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PubMed1979

Immediate and final recall of pictures and words with written or oral tests.

Immediate and delayed recall of pictures and words was examined as a function of semantic or nonsemantic orienting tasks and the type of test (written or oral). As expected, semantic tasks generally led to greater final recall than nonsemantic tasks, with semantic tasks even producing positive recency on the delayed test. The evidence for a picture-word difference was largely restricted to the final recall of items involved in negative decisions; for such items the advantage of semantic tasks was apparent only for pictures. This suggests that "congruity" may be an important factor in picture-word differences, with such differences more apparent for the weaker items from negative judgments. Type of test did not seem to be a major factor in determining level of recall, suggesting that reinspecting the recall protocol during a written immediate test does not contribute substantially to final recall performance.

Color Perception↗
PubMed1977

Competition between memory and perceptual tasks involving physically similar stimuli.

Performance on a perceptual recognition task and a concurrently performed short-term memory (STM) task was studied. The stimuli used in the STM task were either visually similar, acoustically similar, or dissimilar to the stimuli in the perceptual task. The results demonstrated that any type of concurrent list memorization has a detrimental effect upon perceptual performance, but this effect is magnified if the stimuli used in the 2 tasks are visually similar. Acoustic similarity had no effect. The results document the fact that distinct tasks interfere, when the tasks compete for a limited total processing capacity, or when the tasks demand the same visual coding program.

Association↗
PubMed1978

Vertical disparity detection: is there an induced size effect?

Horizontal, vertical, and over-all size differences were introduced in the retinal images of the two eyes of normal subjects during brief presentations of simple foveal targets. Horizontal disparities, whether accompanied by vertical disparities or not, induced the appearance of a rotation of the target around a vertical axis out of the frontal plane, according to the expectation from geometry, but vertical disparities had no effect. Over-all size changes in one eye induced the effect of the horizontal component. Threshold experiments showed that even with practice and error feedback, vertical disparity detection has at most only one-tenth the sensitivity of horizontal disparity detection. Although at variance with findings on the induced size effect obtained under more complex observation conditions, these results confirm that the processing of horizontal disparity plays a special role in the integration of the signals coming from the two eyes.

Depth Perception↗
PubMed1983

[The function of contrast sensitivity in deprivation amblyopia].

Visual deprivation during the first few months of life is known to result in a severe and irreversible visual deficit. Animal models of amblyopia developed during the past 20 years has considerably increased our knowledge of the "sensitive period" during which deprivation can lead to irreversible effects, and of the anatomical and physiological changes underlying this visual deficit. However precise data regarding either the duration of the sensitive period or the nature of the amblyopic deficit are still mostly lacking in humans. Preliminary results on the latter topic are reported in the present paper. Contrast sensitivity function (CSF) has been studied using stationary sinusoidal gratings in three patients with deprivation amblyopia resulting from bilateral congenital cataracts and in nine normal emmetropic subjects. Compared with these control subjects, the three amblyopic patients showed a dramatic decrease of their CSF with a maximal drop in the high and medium spatial frequency range and a relative sparing at low spatial frequencies. Within the framework of current theories of parallel processing of visual information through the geniculostriate pathway, these results indicate that early visual deprivation in man severely affects development of "sustained" channels involved in form perception. Further studies are underway to explore "transcient" channels in similar cases.

Adult↗
PubMed1980

Item and attribute storage of pictures and words in memory.

In two experiments, subjects memorized either line drawings or matching words during acquisition and then judged either pictures or words during recognition, creating four groups (picture-picture, picture-word, word-word, word-picture). The color and spatial location of the acquisition items varied, so that subjects' memory for attribute information could be assessed. The main findings were (a) subjects remembered semantic item information best, followed by spatial and then color information, (b) there was no interaction of distractor type with the format conditions, and (c) overall performance in the picture-word condition was inferior to the picture-picture condition, but word-word and word-picture groups did not differ. The implications of these findings for different representational and processing theories of picture memory are discussed.

Color Perception↗