Knowledge that Transforms

To help explain a regularity in democratic elections, we examined whether choosing to delay making a choice between a focal option and an alternative tends to make people subsequently less likely to choose what they would otherwise have chosen. The results of two experiments demonstrated that participants who were induced to delay making a decision were indeed less likely to choose the descriptively normative option. An additional experiment that primed a sense of doubt in participants provided support for a self-perception account of this result. Electing to delay making a choice is interpreted as an indication of doubt--doubt that tends to be attributed to the most prominent option. Delay-induced doubt about the normative option makes it less likely to be selected.

To analyze complex scenes efficiently, the human visual system performs perceptual groupings based on various features (e.g., color and motion) of the visual elements in a scene. Although previous studies demonstrated that such groupings can be based on a single feature (e.g., either color or motion information), here we show that the visual system also performs scene analyses based on a combination of two features. We presented subjects with a mixture of red and green dots moving in various directions. Although the pairings between color and motion information were variable across the dots (e.g., one red dot moved upward while another moved rightward), subjects' perceptions of the color-motion pairings were significantly biased when the randomly paired dots were flanked by additional dots with consistent color-motion pairings. These results indicate that the visual system resolves local ambiguities in color-motion pairings using unambiguous pairings in surrounds, demonstrating a new type of scene analysis based on the combination of two featural cues.

People tend to rate members of a positive group (e.g., best friends) as superior to the average of that group and members of a negative group (e.g., worst enemies) as inferior to the average of that group. Five experiments tested a new theoretical account of these nonselective superiority and inferiority biases. According to this account, a member's unique attribute (the dimension distinguishing that member positively or negatively from other group members) is used as the standard for comparing that member with other group members. The experimental results supported this hypothesis. When participants compared a randomly selected popular or unpopular vacation destination with other destinations, the target destination's unique attribute was more accessible than its nonunique attributes (Experiments 1-4), and a popular destination was judged less above average if one of its nonunique attributes was the salient comparison standard (Experiment 4). In addition, the unique attribute was used as the comparison standard for evaluating novel stimuli (Experiment 5). Alternative accounts and implications for general comparison processes are discussed.

A common perceptual error consists of binding the features of objects in the wrong combinations. Another common finding is that incongruent thoughts or feelings tend to be rejected by the cognitive system. We combined these two notions and found that the incongruence-suppression rule constrains the binding process. We used a task in which participants were asked to bind either congruent or incongruent features together. Whether those features were digits and physical sizes (Experiment 1) or color words and colored fonts (Experiment 2), we observed a new effect that we refer to as the binding congruency effect: When participants were asked to bind incongruent features together, the error rate increased, and participants replaced the incongruent features with congruent features. Experiment 3 demonstrated that the effect depends on the migration of the relevant feature within the same level.

In two experiments, we investigated the automatic integration of touch across the fingers. Participants made judgments about the roughness of sequences of textures presented to one finger while simultaneously feeling textures of varying roughness with another finger (the distractor digit) on the same hand. Integration across digits was evident when the thumb and index finger were used together, whereas there was a general disruption of attention when the thumb and little finger were used together. In addition, interference was greater when the distractor digit was above the touched surface than when it was below the touched surface. These results suggest that there is integration of information across fingers when people feel textures, but that this integration pattern does not conform to a spread of activation across somatosensory maps.

A classic question in social and organizational psychology is whether low-status persons are more accurate in the perception of their high-status partners than the latter are in their perception of their subordinates. In a series of studies, Snodgrass (1985, 1992) tested this idea. She found that subordinates were more accurate at judging how their bosses viewed them than bosses were at judging how their subordinates viewed them, but that bosses were more accurate at judging how subordinates viewed themselves than subordinates were at judging how bosses viewed themselves. We believe, however, that these results were obscured by stereotype accuracy. Using previously collected data, we found that stereotype accuracy does lead to the pattern previously observed by Snodgrass. We also discovered that when we controlled for stereotype accuracy, subordinates' perceptions were generally more accurate than those of their bosses, which supports Snodgrass's original hypothesis.

In rodents, a pup's experiences in utero and during postnatal development shape its sexual behavior as an adult and how it is perceived by potential mates. We show that the male rat's sexuality is primarily influenced by the postnatal sex ratio of its litter, but not by the litter's prenatal intrauterine sex ratio or the behavior of its mother. Pups from litters with differing prenatal sex ratios were divided into litters with differing postnatal sex ratios. We found that males raised in a female-biased litter exhibited less mounting than males raised in either a male-biased litter or one with an equal sex ratio, and were less attractive to sexually receptive females, eliciting fewer soliciting behaviors, such as hop-darts, and fewer lordosis behaviors. However, the number of intromissions and ejaculations did not differ across groups, which suggests that males from female-biased litters mate as efficiently as males raised in other sex ratios, but do not require as many mounts to do so. The reported differences in sexual behavior did not vary with the quality of maternal behavior or with sexual experience in adulthood.

By the late 19th century, tests of adults' shortterm visual memory—how much one retains from a briefly presented display—had acquired a familiar character: An alphanumeric array was presented, removed, and participants were asked to report the items (Wundt, 1912). These ‘whole report’ tests revealed capacities of 3-4 items (Cattell, 1886; Sperling, 1960). However, participants often felt they had seen more items, but forgotten them before report. A crucial innovation was to ask for just a ‘partial report’, cuing participants to sample from their memory (e.g. a high-pitched tone might cue report of the middle of three rows of letters) (Sperling, 1960). If the cue occurs after display offset (a ‘post-cue’) and the sampled subsets are random, then accurate reports mean all the presented items had been stored. This clever methodological change exposed a new—early, high-capacity (∼9 items), and fast-decaying (∼200 ms half-life)—memory system dubbed ‘iconic memory’ (Neisser, 1967). In this sense, then, the study of infants' visual memory is still rooted in the conventions of the 19th century: No one has yet asked infants for a partial report. This leaves a conspicuous gap in our understanding of visual memory development. Research on infants' visual memory has a similarly long history (e.g. Hunter, 1917; Fantz, 1964; Fagan, 1970; for reviews see Nelson, 1995; Rose, Feldman & Jankowski, 2004). And while there has been ample work on infants' short-term memory, for example recency/primacy effects (Olson, 1979; Cornell & Bergstrom, 1983), short-term capacity has been studied only recently (and iconic memory not at all). These studies though have revealed a striking limitation: young infants' short-term memory capacity seems limited to a single object (see Ross-Sheehy, Oakes, & Luck, 2003 for evidence from visual short-term, <300 ms retention interval, memory; Pelphrey et al., 2004 and Kaldy & Leslie, 2005 for evidence from visual working memory). 6-month-olds, then, have sufficiently well-developed visual acuity to distinguish arguably dozens of objects in a single fixation (Teller, 1997), but short-term memory for only one—a curiously inimical constraint unless this object were very well chosen (e.g. by virtue of high salience, task relevance, or cueing). We argue here that iconic memory is the buffer holding the choices.

What gives Mona Lisas smile such a mysterious quality? Livingstone (2000) has suggested that the portrait changes its expression depending on where on the portrait the observer looks. The mouth, which is the essential feature of Mona Lisas remarkable expression (Kontsevich & Tyler, 2004), appears to form an enigmatic smile. Due to sfumato technique (Gombrich, 2005), this impression of a smile is more prominent in the gradual luminance changes that observers perceive mainly in the periphery of their vision— that is, in low spatial-frequency ranges. It is less prominent in the fine details that observers perceive only at the center of their gaze, in high spatial-frequency ranges.1 Consequent-ly, the subtle smile one perceives while looking at Mona Lisas eyes (when her mouth appears blurred) vanishes when one attempts to verify this impression by looking at