Perceptual learning in humans: Roles of preexposure schedule, feedback, and discrimination assay

In three experiments, humans received preexposure to two compound flavours (AX and BX: saline-lemon and sucrose-lemon) that were presented either in an intermixed (e.g., AX, BX, . . . BX, AX, . . .) or a blocked (e.g., AX, AX, . . . BX, BX. . .) fashion. Subsequently, AXwas paired with an unpleasant bitter taste, and the discriminability of AX and BX was assessed using the accuracy of same/different judgements and by the extent to which any learned dislike of AX generalized to BX. When participants received feedback about the accuracy of their same/different judgements during preexposure those given intermixed preexposure were more accurate in making these judgements during the test than those given blocked preexposure (Experiments 1 and 2A), however, there was no evidence of any learned dislike in these experiments. In Experiment 2B, in which participants did not receive feedback about the accuracy of their judgements, there was no effect of the preexposure regime on same/different judgements, but there was a learned dislike of AX, and this generalized less to BX in participants given intermixed than in those given blocked preexposure. The beneficial effects of intermixed preexposure are consistent with results from other species (chicks and rats), but the differences created by the presence or absence of feedback place constraints on the analysis of these effects.     

Equity, justice, and altruism

According to traditional equity theory, justice is motivated by selfishness. However, critics of equity have argued that it is only one rule of justice that people can apply, and that sometimes other rules of justice are used, such as equality and need, that appear to be altruistically based; that is, they involve sharing and caring in a way that ignores contributions or “inputs” and the probability of receiving outcomes in return. Disagreements have arisen, however, as to the status of these alternative rules as elements of justice, the roles of altruism and selfishness within them, and the relative status of altruism and justice as moral principles. The main aim of this article is to help resolve some of these difficulties by examining the relationship between altruism and justice from the perspective of Wagstaff s theory of Equity as Desert (EAD). This theory integrates a number of allocation rules (including those related to the treatment of offenders) with the concepts of equal opportunity and personal responsibility. One of the advantages of this position is that it enables a conceptual and an empirical distinction to be made between helping and responsiveness to need as altruistic norms, and helping and responsiveness to need as justice norms. It is concluded that there may be something to be gained from viewing core rules of justice in the form of EAD as the sophisticated descendants of the sociobiological concept of reciprocal altruism, that is, a set of algorithms designed to limit both unbridled selfishness and indiscrimi-nate altruism.     

Facilitated Communication as an Ideomotor Response

Forty college students were taught facilitated communication via a commercially available training videotape. They were then asked to facilitate the communication of a confederate, who was described as developmentally disabled and unable to speak. All 40 participants produced responses that they attributed at least partially to the confederate, and most attributed all of the communication entirely to her. Eighty-nine percent produced responses corresponding to information they had received, most of which was unknown to the confederate. Responding was significantly correlated with simple ideomotor responses with a pendulum and was not affected by information about the controversy surrounding facilitated communication. These data support the hypothesis that facilitated communication is an instance of automatic writing, akin to that observed in hypothesis and with Ouija boards, and that the ability to produce automatic writing is more common than previously thought.     

Evaluative Conditioning: Arti-fact or -fiction?-A Reply to Baeyens, De Houwer, Vansteenwegen, and Eelen (1998)

Baeyenset al.(1998) claim that Field and Davey's (1997) controversial study of conceptual conditioning offers little threat to current conceptions of evaluative conditioning. This article addresses some of the questions posed by Baeyenset al.First, some criticisms of the conceptual conditioning study appear to be based on a misunderstanding of the procedure. Second, we address the issues surrounding the so-called Type-X procedure. Specifically, we begin by reviewing the status of studies that have used a procedure different from the Type-X procedure. It is then argued that, although the Type-X procedure has been used in only a portion of EC research, it has been used primarily in those studies whose outcome has been used to argue that evaluative conditioning (EC) is functionally distinct from autonomic conditioning. We then review the evidence from non-Type-X procedures that EC is a distinct form of learning. Finally, an attempt is made to explain why between-subject controls should be used as a matter of course in this field of research.     

After-effects of reinforcement magnitude: Dependence upon context

On a fixed-interval schedule with rat subjects the duration of the post-reinforcement pause was found to be an increasing function of the magnitude of the preceding reinforcer. This relationship was observed when two magnitudes were contrasted closely in time, but not when the subjects were trained on each magnitude until the establishment of stable responding. After the behaviour was stable, the effect of the magnitude of reinforcement re-emerged when 50% of the scheduled reinforcers were omitted. Thus, the positive relationship between the magnitude of reinforcement and the duration of the post-reinforcement pause depended on the context of presentation of a given magnitude.     

On the significance of “double encoding” for the superior recall of pictures to names

Ten-year-old children who were shown pictures of objects immediately preceded by the object's name recalled the material no better than those exposed to the names of the stimuli alone. Both conditions yielded significantly poorer retention than those in which pictures alone were presented or pictures followed by their names. A second study replicated this result. In addition this demonstrated, by a picture and name recognition task, that the effects could not be due to subjects in the “name prior to picture” condition ignoring the pictorial component. These results were interpreted as contradicting the “double encoding” explanation of the superiority of pictures to names in free recall. Parallel visual and verbal encoding of a pictured object does not facilitate retention unless the verbal cue is actively elicited from the subject by the stimulus. The implications of this result for other studies which have employed either simultaneous or sequential presentation of pictures and names are briefly discussed.