Salivary, cardiac and motor indices of conditioning in two sows.

Abstract

The use of the pig as an experimental fmimfti in physiological or psychological research, though infrequent, is not a recent innovation. Yerkes and Coburn in 1015 used two Chester White pigs in a multiple choice problem. Hie feasibility of using the pig as a subject for experimentation is expressed by them as follows: "Although the experimenters had expected much of the pigs because of the indications from casual observation of their behavior, it may be said at once that they proved far more satisfactory subjects than we had dared to hope. Indeed they worked so steadily and uniformly through the investigations that there was practically no loss of time" (23, p. 187). In conclusion they state that "... the pig has proved itself an ideal subject for studies in adaptive behavior" (23, p. 224). It should be noted, however, that this statement refers to pigs that were only five to six months old-young, small, and not very strong.Pavlov ( 15), in a seminar in 1934, summed up his attitude regarding the use of pigs for experimental subjects as follows: "From those pigs from which I wished to obtain gastric juice I obtained nothing.... We spent almost a month on it without obtaining any results and at last had to give it up." In 1934 Liddell, James and Anderson (14) established positive and negative conditioned motor reflexes based on electric shock to the foreleg of the young pig, but with difficulty due to its intractability in the conditioning frame. In 1938 Curtis (3) reported on the development by Sutherland and himself of an inhibitory form of experimental neurosis in the pig, resulting from a complex discrimination procedure; and in 1939 Sutherland (19) established positive and negative salivary conditioned responses.The use of pigs as subjects in the present study was prompted by a number of considerations. The hysteria and temper-tantrums reported of the pig. are of interest to the investigator of experimental neuroses. Furthermore, it was supposed that the stubborn, independent nature of the pig would result in a different type of rapport between subject and experimenter than that found when the friendly or submissive dog or the easily dominated sheep was used. Finally, it was believed that by recording more fully than in previous studies the physiological patterns of the animals' behavior further data could be added to the findings on the comparative physiology of the conditioned reflex.Early indoctrination is a prime requisite in all fl-nifrifti training. This is especially true of the pig, where the rapid growth in strength, height and weight 1 The expenses of this investigation were defrayed in part by a grant from the Josiah Macy, Jr. Foundation to H. S. Liddell. 1 * Critical ratio of percent difference is 3.4. * Critical ratio of percent difference is 9.9. * Critical ratio of difference is 12.8.

The use of pigs in neuroscience: Modeling brain disorders

“…The range of frequency for adequate detection varies between 40 Hz and 40 kHz, and sensitivity is only slightly poorer than for humans (Heffner and Heffner, 1990). Nonetheless, few studies of pig learning have been based upon auditory stimuli (Arnfred et al, 2003;Ernst et al, 2005;Moore and Marcuse, 1945). The olfactory discrimination and sensitivity of pigs is superior (Kristensen et al, 2001;Meese et al, 1975).…”

“…The pig seems as trainable as rats or monkeys. Even though Pavlov had to give up using pigs for conditioning experiments (Moore and Marcuse, 1945), his difficulties have been proved not to be a general phenomenon. The growing number of published learning and memory studies in different pig breeds documents this fact (see for instance Arnfred et al, 2003;Bolhuis et al, 2004;Chaput et al, 1973;Ernst et al, 2005;Hagl et al, 2005;Held et al, 2000Held et al, , 2005Klopfer, 1966;Mendl, 2000, 2004;McLeman et al, 2005;Mendl et al, 1997;Moustgaard et al, 2002Moustgaard et al, , 2004Moustgaard et al, , 2005aSobotka and Brown, 1986;Tanaka et al, 1998;Tanida et al, 1991).…”

Assessing learning and memory in pigs

“…Although Pavlov apparently thought that pigs could not be used as experimental subjects (Moore and Marcuse 1945), evidence has since accumulated that pigs can easily be conditioned (Kratzer 1971), using classical conditioning methods. Yet only a few classical conditioning studies have used pigs, as reviewed in the Sect.…”

“…Classical or Pavlovian conditioning studies in pigs, which imply learning about relations between stimuli, with one stimulus signaling the occurrence of the other (Rescorla 1988 ), were used in the early 1900s. Although Pavlov apparently thought that pigs could not be used as experimental subjects (Moore and Marcuse 1945 ), evidence has since accumulated that pigs can easily be conditioned (Kratzer 1971 ), using classical conditioning methods. Yet only a few classical conditioning studies have used pigs, as reviewed in the Sect.…”

“…In a small-scale study with two pigs, Moore and Marcuse ( 1945 ) examined 4 types of conditioning, including classical conditioning. They attempted to establish a ‘conditioned salivary response’ in an experimental setting similar to that used by Pavlov.…”