Evidence of rapid correlation‐based perceptual category learning by 4‐month‐olds

Young infants are very sensitive to feature distribution information in the environment. However, existing work suggests that they do not make use of correlation information to form certain perceptual categories until at least 7 months of age. We suggest that the failure to use correlation information is a by‐product of familiarization procedures that encourage infants to over encode individual exemplars rather than relations across exemplars. By changing the exemplar presentation regime to one in which exemplars are rapidly (2 s durations) and repeatedly presented we find that 4‐month‐olds can form perceptual categories on the basis of feature correlation information. In addition, this ability emerges rapidly between 114 and 134 days. We argue that the ability to process correlation information is present very early on but that the demonstration of that ability in categorization tasks is mediated by the demands of the task the infant is tested with. Copyright © 2005 John Wiley & Sons, Ltd.     

Asimetría en la amplitud perceptual: implicaciones para la presentación en parafóvea

Resumen

La amplitud perceptual, definida como la zona alrededor del punto de fijación de la que se extrae información funcional para el procesamiento, es mayor a la derecha que a la izquierda de éste, al menos cuando se procesa material verbal. Esta asimetría en la amplitud perceptual ha sido puesta de manifiesto con diferentes paradigmas experimentales que revisamos en este trabajo. Revisamos igualmente las distintas hipótesis que se han propuesto para su explicación, para concluir con algunas implicaciones que este dato pudiera tener para otros estudios que utilizan presentación de material verbal en parafóvea.     

脑梗塞、脑出血病人外显与内隐记忆的实验研究

采用模糊字辨认、自由回忆和再认的方法分别测试脑梗塞、脑出血病人（实验组）与无脑部病变者（对照组）外显记忆和内隐记忆成绩。结果发现：实验组较对照组外显记忆降低，内隐记忆存在。提出病人其记忆功能呈外显记忆损害，内隐记忆保存的特点。这种记忆功能的双重性为此种病人记忆功能康复训练提供了新的实验证据。     

Exploration of anomalous perceptual experiences in migraine between attacks using the Cardiff Anomalous Perceptions Scale

Distortions in sensory experiences that precede a migraine attack have been extensively documented, the most well-known being the visual aura. Distortions in the experience of other senses are also reported as part of an aura, albeit less frequently, together with changes in the perception or ownership of the body or body parts. There are many examples of differences in aspects of visual perception between migraine and control groups, between attacks, but not as much on unusual experiences involving other senses, the sense of the body or the experience of the environment. Seventy-seven migraine (33 with aura) and 74 control participants took part. Anomalous perceptions were experienced by both migraine and control groups, but more with migraine experienced them and rated them as more distressing, intrusive and frequent. Associations with reports of visual triggers of migraine and visual discomfort are presented. This study is the first to show relationships between these factors.     

Using neural response properties to draw the distinction between modal and amodal representations

ABSTRACT

Barsalou has recently argued against the strategy of identifying amodal neural representations by using their cross-modal responses (i.e., their responses to stimuli from different modalities). I agree that there are indeed modal structures that satisfy this “cross-modal response” criterion (CM), such as distributed and conjunctive modal representations. However, I argue that we can distinguish between modal and amodal structures by looking into differences in their cross-modal responses. A component of a distributed cell assembly can be considered unimodal because its responses to stimuli from a given modality are stable, whereas its responses to stimuli from any other modality are not (i.e., these are lost within a short time, plausibly as a result of cell assembly dynamics). In turn, conjunctive modal representations, such as superior colliculus cells in charge of sensory integration, are multimodal because they have a stable response to stimuli from different modalities. Finally, some prefrontal cells constitute amodal representations because they exhibit what has been called ‘adaptive coding’. This implies that their responses to stimuli from any given modality can be lost when the context and task conditions are modified. We cannot assign them a modality because they have no stable relation with any input type.

Abbreviatons: CM: cross-modal response criterion; CCR: conjuntive cross-modal representations; fMRI: functional magnetic resonance imaging; MVPA: multivariate pattern analysis; pre-SMA: pre-supplementary motor area; PFC: prefrontal cortex; SC: superior colliculus; GWS: global workspace     

When All Is Revealed: A Dissociation between Evaluative Learning and Contingency Awareness

Three experiments are reported that address the issue of awareness in evaluative learning in two different sensory modalities: visual and haptic. Attempts were made to manipulate the degree of awareness through a reduction technique (by use of a distractor task in Experiments 1 and 2 and by subliminally presenting affective stimuli in Experiment 3) and an induction technique (by unveiling the evaluative learning effect and requiring participants to try to discount the influence of the affective stimuli). The results indicate overall that evaluative learning was successful in the awareness-reduction groups but not in the awareness-induction groups. Moreover, an effect in the opposite direction to that normally observed in evaluative learning emerged in participants aware of the stimulus contingencies. In addition, individual differences in psychological reactance were found to be implicated in the strength and direction of the effect. It is argued that these results pose serious problems for the contention that awareness is necessary for evaluative learning.