How words anchor categorization: conceptual flexibility with labeled and unlabeled categories‡

abstractLabeled categories are learned faster, and are subsequently more robust than categories learned without labels. The label feedback hypothesis (Lupyan, 2012) accounts for these effects by introducing a word-driven top-down modulation of perceptual processes involved in categorization. By testing categorization flexibility with and without labels, we demonstrate the ways in which labels do and do not modulate category representations. In Experiment 1, transfer involved a change in selective attention, and results indicated that labels did not impact relearning. In Experiment 2, when transfer involved a change in the behavioral response to categories whose structures did not change, a reversal shift, learning the categories with labels speeded recovery. We take this finding as evidence that the augmentation of perceptual processes by words is on the one hand fairly weak without explicit reinforcement, but on the other allows for category representations to be more abstract, allowing greater flexibility in behavior.

Isolation and transcriptional regulation of theKluyveromyces lactisFBA1(fructose-1,6-bisphosphate aldolase) gene

Cloning and transcriptional regulation of the KlFBA1 gene that codes for the class II fructose-1,6-bisphosphate aldolase of the yeast Kluyveromyces lactis are described. KlFBA1 mRNA diminishes transiently during the shift from hypoxic to fully aerobic conditions and increases in the reversal shift. This regulation is mediated by heme since expression was higher in a mutant defective in heme biosynthesis. KlFBA1 transcription is not induced by calcium-shortage, low temperature, or at stationary phase. These data suggest that KlFBA1 plays a role in the balance between oxidative and fermentative metabolism and that this gene is differentially regulated in K. lactis and Saccharomyces cerevisiae, i.e., a respiratory vs. fermentative yeast.Key words: FBA1, fructose-1,6-bisphosphate aldolase, Kluyveromyces, transcriptional regulation, yeast.

The Role of Deployment of Attention in the Overlearning Reversal Effect (ORE) with Aggressive and Nonaggressive Stimuli

The study elucidated the role of deployment of attention in the appearance and magnitude of the overlearning reversal effect (ORE) with simultaneously occurring aggressive and neutral stimulus dimensions in a discrimination reversal-shift paradigm with 60 undergraduate college students. Confirming expectations, significantly larger overlearning reversal effect (ORE) was produced on the number of instrumental response errors and verbalized attentional errors with the less complex and less salient neutral, relevant-stimulus dimension. The findings that greater ORE, as reflected in attentional errors, was observed with the less salient but also less complex neutral stimulus dimension support the attentional explanations of the ORE phenomenon. These results contrast with those observed with traditional geometric stimulus material where greater complexity is associated with greater ORE.

A Comparison of Reversal and Extra Dimensional Shifts in IGBO (Nigerian) Children

Seventy-two Nigerian (Igbo) children learned reversal (R) or extradimensional (ED) shifts under one of the two conditions of locality (Urban or Rural) and one of three conditions of Age (4, or 7, or 10 years). Results showed three significant main effects of shift ( p < 0.001); Age ( p < 0.05), and locality ( p < 0.025). Shift by age interaction was also significant. Reversal shift was more difficult for the younger subjects but performance improved as age increased. The ED-shift did not follow a developmental trend: the 7-year-olds found it more difficult than either the 4-yearor the 10-year-olds. Urban subjects learned both shifts faster than their rural counter-parts, and the 7-year-olds from both localities experienced greater difficulty with the ED-shifts problem than either the 4-year-olds or 10-year-olds. The result were interpreted as consistent with the Kendlers' (1962) mediational theory.