Selective attention and stimulus-reinforcer interactions in the pigeon

The study supplies further evidence that non-associative effects and temporal-spatial similarities between certain combinations of cue and consequence cannot explain all instances of stimulus-reinforcer interactions. Pigeons were trained to press a treadle in the presence of a discriminative compound stimulus either to avoid shock or to obtain a food reinforcer. The compound stimulus was composed of diffuse tone and light cues which had identical temporal patterns of onset, duration and offset. With the avoidance schedule the auditory cue acquired more control than the visual cue; however, when food was the reinforcer, the visual cue exerted more control. This pattern of stimulus control on the appetitive schedule did not change if random shocks were also added, even though these shocks were equal in density to the food presentations and equal in magnitude to those used for the avoidance schedule. Other changes in the appetitive procedure, such as making the tone spatially contiguous with food and removing the light in the food hopper, also failed to alter the relative control by the different cues. Prior training with a food reinforcer did not produce any change in the relative control by the two cues when the birds were retrained on the shock-avoidance schedule. The results suggest that some frequently stated alternatives to selective associability are not adequate explanations of this instance of a stimulus-reinforcer interaction.     

Instrumental responding following reinforcer devaluation

In two experiments, hungry rats were given instrumental lever-press training for an appetitive reinforcer and, in addition, were exposed to another type of food which was not contingent on lever pressing. In the first experiment, exposure to each type of food was on separate days, whereas in the second experiment rats were exposed to each type of food in strict alternation within each session. Subsequently, a food aversion was conditioned to the reinforcer for the experimental group and to the non-contingent food for the control group. In both experiments, animals with an aversion to the reinforcer responded less in an extinction test than animals with an aversion to the non-contingent food. Subsequent reacquisition tests confirmed that the aversion to the non-contingent food in the control group was of comparable strength with that to the reinforcer in the experimental group. The results were discussed in terms of whether the reinforcer is encoded in the associative structure set up by exposure to an instrumental contingency.     

Not Such a Queer Idea: Is There a Case for Same Sex Marriages?

Gay marriages (as such) are not as yet allowed anywhere but the demand for them is increasing. Most countries take a liberal attitude towards marriage: few obstacles are put in its way. But objections to gay marriages continue to be raised. These objections are refuted and the case for gay marriage is assessed through the prism of various forms of liberalism. The normative argument for allowing gay marriage is shown to be both strong and consistent with many of the values upheld by the opponents of such unions.     

The role of illness uncertainty on coping with fibromyalgia symptoms.

This study examined the role of illness uncertainty in pain coping among women with fibromyalgia (FM), a chronic pain condition of unknown origin. Fifty-one FM participants completed initial demographic and illness uncertainty questionnaires and underwent 10-12 weekly interviews regarding pain, coping difficulty, and coping efficacy. Main outcome measures included weekly levels of difficulty coping with FM symptoms and coping efficacy. Multilevel analyses indicated that pain elevations for those high in illness uncertainty predicted increases in coping difficulty. Furthermore, when participants had more difficulty coping, they reported lower levels of coping efficacy. Results were consistent with hypothesized effects. Illness uncertainty accompanied by episodic pain negatively influenced coping efficacy, an important resource in adaptation to FM.