Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 3618256

Spatial frequency, contrast and duration estimation.

Y Stoyanova·N Yakimoff·L Mitrani
View original source ↗Export metadata ↓

Abstract

Duration estimation of square-wave gratings presented for "short" (up to 150 ms) and "long" (above 190 ms) time intervals was studied. The spatial frequency (SF) of the gratings with equal mean luminance and contrast 85% varied from 0.7 to 12 c/deg. Duration estimates were assessed by the method of magnitude estimation. For brief presentations only the duration of high SF gratings was subjectively shorter than the duration of low SF gratings. It was shown that the apparent contrast of the square-wave gratings decreased with the increase of SF. In an experiment on duration estimation of patterns of different contrast it was demonstrated that duration estimates increased with increasing contrast for short presentations only. The apparent contrast of the gratings covarying with SF was supposed to underlie SF influence on short duration estimation. The assumption about different mechanisms operating in short and long duration perception was supported by the results.

Explore related subjects

Analysis of VarianceHumansMethodsPhotic StimulationSpatial BehaviorTime FactorsVisual PerceptionJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Y Stoyanova, N Yakimoff, L Mitrani. 1987. Spatial frequency, contrast and duration estimation.. https://pubmed.ncbi.nlm.nih.gov/3618256/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2014

Molecular heterochrony and the evolution of sociality in bumblebees (Bombus terrestris).

Sibling care is a hallmark of social insects, but its evolution remains challenging to explain at the molecular level. The hypothesis that sibling care evolved from ancestral maternal care in primitively eusocial insects has been elaborated to involve heterochronic changes in gene expression. This elaboration leads to the prediction that workers in these species will show patterns of gene expression more similar to foundress queens, who express maternal care behaviour, than to established queens engaged solely in reproductive behaviour. We tested this idea in bumblebees (Bombus terrestris) using a microarray platform with approximately 4500 genes. Unlike the wasp Polistes metricus, in which support for the above prediction has been obtained, we found that patterns of brain gene expression in foundress and queen bumblebees were more similar to each other than to workers. Comparisons of differentially expressed genes derived from this study and gene lists from microarray studies in Polistes and the honeybee Apis mellifera yielded a shared set of genes involved in the regulation of related social behaviours across independent eusocial lineages. Together, these results suggest that multiple independent evolutions of eusociality in the insects might have involved different evolutionary routes, but nevertheless involved some similarities at the molecular level.

Analysis of Variance↗
PubMed2006

I don't like it because it eats sprouts: conditioning preferences in children.

Although little is known about how preferences develop in childhood, work in adults suggests that evaluative responses to stimuli can be acquired through classical conditioning. In two experiments children were exposed to novel cartoon characters, that were either consistently paired with a picture of a disliked food (Brussels sprouts) or a liked food (ice cream). Relative preferences for these stimuli (and others) were measured before and after these paired presentations (Experiment 1): preferences for the cartoon character paired with Brussels sprouts decreased, whereas preferences for the character paired with ice cream increased. These preferences persisted after 10 un-reinforced trials. Experiment 2 replicated this finding using affective priming as an index of preference for the cartoon characters. These findings demonstrate that preferences to novel stimuli can be conditioned in children and result from associations formed between the stimulus and a stimulus possessing positive or negative valence.

Analysis of Variance↗