Bias in memory predicts bias in estimation of future task duration

Both anecdotal accounts and experimental evidence suggest that people underestimate how long it will take them to complete future tasks. A possible reason for this tendency is that people remember tasks as taking less time than they actually did, with these biased memories causing a corresponding bias in prediction. Two experiments were performed to determine whether or not a systematic bias in memory could explain a similar systematic bias in prediction. In support, it was found that (1) the tendency to underestimate future duration disappears when the task is novel, (2) there is similar bias in estimation of both past and future durations, and (3) variables that affect memory of duration, such as level of experience with the task and duration of delay before estimation, affect prediction of duration in the same way. It appears that, at least in part, people underestimate future event duration because they underestimate past event duration.     

Underestimating the duration of future events: memory incorrectly used or memory bias?

People frequently underestimate how long it will take them to complete a task. The prevailing view is that during the prediction process, people incorrectly use their memories of how long similar tasks have taken in the past because they take an overly optimistic outlook. A variety of evidence is reviewed in this article that points to a different, although not mutually exclusive, explanation: People base predictions of future duration on their memories of how long past events have taken, but these memories are systematic underestimates of past duration. People appear to underestimate future event duration because they underestimate past event duration.     

The broad applicability of memory bias and its coexistence with the planning fallacy: reply to Griffin and Buehler (2005)

People chronically underestimate how long tasks will take. In their original article, the present authors (M. M. Roy, N. J. S. Christenfeld, & C. R. M. McKenzie, suggested a simple, broadly applicable explanation: Biased predictions result from biased memories. In their comment article, D. Griffin and R. Buehler suggested that in many domains in which this memory-bias account appears to out-predict their own account, theirs actually makes no prediction at all. However, the present authors did not suggest that only 1 theory is right but that theirs is consistent with data that prior theories, including their own, cannot explain. Ignoring memories of past tasks is not a complete explanation for the phenomenon if the memories people could consult are themselves biased. Nonetheless, underestimating future task duration is almost certainly multiply determined, and thus our account and theirs can coexist.     

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     

Manipulating memory associations changes decision-making preferences in a preconditioning task

Memories of past experiences can guide our decisions. Thus, if memories are undermined or distorted, decision making should be affected. Nevertheless, little empirical research has been done to examine the role of memory in reinforcement decision-making. We hypothesized that if memories guide choices in a conditioning decision-making task, then manipulating these memories would result in a change of decision preferences to gain reward. We manipulated participants’ memories by providing false feedback that their memory associations were wrong before they made decisions that could lead them to win money. Participants’ memory ratings decreased significantly after receiving false feedback. More importantly, we found that false feedback led participants’ decision bias to disappear after their memory associations were undermined. Our results suggest that reinforcement decision-making can be altered by false feedback on memories. The results are discussed using memory mechanisms such as spreading activation theories.     

儿童的最早记忆特征及其与早期记忆数量的关系

本研究采用记忆流畅性任务和回忆最早记忆的方式考察了9岁和13岁共60名中国城镇独生儿童的早期记忆特征及各特征之间的关系。结果发现:(1)和西方研究相比,中国儿童回忆最早记忆时更多自发提及他人,尤其是父母。(2)最早记忆年龄与早期记忆数量有显著负相关,最早记忆中关于重要他人的记忆容量、社会取向和道德情绪与早期记忆数量有显著正相关。这些结果说明文化渗透对自传体记忆发生的影响,以及提示无论是最早记忆的质量,还是早期记忆的数量,回忆童年记忆背后可能潜藏着共同机制。     

Audience-tuning effects on memory: the role of shared reality

After tuning to an audience, communicators' own memories for the topic often reflect the biased view expressed in their messages. Three studies examined explanations for this bias. Memories for a target person were biased when feedback signaled the audience's successful identification of the target but not after failed identification (Experiment 1). Whereas communicators tuning to an in-group audience exhibited the bias, communicators tuning to an out-group audience did not (Experiment 2). These differences did not depend on communicators' mood but were mediated by communicators' trust in their audience's judgment about other people (Experiments 2 and 3). Message and memory were more closely associated for high than for low trusters. Apparently, audience-tuning effects depend on the communicators' experience of a shared reality.     

More is not necessarily better: Examining the nature of the temporal reference memory component in timing

Three experiments compared the timing performance of humans on a modified temporal generalization task with 1, 3, or 5 presentations of the standard duration. In all three experiments subjects received presentations of a standard duration at the beginning of a trial block and then had to judge whether each of a number of comparison stimuli was or was not the standard. The duration of the standard changed between blocks. The three experiments varied the experimental design (between or within subjects), task difficulty (how closely the comparison stimuli were spaced around the standards), and presence or absence of feedback on performance accuracy. Number of presentations of the standard never affected the proportion of identifications of the standard when it was presented, nor other features of the temporal generalization gradients observed. The implications for the operation of reference memories within the scalar timing system were explored via models that made different assumptions about how the individual presentations of the standard were stored and used.     

Why do temporal generalization gradients change when people make decisions as quickly as possible?

Three experiments investigated temporal generalization performance under conditions in which participants were instructed to make their decisions as quickly as possible (speed), or were allowed to take their time (accuracy). A previous study (Klapproth & Müller, 2008) had shown that under speeded conditions people were more likely to confuse durations shorter than the standard with the standard than in the accuracy conditions, and a possible explanation of this result is that longer stimulus durations are "truncated" (i.e., people make a judgement about them before they have terminated, thereby shortening their effective duration) and that these truncated durations affect the standard used for the task. Experiment 1 investigated performance under speed and accuracy conditions when comparison durations were close to the standard or further away. No performance difference was found as a function of stimulus spacing, even though responses occurred on average before the longest durations had terminated, but this lack of effect was attributed to "task difficulty" effects changing decision thresholds. In Experiment 2, the standard duration was either the longest or the shortest duration in the comparison set, and differences between speed and accuracy groups occurred only when the comparisons were longer than the standard, supporting the "truncation" hypothesis. A third experiment showed that differences between speed and accuracy groups only occurred if some memory of the standard that was valid for more than one trial was used. In general, the results suggest that the generalization gradient shifts in speeded conditions occur because of truncation of longer comparison durations, which influences the effective standard used for the task.     

How do we judge our confidence? Differential effects of meta-memory feedback on eyewitness accuracy and confidence

According to the cue–belief model, we assess confidence in our memories using self-credibility cues that reflect beliefs about our memory faculties. We tested the influence of meta-memory feedback on self-credibility cues in the context of eyewitness testimony, when feedback was provided prior to “testifying” via a memory questionnaire (Experiment 1) and after an initial memory questionnaire but before participants had to retake it (Experiment 2). Participants received feedback (good score, bad score, or none) on a fictitious scale purported to predict eyewitness memory ability. Those given good score feedback before testifying were more confident (but no more accurate) than those given bad score feedback. Feedback also affected confidence (good increased and bad decreased) and accuracy (good increased) after testifying but only on leading questions. These differential effects of meta-memory feedback on confidence for normal and leading questions are not explained by the cue–belief model. Implications for our confidence judgments are discussed.     

Biased lineup instructions and face identification from video images

Previous eyewitness memory research has shown that biased lineup instructions reduce identification accuracy, primarily by increasing false-positive identifications in target-absent lineups. Because some attempts at identification do not rely on a witness's memory of the perpetrator but instead involve matching photos to images on surveillance video, the authors investigated the effects of biased instructions on identification accuracy in a matching task. In Experiment 1, biased instructions did not affect the overall accuracy of participants who used video images as an identification aid, but nearly all correct decisions occurred with target-present photo spreads. Both biased and unbiased instructions resulted in high false-positive rates. In Experiment 2, which focused on video-photo matching accuracy with target-absent photo spreads, unbiased instructions led to more correct responses (i.e., fewer false positives). These findings suggest that investigators should not relax precautions against biased instructions when people attempt to match photos to an unfamiliar person recorded on video.     

Social influence and mental routes to the production of authentic false memories and inauthentic false memories

Two studies assessed the extent to which people incorporated false facts provided by bogus others into their own recognition memory reports, and how these false memory reports were affected by: (a) truth of the information in others’ summaries supporting the false facts, (b) motivation to process stories and summaries, (c) source credibility, and (d) ease of remembering original facts. False memory report frequency increased when false facts in a summary were supported by true information and varied inversely with the ease with which original facts could be remembered. Results from a measure probing participants’ memory perceptions suggest that some false memories are authentic: People sometimes lack awareness of both the incorporation of false facts into their memory reports and where the false facts came from. However, many false memories are inauthentic: Despite reporting a false memory, people sometimes retain knowledge of the original stimulus and/or the origin of false facts.     

Strong memories are hard to scale

People are generally skilled at using a confidence scale to rate the strength of their memories over a wide range. Specifically, low-confidence recognition decisions are often associated with close-to-chance accuracy, whereas high-confidence recognition decisions can be associated with close-to-perfect accuracy. However, using a 20-point rating scale, the authors found that the ability to scale memory strength had its limitations in that a high proportion of list items received the highest rating of 20. Efforts to induce participants to differentiate between these strong memories using emphatic instructions and alternative scales were not successful. Remember/know judgments indicated that these strong and hard-to-scale memories were often based on familiarity (not just recollection). Providing error feedback on a plurals discrimination task finally produced a high-confidence criterion shift. The authors suggest that the ability to scale strong (and almost perfectly accurate) memories may be limited because of the absence of differential error feedback for very strong memories in the past (the kind of differential error feedback that may account for the memory-scaling expertise that participants otherwise exhibit).     

Consolidation-like effects in flashbulb memories: evidence from September 11, 2001

After September 11, 2001, we distributed flashbulb memory questionnaires at 5 different dates: within 48 hr (T1) and at 1 week (T2), 1 month (T3), 3 months (T4), and 1 year (T5). We scored responses for self-reported memory (veracity unverified), memory accuracy (recollection-matched T1 response), and memory consistency (recollection-matched prior responses other than T1). Self-reported memory and subjective confidence remained near ceiling, although the accuracy declined. However, memories given a week or more after September 11 were consistent throughout. We hypothesize that flashbulb memories follow a consolidation-like process: Some details learned later are incorporated into the initial memory, and many others are discarded. After this process, memories stabilize. Therefore, the best predictor of flashbulb memories at long intervals is not the memory as initially reported but memories reported a week or more after the event.     

Bias in conceptual priming

In recent years, Ratcliff, McKoon, and colleagues have argued that priming in perceptual implicit memory tests is the result of biases in information processing. Three experiments are presented that extend this framework to the conceptual implicit memory domain. Participants studied a list of words before receiving a set of general knowledge questions. For some questions, participants studied the correct answer; for others, they studied a similar but incorrect answer. Although study of a correct answer facilitated performance, study of the similar alternative hurt performance. Costs and benefits of previous study were observed in both production and forced-choice tasks. However, there was no benefit of previous study when participants studied both the correct answer and the similar but incorrect alternative. The pattern of results indicates that participants were biased to respond with previously studied words on the conceptual implicit memory test. This pattern is concordant with the biased information-processing approach to priming.     

On the power of autobiographical memories: from threat and challenge appraisals to actual behaviour

Autobiographical memories are a major feature of mental life in humans. However, research on the influence of autobiographical recall on actual behaviour is scarce. We predicted and found that general memories of failure and specific memories of success resulted in worse performance than general memories of success and specific memories of failure. This performance pattern was mediated by task appraisal, suggesting that autobiographical memories (of failure and success) impact performance by shaping the perception of the upcoming task. Combined with the fact that these effects occurred even when the content of autobiographical memories was unrelated to the upcoming task, the present research represents an important step forward in understanding how autobiographical recall influences actual behaviour.     

Why and when peer prediction is superior to self-prediction: the weight given to future aspiration versus past achievement

Peer predictions of future behavior and achievement are often more accurate than those furnished by the self. Although both self- and peer predictions correlate equally with future outcomes, peers tend to avoid the degree of overoptimism so often seen in self-predictions. In 3 studies, the authors tested whether this differential accuracy arises because people give more weight to past behavior when predicting others, but emphasize agentic information, in particular data about their aspiration level, when predicting the self. Studies 1 and 3 showed that the exact same participants rated past behavior more diagnostic of future performance when predicting another person but viewed aspiration-level data as more valuable when someone else was trying to predict them. In Studies 2 and 3 (predicting an upcoming exam score and performance in a lab task, respectively), participants gave greater weight in self-predictions to aspiration-level data than did a yoked peer, who instead gave greater weight to evidence of past achievement. This differential weighting explained why peer predictions tended to be less optimistic and, thus, more accurate. Discussion centers on strategies for predicting future behavior and why people may remain ignorant of their own incompetence despite feedback.     

Processing of ambiguous and unambiguous feedback by depressed and nondepressed college students: schematic biases and their implications for depressive realism

Explored schematic processing as a mechanism for predicting (a) when depressed Ss would be negative relative to nondepressed Ss and (b) when depressed and nondepressed Ss would show biased or unbiased (i.e., "realistic") processing. Depressed and nondepressed Ss performed multiple trials of a task under conditions in which the two groups held either equivalent or different schemas regarding this task. Ss received either an unambiguous or objectively normed ambiguous feedback cue on each trial. In full support of schematic processing, depressed Ss showed negative encoding relative to nondepressed Ss only when their schemas were more negative, and both depressed and nondepressed Ss showed positively biased, negatively biased, and unbiased encoding depending on the relative feedback cue-to-schema match. Depressed and nondepressed Ss' response latencies to unambiguous feedback also supported the occurrence of schematic processing. We discuss the methodological, treatment, and "realism" implications of these findings and suggest a more precise formulation of Beck's schema theory of depression.     

压抑遗忘的影响因素

人在生活中的一些负性经历或无效信息可以通过压抑提取而遗忘,这种遗忘称为压抑遗忘。压抑遗忘不仅受压抑时长、压抑次数、实验材料的情绪效价和唤醒度、期待效应等的影响,还受个体的年龄和精神障碍等的影响。今后应着重考察精神疾病个体记忆控制网络内的连接强度与压抑遗忘的关系,澄清压抑遗忘是否存在补偿机制。     

压抑遗忘的影响因素

人在生活中的一些负性经历或无效信息可以通过压抑提取而遗忘,这种遗忘称为压抑遗忘。压抑遗忘不仅受压抑时长、压抑次数、实验材料的情绪效价和唤醒度、期待效应等的影响,还受个体的年龄和精神障碍等的影响。今后应着重考察精神疾病个体记忆控制网络内的连接强度与压抑遗忘的关系,澄清压抑遗忘是否存在补偿机制。