DescriptionAmerican Journal of Psychology (Volume 21) Fig 2.jpg English: Fig. 2 The female English Sparrow (at the lower right hand corner of the box) opening...
DescriptionAmerican Journal of Psychology (Volume 21) Fig 6.jpg English: The female English Sparrow of Figs. 1-5. Strings now changed to Place 2. She used...
DescriptionAmerican Journal of Psychology (Volume 21) Fig 19.jpg English: The strings are to the left of the door, Place 2. Male Baltimore Oriole 2, instead of working...
DescriptionAmerican Journal of Psychology (Volume 21) Fig 17.jpg English: Male Baltimore Oriole 2. He, during an earlier trial, flew to this post, slipped...
DescriptionAmerican Journal of Psychology (Volume 21) Fig 18.jpg English: Male Baltimore Oriole 2 as he came to open the door after many other attempts...
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