Pure perceptual-based learning of second-, third-, and fourth-order sequential probabilities

There is evidence that sequence learning in the traditional serial reaction time task (SRTT), where target location is the response dimension, and sequence learning in the perceptual SRTT, where target location is not the response dimension, are handled by different mechanisms. The ability of the latter mechanism to learn sequential contingencies that can be learned by the former mechanism was examined. Prior research has established that people can learn second-, third-, and fourth-order probabilities in the traditional SRTT. The present study reveals that people can learn such probabilities in the perceptual SRTT. This suggests that the two mechanisms may have similar architectures. A possible neural basis of the two mechanisms is discussed.     

时间节律的内隐学习及其特征:来自双维度SRT的证据

本文引入双维度SRT方法,以研究时间节律的内隐学习。在第一个实验中,时间节律的内隐学习得到了证明,双维度SRT方法的信度和效果也得到初步验证;实验二则从整体和局部启动角度比较了节律内隐学习和字母序列内隐学习的差异。两个实验得出结论:(1)节律信息可以被内隐地学习到;(2)节律内隐学习和字母序列内隐学习的显露时机不同,前者更加滞后;(3)两者的机制也不同,前者更倾向于以整体方式进行学习。     

Why is p = .90 better than p = .70? Preference for definitive predictions by lay consumers of probability judgements

What do people regard as an informative and valuable probability statement? This article reports four experiments that show participants to have a clear preference for more extreme and higher probabilities over less extreme and lower ones. This pattern emerged in Experiment 1, in which no context was provided, and was further explored in Experiment 2 within a positive and a negative context. The findings were further confirmed in Experiment 3, which employed a Bayesian framework with revisions of opinions. Finally, Experiment 4 showed how preference for high probabilities can lead people to prefer an overconfident to a more well-calibrated (accurate) forecaster. The results are interpreted as manifestations of a search for definitive predictions principle, which asserts that high probabilities are preferred to medium ones and often favored over the corresponding complementary low probabilities on the basis of their capacity to predict the occurrence of single outcomes.     

The proximity heuristic in judgments of accident probabilities

In daily life, probabilities are often assessed informally through the perceived distance to a target event. Accident probabilities are believed to be high when a disastrous outcome appears to be close. This proximity heuristic can lead to exaggerated p(death) estimates in risky situations (Experiment 2), and sometimes higher probabilities for death after near‐accidents than after actual accidents (Experiment 3 and 4). Near‐accidents are also believed to be equally good, or better, predictors of future disasters than actual accidents, despite being less serious and more frequent (Experiment 5). The proximity heuristic influences the way people talk about their own and other people's chances (Experiment 1), and how they prepare to avoid (or, if necessary, to produce) a disastrous outcome (Experiment 6).     

Selective learning enabled by intention to learn in sequence learning

This study investigated whether a target sequence that people intend to learn is learned selectively when it is interleaved with another (non-target) sequence. Three experiments used a serial reaction time task in which different spatial and color stimuli occurred alternately. Each of the two interleaved sequences had structural regularity. Participants in an intentional learning group were instructed to learn the target (spatial) sequence whereas those in an incidental learning group were not. In Experiments 1 and 2 spatial and color sequences were correlated. Results showed that the intentional group learned the spatial sequence better than the incidental group and learned it independently of the color sequence, whereas the incidental group learned the two sequences as a combined sequence. In Experiment 3 the sequences were uncorrelated. Results showed that the intentional group was no longer superior in learning the spatial sequence. Findings indicate that the intention to learn a target sequence enables selective learning of it only when it is correlated with a non-target sequence.     

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.     

Nonconscious temporal cognition: Learning rhythms implicitly

Two experiments demonstrate that people can implicitly learn rhythms. Participants responded to a series of fast-paced beeps by pressing a key as soon as possible after each beep. They were not told that the duration (180, 450, or 1,125 msec) between each keypress and the next beep was specified by a repeating sequence. In both experiments, participants responded significantly faster to predictable, sequenced timing than to random timing but did not show more knowledge of the sequence than did control participants on explicit memory measures. This dissociation was obtained even with an explicit memory test in Experiment 2 that maintained the same context and response metric as the implicit task to maximize the transfer of relevant knowledge. Implications for temporal cognition are discussed.     

Induction of combination rules in two-dimensional function learning

Previous studies have typically found that when people learn to combine two dimensions of a stimulus to select a response, they learn additive combination rules more easily than nonadditive (e.g., multiplicative) ones. The present experiments demonstrate that in some situations people can learn multiplicative rules more easily than other (e.g., additive) rules. Subjects learned to produce specified response durations when presented with stimulus lines varying in length and angle of orientation. When stimuliand correct responses were related by a multiplicative combination of power functions, learning was relatively easy (Experiment 1). In contrast, systematic response biases occurred during the early phases of learning an additive combination of linear functions (Experiment 2) and a more complex (nonadditive and nonmultiplicative) combination of linear functions (Experiment3), suggesting that people have a tendency to induce a multiplicative combination of power functions. However, the initial biases decreased with practice. These results are explained in terms of a revised adaptive regression model of function learning originally proposed by Koh and Meyer (1991). Differences between the present results and previous results in the literature are discussed.     

Can infants map meaning to newly segmented words? Statistical segmentation and word learning

The present experiments investigated how the process of statistically segmenting words from fluent speech is linked to the process of mapping meanings to words. Seventeen-month-old infants first participated in a statistical word segmentation task, which was immediately followed by an object-label-learning task. Infants presented with labels that were words in the fluent speech used in the segmentation task were able to learn the object labels. However, infants presented with labels consisting of novel syllable sequences (nonwords; Experiment 1) or familiar sequences with low internal probabilities (part-words; Experiment 2) did not learn the labels. Thus, prior segmentation opportunities, but not mere frequency of exposure, facilitated infants' learning of object labels. This work provides the first demonstration that exposure to word forms in a statistical word segmentation task facilitates subsequent word learning.     

Retrieval opportunities while multitasking improve name recall

In two experiments we tested whether providing retrieval opportunities while people were multitasking would improve memory for names. College students (n=195) in Experiment 1 did addition problems and intermittently were “introduced” to 12 face–name pairs to learn. For half the names students were given three within-list retrieval opportunities. Name recall (cued with the faces) was tested either immediately or after 24 hours. Retrieval opportunities improved name recall with both immediate and delayed tests. Experiment 2 more closely resembled the multitasking required in a real-life social situation. College students (n=98) viewed a videotape and were asked to learn the names of 12 dormitory residents who were introduced during an ongoing conversation. Retrieval opportunities were provided for 8 of the 12 residents by having them appear three additional times in the video without repeating their names. Retrieval opportunities improved name recall, but the effect was much smaller than in Experiment 1. The present research demonstrates that distributed retrieval can be effective when people are multitasking including when the multitasking involves a conversation.     

Negative priming and sequence learning

Three experiments used a novel sequence learning task, in which participants responded to changes in location of one visual stimulus whilst ignoring another. Experiment 1 demonstrated negative priming effects in this task, in that responses to individual sequence elements were disrupted when the attended stimulus (e.g., red asterisk) appeared at the location taken by the unattended stimulus (e.g., blue asterisk) on the immediately preceding trial. Experiments 2 and 3 found that negative priming effects extended beyond sensitivity to individual items, suggesting that people may be able to learn about sequential features of ignored events as well as about single events in isolation. The results are discussed in relation to current theories of negative priming.     

Implicit motor sequence learning is not purely perceptual

Many reports have indicated that implicit learning of sequences in a choice response time task is primarily perceptual; subjects learn the sequence of stimuli rather than the sequence of motor responses. Three experiments tested whether implicit motor sequence learning could be purely perceptual: no support was found for that hypothesis. Subjects who merely watched stimuli did not learn the sequence implicitly (Experiment 1), and sequence learning transferred robustly to a different set of stimulus cues (Experiment 2). In the final experiment, the stimulus-response mapping was changed at transfer so that one group of subjects pushed the same sequence of keys but saw new stimuli, whereas another group pushed a different sequence of keys but saw the same stimuli. Transfer to the new mapping was shown only if the motor sequence was kept constant, not the perceptual sequence. It is proposed that subjects learn a sequence of response locations in this and similar tasks.     

Taking patterns for chunks: is there any evidence of chunk learning in continuous serial reaction-time tasks?

When exposed to a regular sequence, people learn to exploit its predictable structure. There have been two major ways of thinking about learning under these conditions: either as the acquisition of general statistical information about the transition probabilities displayed by the sequence or as a process of memorizing and using separate chunks that can later become progressively composed with extended practice. Even though chunk learning has been adopted by some theories of skill acquisition as their main building block, the evidence for chunk formation is scarce in some areas, and is especially so in the continuous serial reaction-time (SRT) task, which has become a major research tool in the study of implicit learning. This article presents a reappraisal, replication and extension of an experiment that stands so far as one of the few alleged demonstrations of chunk learning in the SRT task (Koch and Hoffmann, Psychological Res., 63:22–35, 2000). It shows that the effects which were taken as evidence for chunk learning can indeed be obtained before any systematic training and thus surely reflect a preexistent tendency rather than a learned outcome. Further analyses of the effects after extended practice confirm that this tendency remains essentially unchanged over continuous training unlike what could be expected from a chunk-based account of sequence learning.     

Making Probabilistic Relational Categories Learnable

Theories of relational concept acquisition (e.g., schema induction) based on structured intersection discovery predict that relational concepts with a probabilistic (i.e., family resemblance) structure ought to be extremely difficult to learn. We report four experiments testing this prediction by investigating conditions hypothesized to facilitate the learning of such categories. Experiment 1 showed that changing the task from a category‐learning task to choosing the “winning” object in each stimulus greatly facilitated participants' ability to learn probabilistic relational categories. Experiments 2 and 3 further investigated the mechanisms underlying this “who's winning” effect. Experiment 4 replicated and generalized the “who's winning” effect with more natural stimuli. Together, our findings suggest that people learn relational concepts by a process of intersection discovery akin to schema induction, and that any task that encourages people to discover a higher order relation that remains invariant over members of a category will facilitate the learning of putatively probabilistic relational concepts.     

Retrieval opportunities while multitasking improve name recall

In two experiments we tested whether providing retrieval opportunities while people were multitasking would improve memory for names. College students (n=195) in Experiment 1 did addition problems and intermittently were "introduced" to 12 face-name pairs to learn. For half the names students were given three within-list retrieval opportunities. Name recall (cued with the faces) was tested either immediately or after 24 hours. Retrieval opportunities improved name recall with both immediate and delayed tests. Experiment 2 more closely resembled the multitasking required in a real-life social situation. College students (n=98) viewed a videotape and were asked to learn the names of 12 dormitory residents who were introduced during an ongoing conversation. Retrieval opportunities were provided for 8 of the 12 residents by having them appear three additional times in the video without repeating their names. Retrieval opportunities improved name recall, but the effect was much smaller than in Experiment 1. The present research demonstrates that distributed retrieval can be effective when people are multitasking including when the multitasking involves a conversation.     

Implicit learning of first-, second-, and third-order transition probabilities

Most sequence-learning studies have confounded different types of information, making it difficult to know precisely what is learned. Addressing many of the confounds, the current study shows that people can learn 1st-, 2nd-, and 3rd-order transition probabilities. Measures directly assessing awareness of the probabilities show that the knowledge is implicit early in training and becomes explicit with extended training.     

Thomas and Legge’s matching hypothesis for

Thomas and Legge have proposed amatching hypothesis for two-alternative detection and recognition tasks. Given symmetric payoff, S is supposed to match his unconditional response probabilities to the presentation probabilities. More generally, even when payoff is asymmetric, S is supposed to keep his unconditional response probabilities constant across different discriminability levels. Time series analysis is applied here to the response sequences from two auditory amplitude recognition tasks to test both hypotheses. Experiment I obtains a single sequence from each of 16 Ss. Experiment II obtains two sequences at different discriminability levels from each of 24 Ss. Departures from the matching hypothesis are extremely gross in both cases. In addition, Experiment II shows clear changes in the response probabilities across discriminability conditions, though these are not systematic in direction across Ss.     

Visual artificial grammar learning by rhesus macaques (<Emphasis Type="Italic">Macaca mulatta</Emphasis>): exploring the role of grammar complexity and sequence length

Humans and nonhuman primates can learn about the organization of stimuli in the environment using implicit sequential pattern learning capabilities. However, most previous artificial grammar learning studies with nonhuman primates have involved relatively simple grammars and short input sequences. The goal in the current experiments was to assess the learning capabilities of monkeys on an artificial grammar-learning task that was more complex than most others previously used with nonhumans. Three experiments were conducted using a joystick-based, symmetrical-response serial reaction time task in which two monkeys were exposed to grammar-generated sequences at sequence lengths of four in Experiment 1, six in Experiment 2, and eight in Experiment 3. Over time, the monkeys came to respond faster to the sequences generated from the artificial grammar compared to random versions. In a subsequent generalization phase, subjects generalized their knowledge to novel sequences, responding significantly faster to novel instances of sequences produced using the familiar grammar compared to those constructed using an unfamiliar grammar. These results reveal that rhesus monkeys can learn and generalize the statistical structure inherent in an artificial grammar that is as complex as some used with humans, for sequences up to eight items long. These findings are discussed in relation to whether or not rhesus macaques and other primate species possess implicit sequence learning abilities that are similar to those that humans draw upon to learn natural language grammar.     

When and why do people avoid unknown probabilities in decisions under uncertainty? Testing some predictions from optimal foraging theory.

When given a choice between two otherwise equivalent options - one in which the probability information is stated and another in which it is missing - most people avoid the option with missing probability information (Camerer & Weber, 1992). This robust, frequently replicated tendency is known as the ambiguity effect. It is unclear, however, why the ambiguity effect occurs. Experiments 1 and 2, which separated effects of the comparison process from those related to missing probability information, demonstrate that the ambiguity effect is elicited by missing probabilities rather than by comparison of options. Experiments 3 and 4 test predictions drawn from the literature on behavioral ecology. It is suggested that choices between two options should reflect three parameters: (1) the need of the organism, (2) the mean expected outcome of each option; and (3) the variance associated with each option's outcome. It is hypothesized that unknown probabilities are avoided because they co-occur with high outcome variability. In Experiment 3 it was found that subjects systematically avoid options with high outcome variability regardless of whether probabilities are explicitly stated or not. In Experiment 4, we reversed the ambiguity effect: when participants' need was greater than the known option's expected mean outcome, subjects preferred the ambiguous (high variance) option. From these experiments we conclude that people do not generally avoid ambiguous options. Instead, they take into account expected outcome, outcome variability, and their need in order to arrive at a decision that is most likely to satisfy this need.     

Investigating route learning,metacognition, and beacon-based strategies using virtual environments

IntroductionDominant theories of wayfinding may have underestimated the ease with which adults can learn a route, even with minimal exposure to that route.ObjectivesIn this paper we present three different experiments to provide a comprehensive picture of whether adults can learn complex routes consisting of a number of choicepoints, and if so, what strategies they might be employing to do so.Methodand results We found that adults could learn a 15-junction route after only a single experience of the route (Experiment 1) but that they underestimated how good they would be at learning the 15-junction route (Experiment 2). In Experiment 3, we found that when learning a route made up of “T” shaped junctions, participants relied on a “beacon” strategy based on visual matching.ConclusionsCollectively, these findings suggest that adults can learn complex routes, even with as many as 15 choicepoints, very quickly and without the need for repeated exposure. These findings have implications for theories of wayfinding and call into question the need for repeated exposure.