Perspectives on prediction: Does third-person imagery improve task completion estimates?

People typically underestimate the time necessary to complete their tasks. According to the planning fallacy model of optimistic time predictions, this underestimation occurs because people focus on developing a specific plan for the current task and neglect the implications of past failures to meet similar deadlines. We extend the classic planning fallacy model by proposing that a phenomenal quality of mental imagery – the visual perspective that is adopted – may moderate the optimistic prediction bias. Consistent with this proposal, participants in four studies predicted longer completion times, and thus were less prone to bias, when they imagined an upcoming task from the third-person rather than first-person perspective. Third-person imagery reduced people’s focus on optimistic plans, increased their focus on potential obstacles, and decreased the impact of task-relevant motives on prediction. The findings suggest that third-person imagery helps individuals generate more realistic predictions by reducing cognitive and motivational processes that typically contribute to bias.     

判断与决策中的规划谬误

规划谬误是指人们在估计未来任务的完成时间时, 倾向于过度乐观, 低估任务完成时间的一种现象。规划谬误的心理机制主要包括规划谬误理论和记忆偏差理论。规划谬误的影响因素主要有认知因素、动机因素、个体的经验水平、目标任务的性质等。规划谬误的应对策略主要有与过去的经验相联系、从第三人称视角进行估计、任务分解及时间分配。未来的研究主要从规划谬误与策略性误解、乐观偏差、过分自信的关系, 规划谬误的产生根源、规划谬误的跨文化研究、规划谬误的研究范围及应用领域等方面进一步探讨。     

事件时间估计偏差理论述

人们总是倾向低估完成某一任务的时间。计划谬误理论认为,时间低估倾向的原因是人们估计时间时忽视过去完成类似任务的经验,过于关注理想的任务计划和任务情景,从而导致乐观的时间估计。但是基于该理论的一些提高时间估计精确性的策略没有达到预期效果。针对这种不足,记忆偏差理论认为,人们利用的时间记忆带有偏差,从而导致偏差的时间估计。两个理论之间引起一些争论,但如果从解释水平理论的角度可以找到其相通之处     

Overcoming the planning fallacy through willpower: effects of implementation intentions on actual and predicted task‐completion times

Previous work has shown that people often underestimate their task‐completion times (Buehler, Griffin, & Ross, 1994 ). The present research examined whether this optimistic bias may be reduced through the formation of implementation intentions. In an experimental study, participants were requested to complete an assignment within a specified time period. Half of these participants made implementation intentions about where and when they would complete the assignment. The remaining participants were simply given the goal of completing the assignment. The results showed that furnishing participants' goals with implementation intentions led to (a) more optimistic completion predictions, (b) an even greater increase in actual rates of goal completion, and, consequently, (c) a significant reduction in optimistic bias in completion predictions. Furthermore, the reduction in optimistic bias among implementation–intention participants was found to be mediated by a smaller number of interruptions while working on the assignment. Together, these findings attest to the importance of implementation planning in overcoming unrealistic optimism in task‐completion predictions. Copyright © 2000 John Wiley & Sons, Ltd.     

Biases and fallacies, memories and predictions: comment on Roy, Christenfeld, and McKenzie (2005)

Comparative theory testing is a useful method for assessing the value of a new theoretical account such as the memory bias account of optimistic time predictions. However, such comparisons can be misleading when they do not carefully consider the domain limitations of the respective theories. M. M. Roy, N. J. S. Christenfeld, and C. R. M. McKenzie have contrasted the memory bias and planning fallacy accounts in their ability to explain the prevalence and degree of optimistic bias in time predictions. However, the authors argue that many of the points of distinction they draw are actually reflections of the domain limitations of the 2 theories. The authors clarify the definition and scope of the planning fallacy account and show how the apparent contradictions diminish or disappear.     

How long will it take? Power biases time predictions

People tend to underestimate the time it takes to accomplish tasks. This bias known as the planning fallacy derives from the tendency to focus attention too narrowly on the envisaged goal and to ignore additional information that could make predictions more accurate and less biased. Drawing on recent research showing that power induces attentional focus, four studies tested the hypothesis that power strengthens the tendency to underestimate future task completion time. Across a range of task domains, and using multiple operationalizations of power, including actual control over outcomes (Study 1), priming (Studies 2 and 3), and individual differences (Study 4), power consistently led to more optimistic and less accurate time predictions. Support was found for the role of attentional focus as an underlying mechanism for those effects. Differences in optimism, self-efficacy, and mood did not contribute to the greater bias in powerful individuals’ forecasts. We discuss the implications of these findings for institutional decision processes and occupational health.     

We Knew It All Along: Hindsight Bias in Groups

Two studies investigated the occurrence of hindsight distortion in groups as compared to individuals. Competing predictions were derived from four theoretical positions: Memory impairment, response bias, self-presentation, and group polarization. In Experiment 1, small groups vs individuals made hypothetical predictions with or without outcome information. Both individuals and groups were found to distort their predictions in the direction of the alleged outcome. Experiment 2 employed a memory design in which individuals vs groups made a series of predictions for which they subsequently received outcome information which was either above or below their prediction or for which they received no outcome information. Subjects had to recall their initial prediction. Results indicated that (a) hindsight bias was slightly attenuated in groups compared to individuals, (b) groups were more likely to recall their original predictions correctly than individuals, (c) this recall advantage of groups disappeared when time taken to make the initial prediction was held constant, and (d) outcome information affected hindsight bias but not hit rates. Results were interpreted as supporting the response bias perspective.     

Allocating time to future tasks: The effect of task segmentation on planning fallacy bias

The scheduling component of the time management process was used as a "paradigm" to investigate the allocation of time to future tasks. In three experiments, we compared task time allocation for a single task with the summed time allocations given for each subtask that made up the single task. In all three, we found that allocated time for a single task was significantly smaller than the summed time allocated to the individual subtasks. We refer to this as the segmentation effect. In Experiment 3, we asked participants to give estimates by placing a mark on a time line, and found that giving time allocations in the form of rounded close approximations probably does not account for the segmentation effect. We discuss the results in relation to the basic processes used to allocate time to future tasks and the means by which planning fallacy bias might be reduced.     

Collaborative planning and prediction: Does group discussion affect optimistic biases in time estimation?

Intuition and previous research indicate that individuals commonly display an optimistic bias in time prediction. The present studies extend research on task completion forecasts to examine tasks performed collaboratively by groups, and predictions generated through group discussion. Participants predicted—individually and collaboratively—when they would complete upcoming group projects ranging from brief laboratory tasks to extensive real-world projects, and their actual completion times were measured. Results supported the three guiding hypotheses. First, there was an optimistic bias for both individual (Studies 1 and 2) and group predictions (Studies 1–3). Second, predictions generated through group discussion were more optimistic than those generated individually. Third, this “group accentuation” effect was mediated by the informational focus at the time of prediction. Group discussion heightened participants’ tendency to focus primarily on factors promoting successful task completion, and this selective focus on “planning for success” enhanced their optimistic outlook. Discussion centers on theoretical contributions to the individual and group decision making literatures, as well as applied implications for planning and forecasting within organizational contexts.     

The role of prior task experience in temporal misestimation

The effect of experience with a preceding task on the accuracy of predictions of duration was examined in three experiments, where two tasks comprising similar or different mental operators were performed consecutively. Results supported an anchoring account of misestimation, which states that misestimation occurs because predictions are anchored to the duration of the preceding task. Preceding performance of a longer task led to overestimation on a shorter task with similar mental operators (Experiment 1), whereas preceding performance of a shorter task comprising similar or different mental operators led to underestimation on a longer task (Experiments 1 to 3). Contrary to the planning fallacy account (Kahneman & Tversky, 1979), these findings indicate that preceding task performance is considered when predicting duration, but that using such information does not necessarily improve accuracy.     

The role of prior task experience in temporal misestimation

The effect of experience with a preceding task on the accuracy of predictions of duration was examined in three experiments, where two tasks comprising similar or different mental operators were performed consecutively. Results supported an anchoring account of misestimation, which states that misestimation occurs because predictions are anchored to the duration of the preceding task. Preceding performance of a longer task led to overestimation on a shorter task with similar mental operators (Experiment 1), whereas preceding performance of a shorter task comprising similar or different mental operators led to underestimation on a longer task (Experiments 1 to 3). Contrary to the planning fallacy account (Kahneman & Tversky, 1979), these findings indicate that preceding task performance is considered when predicting duration, but that using such information does not necessarily improve accuracy.     

Development of cognitive strategies and self control strategies in 8 to 14-year-old children]

This study examines the interaction between the development of cognitive strategies and self-monitoring abilities in children aged 8 to 14. Children were tested individually on eight proportionality problems presented with the balance-scale task. Cognitive development was assessed by the strategy used and the performance on each problem. The indicators of self-monitoring were: latencies before and after the solution of a problem, self-evaluation of one's ability to make the balance scale stay level, proportion of oriented moves on the balance scale, and persistence on a problem. Children's self-monitoring reactions to failure were assessed by changes in strategies, verbal explanations, self-evaluation of performance, and latencies. Results showed an interaction between the complexity of the items and cognitive level. On more complex items, children of lower cognitive levels had shorter latencies, made more (but less oriented) moves on the balance scale, persisted less in their activity, and had more difficulty to evaluate properly their performance. Following failure, children of lower cognitive levels did a less accurate evaluation of their performance, modified their strategy, and did not change their verbal justification, whereas children of higher cognitive levels did a good evaluation of their performance, did not change their strategy, and had the tendency to change their verbal justification. Following failure, all children took less time planning their activity. The results suggest that self-monitoring abilities develop according to the development of cognitive strategies and are mediated by the complexity of the task.     

Relations between self-efficacy beliefs,self-presentation motives,personal task goals,and performance on endurance-based physical activity tasks

We conducted two studies with the aim of examining the relations between self-presentation motives and physical activity task performance. In study 1, prior to performing an endurance-based physical activity task, 133 undergraduate participants (M_age = 20.89, SD = 5.21) reported acquisitive-agentic and protective-agentic self-presentation motives alongside task self-efficacy, self-presentational efficacy, and their personal task goals. Using a different endurance-based physical activity task in study 2, we also assessed undergraduate participants' (n = 150; M_age = 20.23, SD = 3.34) dispositional exercise-related self-presentation motivation alongside the variables measured in study 1. Bayesian path analyses revealed indirect relations between agentic self-presentation motives and task performance via participants' personal task goals. Findings also indicated that agentic self-presentation motives may act as intermediaries in indirect pathways linking efficacy beliefs and dispositional exercise-related self-presentation motivation to goal processes and task performance. The results contribute to a more nuanced understanding of the relationship between self-presentation motivation and task performance.     

Anxiety and speaking in people who stutter: An investigation using the emotional Stroop task

People with anxiety disorders show an attentional bias towards threat or negative emotion words. This exploratory study examined whether people who stutter (PWS), who can be anxious when speaking, show similar bias and whether reactions to threat words also influence speech motor planning and execution. Comparisons were made between 31 PWS and 31 fluent controls in a modified emotional Stroop task where, depending on a visual cue, participants named the colour of threat and neutral words at either a normal or fast articulation rate. In a manual version of the same task participants pressed the corresponding colour button with either a long or short duration. PWS but not controls were slower to respond to threat words than neutral words, however, this emotionality effect was only evident for verbal responding. Emotionality did not interact with speech rate, but the size of the emotionality effect among PWS did correlate with frequency of stuttering. Results suggest PWS show an attentional bias to threat words similar to that found in people with anxiety disorder. In addition, this bias appears to be contingent on engaging the speech production system as a response modality. No evidence was found to indicate that emotional reactivity during the Stroop task constrains or destabilises, perhaps via arousal mechanisms, speech motor adjustment or execution for PWS.Educational objectives: The reader will be able to: (1) explain the importance of cognitive aspects of anxiety, such as attentional biases, in the possible cause and/or maintenance of anxiety in people who stutter, (2) explain how the emotional Stroop task can be used as a measure of attentional bias to threat information, and (3) evaluate the findings with respect to the relationship between attentional bias to threat information and speech production in people who stutter.     

Superstitious responding and frequency matching in the positive bias and gambler’s fallacy effects

Three studies showed that success in predicting outcomes of a random binary series was associated with the positive bias effect, whereas failure was associated with the gambler’s fallacy effect. Moreover, success increased confidence and failure decreased it. Although explicit instructions that the source generated random output increased the likelihood of predicting an alternation in the series, these instructions had no effect on the relationships between success and the positive bias effect, and failure and the gambler’s fallacy effect. Importantly, intuitions about the randomness or nonrandomness of the source, assessed immediately prior to each trial, did not influence this interaction. These results suggest that people used a win-stay strategy, but that sensitivity to run length counteracted the corresponding lose-shift tendency. The data support a memory-based explanation of the gambler’s fallacy effect, consistent with the account from local representativeness, but the positive bias effect may be an instance of human superstitious responding.     

Does a Positive Bias Relate to Social Behavior in Children With ADHD?

This study examines whether positively biased self-perceptions relate to social behaviors in children with attention-deficit/hyperactivity disorder (ADHD) as compared to control children. The social behaviors of children with ADHD (n = 87) were examined relative to control children (CTL; n = 38) during a laboratory-based dyadic social interaction task. Children with ADHD were subgrouped into those with a positive illusory bias (PIB) in their self-perceptions (ADHD + PIB) versus those without such a bias (ADHD – PIB). Using a behavioral coding system adapted for this study, ADHD + PIB, ADHD – PIB, and CTL participants were compared on objectively coded social behaviors occurring within the context of the social interaction task. Whereas both ADHD groups displayed more disruptive behavior than controls, only the ADHD + PIB group displayed less prosocial behavior and less effortful behavior. This study breaks new ground by examining positively biased self-perceptions as they relate to social behavior in children with ADHD and provides promising new insight into the social problems experienced by these children.     

On the formation of favourable impressions: Associations between self-presentation motives,task behaviour,and others’ evaluations of the self in a team-sport setting

Individuals adopt self-presentation motives in sport settings to shape others’ perceptions of the self. However, the effectiveness of different types of motives in shaping favourable evaluations has not been explored. We examined pathways from 2 × 2 self-presentation motives to others’ evaluative perceptions via task behaviour. Participants (N = 112) reported their self-presentation motives immediately prior to a basketball game, had their behaviours (i.e., shots, time spent on the sideline) recorded via video during the game, then completed agentic (e.g., competent) and communal (e.g., supportive) ratings of their teammates following the game. Structural equation modeling revealed positive pathways from acquisitive motives to behaviour (i.e., acquisitive agency) and favourable evaluations (i.e., acquisitive-agency and -communion). Negative pathways were observed from protective communion to behaviour and others’ evaluations. The findings indicate that different types of self-presentation motives may differ in their impression management effectiveness and may either promote or suppress task behaviour.     

Young children's knowledge of their memory span: effects of task and experience

This study investigated the hypothesis that young children have knowledge about their memory that they may be unable to articulate, but are able to reflect on and use in problem-solving. Forty-eight kindergarteners made one of two types of judgments about their memory span for words. Half of the children made prospective verbal predictions about the number of words they thought they could recall from a list of 10. The other half made concurrent, nonverbal predictions by listening to words on a tape and manually stopping the tape when they heard as many words as they thought they could recall. Children's actual recall for words was then assessed. All children participated in multiple trials to assess the effect of task experience on their predictions. Analyses revealed that predictions made in the concurrent task were significantly more accurate than those made in the prospective task. All children lowered their predictions across trials, although only in the concurrent task were children's final-trial predictions not significantly greater than their actual recall. No meaningful effects or interactions were associated with actual recall scores. These results revealed that young children manifested greater memory knowledge when this knowledge was assessed through their concurrent problem-solving behavior rather than through their prospective verbal predictions.     

On the nature of the conjunction fallacy

In a seminal work, Tversky and Kahneman showed that in some contexts people tend to believe that a conjunction of events (e.g., Linda is a bank teller and is active in the feminist movement) is more likely to occur than one of the conjuncts (e.g., Linda is a bank teller). This belief violates the conjunction rule in probability theory. Tversky and Kahneman called this phenomenon the “conjunction fallacy”. Since the discovery of the phenomenon in 1983, researchers in psychology and philosophy have engaged in important controversies around the conjunction fallacy. The goal of this paper is to explore the most important of these controversies, namely, the controversy about the nature of the conjunction fallacy. Is the conjunction fallacy mainly due to a misunderstanding of the problem by participants (misunderstanding hypothesis) or is it mainly due to a genuine reasoning bias (reasoning bias hypothesis)? A substantial portion of research on the topic has been directed to test the misunderstanding hypothesis. I review this literature and argue that a stronger case can be made against the misunderstanding hypothesis. Thus, I indirectly provide support for the reasoning bias hypothesis.