Knowledge that Transforms

The role of visual attention in task performance has been extensively debated. On the basis of the dimensional-action model, we hypothesized that a major role of attention is to transfer response decisions from targets on which it is focused to high-level centers dealing with response execution. This hypothesis predicts that response decisions for two targets will interact only when attention is focused on both targets, and only when the response to the targets is defined by different dimensions. Three experiments, using the redundancy-gain paradigm, tested and confirmed this prediction. Experiment 1 showed that coactivation of two cross-dimensional targets occurred only when the targets were positioned in the same location, not when they were in separate locations. Experiment 2 manipulated the focus of attention and showed that coactivation can occur even for targets positioned in different locations if they are both within the attentional focus. Experiment 3 showed that this attention-induced coactivation does not occur for targets from the same dimensional module. These results suggest that a major role of attention is postperceptual and involves gating of selected responses to executive functions.

Young children's communication has often been characterized as egocentric. Some researchers claim that the processing of language involves an initial stage that relies on egocentric heuristics, even in adults. Such an account, combined with general developmental difficulties with late-stage processes, could provide an explanation for much of children's egocentric communication. However, the experimental data reported in this article do not support such an account: In an elicited-production task, 5- to 6-year-old children were found to be sensitive to their partner's perspective. Moreover, in an on-line comprehension task, they showed sensitivity to common-ground information from the initial stages of language processing. We propose that mutual knowledge is not distinct from other knowledge relevant for language processing, and exerts early effects on processing in proportion to its salience and reliability.

The purpose of this study was to resolve a paradox in the literature on the effects of body orientation on spatial attention. Neuropsychological studies have found that real or simulated trunk rotation relieves contralesional inattention in patients with unilateral neglect, suggesting that trunk orientation affects how attention is allocated to space. However in two previous studies, trunk orientation did not affect spatial attention in other populations. In this study we investigated the effects of trunk orientation on the performance of a covert attention task by neurologically intact adults. The covert attention task allowed the evaluation of the effects of trunk orientation on both the allocation of attention to space and the ability to shift that attention to new locations. As in previous research, trunk orientation did not affect participants' response times (RTs) to validly cued targets. However rotating participants' trunks to the left increased their RTs to invalidly cued targets on the right and decreased their RTs to invalidly cued targets on the left. These results indicate that trunk orientation induces directional biases in the ability to shift attention. Thus, for intact participants, trunk rotation created lateral biases in the covert attention task similar to those seen in neglect patients.

In the present study, the contributions of spatial and object features to chimpanzees' comprehension of scale models were examined. Seven chimpanzees that previously demonstrated the ability to use a scale model as an information source for the location of a hidden item were tested under conditions manipulating the feature correspondence and spatial-relational correspondence between objects in the model and an outdoor enclosure. In Experiment 1, subjects solved the task under two conditions in which one object cue (color or shape) was unavailable, but positional cues remained. Additionally, performance was above chance under a third condition in which both types of object cues, but not position cues, were available. In Experiment 2, 2 subjects solved the task under a condition in which shape and color object cues were simultaneously unavailable. The results suggest that, much like young children, chimpanzees are sensitive to both object and spatial-relational correspondences between a model and its referent.

Inhibitory tagging is a process that prevents focal attention from revisiting previously checked items in inefficient searches, facilitating search performance. Recent studies suggested that inhibitory tagging is object rather than location based, but it was unclear whether inhibitory tagging operates on moving objects. The present study investigated the tagging effect on moving objects. Participants were asked to search for a moving target among randomly and independently moving distractors. After either efficient or inefficient search, participants performed a probe detection task that measured the inhibitory effect on search items. The inhibitory effect on distractors was observed only after inefficient searches. The present results support the concept of object-based inhibitory tagging.

Are sisters of twin brothers behaviorally or physiologically masculinized? Prenatal exposure to their brothers' androgens and postnatal socialization experiences unique to girls growing up with twin brothers might influence their attitudes, pubertal development, and reproductive histories. To investigate, we studied age- and cohort-matched samples of Finnish sisters from same-sex and opposite-sex twin pairs. Using data from two ongoing longitudinal studies of consecutive birth cohorts of Finnish twins, we assessed pubertal development at ages 11 and 14 and endorsement of attitudes associated with femininity at age 16. We also studied fertility in Finnish women from same- and opposite-sex twin pairs born from 1958 through 1971, obtaining information on their child-bearing histories when they were ages 15 to 28. Results of each comparison were unambiguously negative: There was no evidence of differences between sisters from same- and opposite-sex twin pairs, and thus, no evidence of either androgenization or cross-sex socialization.

Extreme variation in the accessibility of autobiographical memory is a major characteristic of functional amnesia. On the basis of its ability to temporarily disrupt the retrieval of memory material, posthypnotic amnesia (PHA) has been proposed as a laboratory analogue of such amnesia. However, most PHA research has focused on relatively simple, nonpersonal information learned during hypnosis. This experiment extended PHA to autobiographical memory by examining high- and low-hypnotizable subjects' explicit and implicit memory of two autobiographical episodes, one of which was targeted by a PHA suggestion. The effects of PHA were consistent with the major features of functional amnesia: PHA disrupted retrieval of autobiographical information, produced a dissociation between implicit and explicit memory, and was reversible. The nature of PHA's effect on autobiographical memory and the potential utility of a PHA paradigm for investigating functional amnesia are discussed.

We demonstrate that presentation of information about quantities, whether expressed in natural language or by using numbers, induces a perspective that influences subsequent processing. Experiment 1 shows this to be true for natural language quantifiers, with negative and positive expressions inducing different perspectives. In Experiment 2, we examined the application of this idea to the specific case of perspectives induced by describing products as containing x% fat or as being x% fat free. We found that the percentage-fat description appears to induce a perspective that is sensitive to the level offat being depicted, with products being judged as less healthy at higher amounts of fat. However, this effect was lessened (Experiment 2) or eliminated (Experiment 3) with the percentage-fat-free description. The experiments suggest the fat-free perspective blocks access to assumptions about healthy fat levels.

We used primed matching to examine the microgenesis of perceptual organization for familiar (upright letters) and unfamiliar (inverted letters) visual configurations that varied in the connectedness between their line components. The configurations of upright letters were available for priming as early as 40 ms, irrespective of connectedness between their line components. The configurations of connected inverted-letter primes were also available this early, but the configurations of disconnected inverted letters were not available until later These results show that past experience contributes to the early grouping of disconnected line segments into configurations. These findings suggest an interactive model of perceptual organization in which both image-based properties (e.g., connectedness) and input from object memories contribute to perceptual organization.

Although transient changes in luminance have been well documented to automatically attract attention to their location, experiments looking at abrupt changes in color have failed to find similar attentional capture. These results are consistent with current theories of the role of the magnocellular (M) and parvocellular (P) streams that postulate that the M stream, which is "color-blind," plays the dominant role in guiding attention and eye movements. The experiment reported here used stimuli that contained only information defined by color, and masked residual luminance information with dynamic noise, to assess the capacity of purely chromatic cues to automatically guide spatial attention. Such stimuli were as effective as those containing large luminance signals in guiding attention. To the extent that these purely chromatic signals isolated the P stream, these results suggest that this stream is also capable of automatic attentional capture. Hence, color vision not only aids target identification but also is a strong aid for target detection and localization.