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| Schedule Effects III |
| Tuesday, May 29, 2012 |
| 9:00 AM–10:20 AM |
| 609 (Convention Center) |
| Area: EAB |
| Chair: John R. Smethells (Central Michigan University) |
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| Stimulus Control by Flash Rate in Rats |
| Domain: Basic Research |
| JOHN R. SMETHELLS (Central Michigan University), Andrew T. Fox (University of Kansas), Stefanie Stancato (Central Michigan University), Mark P. Reilly (Central Michigan University) |
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| Abstract: Flashing lights at different rates is sometimes used to signal distinct schedule components in experiments with rats. However, little research exists on the extent to which rats can actually discriminate flash rates. Two experiments were conducted to explore this issue. Experiment 1 employed four rats in a discrete-trials conditional discrimination procedure where a 1 or 5 Hz flash rate indicated which of two lever responses would be reinforced (i.e., 1 Hz = respond left; 5 Hz = respond right). During test sessions, responses to intermediate sample stimuli revealed that flash rate produces the same sigmoidal psychophysical function as other types of stimuli (e.g., light duration). In Experiment 2, rats responded under a mult VI 60 EXT schedule where components were differentially signaled with 1.56 and 3.13 Hz flashing stimulus lights. Test sessions examined responding occasioned by a range of flash rates (0.63 Hz to 8.3 Hz). Similar to other types of stimuli (e.g., light wavelength), peak shift was observed. Various flash rates can serve as discriminative or conditional stimuli and appear to be similar to other stimulus modalities. |
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Behavioural Economics of Food Choices of the Common Brushtail Possum (Trichosurus vulpecula) |
| Domain: Basic Research |
| KRISTIE E. CAMERON (University of Waikato), Lewis A. Bizo (University of Waikato), Nicola J. Starkey (University of Waikato) |
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| Abstract: The demand for six different foods was assessed using a concurrent available Fixed and Progressive Ratios for the Common Brushtail Possum. Responses to the left lever were reinforced with timed access to one food type on a FR 30, and responses to the right lever were reinforced according a geometric PR schedule with timed access to another food type. The food pairs were based on the results of single and paired stimulus preference assessments combinging pairs of mushroom, egg, foliage, blackberry, raw chicken, egg and locust. Cross-point demand functions showed the shift from the PR schedule to the constant FR 30 schedule occurred at about 30 responses for most food pairs. Cross-points that occurred before the equivalence point suggested a preference for food available on the FR schedule as the possum responded more for this food over responding on the PR schedule which initially required fewer responses. There was no significant difference in overall elasticity between the foods. This means that as the response requirement increased, responding decreased. Pooled consumption data from within each pair of foods showed inelastic demand for several preferred foods when paired with non-preferred foods. These data show that the context for assessing demand affects the conclusions of food preference. |
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Investigating Picture/Object Transfer in Hens |
| Domain: Basic Research |
| RENEE RAILTON (University of Waikato), Therese Mary Foster (University of Waikato), William Temple (University of Waikato) |
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| Abstract: In animal research, artificial 2-dimensional stimuli (e.g., photographs or slides) have often been used as substitutes for real animals or objects. There is, however, relatively little research addressing the issue of whether animals can or do interpret such 2-dimensional stimuli as the 3-dimensional objects they represent and the results of such research are often conflicting. This paper will report a series of experiments that attempted to assess whether hens transferred a discrimination of 3-dimensional objects to 2-dimensional photographs of those objects, and vice versa. It was found that the hens could discriminate based on color but had difficulty learning to discriminate between the objects when discrimination was based on shape alone. None of the hens transferred their discrimination to the alternative stimuli. It was concluded that hens do not respond to objects depicted in pictures in the same way they do to the real objects. Thus, caution is needed when using 2-dimensional images as representations of 3-dimensional objects. |
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