A Numerosity Cognition Study Based On Numerosity Adaptation

Most behavioral studies of numerosity cognition, e. g, numerosity deciding paradigm, have indirectly explored various features of numeral processing because of the implicit property of numerosity representation. Previous studies brought about some inconsistent results in the effects of non-numeral cues on numerosity judgements. Numerosity judging tasks may not reflect real status of numerosity perception, given the non-numeral cues or strategies that probably used when adults were making decisions. So, we need to analyze the results of numerosity judging tasks deeply and adopt more effective paradigm to study numerosity cognition.Numerosity adaptation aftereffect refers to the adaptation to the numeral property of stimuli, with an aftereffect that can be revealed by changes of perceived numerosity in following numerosity judging tasks. A current debate of the numerosity adaptation effect focused on whether it was really driven from processing of stimuli’s numerosity, or it was actually a result of processing of surface information. If it is really an aftereffect based on numerosity processing, then the numerosity adaptation paradigm could be an effective way to study numerosity cognition.The present study consisted of three parts. The first part (Experiment1and2) decided whether numeral judging tasks could steadily reflect numerosity perception by examing effects of different visual cues on judging task performances and analyzing data based on signal detecting theory, assuming that object representation had significantly influence on numerosity perception. The second part (Experiment3and4) explored the interrelationship among surface information, numerosity perception and adaptation, proposing that adaptation of numerosity was based on perceived numerosity, and surface information could not affect the numerosity adaptation effect unless it affected the perception of numerosity. In the third part (Experiment5,6and7), we investigated the properties of numerosity adaptation aftereffects with and without consciousness using continuous flash suppression paradigm, suggesting that different mechanisms existed in processing of numerosity under different consciousness conditions. Meanwhile, we discussed the relationship between object representation and numerosity cognition through our paper, disclosing the crucial role of object representation in numerosity cognition gradually during these three studies.The main findings of this study are as follows:(1) Numerosity deciding tasks did not accurately reflect real status of numerosity perception, since they were apt to be affected by strategies. Different non-numerical visual features had different mechanisms of affecting numeral deciding tasks. Some features only affected judging strategies, such as dots’ size or shape, whereas chunking (i.e, dots’ clustering or perceptual grouping) could affect numerosity perception directly by changing the ability of numerosity discrimination.(2) Subjects were not able to decide total number of dots directly when dots were chunking. Whereas they could roughly response according to the number of chunks, which suggested that cognition system process numerosity on the basis of object representation.(3) Numerosity adaptation aftereffects remained constant as long as varied texture characteristics had no effects on the perception of numerosity. Otherwise, it would be apparently affected when the perceived numerosity was interfered with the changing of texture. Therefore, numerosity adaptation aftereffects were a kind of adaptation based on perceived numerosity, rather than co-products driven from processing of surrogate surface features.(4) Even when stimuli were unconsciously perceived, the numerosity properties of them can be adapted to. When participants adapted for same period of time, the aftereffect of numerosity adaptation with consciousness was significantly greater than that without consciousness.(5) Different mechanisms of cognition progressing existed in numerosity adaptation across different consciousness conditions. In other words, numerosity adaptation aftereffects were shown to be primarily binocular and affected by chunking with consciousness, while they were seemed to be primarily monocular and not affected by chunking without consciousness. With consciousness, numerosity properties involved high-level cognition processes and chunking could affect the processing procedure of numerosity by changing object representation.In summary, numerosity deciding tasks were not ensured to reflect real status of numerosity perception, while numerosity adaptation paradigm could be an effective way to study numerosity cognition. There was a close connection between object representation and numerosity cognition. With consciousness, numerosity cognition could be built on the cognitive stage of object representation.