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T J Reynolds

Publications and source records attributed to T J Reynolds.

7 recordsLinked to original sources
PubMed1981

Stimulus interaction and between-trials proactive interference in monkeys.

Most theoretical accounts of proactive interference in delayed-matching-to-sample paradigms focus on processes linked to time. Two experiments questioned this exclusive focus on temporal facts. Between-trials proactive interference was studied in a situation in which the similarity of consecutive trials was varied along the dimensions of color, form, and position. All of these factors as well as the similarity of sample and test contexts contributed to memory performance. A mathematical model based on the assumptions that similarity strongly influences memory-based judgements and that overall similarity is determined by the multiplicative interaction of component dimensions gave an excellent qualitative and quantitative account of the data in both experiments. These results support a broader view of factors determining proactive interference and are inconsistent with the idea that these multiple factors can be treated as independent.

Animals↗
PubMed1980

Stimulus similarity and retroactive interference and facilitation in monkey short-term memory.

Four experiments examined the effects of similarity between the sample and an interpolated stimulus in a modified delayed-matching-to-sample (DMTS) paradigm. The basis trial sequence was as follows: (a) a sample was presented, and the response to it was either rewarded or nonrewarded, (b) an interpolated stimulus was presented, and the response to it was either rewarded or nonrewarded, and (c) after a delay interval a choice test was given between the initial sample and a new stimulus, with the sample being correct if it had been initially rewarded and incorrect if it had been initially nonrewarded. When the sample and the interpolated stimulus were associated with opposite outcomes (sample rewarded, interpolated stimulus not rewarded or sample not rewarded, interpolated stimulus rewarded), retroactive interference was observed to increase as the similarity of the two stimuli increased. When the two stimuli were either both rewarded or both nonrewarded, retroactive facilitation was observed so long as the sample and interpolated stimuli were similar along either the relevant or an irrelevant dimension. Finally, test probes involving the interpolated stimulus and a new stimulus revealed asymmetrical interactions such that the interpolated stimulus influenced performance on the initial stimulus more than the initial stimulus altered performance on the interpolated stimulus. Taken as a whole, the results are inconsistent with the idea that alternative stimuli are encoded independently of each other. At best, independence may hold only for cases in which the stimuli are not similar to each other.

Animals↗
PubMed1979

Early postnatal physical and behavioural development of degus (Octodon degus).

6 litters of Octodon degus were studied from birth to 10 days of age. Newly-born degus (mean weight 14.6 g) had open eyes, upper and lower pigment, fur, and teeth. Within 3-4 hours of birth they were able to walk supporting their full weight, right themselves rapidly, sit upright on their haunches, or rear upright with support, and vocalize. By the 1st or 2nd day, the young animals displayed functional grooming (face washing, hind-paw scratching, rapid head-shake). Solid food was ingested from day 6, although newborns chewed wood chips and 3-day olds gnawed dried faeces. Young degus were tested daily in an open field apparatus and showed increased activity and exploration, with repeated testing while decreasing distress vocalization after the 4th or 5th day. Degus are proposed for the study of developmental topics since their degree of development at birth allows for immediate testing. The degus studied here seem to be more fully developed at birth than those studied in Britain.

Animals↗
PubMed1977

The ontogeny of plasma osmolality and intravascular volume maintenance during short-term starvation in rats.

Body fluid deviations were examined in albino rats of both genders between 30 and 100 days of age during food deprivation. Plasma volume declined with age in free-feeding control groups. Hypovolemia induced by starvation (4 days) was more intense in 30- to 60-day-old animals than in 80- and 100-day groups. Plasma ismolality concentration of control groups indicated increases with age leveling off after 60 days. The initiation of drinking during fasting was accompanied by physiologically significant elevations in plasma osmolality over ad libitum concentrations at each age tested. In a second experiment, repeated exposure to short periods of food deprivation (2 days) during development resulted in the maintenance of intravascular fluid at control volumes. Longer periods (4 days) of deprivation did not result in savings of intravascular volume loss evidenced during starvation. These results suggest that rats compensate for hypovolemia induced by short-term starvation when provided experience with food restriction during development.

Animals↗