Erratum to Aggression in rats as a function of nonreward in a straight alley

Abstract

Ab8traet After being trained in a straight alley for 100% food reward, 12 female albino rats were tested in a double straight alley in pairs on a random 50% schedule of reinforcement. At the end of a 30-sec. interval in the goal box, the Ss were allowed free access to one another for an additional 60 sec., during which time, measures of aggression were taken according to the Klein-Hall scale of aggressiveness. Significantly more overt aggression occurred following nonreinforced trials than after reinforced trials. With a few reservations, the results are interpreted as lending support to the notion of frustrative nonreward in partial reinforcement situations. Introd.etlon The use of f r u s t rat ion as an interpretation of or explanation for the effects of partial reinforcement has, within the last 15 years, become quite popular. Stemming mainly from the work of Amsel & Roussel (1952) an abundance of data has been gathered in support of such a notion (e.g, Amsel , 1958; Amsel, 1962). To date, measures of running speed in different segments of an alley (e.g, Goodrich , 1959), and indices of resistance to extinction (e .g. Weinstock, 1954) constitute the vast majority of dependent variables from which the so-called frustration effect has been inferred. At the initial suggestion of Dollard et al (1939) numerous investigators have sought to demonstrate a relationship between the administration of frustration operations and subsequent indices of aggression , with the result that considerable data have been gathered in support of the "frustration-aggression" hypothesis (e .g, BUSS , 1961). However, an attempt to relate the effect of frustrative nonreward or partial reinforcement to aggression, in terms of the traditional straight alley situation, has yet to be made. Subjeet8 and Apparatu8 Twelve 150 day old experimentally naive female albino rats, housed in cages of three, from the colony maintained by the Washington State University Psychology Department, served as Ss, The apparatus consisted essentially of two parallel 55-in runways separated by a piece of plywood running Iengthwise between both alleys. Each alley was 4 in wide, with a 9-in start box, and a 10-in goal box. In addition to the standard start box and goal box guillotine doors, each of the adjacent goal boxes were separated by another guillotine door which could be manipulated by the E so as to allow Ss access to one another under the appropriate conditions. A plywood Psychon. Sci. , 1965 , Vol. 3 floor was used and the entire apparatus was painted flat black. Proeedure Following 12 days of 23-hr. food deprivation, during which time each S was handled for approximately 3 min. per day, preliminary training was begun and consisted of two days of 10-min. free exploration periods in the alley. Subsequent to familiarization, 40 training trials were given over a period of 12 consecutive days. Training consisted of running two Ss, one in each alley, through the apparatus for five 97-mg food pellets in the goal box on a continuous or 100% reinforcement schedule. Upon entering the goal box each S was allowed 30 sec. to consume the food reward before being removed . During training both alleys were utilized simultaneously, but the guillotine door separating the two goal boxes was always left closed. Each S received one training trial on Days 1 and 2, and two trials on Day 3. Following this, four trials were administered each day with an interval of approximately 15 min. and at an average of 22 1/2 hr. of food deprivation. Test trials were essentially the same as training trials, except that all Ss were switched to a random 50% schedule of reinforcement. At the end of the initial 30-sec. interval in the goal box the guillotine door separating the two goal boxes was raised and the pair was allowed free access to one another for an additional 60 sec., during which time, measures of aggression were taken accor ding to the Klein-Hall seven point scale of aggressiveness between rats (Hall & Klein, 1942). Twenty-four test trials were run over a period of six consecutive days (four trials per day), and Ss were randomly assigned to different pairs on each trial. The intertrial interval during testing was approximately 20 min. and Ss were run at an average of 221/4 hr. of food deprivation. During testing it was necessary to put glass over the goal boxes in order to retain the Ss in the apparatus for the required length of time. Re8ult8 The randomly selected pairs were treated as repli-cations and a three-dimensional analysis of variance was computed. The difference in terms of overt aggression, as measured by the Klein-Hall scale on reinforced vs. nonreinforced trials, proved to be significant well beyond the .001 level (F=127 .09, df=1/5, p< .001); with the mean aggression scores over all pairs being 6.83 for nonreinforced trials and 1.67 for reinforced trials. Since the trials effect and all of the various interactions were nonsignificant, multiple comparisons were not made. 99