I.R. Inglis

REVIEW: THE CENTRAL ROLE OF UNCERTAINTY REDUCTION IN DETERMINING BEHAVIOUR

In complex and stochastic environments the ability to cope with the unexpected is essential for survival. This paper describes a motivational framework founded on the need to reduce uncertainty. It is centred around a merging of classifier systems, taken from the field of artificial intelligence, with the information-primacy approach to animal motivation. It is proposed that in order to deal with uncertainty the animal constructs cognitive models of its environment that are composed of hierarchies of condition-action rules. There is parallel activation of several rules at any given time, and these rules compete to determine behaviour. The rules found to be the best predictors (and may in addition have resulted in reinforcement) gain strength, whilst the less successful rules lose strength over time. Unexpected events trigger the generation of families of new rules which are then subject to environmental selection. The efficient operation of the cognitive model requires the continual reduction of uncertainty, so that information-gathering behaviour forms a substratum upon which other, more obviously goal directed, behaviours occur. High need states can break into this ongoing behaviour and give it a special direction. The framework is related to the inherent variability of behaviour, the failure of certain reinforcement contingencies to control behaviour, and approach/avoidance behaviour towards novel stimuli.

Foraging behaviour of wild rats (Rattus norvegicus) towards new foods and bait containers

Abstract Groups of wild rats (Rattus norvegicus) were housed in large arenas and their foraging behaviour towards unfamiliar food, novel food and novel food containers was monitored using remote sensing equipment. Three main findings resulted from the study. There is a large individual variation in the responses to new foods and food containers placed in the home range. There is a clear sex difference in that, although males and females take approximately the same weight of food over a 24 h period, females forage in many short visits (mean = 28.4, SE = 1.3 per day) whilst males take fewer, longer feeding visits (mean = 15.3, SE = 1.9). The most important findings is that neophobia to new food containers is far stronger than neophobia to new foods. This effect is sufficient to create practical control problems when rodenticide bait is used within bait containers. A possible way to overcome this problem is discussed.

The responses of dark-bellied brent geese to models of geese in various postures

Abstract Models of brent geese in the head up, extreme head up, and head down postures were combined in various ratios to form model flocks. These were placed in a field regularly visited by brent, and the responses of the geese to the flocks were recorded. The data agreed with the prediction that the extreme head up models would be aversive while the head down models would be attractive. The head up models were more aversive than the head down models but only when both types were combined in flocks with extreme head up models. Geese appeared to monitor the proportion of extreme head up models in a flock.

The Responses of Woodpigeons (Columba Palumbus) To Pigeon Decoys in Various Postures: a Quest for a Super-Normal Alarm Stimulus

1. It has been suggested (MURTON, 1974) that the white wing marks of the woodpigeon (Columba palumbus) could form a visual alarm signal; the species has no auditory alarm call. Experiments were conducted to investigate this possibility with the long term goal of developing an efficient scarer for this species. 2. Preference experiments were conducted over four summers. Pigeons coming to a preferred feeding site were given the opportunity of settling within one of two areas containing woodpigeon decoys (i.e. corpses) of various types. 3. Woodpigeons preferred to settle with closed-winged decoys than with open-winged decoys. This was because close-winged decoys were attractive but also because open-winged decoys were repellent. The attractive properties of closed-winged decoys were not species specific; closed-winged stock doves (Columba oenas) decoys were just as attractive. The repellent properties of the open-winged decoys resulted not from the novel posture or from the body of the decoy but solely from the outstretched pair of wings. More specifically the white wing marks were necessary for this effect; open-winged decoys with no wing marks were not repellent. 4. Decoys with modified wing marks were tested to try to obtain super-normal repellency. Doubling the area of the wing marks produced such an effect. 5. Although the exposure of the wing marks is a necessary and sufficient condition for a repellent effect, the open-winged posture is rarely seen in a living woodpigeon. The marks are usually visible as an oscillating pattern. The likely importance of the rate of oscillation of this pattern is discussed.

Symptom-dependent taste aversion induced by an anticoagulant rodenticide in the brown rat (Rattus norvegicus).

In a series of 3 experiments with different experimental paradigms, feeding patterns of laboratory rats (Rattus norvegicus) were monitored in 2-choice feeding tests after intubation with a sublethal dose of an anticoagulant rodenticide. We report for the first time that contrary to accepted wisdom, anticoagulants can induce taste aversions. Furthermore, we report behavioral symptoms within the 1st day after dosing. Our data suggest that the taste aversion is induced through an inhibition of the vitamin K cycle and is transient, attenuating over the same period as the levels of vitamin K-dependent proteins return to normal. Because the taste aversion is expressed most strongly when symptoms are most pronounced and is not expressed after symptoms have disappeared, we term this novel form of control symptom-dependent taste aversion.