TABLE IV. TIME REQUIRED TO ESCAPE FROM CAGE BY USING LATCH
| Animals | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Trials, 4 daily. | A | B | C | E | F | G | H | I | Av. | Daily Average |
| ' " | ' " | ' " | ' " | ' " | ' " | ' " | ' " | ' " | ' " | |
| (1) | :03 | :06 | 3:20 | :08 | :03 | 1:10 | 4:30 | :23 | 1:13 | |
| (2) | :05 | 1:10 | :59 | 1:50 | 2:00 | :10 | 2:46 | 1:00 | 1:00 | |
| (3) | 5:28 | :29 | 1:04 | :21 | :29 | :52 | 2:33 | 4:05 | 1:55 | |
| (4) | :31 | 1:45 | 3:52 | :14 | :06 | :23 | 2:40 | 2:30 | 1:30 | (1:25) |
| (5) | :15 | :10 | 2:25 | :03 | :10 | :07 | :31 | :50 | :34 | |
| (6) | :17 | 2:00 | 5:03 | :03 | :05 | :15 | :39 | :10 | 1:04 | |
| (7) | :08 | :20 | :36 | :31 | :03 | :11 | :30 | :46 | :23 | |
| (8) | :03 | :54 | :47 | :28 | :03 | :55 | :06 | :47 | :30 | (:38) |
| (9) | 1:12 | :34 | :39 | :17 | :03 | :04 | :21 | :20 | :26 | |
| (10) | :02 | :19 | :28 | :07 | :01 | :03 | :20 | :47 | :16 | |
| (11) | :02 | :51 | :09 | :14 | :03 | :02 | 1:46 | :47 | :29 | |
| (12) | :02 | :15 | :24 | :12 | :02 | :02 | 1:17 | :27 | :20 | (:23) |
| (13) | :03 | :19 | :22 | :07 | :06 | :04 | :48 | :11 | :15 | |
| (14) | :02 | :15 | :22 | :09 | :02 | :02 | :20 | :19 | :11 | |
| (15) | :08 | :06 | :12 | :05 | :02 | :02 | :03 | :06 | :06 | |
| (16) | :03 | :18 | :44 | :10 | :02 | :03 | :02 | :21 | :13 | (:11) |
| (17) | :02 | :17 | :41 | :03 | :07 | :07 | :11 | :06 | :12 | |
| (18) | :02 | :42 | :26 | :05 | :01 | :03 | :31 | :15 | :16 | |
| (19) | :04 | :13 | :48 | :04 | :01 | :02 | :15 | :14 | :13 | |
| (20) | :04 | :32 | :35 | :04 | :01 | :02 | :08 | :22 | :15 | (:14) |
| (21) | :03 | :13 | :10 | :13 | :09 | :01 | 1:10 | :16 | :17 | |
| (22) | :03 | :05 | :10 | :11 | :03 | :02 | :39 | :26 | :12 | |
| (23) | :02 | :07 | :17 | :05 | :03 | :15 | :20 | :26 | :12 | |
| (24) | :02 | :14 | :04 | :02 | :01 | :02 | :09 | 1:03 | :12 | (:12) |
| (25) | :01 | :03 | :05 | :04 | :01 | :02 | :31 | :24 | :09 | |
| (26) | :02 | :04 | :08 | :01 | :01 | :05 | 1:34 | :33 | :19 | |
| (27) | :02 | :03 | :03 | :03 | :10 | :05 | :15 | :39 | :10 | |
| (28) | :02 | :04 | :03 | :01 | :06 | :05 | :23 | :51 | :12 | (:12) |
| (29) | :02 | :04 | :10 | :03 | :02 | :06 | :23 | :21 | :09 | |
| (30) | :01 | :03 | :03 | :02 | :11 | :02 | :09 | 1:08 | :12 | |
| (31) | :21 | :03 | :11 | :03 | :01 | :03 | :28 | :11 | :10 | |
| (32) | :03 | :02 | :04 | :02 | :01 | :03 | :11 | :42 | :09 | (:10) |
| (33) | :02 | :02 | :03 | :10 | :01 | :03 | :18 | :17 | :07 | |
| (34) | :02 | :02 | :03 | :02 | :01 | :03 | :11 | :11 | :04 | |
| (35) | :01 | :02 | :03 | :02 | :01 | :02 | :18 | :09 | :05 | |
| (36) | :01 | :03 | :03 | :03 | :03 | :02 | :04 | :10 | :04 | (:05) |
| (37) | :01 | :02 | :07 | :02 | :04 | :01 | :11 | :09 | :05 | |
| (38) | :01 | :02 | :02 | :02 | :02 | :01 | :08 | :03 | :03 | |
| (39) | :02 | :04 | :11 | :01 | :02 | :02 | :14 | :08 | :06 | |
| (40) | :01 | :02 | :03 | :01 | :01 | :03 | :10 | :03 | :03 | (:04) |
The periods here were similar to those given in the maze tests—the time was long at first, then it shortened very rapidly for a few trials, then more slowly but still constantly, until the act became thoroughly familiar. The process was one of "trial and error" throughout. As before, various lapses occurred, even although the animals were as persistent as usual in their efforts to escape. When the lever was moved to the side or back of the box, none of the animals could escape. In general, pigeons show less ingenuity in dealing with latches than do sparrows, according to Porter's[205] observations, although in some other tests they are equally apt.
B. Pecking Tests
The preceding series of trials proved the animals' ability to utilize certain touching or clawing movements, at first accidental, in making an escape, and showed that these could become highly specialized. Desiring to carry out similar tests in the case of pecking movements, which are quite as natural to pigeons, I arranged a contrivance by means of which the act of pecking at corn-grains fastened to a small piece of cardboard (placed just outside the cage, but within easy reach through an opening in the wire) would open the cage-door by making a delicate electrical contact. Four animals were tested.
On entering the cage they endeavored to escape as before; failing in this they began pecking about until they found the corn-grains and made the contact which opened the door and allowed them to escape to the food without. Three of the animals made their escape in this way several times; but the habit seemed to be one that could not be readily learned, as the successive periods showed little shortening.
Thinking that the pecking of things at a definite place perhaps complicated the matter, I removed the electrical apparatus and arranged to open the door myself by pulling a string whenever the pigeon pecked anywhere upon entering the box. Preliminary experiments with Bird J indicated some ability to profit by this kind of experience. As the act of pecking could be used to advantage in a series of imitation trials, this animal only was allowed to learn to escape by actually pecking; the others were reserved for the imitation tests next to be reported.
C. Imitation Tests
In the experiments already reported the animals were used individually and usually out of sight of the others, although in the same room and within hearing of them. When efforts were made in some of the experiments to test the animals in a separate room, signs of fear and discontent were often noticed, and it was necessary to return to the first room to continue the tests. Some instances were noticed in which a pigeon would do what it saw another doing. For example, one of my subjects would not eat one day, being ill apparently; but when I put two others into the compartment with it, and they began eating the food lying about, it also began pecking. Its act could not have been due to its only then happening to see the corn, for it had before looked toward the food when this was thrown to it.