Research on twins and unrelated persons living together indicates that, although differences in intelligence between persons are caused by both genetic and environmental factors, similarities--and especially those between adults--are mostly or exclusively due to shared genes. However, twin and adoption designs have been criticized for incorrectly estimating the effects of the environment on the similarity between relatives, and studies of environmental effects in other family constellations may be enlightening. In a sample comprising more than 334,000 pairs of brothers (ages 18-21 years) who were tested at the mandatory conscription for military service in Norway, correlations between brothers' intelligence-test scores decreased with increasing age difference between the brothers. This result indicates that family environmental factors have an impact on the intelligence of young adults. Analyses of subgroups defined by family size and parental education demonstrated that the effects of age difference are essentially independent of these factors.
We contrasted visual search for targets presented in prototypical views and targets presented in nonprototypical views, when targets were defined by their names and when they were defined by the action that would normally be performed on them. The likelihood of the first fixation falling on the target was increased for prototypical-view targets falling in the lower visual field. When targets were defined by actions, the durations of fixations were reduced for targets in the lower field. The results are consistent with eye movements in search being affected by representations within the dorsal visual stream, where there is strong representation of the lower visual field. These representations are sensitive to the familiarity or the affordance offered by objects in prototypical views, and they are influenced by action-based templates for targets.
This study compared the influence of categorization on perceptual processing in adults with autistic spectrum disorders (ASD) and normal control participants. Participants were asked to categorize hybrid faces (composed of two overlapped faces of different spatial bandwidths) by gender and emotion. Control participants exhibited a bias for low-pass information during gender categorization and a bias for high-pass information during emotion categorization. By contrast, adults with ASD showed the same low-pass bias in both tasks. This absence of a shift in processing style in the ASD group is discussed in terms of diminished top-down modulation in autism.
Understanding the dynamics of how separate features combine to form holistic object representations is a central problem in visual cognition. Feature attribution (also known as feature transposition and feature inheritance) refers to the later of two stimuli expressing the features belonging to the earlier one. Both visual masking and apparent motion are implicated in feature attribution. We found that when apparent motion occurs without masking, it correlates positively with feature attribution. Moreover, when apparent motion occurs with masking, feature attribution remains positively correlated with apparent motion after the contribution of masking is factored out, but does not correlate with masking after the contribution of apparent motion is similarly factored out. Hence, motion processes on their own provide the effective medium for feature attribution. Our results clarify the dynamics of feature binding in the formation of integral and unitary object representations in human vision.
Two experiments demonstrated striking, reversible forgetting effects that occurred even for a list of expletives. The experiments used a procedure based on the classic memory mechanisms of interference and retrieval cuing. Interference reduced recall dramatically, although appropriate cues triggered complete recovery. Distinctive, emotionally charged materials were quite susceptible to the forgetting and recovery effects. Thus, powerful forgetting effects can be obtained when participants have no intentions to forget and the materials involved are distinctive, emotional materials with sexual and violent content. This forgetting is reversible with appropriate cues. The false-memory debate can and must be informed by experimental investigations not only of false memories, but also of blocked and recovered memories.
Multisensory integration in humans is thought to be essentially a brain phenomenon, but theories are silent as to the possible involvement of the peripheral nervous system. We provide evidence that this approach is insufficient. We report novel tactile-auditory and tactile-visual interactions in humans, demonstrating that a facilitating sound or visual stimulus that is exactly synchronous with an excitatory tactile signal presented at the lower leg increases the peripheral representation of that excitatory signal. These results demonstrate that during multisensory integration, the brain not only continuously binds information obtained from the senses, but also acts directly on that information by modulating activity at peripheral levels. We also discuss a theoretical framework to explain this novel interaction.
In three studies, we explored the existence of an evolved sensitivity to the peak that would be consistent with the evolutionary origins of many basic human preferences. Activating the evolved motive of mating activates related adaptive mechanisms, including a general sensitivity to cues of growth and decay associated with determining mate value in human courtship. These studies show that priming the mating goal also activates an evaluative bias that influences how people evaluate cues of growth. Specifically, living kinds that are immature or past their prime are devalued, whereas living kinds that are at their peak become increasingly valued. Study 1 establishes this goal-driven effect for human stimuli indirectly related to the mating goal. Studies 2 and 3 establish that the evaluative bias produced by the activated mating goal extends to living kinds, but not artifacts.
Grapheme-color synaesthesia is an unusual condition in which letters and digits generate involuntary experiences of color. In this article, we show that grapheme-color synaesthetes make nonrandom associations that are best described by an understanding of color language, and that different measures of such associations converge to illustrate a nonarbitrary relationship for all people between color names and color space. We focus on a recent study (Beeli, Esslen, & Jancke, 2007) that presented the ostensibly novel finding of a relationship between the colors that synaesthetes associate with graphemes and the frequencies of those graphemes. However, in a study published 2 years earlier (Simner et al., 2005), but not cited by Beeli et al., we had already established that grapheme frequencies are important. We showed that high-frequency graphemes tend to be paired with high-frequency color names (e.g., ared) in verbal reports of synaesthetic associations. Beeli et al. measured the hue, saturation, and luminance (HSL) of synaesthetic colors and showed inter alia) that grapheme frequency was correlated with the colors' saturation. In this Commentary, we compare data from our previous study with those of Beeli et al. and empirically demonstrate that synaesthetic colors are best accounted for by color naming; we also suggest that the similarity across the two studies may be indicative of an independent relationship between color naming and color space for all people. We reanalyzed the data from Beeli et al. in order to demonstrate three facts: that, as we predicted (Simner et al., 2005), their synaesthetes shared certain grapheme-color associations (e.g., a was associated with red more often than predicted by chance); that, also as we predicted, these grapheme-color combinations reflect a positive correlation between grapheme frequency and color-name frequency; and finally, that certain aspects of the HSL color space (upon which Beeli et al. based their conclusions) may be predicted from color naming. We converted the synaesthetic color choices from the graphemecolor synaesthetes tested by Beeli et al. (their Fig. 1) into the 11 irreducible color terms from Berlin and Kay (1969; i.e., black, white, red, yellow, green, blue, brown, orange, purple, pink, and gray). Our coding was performed by two independent assessors, with any disagreements resolved by a third coder. We then performed upper-tail binomial analyses, which showed that certain grapheme-color combinations occurred significantly more often than would be predicted by chance. For example, Figure 1 illustrates the distribution of blue and white color associations
Word-order rules impose major constraints on linguistic behavior. For example, adjectives appear before nouns in English, and after nouns in French. This means that constraints on word order must be language-specific properties upheld on-line by the language system. Despite the importance of these rules, little is known about how they operate. We report an influence of word order on the activation of phonological representations. Participants were presented with colored objects and asked to name either the colors or the objects; the phonological similarity between the object and color names was manipulated. French speakers showed a phonological congruency effect in color naming, but not in object naming. English participants yielded the opposite pattern: a phonological effect in object naming, but not in color naming. Differences in the typical order of nouns and adjectives in French and English provide a plausible account for this cross-linguistic contrast. More generally, these results provide direct evidence for the operation of word-order constraints during language production.