Distractor effect on the latent inhibition of conditioned flavor aversion in rats

Abstract

Nonreinforced exposure to a stimulus before conditioning reliably retards the acquisition of conditioned responding to that stimulus. Several experiments have found that this "latent inhibition effect" (Lubow, 1973) is attenuated if the stimulus (target) is preexposed in compound with a second stimulus (distractor) (e.g., Best, Gemberling, & Johnson, 1979;Honey & Hall, 1988;Lubow, Schnur, & Rifkin, 1976;Matzel, Schactman, & Miller, 1988; but see also, e.g., Mercier & Baker, 1985;Rudy, Krauter, & Gaffuri, 1976, for negative findings). These results seem to require an account which assumes some competing process between the target and the distractor during preexposure, for example reciprocal overshadowing in association with inattentional response (Lubow, 1989;Lubow, Weiner, & Schnur, 1981) or competition for access to short-term memory (Wagner, 1978(Wagner, , 1981.Distractor effect on the latent inhibition of conditioned flavor aversion in rats 1 KIYOSHI ISHII Department of Psychology, School of Letters, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan YASUAKI HAGA Department of Psychology, School of Letters, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan YUTAKA HISHIMURA Department of Psychology, Faculty of Humanities, Niigata University, Ikarashi, Niigata 950-2181, Japan Abstract: Using a conditioned flavor aversion procedure with rats as subjects, the effect of the addition of a distractor stimulus on the magnitude of the latent inhibition effect was examined. Experiment 1 showed that latent inhibition to vinegar was attenuated by the addition of sucrose during preexposure. On the other hand, sucrose added during conditioning to vinegar did not attenuate latent inhibition. It was also found that the degree of latent inhibition to the vinegar-sucrose compound solution was less when vinegar alone was preexposed (i.e., when sucrose was added only during conditioning) than when the compound solution was preexposed (i.e., when sucrose was added both during preexposure and during conditioning). Experiment 2 gave similar results but with sucrose assigned as the target flavor and vinegar as the distractor. These findings are in full agreement with the generalization decrement account of latent inhibition.

Comparison of nutritive and nonnutritive stimuli in intestinal and oral conditioned taste aversion paradigms.

“…Generalization decrement of this type (between separate elements and a compound) has previously been observed by using a latent inhibition design in which two taste stimuli were originally preexposed independently prior to training and were then presented in simultaneous compound during an aversion training phase. Reduced latent inhibition was observed relative to group preexposed to the compound, an effect attributed to generalization decrement, as normal latent inhibition was found when the component stimuli were presented as a serial rather than a simultaneous (i.e., mixed) compound (Gomez & Ramirez, 1993;Ishii, Haga, & Hishimura, 1999;Ramirez & Aguilar, 1992). This result supports the notion that the nutrient and the nonnutritive flavor elements of the compound presented during the training phase of the present experiment were detected as independent stimuli, possibly via two separate sensory mechanisms, in the GI tract.…”

Determinants of cue interactions

“…Ishii et al (1999, Experiment 2) also observed summation of latent inhibition and overshadowing in a conditioned taste aversion preparation when using a training context other than the home cages. The rather consistent finding of summation of latent inhibition and overshadowing from different laboratories using CTA preparations certainly suggests that a counteraction effect is at least difficult to observe in the CTA preparation.…”