies, a three-event variant of the classical Linda scenario (Tversky and Kahneman, 1983) was contrasted with estimates of Norway’s chances in three coming World Cup soccer matches. Conjunction errors occurred even in the latter, real-life prediction task, but much less frequently than in the fictional Linda case. Magnitude of the conjunction effect was found to be dependent upon type of constituent (fictional versus dispositional), unequal versus equal probabilities of constituent events, prediction of positive versus negative outcomes, and, for real-life predictions only, umber of constitutent events. Fictional probability ratings were close to but lower than representativenss ratings, giving evidence for a representativeness and adjustment-for-uncertainty strategy, whereas probabilities of real-life events were given a causal model interpretation.     

Syntax and intentionality: An automatic link between language and theory-of-mind

Three studies provided evidence that syntax influences intentionality judgments. In Experiment 1, participants made either speeded or unspeeded intentionality judgments about ambiguously intentional subjects or objects. Participants were more likely to judge grammatical subjects as acting intentionally in the speeded relative to the reflective condition (thus showing an intentionality bias), but grammatical objects revealed the opposite pattern of results (thus showing an unintentionality bias). In Experiment 2, participants made an intentionality judgment about one of the two actors in a partially symmetric sentence (e.g., “John exchanged products with Susan”). The results revealed a tendency to treat the grammatical subject as acting more intentionally than the grammatical object. In Experiment 3 participants were encouraged to think about the events that such sentences typically refer to, and the tendency was significantly reduced. These results suggest a privileged relationship between language and central theory-of-mind concepts. More specifically, there may be two ways of determining intentionality judgments: (1) an automatic verbal bias to treat grammatical subjects (but not objects) as intentional (2) a deeper, more careful consideration of the events typically described by a sentence.     

A sampling approach to biases in conditional probability judgments: beyond base rate neglect and statistical format

Conditional probability judgments of rare events are often inflated. Early accounts assumed a general deficit in using statistical base rates. More recent approaches predict improvement when problems are presented in frequency format or refer to natural categories. The present theory focuses on sampling processes. Experiment 1 showed that a seeming advantage of frequency over probability formats is due to a confounded factor, the need to mentally transform stimulus samples. An information search paradigm was used in Experiment 2. When sampling by the predictor, the probability to be estimated, p(criterion/predictor), was conserved in the samples and judgments were quite accurate. However, when sampling by the criterion, the low base-rate event was strongly overrepresented, accounting for the entire bias. Judgments were quite sensitive to the sampled data, but failed to take sampling constraints into account, as shown in Experiments 3 and 4.     

Proximity bias: Interactive effect of spatial distance and outcome valence on probability judgments

Across a range of decision contexts, we provide evidence of a novel proximity bias in probability judgments, whereby spatial distance and outcome valence systematically interact in determining probability judgments. Six hypothetical and incentive-compatible experiments (combined N = 4007) show that a positive outcome is estimated as more likely to occur when near than distant, whereas a negative outcome is estimated as less likely to occur when near than distant (studies 1–6). The proximity bias is explained by wishful thinking and thus perceptions of outcome desirability (study 3), and it does not manifest when an outcome is less relevant for the self, such as the case of outcomes with little consequence for the self (studies 4 and 5) or when estimating outcomes for others who are irrelevant to the self (study 6). Overall, the proximity bias we document deepens our understanding of the antecedents of probability judgments.     

Verbal self-reports about matching to sample: effects of the number of elements in a compound sample stimulus.

Adults' self-reports about their choices in a delayed matching-to-sample task were studied as a function of the number of elements (one, two, or three) in a compound sample stimulus. Signal-detection analyses were used to examine control of self-reports by the number of sample elements, by the speed and accuracy of choices reported about, and by several events contingent on self-reports. On each matching-to-sample trial, a sample element appeared as one of two comparison stimuli. Choice of the matching element, if made within 500 ms of the onset of the comparison stimuli, produced points worth money or chances in a drawing for money, depending on the subject. After each choice, subjects pressed either a "yes" or "no" button to answer a computer-generated query about whether the choice met the point contingency. The number of sample elements in the matching-to-sample task varied across trials, and events contingent on self-reports varied across experimental conditions. In Experiment 1, the conditions were defined by different combinations of feedback messages and point consequences contingent on self-reports, but self-reports were systematically influenced only by the sample-stimulus manipulation. Self-report errors increased with the number of sample elements. False alarms (inaccurate reports of success) were far more common than misses (inaccurate reports of failure), and false alarms were especially likely after choices that were correct but too slow to meet the point contingency. Sensitivity (A') of self-reports decreases as the number of sample elements increased. In addition, self-reports were more sensitive to choice accuracy than to choice speed. All subjects showed a pronounced bias (B'H) for reporting successful responses, although the bias was reduced as the number of sample elements increased and successful choices became less frequent. Experiment 2 demonstrated that the failure of point contingencies to influence self-reports in the first experiment was not due to a general ineffectiveness of the point consequences. Rates of inaccurate self-reports decreased when they resulted in point losses and increased when they resulted in point gains.     

Verbal probabilities: a question of frame?

Verbal expressions of probability and uncertainty are of two kinds: positive (‘probable’, ‘possible’) and negative (‘not certain’, ‘doubtful’). Choice of term has implications for predictions and decisions. The present studies show that positive phrases are rated to be more optimistic (when the target outcome is positive), and more correct, when the target outcome actually occurs, even in cases where positive and negative phrases are perceived to convey the same probabilities (Experiments 1 and 2). Selection of phrase can be determined by linguistic frame. Positive quantifiers (‘some’, ‘several’) support positive probability phrases, whereas negative quantifiers (‘not all’) suggest negative phrases (Experiment 3). Positive frames induced by numeric frequencies (e.g. the number of students to be admitted) imply positive probability phrases, whereas negative frames (e.g. the number of students to be rejected) call for negative probability phrases (Experiment 4). It is concluded that choice of verbal phrase is based not only on level of probability, but also on situational and linguistic cues. Copyright © 2002 John Wiley & Sons, Ltd.     

The relativity of linguistic intuition: The effect of repetition on grammaticality judgments

Three experiments were performed to show the relativity of linguistic intuition in grammaticality judgments. In Experiment 1, 12 students judged the relative grammaticality of isolated sentences twice, receiving a repetition treatment between the two judgments. During the repetition phase, they were exposed to a repeated presentation of sentences. The findings show that the repetition treatment makes a judgment criterion more stringent for both grammatical and ungrammatical sentences. In Experiment 2, a release-from-the-proactive-inhibition paradigm was used. Twelve students first judged the grammaticality of the isolated sentences, then received the repetition treatment, and finally, made a second judgment for the sentences embedded in context. No change in judgment criterion was found for the second judgment. Judgments of the ungrammatical sentences, when embedded in context, were found to be more lenient. In Experiment 3, 12 students judged sentences embedded in context. No change in judgment criterion was found. These findings are interpreted as suggesting that linguistic intuitions as revealed in grammaticality judgments are not absolute but relative in that they are easily influenced by repetition and other variables, such as embedded context.     

The dependence of the conjunction fallacy on subtle linguistic factors

Summary The three experiments reported in this article are concerned with moderating conditions of the so-called conjunction fallacy. Although the conjunction of two events (A&B) is necessarily less probable than one event alone, intelligent people's judgments sometimes violate this logical principle when it is easier to think about or imagine the conjunction A&B than the component event A. It was hypothesized that the fallacy might be reduced either by a priming treatment (directing the participants' attention to the logical rule prior to the conjunctions tasks) or by a linguistic manipulation (replacing the ambiguous term probability by the term frequency. Experiment 1 shows that the bias is drastically reduced by the subtle linguistic manipulation and suggests that the fallacy is partly due to a common misunderstanding of the probability concept. The lack of a priming effect seems to imply that cueing or activation of logical schemata is not a critical factor. Experiment 2 replicates the linguistic influence under slightly modified task conditions, and Experiment 3 corroborates the ineffectiveness of the priming factor using a stronger priming treatment.     

Subjective probabilities and moral judgments

The two experiments reported here examined the relationship between subjective probability estimates and moral judgments (credit and blame assignment, trait attributions, and behavior evaluations). Subjects read about situations that varied in outcome valence (moral or immoral); in addition, the nature of situational demands (Experiment 1) or behavior frequency (Experiment 2) was varied. In the first experiment, subjective probabilities were related to judgments of immoral behaviors (but not moral behaviors), whereas the situational demands only had an impact on judgments of moral behaviors. Experiment 2 included a wider range of behavioral situations, and the probability estimates and moral judgments were assessed independently. In contrast to the first experiment, subjective probabilities were related to trait and behavior ratings of both moral and immoral acts. Consistent with the first experiment, however, subjective probabilities predicted blame but not credit. Across both studies, the prior expectancies were more strongly related to evaluations of immoral acts than moral acts. Implications for understanding the determinants of judgments of moral and immoral acts are discussed.     

Interpreting conjoined noun phrases and conjoined clauses: Collective versus distributive preferences

Two experiments are reported that show that introducing event participants in a conjoined noun phrase (NP) favours a single event (collective) interpretation, while introducing them in separate clauses favours a separate events (distributive) interpretation. In Experiment 1, acceptability judgements were speeded when the bias of a predicate toward separate events versus a single event matched the presumed bias of how the subjects' referents were introduced (as conjoined noun phrases or in conjoined clauses). In Experiment 2, reading of a phrase containing an anaphor following conjoined noun phrases was facilitated when the anaphor was they, relative to when it was neither/each of them; the opposite pattern was found when the anaphor followed conjoined clauses. We argue that comprehension was facilitated when the form of an anaphor was appropriate for how its antecedents were introduced. These results address the very general problem of how we individuate entities and events when presented with a complex situation and show that different linguistic forms can guide how we construe a situation. The results also indicate that there is no general penalty for introducing the entities or events separately—in distinct clauses as “split” antecedents.     

Directional verbal probabilities: inconsistencies between preferential judgments and numerical meanings

Verbal probability expressions (e.g., it is possible or doubtful) convey not only vague numerical meanings (i.e., probability) but also semantic functions, called directionality. We performed two experiments to examine whether preferential judgments are consistent with numerical meanings of verbal probabilities regardless of directionality. The results showed that because of the effects of directionality, perceived degrees of certainty for verbal probabilities differed between a binary choice and a numerical translation (Experiment 1), and decisions based on a verbal probability do not correspond to those based on a numerical translation for verbal probabilities (Experiment 2). These findings suggest that directionality of verbal probabilities is an independent feature from numerical meanings; hence numerical meanings of verbal probability alone remain insufficient to explain the effects of directionality on preferential judgments.     

The Negative Effect of Probability Assessments on Decision Quality

It is commonly assumed that uncertain information can be reduced to numerical probabilities without biasing preferences. It is also implicitly assumed in much research and many applications that people can express these probabilities. In contradiction to these assumptions Experiment 1 shows that the production of probability assessments biases decisions in an n-person game. Experiment 2 shows that the explicit assessment of numerical probabilities renders choices between gambles concerning future basketball events less optimal. These findings seem to be a result of overweighting the probability dimension relative to the payoff dimension given numerical judgments. Experiment 2 also suggests that without explicit numerical probability judgments subjects are less likely to violate the dominance principle. The theoretical and practical implications of the results are discussed.     

Accuracy of confidence judgments: Stability and generality in the learning process and predictive validity for learning outcome

One aspect of metacognition is the monitoring of memory or comprehension measured with retrospective confidence judgments after test taking. The research questions of the present study were whether different measures for the accuracy of such confidence judgments are stable over learning time, whether they generalize over two different tests, and whether they predict the learning outcome. In order to answer these questions, a study was conducted in which university students (N = 113) learned about the basic concepts of operant conditioning for 30 min. Knowledge tests with confidence judgments presented after each item were obtained before learning, after 10 min, and at the end of the learning session. Bias and absolute bias were calculated as absolute measures of accuracy, and gamma, Pearson’s r, andd _a were calculated as relative measures of accuracy. The results showed that the absolute measures were stable, but that the relative measures were not. Furthermore, absolute bias, gamma, and Pearson’s r obtained 10 min after the beginning of the learning process predicted the learning outcome. The results are discussed with regard to research on different measures of accuracy for confidence judgments.     

Exposure to sexism can decrease implicit gender stereotype bias

Two studies examined the effect of exposure to sexism on implicit gender bias, focusing specifically on stereotypes of men as competent and women as warm. Male and female participants were exposed to sexism or no sexism. In both Experiment 1 (Implicit Association Task; N = 115) and Experiment 2 (Go/No‐go Association Task; N = 167), women who had been exposed to sexist beliefs demonstrated less implicit gender stereotype bias relative to women who were not exposed to sexism. In contrast, exposure to sexism did not influence men's implicit gender stereotype bias. In Experiment 2, process modelling revealed that women's reduction in bias in response to sexism was related to increased accuracy orientation and a tendency to make warmth versus competence judgments. The implications of these findings for current understandings of sexism and its effects on gender stereotypes are discussed.     

The More You Ask For,the More You Get: Anchoring in Personal Injury Verdicts

The ‘anchoring and adjustment’ bias was demonstrated in a personal injury case using mock jurors. In Experiment 1, the ad damnum, or requested compensation, was manipulated across participants. In Experiment 2, anchors were operationalized as the strength of the legal evidence. Both monetary and causal anchors systematically influenced judgments of the probability that the defendant caused the plaintiff's injuries, compensation awarded, and perceptions of the litigants. These results indicate that anchoring occurs in legal applications, and that plaintiffs would do well to request large compensation awards. In addition, anchors expressed on one scale affected judgments expressed on another scale. This cross-modality anchoring stands in contrast to previous studies. Finally, these anchoring effects are unlikely to be explained by either demand effects or perceived relevance of the anchor.     

Remember judgments and the constraint of direct experience

The most direct assessment of episodic memory is provided by Remember versus Know judgments of recalled or recognised items. We investigate whether Remember judgments reflect episodic memories as a re-experience of formerly experienced events (mental time travel). If they do, they must obey the direct experience constraint: only directly experienced events can be re-experienced but not when the event is known through indirectly conveyed information. In two Experiments participants saw simple events in Power Point, e.g. a car exploding. In the direct experience condition these events were directly perceived. In three further conditions information about the object (particular car), the kind of event (explosion), or both were verbally conveyed. After controlling for a potential encoding specificity effect in Experiment 1, the frequency of Remember judgments was twice as high in the direct experience condition than in the other three conditions. This suggests that Remember judgments are—at least to some degree—subject to the direct experience constraint.