Knowledge that Transforms

The normal development of adaptive behavior in humans depends on the integration of visual attention and body movement, yet little is known about the initial state of movement-attention coupling at the beginning of postnatal life. We studied 1- and 3-month-old infants during extended periods of visual exploration and found that spontaneous shifts of gaze are preceded by rapid changes in general body movement. The results reveal a tight link between motor activation and overt attention on a time scale of seconds or less. This link undergoes substantial developmental change in the first few weeks after birth. During that time, phasic motor activation may play a key role in visual exploration by helping to unlock gaze when the environment is unchanging.

Most events are processed by a number of neural pathways.These pathways often differ considerably in processing speed.Thus, coherent perception requires some form of synchronization mechanism.Moreover, this mechanism must be flexible, since neural processing speed changes over the life of an organism.Here we provide behavioral evidence that humans can adapt to a new intersensory temporal relationship (which was artificially produced by delaying visual feedback).The conflict between these results and previous work that failed to find such improvements can be explained by considering the present results as a form of sensorimotor adaption.

Glass patterns have been used to examine mechanisms underlying form perception. The current investigation compared detection of Glass patterns by pigeons and humans and provides evidence for substantial species differences in global form perception. Subjects were required to discriminate, on a simultaneous display, a random dot pattern from a Glass pattern. Four different randomly presented Glass patterns were used (concentric, radial, parallel-vertical, and parallel-horizontal). Detection thresholds were measured by degrading the Glass patterns through the addition of random noise. For both humans and pigeons, discrimination decreased systematically with the addition of noise. Humans showed detection differences among the four patterns, with lowest thresholds to radial and concentric patterns and highest thresholds to the parallel-horiZontal pattern. Pigeons did not show a detection difference across the four patterns. Implications for differences in neural processing of complex forms are discussed.

It is widely assumed that the allocatian of spatial attention results in the "selection" of attended objects or regions of space. That is, once a stimulus is attended, all its feature dimensions are processed irrespective of their relevance to behavioral goals. This assumption is based in part on experiments showing significant interference for attended stimuli when the response to an irrelevant dimension conflicts with the response to the relevant dimension (e.g., the Stroop effect). Here we show that such interference is not due to attending per se. In two spatial cuing experiments, we found that it was possible to restrict processing of attended stimuli to task-relevant dimensions. This new evidence supports two novel conclusions: (a) Selection involves more than the focusing of attention per se: and (b) task expectations play a key role in detertnining the depth of processing of the elementary feature dimensions of attended stimuli.

Our studies revealed two stable modes of perceptual organization, one based on attributes of auditory sensory elements and another based on attributes of patterned sensory variation composed by the aggregation of sensory elements. In a dual-task method, listeners attended concurrently to both aspects, component and pattern, of a sine wave analogue of a word. Organization of elements was indexed by several single-mode tests of auditory form perception to verify the perceptual segregation of either an individual formant of a synthetic word or a tonal component of a sinusoidal word analogue. Organization of patterned variation was indexed by a test of lexical identification. The results show the independence of the perception of auditory and phonetic form, which appear to be differently organized concurrent effects of the same acoustic cause.

Two studies assessed the development of children's understanding that thoughts and feelings are closely interlinked. These studies showed that, unlike 8-year-olds and adults, 5-year-olds seldom explained a sudden change in emotion that had no apparent external cause by appeal to the occurrence of a thought. They also tended not to recognize that a person who is feeling sad is probably also thinking sad thoughts, or that people may be able to make themselves feel happy just by thinking of something happy. These results are consistent with evidence that young children tend to be unaware of the stream of consciousness and have poor introspective skills. A possible developmental sequence leading to an understanding of these thought-feeling links is proposed.

U.S. math-science graduate students possessing world-class talent (368 males, 346 females) were assessed on psychological attributes and personal experiences in order to examine how their talents emerged and developed. Comparisons were made, using similar assessments, with mathematically talented students (528 males, 228 females) identified around age 13 and tracked into adulthood by the Study of Mathematically Precocious Youth (SMPY). Well before college, both samples were academically distinguished: however, the graduate students could be identified during adolescence as a subset of mathematically talented youths based on their nonintellectual attributes. Their profiles corresponded to what earlier psychological studies found to characterize distinguished (and exclusively male) scientists: exceptional quantitative reasoning abilities, relatively stronger quantitative than verbal reasoning ability, salient scientific interests and values, and finally, persistence in seeking out opportunities to study scientific topics and develop scientific skills. On these attributes, sex differences were minimal for the graduate students (but notfor the SMPY comparison groups). Developing exceptional scientific expertise apparently requires special educational experiences, but these necessary experiences are similar for the two sexes.

When observers face directly toward the incline of a hill, their awareness of the slant of the hill is greatly overestimated, but motoric estimates are much more accurate. The present study examined whether similar results would be found when observers were allowed to view the side of a hill. Observers viewed the cross-sections of hills in real (Experiment 1) and virtual (Experiment 2) environments and estimated the inclines with verbal estimates, by adjusting the cross-section of a disk, and by adjusting a board with their unseen hand to match the inclines. We found that the results for cross-section viewing replicated those found when observers directly face the incline. Even though the angles of hills are directly evident when viewed from the side, slant perceptions are still grossly overestimated.

People's beliefs about how memory works can affect their inferences from experienced difficulty of recall. Participants were asked to recall either 4 childhood events (experienced as an easy task) or 12 childhood events (experienced as a difficult task). Subsequently, they were led to believe that either pleasant or unpleasant periods of one's life fade from memory. When the recall task was difficult (12 events), participants who believed that memories from unpleasant periods fade away rated their childhood as less happy than participants who believed that memories from pleasant periods fade away. The opposite pattern was observed when the recall task was easy (4 events). This interplay of recall experiences and memory beliefs suggests that the judgmental impact of subjective experiences is shaped by beliefs about their meaning. It also suggests that the recall difficulty in clinical memory work may lead a person to make negative inferences about his or her childhood, provided the person shares the popular belief that memory represses negative information.