The Magic Number 4 ± 0: A New Look at Visual Numerosity Judgements

@article{Atkinson1976TheMN,
  title={The Magic Number 4 ± 0: A New Look at Visual Numerosity Judgements},
  author={Janette Atkinson and Fergus William Campbell and Marcus R Francis},
  journal={Perception},
  year={1976},
  volume={5},
  pages={327 - 334}
}
Visual numerosity judgements were made for tachistoscopically presented linear arrays of dots or lines. The interelement interval (which could be specified in spatial frequency terms) was constant for a given array but varied across conditions. A clear limit in the accuracy of numerosity judgements was found to be set at 4 for regularly spaced elements with spatial frequencies below approximately 10 cycles/deg (element and interelement interval of 0·05 deg). This limit in terms of accuracy is… 

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