Estes, Wellman & Woolley (1989) have shown that children as young as 3 years of age can distinguish between mental entities such as an image or dream of an object and a real object. Nevertheless, children often show persistent fear of imaginary creatures, particularly monsters (Jersild, 1943). To find out what conception children have of such imaginary creatures, 4‐ and 6‐year‐olds were questioned about three types of item: real items (e.g. a cup), ordinary imagined items (e.g. an image of a cup) and supernatural imagined items (e.g. an image of a monster). In two experiments, both age groups sharply differentiated the real items from both types of imagined item. Despite this apparently firm grasp of the distinction between fantasy and reality, two further experiments showed that 4‐ and 6‐year‐olds are not always certain that a creature that they have imagined cannot become real. Having imagined a creature inside a box, they show apprehension or curiosity about what is inside the box, and often admit to wondering whether the creature is actually inside. The experiments suggest that children systematically distinguish fantasy from reality, but are tempted to believe in the existence of what they have merely imagined.

This study consisted of two experiments, one in rats and one in human volunteers, that used the identical progressive ratio (PR) operant procedure. In both experiments, responding was reinforced under a progressively increasing work requirement, and different groups of subjects received reinforcers that varied in sweetness. In experiment 1, rats were subjected to chronic mild stress, a well-validated animal model of depression. Performance under the PR schedule increased in subjects reinforced with conventional precision pellets (which contain 10% sucrose) or very sweet pellets, but not in subjects reinforced with sugar-free pellets. In experiment 2, volunteers were subjected to a depressive musical mood induction. Performance under the PR schedule increased in subjects reinforced with chocolate buttons, but not in subjects reinforced with with buttons made from the relatively unpalatable chocolate substitute carob. In experiment 2, depressive mood induction also increased chocolate craving, as measured by a novel questionnaire, and there were significant correlations between chocolate craving and chocolate-reinforced PR performance. These results suggest that performance under the PR schedule provides a measure of craving rather than reward, and that craving for sweet rewards is increased by depressive mood induction in both animal and human models. Implications for the interpretation of pharmacological studies using the PR procedure are also discussed.

We studied the epidemiology of Heligmosomoides polygyrus (Nematodd) in the wood mouse (Apodemus sylvaticus) in an arable ecosystem, and investigated any association between infection and the movement patterns of male mice by manipulating worm burdens. Methods included the live‐trapping of mice, estimation of worm burdens by faecal analysis, administration of either an anthelminthic or water (as a control) and the radio‐tracking of selected animals. Heligmosomoides polygyrus showed an overdispersed distribution pattern, with prevalence tending to be higher in males and heavier mice. Prevalence and intensity peaked in spring and declined in autumn both in the entire population and in adults. This seasonality in the arable ecosystem in comparison to woodland may arise due to the direct and indirect impact of agricultural practice. To investigate the link between infection and movements, radio‐tracked mice were classed as either‘Uninfected’or‘Infected’; mice were also classed as either‘Control’or‘Dosed’. There were no significant differences in movement parameters between‘Infected/Dosed’and‘Infected/Control’, possibly because treatment was not administered sufficiently frequently. Both‘Infected’classes of mice moved significantly faster than‘Uninfected’ones, and‘Infected/Dosed’mice moved significantly further than‘Uninfected’ones. The percentage of time spent moving was also greater, and the home range area was larger, for‘Infected/Dosed’and‘Infected/Control’than for‘Uninfected’mice. The observed differences in movement may have been the result of either the behaviour of mice influencing their parasite load or the parasite manipulating its host.

This review suggests that c/mECT is efficacious for the prevention of relapse/recurrence of major depression and that efficacy is increased when c/mECT is provided in combination with antidepressant medication and at flexible treatment intervals, responsive to early signs of recurrence.

The rhythmicity of egg production by Heligmosomoides polygyrus (Nematoda) in wild caught wood mice (Apodemus sylvaticus) was studied. Faecal production followed a 24 h cycle, with peaks at 0400 h and troughs at 1300–1900 h. The patterns in eggs per gram of faeces (EPG) and total eggs were similar to each other, though the former was more accentuated. Both of these followed a 24 h cycle, with peaks coinciding with troughs in faecal production and vice versa. Faecal weight was inversely correlated with EPG, but was not significantly correlated with total eggs. The pattern in EPG presumably reflected the effect of faecal production on the total eggs excreted in each 3 h period. The observed cycle in total eggs probably describes the pattern of egg production by the worm, although other factors, such as the host's intestinal rhythms, may contribute to this cycle.