They showed one group of 24 dogs two images projected onto a screen, one of a large dog, the other a small one. The dogs were then played the recording of growl from either small or large dog which came from between the two images.
研究人员首先在屏幕上向一组（24只）狗放映大小不同的两只狗的图片，然后将图片中大狗或者小狗的叫声录音放给这些狗听。
The results showed that 20 of the 24 test dogs looked at the image of the appropriate-sized dog first and looked at it longest.
结果显示，有20只狗都先向正确的实验对象望去，并且观望的时间较长。
资料图:狗有"听声音辨大小"特异功能
A control group of 24 dogs were also played the dog growls but were instead shown silhouettes of large and small cats or geometric shapes.
科学家给参照组24只狗放映大小不等的猫或几何形状的阴影图片以代替原来狗的图片，并同时播放狗叫声。
Most of the dogs in this group looked first at the image on the left, a finding that supports earlier studies that have found dogs tend to look to the left when presented with something unexpected.
这一组大部分的狗都看左边的图片，这一发现支持狗看到意想不到的事物时，倾向于向左看的早期研究发现。