Phonological and orthographic factors in the word-superiority effect

Phonological and orthographic aspects of a letter string were found to affect the identification of a component letter in three experiments. All involved a fixed set of target vowels presented in a fixed position in letter strings. Manipulations of the phonological nature of the target or the orthographic character of the string were made by adding a letter with the postexposure mask to the original CVC trigram. In Experiment 1, the addition of an E with the mask as a final letter to the string changed the pronunciation of the target vowel, whereas the addition of an S did not. Identification accuracy was higher with the S mask. In Experiment 2, either E or D could be added to CVCs that were equally orthographic but differentially pronounceable. The same added letter had quite different effects on accuracy, depending on its effect on target pronunciation and the orthographic regularity of the string. In Experiment 3, performance on targets in orthographic CVCs was lowered to the level of nonorthographic CVCs by adding a letter that rendered the entire string nonorthographic. The results are explained by assuming that phonological and graphemic codes are developed simultaneously but maintained in a nonindependent manner.     

Masking and the identification of characters presented simultaneously and sequentially to the parafovea

Summary The effects of masking and simultaneous vs sequential exposure on identification accuracy of parafoveally presented pairs of stimuli were examined in four experiments. When masking figures were continuously present in positions not occupied by stimulus characters, accuracy of identification was significantly poorer on the relatively central member of a pair when members were simultaneously exposed and when the central member was exposed second. When masking figures were not used, performance was significantly poorer on the central member only when pair members were exposed simultaneously. Requiring the identification of both members of the pair produced a different ordering of overall accuracy among the simultaneous and sequential conditions from when only one member was identified. It was concluded that asymmetric lateral inhibition of feature extraction operated only when target and nontarget were simultaneously present. An additional source of asymmetric disruption occurs when masking figures flanking the target change before or with the appearance of the target.     

Influences of target and nontarget shapes on target identification

The orientation of a nontarget in a location-cuing paradigm has been shown to affect accuracy of identification of target orientation when modified plus-signs (Ts) are the stimuli. In the current study, similar effects were found with Landolt C (C) stimuli. Both shapes of targets were identified by orientation. Moreover, targets were affected by nontargets whether both target and nontarget were the same shape or if they were different shapes. A single nontarget with an orientation that matched that of the target improved accuracy of identification of target orientation, whereas a nontarget with an orientation that did not match that of the target impaired accuracy of identification of target orientation, even though the nontargets appeared in locations that were never cued and could never contain targets. The data are consistent with either the Variable and Permeable Filters metaphor or a response competition account. Received: 1 July 1998 / Accepted: 22 October 1998     

Alcohol, neurotransmitter systems, and behavior

Alcohol affects several neurotransmitter systems within the brain. In this article, the author describes its effects on 5 major ones: glutamate, gamma-amino-butyric acid (GABA), dopamine, serotonin, and opioid systems. The author also notes the interactions and interdependencies of these transmitters, and provides details on both immediate effects and long-term adaptations. Last, the author explains several psychopharmacological treatments for alcoholism and the effects of these treatments on transmitters, and draws conclusions.     

Timing of facilitatory and inhibitory effects of visual attention

Three experiments were conducted to investigate influences on the precue-to-target delay at which response facilitation is first replaced by inhibition of return (IOR). In Experiment 1, different ranges of delays were used; the interpolated delay at which faster RTs for matching precue and target locations changed to slower RTs was inversely related to the length of the range of precue-to-target delays within a block of trials. These findings were replicated in Experiment 2, which additionally showed that task difficulty provided an insufficient explanation for the delay in the changeover time. These data allowed the conclusion that a shorter range of precue-to-target delays results in later onset of IOR than does a longer range of delays. The data from Experiment 3 suggested that a single character on the target screen confounds the interpretation of possible facilitation and/or inhibition due to the allocation of attention. These results were related to other reported findings and to theories of attention allocation.     

Analog versus discrete shifts of attention across the visual field

Summary Two discrimination experiments were run to investigate analog versus discrete properties of a shift of visual spatial attention. Central cuing was used in Experiment 1, whereas peripheral cuing was used in Experiment 2. Presentation of a probe stimulus between fixation and the target (Distance 1), opposite fixation from the target (Distance 3), or away from an imaginary line running from the target through fixation (Distance 2) permitted a fine-grained analysis of attention at those loci across target-probe delays. D-prime analyses in both experiments suggest that attention is shifted in a discrete manner between locations. Sensitivity to probes was generally greater when the probe was aligned with the target and fixation, with Distance 3 equal to Distance 1, than when it was away (at Distance 2). Analysis of sensitivity to targets across cue-probe delays suggests that attention was directed to the probe upon its appearance.This research was supported by a grant from the National Science Foundation (BNS87-20421).     

Scanning,holistic encoding,and the word-superiority effect

The role of holistic encoding induced by scanning in the superior identifiability target letters in orthographic strings (words) enjoy over those in strings of unrelated letters was examined in two experiments. Both the set of potential targets and the critical position in the letter arrays were predesignated. One group in each experiment was induced to scan each array from left to right in a dot-counting task. A dot could precede the array to its left and/or appear with the array to its right. Only this group displayed the word superiority. For the second group in the first experiment, any dot(s) present always appeared with the array. The second group in the second experiment was shown no dots but, rather, performed the letter-identification task only. The absence of a word-superiority effect in other studies is related to holistic encoding stemruing from scanning requirements, and the implications for positional uncertainty explanations of the phenomenon are discussed.     

Some Effects of Reduction of Extra-Classroom Crowding in a School Environment

The effects of reduced enrollment were studied by examining two architecturally identical schools. One school experienced a 43% reduction in enrollment while the other's enrollment remained constant. Reduction in enrollment had a number of positive benefits, including improved attitudes about the school environment and reduced faculty absenteeism. Findings regarding academic performance were less clear.     

Inhibition of feature extraction with multiple instances of the target feature in different orientations

Summary Analyses of alphabetic confusion matrices have produced feature lists defined in terms of confusability of characters thought to contain them. Identical shapes of low confusability (e.g., b, d, p, q) therefore share few or no features. Several researchers have observed mutual inhibition of feature extraction with simultaneously presented confusable shapes. Mutual inhibition observed in the current experiments provides a basis for a definition of features in terms of orientation-independent structural relationships. In the first experiment, four alphanumeric characters were each confused with one other character in this same set; however, when another set was formed by reorienting some of these same shapes to become different characters (e.g., 6 to 9), these confusions disappeared. In the second experiment, characters within each set were exposed parafoveally in pairs to different groups of subjects. If members of a pair were similar in shape (disregarding orientation), identification accuracy was poorer than if they were not. Similar shapes in the same orientation were not signficantly more mutually inhibiting than similar shapes in different orientations.     

Being proven wrong elicits learning in children – but only in those with higher executive function skills

This study investigated whether prompting children to generate predictions about an outcome facilitates activation of prior knowledge and improves belief revision. 51 children aged 9–12 were tested on two experimental tasks in which generating a prediction was compared to closely matched control conditions, as well as on a test of executive functions (EF). In Experiment 1, we showed that children exhibited a pupillary surprise response to events that they had predicted incorrectly, hypothesized to reflect the transient release of noradrenaline in response to cognitive conflict. However, children's surprise response was not associated with better belief revision, in contrast to a previous study involving adults. Experiment 2 revealed that, while generating predictions helped children activate their prior knowledge, only those with better inhibitory control skills learned from incorrectly predicted outcomes. Together, these results suggest that good inhibitory control skills are needed for learning through cognitive conflict. Thus, generating predictions benefits learning – but only among children with sufficient EF capacities to harness surprise for revising their beliefs.