Lavinia Chai Mei Tan

• Psychology
• Reed College

Rats were given repeated choices between social and nonsocial outcomes, and between familiar and unfamiliar social outcomes. Lever presses on either of 2 levers in the middle chamber of a 3‐chamber apparatus opened a door adjacent to the lever, permitting 45‐s access to social interaction with the rat in the chosen side chamber. In Experiment 1, ra...

Rats were studied in social-release procedures, in which lever presses by one rat released a second rat from a tube restraint for a period of social interaction. Both the fixed-ratio price and the duration of social contact were varied systematically on a within-subject basis, generating a total of 27 demand functions across six subjects. Overall,...

The present research measured social reinforcement in rats, using a social-release procedure in which lever presses permitted 10-s access to a familiar social partner. The work requirements for reinforcement increased systematically according to progressive-ratio (PR) schedules. Social and food reinforcement value were compared across blocks of ses...

Pigeons' demand and preference for specific and generalized tokens was examined in a token economy. Pigeons could produce and exchange different colored tokens for food, for water, or for food or water. Token production was measured across three phases, which examined: (1) across-session price increases (typical demand curve method); (2) within-ses...

Does socially desirable responding (SDR) represent a threat to the validity of dynamic risk assessment in sex offenders’ self-reports? We studied a sample of men (N = 218) who completed a psychometric assessment battery while enrolled at Kia Marama, a prison-based treatment program for sexual offenders against children. SDR, as measured by the Marl...

Three pairs of rats were trained to synchronize their lever pressing according to a mutual reinforcement contingency, in which alternating lever presses that fell within a 500-ms window were reinforced with food. In Experiment 1, rats worked in adjacent chambers separated by a transparent barrier, and the effects of the mutual reinforcement conting...

The present study examined the social foraging of rats in an open arena. The relative quantity of food varied across two food sources, or "patches." Five food quantity ratios (1:1, 1:2, 1:8, 8:1, 2:1) were presented in a series of 30-min sessions. Ratios varied randomly across 6-min components within sessions (Phase 1), or in a consistent order acr...

To update trends in mortality by ethnic group from the New Zealand Census-Mortality Study (NZCMS), by additionally linking 2004-06 mortality records to the 2001 Census. To investigate possible bias from this extended linkage, especially for Pacific and Asian people who emigrate more frequently. Anonymous and probabilistic record linkage of 2004-06...

Group and individual choice behavior in dynamic social environments was examined in a laboratory foraging analogue. Five rats were studied across multiple sessions in a free-ranging paradigm, where food reinforcement was delivered from two patches according to variable time intervals. Five reinforcement ratios (1:1, 1:4, 1:8, 8:1, 4:1) were present...

The nonverbal discrimination of relative and absolute number of sequential visual stimuli was investigated with humans in bisection, reproduction, and report tasks. Participants viewed a sequence of 40 red and black objects on each trial, randomly intermixed, and had to identify the number of red objects, which varied from 1 to 20. To prevent the u...

To identify patient factors that are associated with a higher risk of comorbidity, and to assess the impact of comorbidity on risk of in-hospital death, length of stay and 5-year all-cause survival among a large cohort of patients with colon cancer in New Zealand. Comorbidity data were collected from patients who were diagnosed with colon cancer an...

We trained 4 pigeons in a numerical bisection task to discriminate between pairs of keylight flashes with a ratio of 1:3 (2 vs. 6, 4 vs. 12, and 8 vs. 24) that were presented in a sample phase. Responses to the blue key were reinforced after a sequence of a larger number of flashes, and responses to the white key were reinforced after a sequence of...

To provide an update for the assessment of discrepancies in ethnicity counts in the 2001 census and mortality data for the 2004-2006 period. 2001 census anonymously and probabilistically linked to 5 years of subsequent mortality data (135,849 eligible mortality records), allowing a comparison of ethnicity recording for the years 2001-2004 and 2004-...

The retention interval (RI) between the sample and production phase in a numerical reproduction task was varied to determine whether a "produce-small" effect would be obtained with increased delays. Four pigeons were trained with a retention interval of 2s, and then tested with intervals of 0.5s and 8s. Results showed a number-dependent, "produce-l...

Social desirability--the desire to make a favorable impression on others-poses a significant threat to the validity of self-reports. This review examines research on social desirability in both forensic and nonforensic populations with the goal of identifying how best to minimize threats to the validity of research with sexual offenders. Although s...

Pigeons were trained to match the number of responses made during a production phase to the number of keylight flashes (2, 4, or 6) in a previous sample phase. In Experiment 1, there were 2 conditions in which the flashes were programmed to occur at a constant rate or within a constant overall duration. For both conditions, although accuracy was re...

The ability to discriminate relative and absolute number has been researched widely in both human and nonhuman species. However, the full extent of numerical ability in nonhuman animals, and the nature of the underlying numerical representation, on which discriminations are based, is still unclear. The aim of the current research was to examine the...