The photo-lickerandum: A device for detecting the licking response,with capability for near-instantaneous programming of variable quantum reinforcement

A combined operandum-feeder is described that eliminates the necessity of passing an electrical sensing current through S while detecting and reinforcing tongue-licking responses. A glass nozzle for dispensing liquid reinforcers is situated just above a small separation in a loop of photo-conducting Sterite tubing; licks at a tiny area below the nozzle break a light beam and are detected via a photo-resistor and associated circuitry. Data are presented from a study in which rats worked at the operandum on a mult FR 40 ext schedule; performance and records are comparable to those obtained via conventional electronic sensing. Applications of the photo-lickerandum and an associated variable-quantum reinforcing system are suggested.     

Dietary restraint of bulimic subjects following cognitive-behavioral or pharmacological treatment

The pre and posttreatment self-monitored caloric intake of bulimic subjects treated with either cognitive-behavioral therapy or imipramine was compared. Results indicated that both groups equally and successfully reduced purged calories but that only cognitive-behaviorally treated subjects increased non-purged caloric intake. These results show that cognitive-behavioral treatment lessens dietary restraint whereas imipramine treatment of bulimia nervosa does not. These findings are discussed and it is suggested that they may account for the superior therapeutic maintenance following cognitive-behavioral treatment when compared with pharmacological treatment of bulimia nervosa.     

Effects of eye movements on the rate of discovery and the vividness of visual images

Two studies investigated the effects of eye movements on the rate of discovery and the vividness of visual images. Eye movements were manipulated by having three conditions: (1) The Ss were instructed to make eye movements while generating images to noun pairs; (2) the Ss were instructed not to make eye movements, but to think about making eye movements while generating images to noun pairs; (3) the Ss were instructed not to make eye movements and not to think about making eye movements while generating images to noun pairs. In addition, the ease of generating images was manipulated by using noun pairs that differed in their image-evoking capacity; five of the noun pairs consisted of high imagery-evoking nouns and five consisted of low imagery-evoking nouns. The two experiments were similar, with the exception that a between-groups design was used in Experiment 1, whereas Experiment 2 employed a within-Ss design. The results of both experiments showed highly significant effects of noun-pair type on both the rate of discovery and the vividness of images, with the fastest and most vivid images occuring to the high-imagery noun pairs. The effects of the eye-movement conditions on the rate of discovery and the vividness of the images were not significant in either experiment, and these findings are discussed in terms of the relationship of ocular activity to imagery.     

Partial negative reinforcement: fixed-ratio escape

Rats were unable to sustain performance when eight bar-presses turned off shock (−FR 8). In a second experiment, thirsty rats were able to maintain a moderate response rate when performance on −FR 8 was also reinforced with water. Some rats continued to bar-press on −FR 8 after withdrawal of positive reinforcement, but at a much lower rate. A possible explanation of the results is that during intermittent escape conditioning in a free-responding situation the absence of shock itself acquires aversive properties.     

Orienting attention within visual fields: how efficient is interhemispheric transfer?

Five experiments are reported examining the effect of attentional orienting on lexical decisions within visual half-fields. In Experiment 1, following baseline performance, subjects were instructed to improve performance to the right or left of the fixation point. In Experiment 2, trials were run in blocks with all items to one side of the fixation point. In Experiment 3, completely valid position indicators as to the location of the next item to be shown were presented prior to the stimulus item. In Experiment 4, to examine practice effects, no instructions or cuing were given to subjects. In Experiment 5, subjects were urged to improve performance, but with no instructions as to location. As a summary of our results, it can be stated that (a) consistent visual field differences in lexical decision performance are present, even when subjects were informed, prior to viewing, of the spatial location of the next stimulus item. (b) Lexical decision information initially input to one cerebral hemisphere is primarily processed in that hemisphere. Interhemispheric transfer of this type of language information seems to be done primarily as the end product of a cognitive process.     

Daily Occupations,Routines, and Social Participation of Homeless Young People

Homelessness disrupts young people’s participation in the productive occupations that facilitate transition to adulthood, impairs social connections, and has a disorganizing effect on their time use. Semi-structured focus group interviews were used to explore how 19 homeless young people perceived their daily routines, meaningful occupations, and social participation to be impacted by the experience of homelessness. Occupational therapy practitioners can use the findings from this study to inform the development of comprehensive community-based programming aimed at increasing social opportunities, developing balanced, healthy routines, decreasing intrinsic and extrinsic barriers to residential stability, and promoting participation in productive and leisure occupations.