A forced-choice study of edge detectors in the human visual system

Psychophysical studies using masking procedures to investigate the possible existence of edge detectors in the human visual system have typically been flawed by methodological errors and omissions that make their findings uninterpretable. An example of such a study is given and evaluated, and a replication of that study, using a spatial forced-choice methodology, is reported in detail. The results of this replication are shown to contradict the critical findings of the earlier study; furthermore, it is suggested that any ambiguities in the results of this replication can be interpreted in terms of methodological and procedural factors, rather than in terms of higher-order neurological constructs. Finally, a further test of this methodological interpretation is proposed.     

Space is special in Sign

Following groundbreaking work by linguists and cognitive scientists over the past thirty years, it is now generally accepted that sign languages of the deaf, such as ASL (American Sign Language) or BSL (British Sign Language), are structured and processed in a similar manner to spoken languages. The one striking difference is that they operate in a wholly non-auditory, visuospatial medium. How does the medium impact on language processing itself?     

Recognition deficits resulting from focussed attention in aphasia

Summary Two nonverbal short-term memory tasks, a Picture Recognition and a Paired Association Task, were performed by matched groups of aphasics and brain-damaged controls (N=52 each). For both tasks the alternatives on the answer forms differed systematically on three dimensions, one of which had been highlighted experimentally for each item before the target picture was indicated. In both tasks aphasics made more errors than braindamaged controls only with respect to those features that had been stressed beforehand; they were less able than controls to take advantage of focussed attention. The number of these errors was correlated with performance in the Token Test, a picture naming and a word comprehension task.There were no differences between the groups in response to variations in the semantic saliency of the discriminating features or in the semantic and phonetic relationship between words denoting the reference stimuli. The lack of interactions might have been due to a strong ceiling effect in both tasks.     

The effects of false feedback on attributed arousal and rated attractiveness in female subjects1

In an expanded version of the Valins false feedback paradigm, female subjects viewed ten slides of seminude males accompanied by either an increase or no change in amplified heart beats. Heart rate increase slides were rated as both more attractive and more arousing than no-change slides. These two measures were highly correlated, and did not differ significantly in the degree to which they were influenced by feedback. Subjects also showed significantly greater changes in actual heart rate for the increasing feedback slides than for the no-change slides, although the feedback produced no corresponding differences in GSR. Despite the effects on both subjective report and cardiac activity, correlations between these two measures were generally nonsignificant. Subjects classified as high in autonomic perception showed no significant relationship between actual cardiac activity and slide ratings, nor were they more influenced in their ratings by the feedback than subjects low in autonomic perception. Implications for the false feedback paradigm and for current issues in the social psychology and psychophysiology of emotion are discussed.     

Analytical competence and language impairment in aphasia

Matched groups of Broca's and Wernicke's aphasics, brain-damaged patients without aphasia and chronic schizophrenics were tested in a nonverbal matching task where the subject had to indicate which of two pictures was more closely linked to a clue picture. Eight additional verbal and nonverbal reference tasks were administered. Both aphasic groups performed worse than brain-damaged controls when the identification of individual attributes or actions shared by clue and referent was required, but were unimpaired when the two had a set of referential-situational associations in common. Factor analyses resulted for both groups in two factors, one of which represents general Language Impairment. For the Broca's aphasics this factor was closely related to general organic deficit as measured by the Trail Making Test; for the Wernicke's aphasics it was associated with tasks which might be considered illustrative of analytical competence in isolating and comparing individual features of objects or concepts.     

Multi-level mental representations of written,auditory, and audiovisual text in children and adults

We examined whether the comprehension of narrative texts differed between auditory, audiovisual, and written text presentations in a sample of 8- and 10-year-olds and adults. Based on multi-level theories of text comprehension that assume text comprehension to involve at least three levels of mental representation, we applied a sentence recognition task that enabled the separate assessment of the memory of the text surface, text base, and the situation model. Results indicate that 8-year-olds benefit from audiovisual and auditory text presentations in comparison with written text presentations in terms of their memory of situation model information. For 10-year-olds and adults, their text comprehension did not differ between audiovisual, auditory, and written text presentations. Additionally, the mode of text presentation had no effect on the memory of text surface and text base information.     

Children's and Adults’ Ability to Build Online Emotional Inferences During Comprehension of Audiovisual and Auditory Texts

Two studies examined inferences drawn about the protagonist's emotional state in movies (Study 1) or audiobooks (Study 2). Children aged 5, 8, and 10 years old and adults took part. Participants saw or heard 20 movie scenes or sections of audiobooks taken or adapted from the TV show Lassie. An online measure of emotional inference was designed that assessed the ability of the participants to understand the main protagonist's emotional state. The participants’ emotional knowledge and media literacy were assessed as further variables. The results of the studies provide evidence that children from the age of 5 build emotional inferences when both watching movies and listening to audiobooks. A developmental trend exists with regard to the precision of the emotional inferences. Media literacy and emotional knowledge differed in terms of their influence on the ability to generate inferences, which was dependent on the age of the participant and the presentation mode.     

The onset and mastery of spatial language in children acquiring British Sign Language

In the course of language development children must solve arbitrary form-to-meaning mappings, in which semantic components are encoded onto linguistic labels. Because sign languages describe motion and location of entities through iconic movements and placement of the hands in space, child signers may find spatial semantics-to-language mapping easier to learn than child speakers. This hypothesis was tested in two studies: a longitudinal analysis of a native signing child's use of British Sign Language to describe motion and location events between the ages 1–10 and 3–0, and performance of 18 native signing children between the ages of 3–0 and 4–11 on a motion and location sentence comprehension task. The results from both studies argue against a developmental advantage for sign language learners for the acquisition of motion and location forms. Early forms point towards gesture and embodied actions followed by protracted mastery of the use of signs in representational space. The understanding of relative spatial relations continues to be difficult, despite the iconicity of these forms in the language, beyond 5 years of age.