Positive and negative mediation as a function of whether the absent cue was previously associated with the outcome

Abstract

After presenting two cues, A and B, together, later pairings of one of the cues alone with an outcome can generate changes in the associative value of the absent cue. These changes can be in the same direction as the present cue (i.e., positive mediation) or in the opposite direction to the present cue (i.e., negative mediation). We found both mediational effects in a human contingency task. In addition, we found that the direction of the change was determined by the existence of a prior association between the absent cue and the outcome. When a prior association exists, the absent cue tends to change its value in the opposite direction to the present cue, whereas when there is no prior association, the absent cue tends to change its value in the same direction as the present cue. Recent associative models (Stout & Miller, 2007) can explain our results.

Keywords:

• Associative learning
• Causal judgements
• Causal learning

Support for this research was provided by Dirección General de Investigación of the Spanish Government (Grant SEJ2007–63691/PSIC), Departamento de Educación, Universidades e Investigación of the Basque Government (Grant PI2008–9), and Dirección General de Investigación, Tecnología y Empresa of the Junta de Andalucía (Grant SEJ-406). We would like to thank Miguel A. Vadillo and Ed Wasserman for illuminating discussions concerning this research.

Notes

¹ Brogden (1939) presented the bell and the light (let us call them Cue A and Cue B, respectively) simultaneously. If the cues are presented sequentially (that is, A → B), the standard explanation is that, at the time of testing, Cue B is able to elicit a conditioned response by means of the associative chain A → B → outcome. Although this explanation seems quite straightforward when A and B are presented sequentially, it has problems in accounting for the case in which A and B are presented simultaneously (as in Brogden's study and as it is in our experiment) or using a backward sensory preconditioning procedure (see Hall, 1996, for a complete explanation of these different cases). So, even when the associative chain might have a role at the time of testing in the case of sequential forward sensory preconditioning, it also seems likely that the associatively activated representation of a cue can acquire associative strength during training in the simultaneous and backward procedures. Because we present the cues in our compounds simultaneously, we assume, for the time being, that learning processes are taking place when the cues are absent during training.

² It has to be noted that Pearce's (1987, 1994) configural theory does predict negative mediation but, even when this theory assumes that stimuli are processed configurally, it uses elemental information to determine the level of generalization between two configurations.