If an animal drinks a solution containing ethyl alcohol when another fluid is available, it is difficult to know what this selection actually means. Facing the scientist are exceedingly complex variables: those inherent in the environmental situation as well as those associated with the animal itself. We, the human observers, recording events and watching through the mesh of the cage, can only attempt to identify the factors which are responsible for the animal’s choice of an alcohol solution.

The Determinants of Alcohol Preference in Animals

Ethanol Self-Administration: Infrahuman Studies1

Alcoholism is a familial disorder. Studies have repeatedly shown a high prevAlcnce of alcoholism among the relatives of alcoholics. “Familial” however, is not synonymous with “hereditary.” Speaking French may also be familial but presumably not because of genes.

Heredity and Alcoholism

Traditional difficulties in procuring wild rats can be overcome by trapping in an unstable environment (e.g., land-fill) where the natives do not fear strange objects such as traps. Techniques for trapping, transferring to, and maintaining in the laboratory are outlined, and apparatus for handling and housing, including the breeding situation, is described. Conclusion: Simple precautions render the wild rat nearly as easy to breed and use in conventional laboratory tasks as domesticated rats.

/pdf/laboratorizing-the-wild-rat-rattus-norvegiens-6dggasqbkf.pdf

Laboratorizing the wild rat (Rattus norvégiens)

Data are reported for laboratory rats required to ingest a 7% EtOH solution to avoid shock, attain food, or for no primary reinforcement. When alcohol ingestion was coupled with shock avoidance or no reinforcer, no increase in ad lib alcohol consumption resulted. The use of ethanol ingestion as a food producing operant, however, yielded a significant but temporary increase in voluntary EtOH consumption subsequent to the conditioning procedure. The use of a positive reinforcing agent as an inducement toward voluntary EtOH consumption in the rat is suggested as possibly being superior to the more traditional stress avoidance techniques.

/pdf/ethanol-ingestion-as-an-operant-response-2u197l5y3k.pdf

Ethanol ingestion as an operant response

A group of domestic rats and a group of wild pack rats were exposed to food and a 20% alcohol solution continuously for 20 weeks. Subsequently, both groups were exposed to food, alcohol solution, and water for nine weeks. No major changes in alcohol consumption rates occurred in either group within either of the two periods. Alcohol consumption decreased for both groups when the choice situation (alcohol vs water) was instituted. This decrease was more pronounced for domestic rats than for wild rats. The results are discussed in terms of potential physiological or other pre-experimental factors affecting alcohol consumption rate.

/pdf/alcohol-consumption-in-domestic-and-wild-rats-130s9nbz7q.pdf

Alcohol consumption in domestic and wild rats

Ad lib alcohol selection level was shown to remain quite stable within individual rats during 26 weeks of access to 6% EtOH and water. Intersubject variability was high and did not alter systematically over time. The results were taken as contradictory to the hypothesis that history of exposure to, or consumption of alcohol affects the subsequent level of alcohol consumption, but to indicate that pre-experimental variables strongly affect consumption rate.

/pdf/intersubject-and-intrasubject-variability-in-the-consumption-nck2e4q1o1.pdf

Intersubject and intrasubject variability in the consumption of alcohol

In a group testing procedure, 480 Ss were given a single trial to learn a list of five nonsense syllables, presented one at a time in order. Ss were given an interpolated interval of 0, 15, or 30 sec in which they were required to cancel vowels from lists of random letters. At the end of the interval they were required to recall either the first, middle, or last syllable in the list. Results revealed a significant effect associated only with serial position.

/pdf/intra-list-interference-in-single-trial-short-term-memory-2yxhu67da7.pdf

Intra-list interference in single trial short-term memory

An apparatus allowing a rat’s drinking response to terminate shock or deliver food is described. The system is constructed of commercial components and is sensitive to the intermittent, but regular, signal generated by a rat in the act of drinking.

/pdf/stimulus-control-through-the-licking-response-3gv4h2tg6f.pdf

Stimulus control through the licking response

/pdf/reply-to-boice-and-aspey-1tt7oigy09.pdf

Erhard O. Eimer

Papers

Alcohol consumption in domestic and wild rats

Intersubject and intrasubject variability in the consumption of alcohol

Intra-list interference in single trial short-term memory

Stimulus control through the licking response

Reply to Boice and Aspey