Associative symmetry by pigeons after few-exemplar training

The present experiment investigated whether pigeons can show associative symmetry on a two-alternative matching-to-sample procedure. The procedure consisted of a within-subject sequence of training and testing with reinforcement, and it provided (a) exemplars of symmetrical responding, and (b) all prerequisite discriminations among test samples and comparisons. After pigeons had learned two arbitrary-matching tasks (A-B and C-D), they were given a reinforced symmetry test for half of the baseline relations (B1-A1 and D1-C1). To control for the effects of reinforcement during testing, two novel, nonsymmetrical responses were concurrently reinforced using the other baseline stimuli (D2-A2 and B2-C2). Pigeons matched at chance on both types of relations, thus indicating no evidence for symmetry. These symmetrical and nonsymmetrical relations were then directly trained in order to provide exemplars of symmetry and all prerequisite discriminations for a second test. The symmetrical test relations were now B2-A2 and D2-C2 and the nonsymmetrical relations were D1-A1 and B1-C1. On this test, 1 pigeon showed clear evidence of symmetry, 2 pigeons showed weak evidence, and 1 pigeon showed no evidence. The previous training of all prerequisite discriminations among stimuli, and the within-subject control for testing with reinforcement seem to have set favorable conditions for the emergence of symmetry in nonhumans. However, the variability across subjects shows that methodological variables still remain to be controlled.     

联想学习对消费行为的影响：基于产品搜索经验的视角

消费者能够基于长期形成的联结产生预期并引导产品搜索。然而,在实际搜索过程中,消费者可能会遭遇符合预期的经验或违反预期的经验。本研究主要探讨基于不同产品搜索经验的联想学习影响消费行为的机制,主要涉及(1)消费者是否会基于产品搜索经验的联想学习产生“违反预期”的预期,并且影响随后搜索中的注意加工;(2)违反预期和符合预期的产品搜索经验对任务无关信息的联想学习所产生的影响,同时关注先前短期的联想学习能否建立预期从而引导随后的产品注意搜索过程;(3)基于产品搜索经验的联想学习对产品偏好的影响,并将行为偏好和大脑奖赏进行联系。本研究有助于阐明消费情境中产品搜索对消费者行为和大脑的影响机制,为营销应用中通过改变消费体验、促进产品购买提供实证依据。     

Stimulus-driven and goal-driven effects on Pavlovian associative reward learning

It has been shown that pure Pavlovian associative reward learning can elicit value-driven attentional capture. However, in previous studies, task-irrelevant and response-independent reward-signalling stimuli hardly competed for visual selective attention. Here we put Pavlovian reward learning to the test by manipulating the extent to which bottom-up (Experiment 1) and top-down (Experiment 2) processes were involved in this type of learning. In Experiment 1, the stimulus, the colour of which signalled the magnitude of the reward given, was presented simultaneously with another randomly coloured stimulus, so that it did not capture attention in a stimulus-driven manner. In Experiment 2, observers performed an attentionally demanding RSVP-task at the centre of the screen to largely tax goal-driven attentional resources, while a task-irrelevant and response-independent stimulus in the periphery signalled the magnitude of the reward given. Both experiments showed value-driven attentional capture in a non-reward test phase, indicating that the reward-signalling stimuli were imbued with value during the Pavlovian reward conditioning phases. This suggests that pure Pavlovian reward conditioning can occur even when (1) competition prevents attention being automatically allocated to the reward-signalling stimulus in a stimulus-driven manner, and (2) attention is occupied by a demanding task, leaving little goal-driven attentional resources available to strategically select the reward-signalling stimulus. The observed value-driven attentional capture effects appeared to be similar for observers who could and could not explicitly report the stimulus–reward contingencies. Altogether, this study provides insight in the conditions under which mere stimulus–reward contingencies in the environment can be learned to affect future behaviour.     

Effects of syllable structure in aphasic errors: implications for a new model of speech production

Current models of word production assume that words are stored as linear sequences of phonemes which are structured into syllables only at the moment of production. This is because syllable structure is always recoverable from the sequence of phonemes. In contrast, we present theoretical and empirical evidence that syllable structure is lexically represented. Storing syllable structure would have the advantage of making representations more stable and resistant to damage. On the other hand, re-syllabifications affect only a minimal part of phonological representations and occur only in some languages and depending on speech register. Evidence for these claims comes from analyses of aphasic errors which not only respect phonotactic constraints, but also avoid transformations which move the syllabic structure of the word further away from the original structure, even when equating for segmental complexity. This is true across tasks, types of errors, and, crucially, types of patients. The same syllabic effects are shown by apraxic patients and by phonological patients who have more central difficulties in retrieving phonological representations. If syllable structure was only computed after phoneme retrieval, it would have no way to influence the errors of phonological patients. Our results have implications for psycholinguistic and computational models of language as well as for clinical and educational practices.     

Learning from your mistakes: does it matter if you’re out in left foot,I mean field?

Studies have shown that generating errors prior to studying information (pencil–?) can improve target retention relative to passive (i.e., errorless) study, provided that cues and targets are semantically related (pencil–ink) and not unrelated (pencil-frog). In two experiments, we manipulated semantic proximity of errors to targets during trial-and-error to examine whether it would modulate this error generation benefit. In Experiment 1, participants were shown a cue (band–?) and asked to generate a related word (e.g., drum). Critically, they were given a target that either matched the semantic meaning of their guess (guitar) or mismatched it (rubber). In Experiment 2, participants studied Spanish words where the English translation either matched their expectations (pariente–relative) or mismatched it (carpeta–folder). Both experiments show that errors benefit memory to the extent that they overlap semantically with targets. Results are discussed in terms of the retrieval benefits of activating related concepts during learning.     

Face value: testing the utility of contextual face cues for face recognition

The presence of multiple faces during a crime may provide a naturally-occurring contextual cue to support eyewitness recognition for those faces later. Across two experiments, we sought to investigate mechanisms underlying previously-reported cued recognition effects, and to determine whether such effects extended to encoding conditions involving more than two faces. Participants studied sets of individual faces, pairs of faces, or groups of four faces. At test, participants in the single-face condition were tested only on those individual faces without cues. Participants in the two and four-face conditions were tested using no cues, correct cues (a face previously studied with the target test face), or incorrect cues (a never-before-seen face). In Experiment 2, associative encoding was promoted by a rating task. Neither hit rates nor false-alarm rates were significantly affected by cue type or face encoding condition in Experiment 1, but cuing of any kind (correct or incorrect) in Experiment 2 appeared to provide a protective buffer to reduce false-alarm rates through a less liberal response bias. Results provide some evidence that cued recognition techniques could be useful to reduce false recognition, but only when associative encoding is strong.     

Caffeine reduces the impact of drowsiness on driving errors

AimThe study examined the moderating effect of repeat-dose, chewing gum-administered caffeine on the well-established relationship between drowsiness and driving performance, under the conditions of accumulating sleep loss.Method50-h sleep deprivation protocol with a double-blind, placebo-controlled design. Eleven volunteers (6 male), aged 18–28 years were screened for pre-existing medical conditions (including sleep disturbances), tobacco and recreational drug use, recent time-zone travel and shift-work. They were randomly allocated to placebo or caffeine group and administered 4 oral doses of either caffeinated gum pellets (200 mg/dose) or non-caffeinated placebo gum every two hours (01:00, 03:00, 05:00, 07:00) on the first and second nights of the protocol. Participants were constantly monitored and remained awake for 50 h, while performing 15 identical, evenly-spaced 40-min monotonous driving tasks in a medium-fidelity moving-base driving simulator. Their drowsiness was monitored with a spectacle frame-mounted infra-red sensor registering ocular parameters and converting them into a Johns Drowsiness Scale (JDS) score every 60 s. Lane keeping and speed variability measures were used to assess driving performance.ResultsDriving performance declined and drowsiness increased from the first simulated drive to the last. When driving performance was examined in one-minute epochs synchronised with JDS scores, both lateral lane positioning and speed variability were found to be associated with drowsiness. The strength of this association was significantly weaker in the caffeine group, compared to placebo. Placebo group replicated the linear relationship between drowsiness and driving errors across the full range of JDS scores. This pattern was significantly weaker under the caffeine condition, and was even reversed at the upper range of JDS, with higher JDS scores not resulting in further degradation of driving performance. This dissociation between drowsiness and driving errors persisted across the 24-h cycle under the caffeine condition, despite caffeine being administered only during early morning hours.ConclusionStrategically timed, repeat 200 mg doses of caffeine administered via chewing gum can mitigate fatigue-induced impairments in driving performance by not only reducing drowsiness but also by significantly weakening its impact on driving errors. This dual effect of sustained drowsiness reduction and the dissociation between drowsiness levels and driving errors seems worth further investigation as it might offer an effective emergency countermeasure against driver drowsiness and its subsequent conversion into potentially fatal driving errors.     

感知觉加工与概念加工对联结记忆中图片优势效应的影响

本研究采用联结再认范式考察联结记忆中感知觉水平和概念加工程度对图片优势效应的影响。实验1通过呈现清晰或模糊的词语或图片对操纵了感知觉水平,结果发现只有在清晰条件下图片优势效应才会出现;实验2则在模糊条件下通过要求被试想象两个项目之间的关系操纵了概念加工程度,结果发现在有概念加工条件下,出现了图片优势效应。研究结果表明：（1）降低的感知觉水平会导致联结记忆中的图片优势效应消失;（2）对模糊项目对进行概念加工会使联结记忆中出现图片优势效应。