A Comparison of Latent Inhibition and Learned Irrelevance Pre-Exposure Effects in Rabbit and Human Eyeblink Conditioning

The learning of an association between a CS and a US can be retarded by unreinforced presentations of the CS alone (termed latent inhibition or LI) or by un-correlated presentations of the CS and US (termed learned irrelevance or LIRR). In rabbit eyeblink conditioning, there have been some recent failures to replicate LI. LIRR has been hypothesized as producing a stronger retardation effect than LI based on both empirical studies and computational models. In the work presented here, we examined the relative strength of LI and LIRR in eyeblink conditioning in rabbits and humans. In both species, a number of preexposure trials sufficient to produce LIRR failed to produce LI (Experiments 1 & 3). Doubling the number of CS pre-exposures did produce LI in rabbits (Experiment 2), but not in humans (Experiment 4). LI was demonstrated in humans only after manipulations including an increased inter-trial interval or ITI (Experiment 5). Overall, it appears that LIRR is a more easily producible pre-exposure retardation effect than LI for eyeblink conditioning in both rabbits and humans. Several theoretical mechanisms for LI including the conditioned attention theory, stimulus compression, novelty, and the switching theory are discussed as possible explanations for the differences between LIRR and LI. Overall, future work involving testing the neural substrates of pre-exposure effects may benefit from the use of LIRR rather than LI.     

Context specificity of latent inhibition in taste aversion learning

In three experiments rats were given injections of LiCl after consuming distinctively flavoured water. The rats developed an aversion to the flavour and in all experiments the magnitude of the aversion was found to be reduced in subjects that had received pre-exposure to the flavour without aversive consequences. Experiment 1 demonstrated this pre-exposure effect to be a case of latent inhibition. The remaining experiments investigated the effects of pre-exposing the flavour in a context different from that used for conditioning. It was found (Experiment 2) diat latent inhibition transferred perfectly when the context change consisted of a move from one home cage to another. Context specificity of latent inhibition was found (Experiment 3) only when the subjects were given daily sessions in die experimental contexts, these being cages different from the home cage.     

A search for context-stimulus associations in latent inhibition

Six experiments investigated the effects of pre-exposure to a tone on the subsequent acquisition of conditioned suppression by rats. In Experiments 1-3 the response suppressed was drinking; in Experiments 4-6 it was food-rewarded lever pressing. Repeated exposure to the tone resulted in latent inhibition, i.e., a retardation in the acquisition of suppression. The size of the latent inhibition effect was reduced when a different context was used for conditioning from that used for pre-exposure (Experiment 2). When the context remained the same throughout, a phase of exposure to the context alone, interposed between pre-exposure and conditioning, had no influence on the size of the latent inhibition effect ultimately observed. This last result casts doubt upon Wagner's (1976, 1979) theory of the role of contextual factors in latent inhibition, and alternative accounts are considered.     

Book reviews

Thomassen, A., Keuss, P. and van Galen, G. (Eds.). Motor aspects of handwiriting. Amsterdam: North-Holland. 1984. Pp 354. ISBN 0444-86774-0. $50.

Klatskyk, R. L. Memory and awareness. New York: W. H. Freeman. 1984. Pp. 155. ISBN 0-7167-1600-3. £9.95.

Longman Dictionary of Psychology and Psychiatry. New York: Longman. 1984. ISBN 0-582-28257, pp 816, £46.00.

Kintsch, W., Miller, J. R., and Polson, P. G. Methods and tactics in cognitive seience. Hilisadale, N.J.: Lawrence Erlbaum Associates. 1984. Pp. xii+324. ISBN 0-89859-372-1. £27.50.

Dubery, F. and Williats, J. Perspective and other drawing systems. London: The Herbert Press. 1983. Pp. 128. ISBN 0-906969 -25-5. £4.95.

Morris, P. E. and Hampson, P. J. Imagery and consciousness. London: Academic Press. 1983. Pp. 341. ISBN 0-12-507680-0. $36.50.

Bundy, A. The computer modelling of mathematical reasoning. London: Academic Press. 1983. Pp. 322. ISBN 0-12-141252-0. $15.00.

Jeeves, M. A. and Greer, G. B. Analysis of structural learning. London: Academic Press. 1983. Pp. 265. ISBN 0-12-382080-4. $40.00.

Taylor, I. and Taylor, M. M. The psychology of reading. New York: Academic Press, 1983. Pp. 511. ISBN 0-12-684080-6 $29.50.

Wade, N. J. (Ed.). Brewster and Wheatstone on vision. London: Academic Press. 1984. Pp. 358. ISBN 0-12-729550-X. $39.00.

Harre, R. and Lamb, R. The encyclopedic dictionary of psychology. Oxford: Blackwell. 1983. ISBN 0-631-12663-5. £55.00.

Kail, R. and Spear, N. E. (Eds.). Comparative perspectives on the development of memory. Hillsdale, N. J.: Lawrence Erlbaum Associates. 1984. Pp. x+ 374. ISBN 0-89859-317-4. £37.50.

R. Hockey (Ed.). Stress and fatigue in human performance. London: Wiley. 1983. ISBN 0-471 10-265-2. £16.50.

Sarris, V. and Parducci, A. (Eds.). Perspectives in psychological experimentation: Toward the year 2000. Hillsdale, N. J.: Lawrence Erlbaum Associates. 1984. Pp. 370. ISBN 0-89859-272-9. £33.30.     

Automatic and strategic effects in the guidance of attention by working memory representations

Theories of visual attention suggest that working memory representations automatically guide attention toward memory-matching objects. Some empirical tests of this prediction have produced results consistent with working memory automatically guiding attention. However, others have shown that individuals can strategically control whether working memory representations guide visual attention. Previous studies have not independently measured automatic and strategic contributions to the interactions between working memory and attention. In this study, we used a classic manipulation of the probability of valid, neutral, and invalid cues to tease apart the nature of such interactions. This framework utilizes measures of reaction time (RT) to quantify the costs and benefits of attending to memory-matching items and infer the relative magnitudes of automatic and strategic effects. We found both costs and benefits even when the memory-matching item was no more likely to be the target than other items, indicating an automatic component of attentional guidance. However, the costs and benefits essentially doubled as the probability of a trial with a valid cue increased from 20% to 80%, demonstrating a potent strategic effect. We also show that the instructions given to participants led to a significant change in guidance distinct from the actual probability of events during the experiment. Together, these findings demonstrate that the influence of working memory representations on attention is driven by both automatic and strategic interactions.     

When sentimental rules collide: "norms with feelings" in the dilemmatic context

According to a recently prominent account of moral judgment, genuine moral disapprobation is a product of two convergent vectors of normative influence: a strong negative affect that arises from the mere consideration of a given piece of human conduct and a (socially acquired) belief that this conduct is wrong (Nichols, 2002). The existing evidence in favor of this “norms with feelings” proposal is rather mixed, with no obvious route to an empirical resolution. To help shed further light on the situation, we test a previously unexamined prediction that this account logically yields in a novel dilemmatic context: when individuals are faced with a moral dilemma that pits two or more “affectively-charged” moral norms against each other, the norm underwritten by the strongest feeling ought to determine the content of dilemmatic resolution. Across three studies, we find evidence that directly challenges this prediction, offering support for a Kolhberg-style “rationalist” alternative instead. More specifically, we find that it is not the participants’ degree of norm-congruent emotion (whether situationally or dispositionally assessed) or its correlates, but rather their appraisal of the relative costs associated with various alternative courses of action that appears to be most predictive of how they resolve the experimentally induced moral conflict. We conclude by situating our studies within an overarching typology of moral encounters, which, we believe, can help guide future research as well as shed light on some current controversies within this literature.     

The random effects prep continues to mispredict the probability of replication

In their reply, Lecoutre and Killeen (2010) argue for a random effects version of p_rep, in which the observed effect from one experiment is used to predict the probability that an effect from a different but related experiment will have the same sign. They present a figure giving the impression that this version of p_rep accurately predicts the probability of replication. We show that their results are incorrect and conceptually limited, even when corrected. We then present a meaningful evaluation of the random effects p_rep as a predictor and find that, as with the fixed effects p_rep, it performs very poorly.