Spatially Located Visual CS Effects in Conditioned Shuttlebox Avoidance in Goldfish: A Phototactic Explanation
Earlier work found that goldfish (Carassius auratus) acquire a conditioned avoidance shuttle response (CASR) differentially as a function of CS location (same, opposite, or both tank ends) when the CS is a sudden onset of illumination, and hypothesized that subjects acquire an aversion to the light. The present study finds no evidence for a conditioned aversion, but shows initial negative phototactic effects in the onset illumination situation which occurs without acquisition. Additionally, when the localized CS is a color change rather than an illumination change, the differential effects between same and both do not occur, and the very low CASR acquisition of the opposite group is strikingly similar to a no-CS group, indicating a very low-magnitude CS for this condition. Using the negative phototaxis explanation, the failure of subjects to acquire a CASR differentially to a light offset, which does not yield the phototactic response, is understandable.