Search reaction time for single targets in multiletter stimuli with brief visual displays

The same set of Ss was run In an LT (single late target letter followed an earher multiletter display) and an ET (single early target preceded a later multiletter display) condition. On one-half the trials, the multiletter set included the target. and on the other half, the target was absent. The task of S was to push the “yes” (“no”) button if the target was present (absent), and reaction times were recorded. The most plausible processing model assumed that LT comparisons took place in a verbal-acoustic store and that ET comparisons took place in a visual store. It further assumed that processing within these stores was self-terminating, with rates that differed on “same” and “different” comparisons and which changed as the multiletter set increased. Classes of serial and parallel models that are falsified or supported by the present and similar data are discussed.     

Children's comprehension of comparative forms

Children aged from 3.5 to 5.5 years were tested on their comprehension of the terms taller, shorter, more, and less in five types of sentences: truncated, explicit standard, expanded explicit standard, two-dimensional second-clause subject noun, and two-dimensional second-clause subject pronoun. Many childen performed poorly on less and shorter in truncated sentences; the presence of explicit comparative cues did not improve these children's performance. Children who performed perfectly on truncated sentences still had difficulty understanding two-dimensional comparisons, especially those with a second-clause subject pronoun. These children interpreted only the first clause of the second-clause subject pronoun sentences. The results suggest that many children are capable of understanding two-dimensional comparisons, but perform poorly on the second-clause subject pronoun sentences because of uncertainty about the referent of the pronoun.     

Further experiments on the olfactory thresholds of pure chemical substances, using the “Sniff-Bottle method”

“Sniff-Bottle” method of determining olfactory thresholds under conditions of adaptation to a second olfactory stimulus, as described by Cheesman and Mayne (1953), has been further developed. Their study was limited to the mutual adaptation effects of three substances. The original matrix of nine quantities, described as degrees of community of odour property, has been revised and extended to include a fourth stimulus-substance. It is suggested that the matrix now obtained shows a definite pattern characteristic of consistent mutual relationships between the substances. A number of shortcomings in the original technique are discussed, and the appropriate emendations described.     

Influence of correlated visual cues on auditory signal detection

Two experiments investigated the effects on auditory signal detection of introducing visual cues that were partially correlated with the signal events. The results were analyzed in terms of a detection model that assumes that such cue-signal correlations will not affect sensitivity, but will instead cause the subject to develop separate response biases for each cue. The model specifies a functional relationship between the asymptotic values of these cuecontingent biases. The overall results of the experiments supported the detection assumptions of the model and the general bias learning assumption, but indicated a more complex learning process than that specified by the model.     

Self-terminating versus exhaustive processes in rapid visual and memory search: An evaluative review

A major issue in elementary cognition and information processing has been whether rapid search of short-term memory or a visual display can terminate when a predesignated target is found or whether it must proceed until all items are examined. This study summarizes past and recent theoretical results on the ability of self-terminating and exhaustive models to predict differences in slopes between positive (target-present) and negative (target-absent) set-size functions, as well as position effects. The empirical literature is reviewed with regard to the presence of slope differences and position effects. Theoretical investigations demonstrate that self-terminating models can readily predict the results often associated with exhaustive processing, but a very broad class of exhaustive models is incapable of predicting position effects and slope differences typically associated with self-termination. Because position effects and slope differences are found throughout the rapid search literature, we conclude that the exhaustive processing hypothesis is not tenable under common experimental conditions.     

The development of attentional orienting during the school‐age years

This study was designed to assess the development of spatial attentional orienting during the school‐age years. To that end, we used a cost‐benefit attentional cueing task with short (100 ms) and long (800 ms) cue‐to‐target intervals to examine attentional processing independent of motor skills and perceptual processing in 200 7–17‐year‐olds and 40 adults. We found that orienting attention, disengaging attention and visual processing in an unattended location, were all progressively more accurate and faster with increasing age. Our data thus suggest that the efficiency of attentional orienting improves in an age‐related manner throughout the school‐age years.     

Studying visual search using systems factorial methodology with target—distractor similarity as the factor

Systems factorial technology (SFT) is a theory-driven set of methodologies oriented toward identification of basic mechanisms, such as parallel versus serial processing, of perception and cognition. Studies employing SFT in visual search with small display sizes have repeatedly shown decisive evidence for parallel processing. The first strong evidence for serial processing was recently found in short-term memory search, using target-distractor (T-D) similarity as a key experimental variable (Townsend & Fifi?, 2004). One of the major goals of the present study was to employ T-D similarity in visual search to learn whether this mode of manipulating processing speed would affect the parallel versus serial issue in that domain. The result was a surprising and regular departure from ordinary parallel or serial processing. The most plausible account at present relies on the notion of positively interacting parallel channels.