Does color synesthesia pose a paradox for early-selection theories of attention?

Abstract— P.M. is a synesthete who experiences colors when viewing alphanumeric symbols. Her search for a target differing from distractors by a synesthetic color feature takes the form of a pop-out search. Thus, it would seem that synesthesia can occur preattentively. However, discrepancies between the regression functions of response times observed in target-present trials and target-absent trials, and the fact that fast response times occur only when the target is within a few degrees of visual angle from fixation, indicate that P.M.'s synesthesia does not occur preattentively, but rather is within the focus of attention. We conclude that synesthesia is a genuine perceptual phenomenon that can have substantial influence on visual processing.     

Perceiving action identity: how pianists recognize their own performances

Can skilled performers, such as artists or athletes, recognize the products of their own actions? We recorded 12 pianists playing 12 mostly unfamiliar musical excerpts, half of them on a silent keyboard. Several months later, we played these performances back and asked the pianists to use a 5-point scale to rate whether they thought they were the person playing each excerpt (1 = no, 5 = yes). They gave their own performances significantly higher ratings than any other pianist's performances. In two later follow-up tests, we presented edited performances from which differences in tempo, overall dynamic (i.e., intensity) level, and dynamic nuances had been removed. The pianists' ratings did not change significantly, which suggests that the remaining information (expressive timing and articulation) was sufficient for self-recognition. Absence of sound during recording had no significant effect. These results are best explained by the hypothesis that an observer's action system is most strongly activated during perception of self-produced actions.     

Comments on "Rapid motor adaptations to subliminal frequency shifts during syncopated rhythmic sensorimotor synchronization" by Michael H. Thaut and Gary P. Kenyon (Human Movement Science 22 [2003] 321-338)

Thaut and Kenyon [Human Movement Sci. 22 (2003) 321] have shown that, in a task requiring tapping in antiphase with a metronome, the response period adapts rapidly to a small (+/-2%) change in the stimulus period, whereas the relative phase between stimulus and response returns to its pre-change value only very gradually. On the basis of these and earlier findings, Thaut and Kenyon argue that period adaptation is rapid and subconscious, whereas phase adaptation is slow and dependent on awareness of a phase error. This interpretation is at variance with results in the literature suggesting that phase correction is rapid and subconscious, whereas period correction is slow and dependent on awareness of a period mismatch. Although differences in terminology (adaptation versus correction) play a role in this conflict, it primarily reflects different conceptions of sensorimotor synchronization and different interpretations of empirical findings. By excluding from their model a central timekeeper or oscillator with a flexible period, Thaut and Kenyon have omitted an essential component of human timing control that is needed for a proper explanation of their results.     

Failure to construct and transfer correct representations across probability problems

Previous studies carried out on "purely random" situations (with dice or poker chips) show the difficulties encountered by people in such situations, however simple they may be. In fact, in this type of situation, prior knowledge guides spontaneous representations, and the "errors" observed could be explained by the activation of "implicit models" which form the basis of erroneous representations. 42 statistically na?ve undergraduates were given several variants of a probability problem on which errors are common. In a learning phase, subjects were given four problems involving geometric figures which were pairwise related by complementarity and equivalence relations. In a subsequent transfer phase, they were given a fifth problem involving poker chips, which was structurally isomorphic to the fourth geometric-figures problem. The findings show that people do not realize the relations between problems, and that transfer occurred only for the subset of subjects who performed correctly on the training problems of the learning phase. These results appear to have some significant implications in teaching mathematical concepts.     

Rate limits in sensorimotor synchronization with auditory and visual sequences: the synchronization threshold and the benefits and costs of interval subdivision

Synchronization of finger taps with an isochronous event sequence becomes difficult when the event rate exceeds a certain limit. In Experiment 1, the synchronization threshold was reached at interonset intervals (IOIs) above 100 ms with auditory tone sequences (in a 1:4 tapping task) but at IOIs above 400 ms with visual flash sequences (1:1 tapping). Using IOIs above those limits, the author investigated in Experiment 2 the reduction in the variability of asynchronies that tends to occur when the intervals between target events are subdivided by additional identical events (1:1 vs. 1:n tapping). The subdivision benefit was found to decrease with IOI duration and to turn into a cost at IOIs of 200-250 ms in auditory sequences and at IOIs of 450-500 ms in visual sequences. The auditory results are relevant to the limits of metrical subdivision and beat rate in music. The visual results demonstrate the remarkably weak rhythmicity of (nonmoving) visual stimuli.     

Do separate processes identify objects as exemplars versus members of basic-level categories? Evidence from hemispheric specialization

When an object is identified as a specific exemplar, is it analyzed differently than when it is identified at the basic level? On the basis of a previous theory, we predicted that the left hemisphere (LH) is specialized for classifying objects at the basic level and the right hemisphere (RH) is specialized for classifying objects as specific exemplars. To test this prediction, participants were asked to view lateralized pictures of animals, artifacts, and faces of famous people; immediately after each picture was presented, a label was read aloud by the computer, and the participants decided whether the label was correct for that picture. A label could name the object at either the basic level (e.g., bird) or as an exemplar (e.g., robin). As predicted, we found that basic-level labels were matched faster when pictures were presented in the right visual field (and hence encoded initially in the LH), whereas exemplar labels were matched faster when pictures were presented in the left visual field (and hence encoded initially in the RH).     

Balancing the ledger: An application of Nagy's theories to the study of continuity and change among generations

This study uses an interpretive interview method to examine the micro-processes of generational continuity and change among a group of social activists. Boszormenyi-Nagy's theory of responsibility between generations, alternative models outside the family, and choice are used to explain the instances of change. Implications for research and practice are addressed.     

Wilderness family therapy: Experiential dimensions

This paper describes the process in which families participate in a wilderness experience. Metaphors such as climbing or paddling a canoe are translated into daily living patterns to deepen individual and family self-knowledge, self-esteem, and intimacy.