The sources of developmental differences in children's incidental processing during discrimination trials

Crane and Ross reported that second graders learned more than sixth graders about attributes made relevant after solution of a discrimination task. Here two experiments are reported that enlighten the sources of this developmental difference. Both make use of an experimental technique whereby children verbalize their hypotheses during solution of a discrimination problem. The results indicate that ten-year-olds do not learn about incidental attributes that they tested while irrelevant in the pre-solution period, but that five-year-olds and seven-year-olds do. Children of all three ages process incidental information about attributes that they did not sample pre-solution. With some qualification, the incidentally processed information is retained throughout a five-minute delay interval. The results bear on developmental trends in the distribution of attention and on theoretical accounts of incidental learning in discrimination tasks.     

Texture gradient effectiveness in the perception of surface slant

To assess the development of monocular slant perception as well as the relative effectiveness of different sources of information, children in first, third, and fifth grades and college adults were asked to make judgments of surface slant on the basis of monocular texture gradient information. Accuracy of judgment increased with increasing age. In addition, differences in gradient effectiveness were found. Compression gradients were relatively ineffective sources of information, whereas perspective and multiple gradients resulted in greater accuracy. The results suggest limitations on the specificity of certain forms of gradients.     

Individual differences in speed of phonemic analysis, visual analysis, and reading.

College student subjects (Ss) classified phrases as making sense or not according to sound in one condition, according to visual appearance in another, and in abasic task in which either strategy would yield right answers. Ss who were relatively fast in the visual condition were faster at the basic task than Ss who were relatively fast in the sound condition. Other results suggested that the former Ss used a visual strategy in the basic task while the latter used a phonemic strategy.     

Left hemisphere superiority for pronounceable nonwords,but not for unpronounceable letter strings

Right-handed adults were asked to identify bilaterally presented linguistic stimuli under three experimental conditions. In Condition A, stimuli were three-letter pronounceable nonwords (such as TUP), and subjects were asked to report them by naming them. In Condition B, stimuli were three-letter pronounceable nonwords, and subjects were asked to report them as strings of letters. In Condition C, stimuli were more or less unpronounceable letter strings (such as UTP) created by rearranging the letters of pronounceable nonwords, and subjects reported them as strings of letters. Pronounceable nonwords were found to be better identified from the right visual hemifield irrespective of the way in which they were reported. Unpronounceable letter strings did not produce any visual hemifield difference. Nonwords are of interest because they can be seen as potential words that lack both specific semantic properties and entries in the subject's internal lexicon. The results of the experiment are consistent with the view that both the left and right cerebral hemispheres are able to identify letters but the left hemisphere is more sensitive to the pronounceability of the nonwords. This may happen either because the left hemisphere can make better use of resemblances to real words or because it has access to spelling to sound correspondence rules.     

Modality-specific interference with overt mediation by pigeons in a delayed discrimination task

Pigeons were trained on a delayed discrimination task in which they were rewarded for pecking a white terminal stimulus (TS) presented 5 sec after a green initial stimulus (IS) and for not pecking the white TS when it followed a red IS. Each bird bridged the memory interval (MI) with overt mediational behaviors. Nevertheless, sustained retroactive interference (RI) effects were produced by houselight illumination (Experiments 1 and 3), and mild shock pulses (Experiment 5) but not white noise (Experiment 2) presented during the MI. Although the magnitude of the light-induced RI effect was proportional to the duration of houselight illumination (Experiment 4), the beginning-end effect described by W. A. Roberts and D. S. Grant (Journal of Experimental Psychology: Animal Behavior Processes, 1978, 4, 219–236) was not observed. These results not only attest to the between-task robustness of both light-induced RI and modality-specific effects with pigeons, but also support the hypothesis that RI effects result from the disruption of mediational activities possibly analogous to rehearsal. The results further demonstrate that an event interpolated within the MI need not be unexpected or novel to produce RI. Furthermore, the interpolated event can produce modality-specific RI effects even though it effects a different sense than do the IS and TS.     

“in”, “on”, and “under” revisited

The present study presents evidence that young children's comprehension of the locatives ‘in’, ‘on’, and ‘under’ is, at least in part, contextually determined. Children aged 1;6–3;0 were given tasks with verbal instructions which were either contextually congruent or incongruent. The results were interpreted in terms of the non-linguistic as well as linguistic strategies apparently used to interpret speech. The results and interpretation are in contrast to those of earlier research.