Motion onset captures attention

Although visual motion may seem salient, motion per se does not automatically attract attention. We show here, however, that the onset of motion does indeed attract attention. In three experiments, subjects identified target letters in displays that contained targets and distractors. There was no advantage for moving letters among static ones, but there was an advantage for objects that had recently started to move despite the fact that the motion was uninformative. If some additional time was allowed to elapse after motion onset, inhibition of return slowed responding to the item that had started to move—a further sign that the motion onset had captured attention. Finally, detection of target letters was found to be independent of the number of distractors in the display if the target had undergone motion onset, also indicative of attentional capture. We discuss the adaptive significance of sensitivity to onsets in the presence of a relative insensitivity to ongoing motion.     

Prototypes in category learning: the effects of category size, category structure, and stimulus complexity

Although research in categorization has sometimes been motivated by prototype theory, recent studies have favored exemplar theory. However, some of these studies focused on small, poorly differentiated categories composed of simple, 4-dimensional stimuli. Some analyzed the aggregate data of entire groups. Some compared powerful multiplicative exemplar models to less powerful additive prototype models. Here, comparable prototype and exemplar models were fit to individual-participant data in 4 experiments that sampled category sets varying in size, level of category structure, and stimulus complexity (dimensionality). The prototype model always fit the observed data better than the exemplar model did. Prototype-based processes seemed especially relevant when participants learned categories that were larger or contained more complex stimuli.     

Journey to the center of the category: the dissociation in amnesia between categorization and recognition

The authors' theoretical analysis of the dissociation in amnesia between categorization and recognition suggests these conclusions: (a) Comparing to-be-categorized items to a category center or prototype produces strong prototype advantages and steep typicality gradients, whereas comparing to-be-categorized items to the training exemplars that surround the prototype produces weak prototype advantages and flat typicality gradients; (b) participants often show the former pattern, suggesting their use of prototypes; (c) exemplar models account poorly for these categorization data, but prototype models account well for them; and (d) the recognition data suggest that controls use a single-comparison exemplar-memorization process more powerfully than amnesics. By pairing categorization based in prototypes with recognition based in exemplar memorization, the authors support and extend other recent accounts of cognitive performance that intermix prototypes and exemplars, and the authors reinforce traditional interpretations of the categorization-recognition dissociation in amnesia.     

The role of meaning and familiarity in mental transformations

Eighty-four participants mentally rotated meaningful and meaningless objects. Within each type of object, half were simple and half were complex; the complexity was the same across the meaningful and meaningless objects. The patterns of errors were examined as a function of the type of stimuli (meaningful vs. meaningless), complexity, and angle of rotation. The data for the meaningful objects showed steeper slopes of rotation for complex objects than that for simple objects. In contrast, the simple and complex meaningless objects showed comparable increases in error rates as a function of angle of rotation. Furthermore, the slopes remained comparable after pretraining that increased familiarity with the objects. The results are discussed in terms of underlying representations of meaningful and meaningless objects and their implications to mental transformations. The data are consistent with a piecemeal rotation of the meaningful stimuli and a holistic rotation of the meaningless stimuli.     

PET evidence for multiple strategies of categorization

It is widely held that people use multiple strategies to categorize their experiences in the world. We conducted a pair of neuroimaging experiments to identify the neural correlates of two of these strategies— rule application and exemplar similarity. Participants were instructed to perform either a ruleor an exemplar-based categorization task while changes in cerebral blood flow were measured using positron emission tomography. Patterns of neural activity were consistent with the predictions of cognitive models of rule- versus exemplar-based categorization and with existing neuroscience data. The identification of strategy-specific neural patterns offers future researchers a diagnostic tool for assessing strategy use in other situations.     

Investigating the influence of social desirability on personality factor structure

This study provides a comprehensive investigation into whether social desirability alters the factor structure of personality measures. The study brought together 4 large data sets wherein different organizational samples responded to different personality measures. This facilitated conducting 4 separate yet parallel investigations. Within each data set, individuals identified through a social desirability scale as responding in an honest manner were grouped together, and individuals identified as responding in a highly socially desirable manner were grouped together. Using various analyses, the fit of higher order factor structure models was compared across the 2 groups. Results were the same for each data set. Social desirability had little influence on the higher order factor structures that characterized the relationships among the scales of the personality measures.     

Renatus renatus: the Cartesian tradition in British neuroscience and the neurophilosophy of John Carew Eccles

J. C. Eccles (1903-1997) had a highly distinguished career in neurophysiology, being awarded the Nobel Prize for Medicine or Physiology in 1963. This paper sets him within the Cartesian tradition of British neurophysiology initiated by Thomas Henry Huxley in the mid-19th century. It shows how the mind-brain problematique of the Cartesian tradition troubled him throughout his career, leading him finally to a solution in terms of quantum microphysics and microphysiology. This position, which has subsequently become fashionable, is discussed and shown (at least in the form Eccles espoused) to provide no solution to the problem posed by Descartes in the early 17th century.     

Preserved implicit learning on both the serial reaction time task and artificial grammar in patients with Parkinson's disease

Thirteen nondemented patients with Parkinson's disease (PD) were compared with age-matched controls on two standard tests of implicit learning. A verbal version of the Serial Reaction Time (SRT) task was used to assess sequence learning and an artificial grammar (AG) task assessed perceptual learning. It was predicted that PD patients would show implicit learning on the AG task but not the SRT task, as motor sequence learning is thought to be reliant on the basal ganglia, which is damaged in PD. Patients with PD demonstrated implicit learning on both tasks. In light of these unexpected results the research on SRT learning in PD is reconsidered, and some possible explanations for the sometimes conflicting results of PD patient samples on the SRT task are considered. Four factors which merit further study in this regard are the degree to which the SRT task relies on overt motor responses, the effects of frontal lobe dysfunction upon implicit sequence learning, the effects of cerebellar degeneration, and the degree to which the illness itself has advanced.