Form of redundancy as a determinant of tachistoscopic word recognition

Single letters and redundant CVCs and CCCs were presented at threshold durations and followed by a pattern mask. Performance on three-letter stimuli was greater than on single letters. The increased performance was consistent with a state model of perceptual independence. Conditional redundancy increased the frequency with which all three letters were accurately reported as compared to correlational redundancy. Meaning and pronounceability had little effect on performance.     

Creative reasoning in formal discussion

Systems of formal dialectics articulate methods of conflict resolution. To this end they provide norms to regulate verbal exchanges between the Proponent of a thesis and an Opponent. These regulated exchanges constitute what are known as formal discussions.One may ask what moves, if any, in formal discusions correspond to arguing for or against the thesis. It is claimed that certain moves of the Proponent's are properly designated as arguing for the thesis, and that certain moves of the Opponent purport to criticize the tenability or the relevance of the reasons advanced. Thus the usefulness of formal dialectic systems as models for reasonable argument is vindicated.It is then proposed to make these systems more realistic by incorporating in them a norm of Creative Reasoning that removes the severe restrictions to which the Proponent's arguing was hitherto subject. As a consequence, a certain type of irrelevant reason is no longer automatically excluded. Therefore, it is proposed to extend the Opponent's rights to exert relevance criticism. The new dialectic systems are shown to be strategically equivalent to the original ones. Finally, it is stressed that the Opponent's criticism should not be designated as arguing against the thesis. The Opponent criticizes, but does not argue.     

A procedure for obtaining young children’s reports of olfactory stimuli

Young children (ages 2 to 5) have proved to be difficult subjects for obtaining valid reports of their ratings of olfactory stimuli. Thirty-six preschoolers were tested on benzaldehyde (a pleasant odor) and on dimethyl disulfide (an unpleasant odor) using a smiling or frowning face as a response format. The results showed the ability of young children to discriminate between pleasant and unpleasant odors.     

Is recognition accuracy really impaired when the target is repeated in the display?

Bjork and Murray (1977) have presented a feature-specific interactive channels model that predicts perceptual interference between letters presented simultaneously in visual displays. Maximum interference is predicted when a target letter is presented with an identical letter. In their experiment, Bjork and Murray found support for their model, but their results could have occurred artifactually from response biases of their subjects. Santee and Egeth (1980) used a different paradigm that eliminated the possibility of this particular response bias and reported that their data supported the feature-specific model. However, the present paper shows that analysis of their data by Santee and Egeth was incomplete and the comparisons inappropriate. In two experiments that used the Santee and Egeth paradigm, we failed to find support for the feature-specific model when more detailed analyses of the data were undertaken. In a third experiment, one that used the Bjork and Murray paradigm, but with control of response bias, no significant or suggestive evidence was found that feature similarity between noise and target letters affected recognition of the latter.     

The importance of being first: A tachistoscopic study of the contribution of each letter to the recognition of four-letter words

Three studies investigated the effect on the response time for voicing a four-letter word of delaying one of the letters or the entire word for intervals of up to 500 msec. Experiment I found delay of the first letter most detrimental, while delay of the second, third, or fourth letter facilitated performance. Experiment II confirmed these findings and indicated that delay of the entire word produced response times similar to delay of the first letter. Experiment III investigated the possibility that knowledge of the pronunciation of the first letter was the essential factor in facilitating performance when later letters were delayed. It was concluded that when pronunciation of the first letter was known, Ss were able to begin processing the word immediately.     

Decision making and the P300 component of the cortical evoked response

The amplitude of P300, and of other components of the evoked potentials, was examined during a task which required Ss to make a response appropriate to the conjoint properties of two rapidly successive visual patterns. In one set of conditions, the task was structured such that both stimuli were needed for the choice judgment. In another set of conditions, the task was changed from choice to simple RT by presenting the patterns in a predictable order. It was observed that P300 was enhanced during the choice RT conditions and that this enhancement was present only for the P300 following the stimulus permitting the choice and not the other, relevant but not decisive, stimulus appearing in close temporal proximity. An appreciable degree of independence between P300 and other components was indicated by the appearance of P300 under conditions in which other evoked potential components were entirely refractory. The data support an account for P300 in terms of poststimulus processes, such as decision making, and not in terms of preparatory adjustments.     

Interocular non-independence

Binocular interaction was studied by presenting a different letter form to each eye via a dichopic tachistoscope. The two dissimilar letters were presented simultaneously or at short delay internals of 0–200 msec and were either presented on corresponding or non-corresponding retinal areas. At delay internals of less than 100 msec stimulation of corresponding areas resulted in identification performance below that to be expected on the basis of independent chances to perceive. Stimulation on non-corresponding areas resulted in both presented letters being identified at the accuracy level predicted by an independence assumption.     

The perception of multiple simultaneously presented forms as a function of foveal spacing

Using five capital letters as the form stimuli and tachistoscopic presentation, an exposure duration was determined for each S that yielded 80% identification accuracy when single letter displays were presented. Then the increment in exposure duration necessary for a correct identification of all letters on a display on 80% of the trials was determined for 2, 3, and 4 letter displays. In view of evidence that perceptual independence breaks down when stimuli are spaced much closer than 1° apart in the fovea, the effect of different foveal spacing of the form stimuli in the display was studied. Spacings of 1/2, 3/4, and 1° of angle were employed. Less than a 30% increment in exposure duration was necessary to recognize 2 form displays at the same accuracy level as single form. But no further increase in exposure duration was necessary to recognize 3 and 4 form displays at the same accuracy criterion. Evidence for positive correlation of sensory perceptual error for forms spaced less than 1° apart in the fovea was found.