The Faulty Magnitude Detector: Why SNARC‐Like Tasks Cannot Support a Generalized Magnitude System

Do people represent space, time, number, and other conceptual domains using a generalized magnitude system (GMS)? To answer this question, numerous studies have used the spatial‐numerical association of response codes (SNARC) task and its variants. Yet, for a combination of reasons, SNARC‐like effects cannot provide evidence for a GMS, even in principle. Rather, these effects support a broader theory of how people use space metaphorically to scaffold their understanding of myriad non‐spatial domains, whether or not these domains exhibit variation in magnitude.     

Effects of Pointing Rate and Availability of Visual Feedback on Visual and Proprioceptive Components of Prism Adaptation

While looking through laterally displacing prisms, subjects pointed 60 times straight ahead of their nose at a rate of one complete movement every 2 or 3 s, with visual feedback available early in the pointing movement or delayed until the end of the movement. Sagittal pointing was paced such that movement speed covaried with pointing rate. Aftereffect measures (obtained after every 10 pointing trials) showed that when the limb became visible early in a pointing movement, proprioceptive adaptation was greater than visual, but when visual feedback was delayed until the end of the movement, the reverse was true. This effect occurred only with the 3-s pointing rate, however. With the 2-s pointing rate, adaptation was predominately proprioceptive in nature, regardless of feedback availability. Independent of the availability of visual feedback, visual adaptation developed more quickly with 3-s pointing, whereas proprioceptive adaptation developed more rapidly with 2-s pointing. These results are discussed in terms of a model of perceptual-motor organization in which the direction of coordinative (guidance) linkage between eye-head (visual) and hand-head (proprioceptive) systems (and consequently the locus of discordance registration and adaptive recalibration) is determined jointly by pointing rate and feedback availability. An additional effect of pointing rate is to determine the rate of discordant inputs. Maximal adaptive recalibration occurs when the input (pointing) rate matches the time constant of the adaptive encoder in the guided system.     

Developmental sequences in the age of onset of disruptive child behaviors

Retrospective and prospective reports of the onset of disruptive child behaviors were analyzed in a sample of clinic-referred boys. The younger boys (ages 7–9 years), compared with the older boys (ages 10–12 years), showed the highest level of disruptive behavior and, judging from mothers' reports, had the fastest progression of onsets from less serious to more serious problem behaviors. Despite some overlap, developmental sequences in problem behavior within the domains of hyperactivity/inattention, oppositional behavior, and conduct problems were similar across the two age groups. This was also the case for developmental sequences of overt or confrontive problem behaviors and covert or concealing conduct problems. Sequences of the onset of oppositional behavior and conduct problems were validated through prospective data, based on the information from mothers, teachers, and boys themselves. The implications of the findings are discussed for the formulation of developmental pathways of behavior and the analysis of causal factors.