EXPRESS: Inhibitory causal structures in serial and simultaneous feature negative learning

We have previously reported that human participants trained with a simultaneous feature negative discrimination (intermixed A+ / AB- trials) show only modest transfer of inhibitory properties of the feature B to a separately trained excitor in a summation test (Lee & Lovibond, 2021). Self-reported causal structure suggested that many participants learned that the effect of the feature B was somewhat specific to the excitor it had been trained with (modulation), rather than learning that the feature prevented the outcome (prevention). This pattern is reminiscent of the distinction between negative occasion-setting and conditioned inhibition in the animal conditioning literature. However, in animals, occasion-setting is more commonly seen with a serial procedure in which the feature (B) precedes the training excitor (A). Accordingly, we ran three experiments to compare serial with simultaneous training in an allergist causal judgment task. Transfer in a summation test was stronger to a previously modulated test excitor compared to a simple excitor after both simultaneous and serial training. There was a numerical trend towards a larger effect in the serial group, but it failed to reach significance and the Bayes Factor indicated support for the null. Serial training had no differential effect on self-reported causal structure, and did not significantly reduce overall transfer. After both simultaneous and serial training, transfer was strongest in participants who reported a prevention structure, replicating and extending our previous results to a previously modulated excitor. These results suggest that serial feature negative training does not promote a qualitatively different inhibitory causal structure compared to simultaneous training in humans.

Assessment of operator performance during oocyte retrievals: residents’ learning curve and continuous monitoring of senior physicians

Background The learning curve cumulative summation test (LC CUSUM test) allows to define an individualized learning curve and determine the moment when clinical proficiency is attained. After acquisition of the skills, the cumulative summation test (CUSUM test) allows to monitor the maintenance of the required level over time. The LC CUSUM test has been frequently used in the field of Obstetrics and Gynecology (Ob/Gyn) for several procedures, but only once for OR. Methods We performed a retrospective study at Angers university hospital between May 2017 and September 2018. Seven Ob/Gyn residents and 5 senior physicians were included, and all OR performed during that time (n = 690) were analyzed. The performance index assessed was the oocyte retrieval rate (ORR), defined as the ratio of oocytes retrieved to follicles aspirated. We used the LC CUSUM test to analyze the learning curves of residents, and the CUSUM test to monitor the performance of senior physicians. An ORR ≥50% in 60% of retrievals was defined as the threshold for clinical proficiency. Results Six hundred seventy-four oocyte retrieval (OR) were included: 315 were performed by residents, 220 by senior physicians, and 139 by both residents and physicians (mixed retrievals). Four residents (57%) reached the threshold after aspirating 82, 67, 53 and 46 ovaries, respectively. The mean number of ovaries aspirated in order to reach clinical proficiency was 62, and the mean number of weeks needed was 21. The duration of the learning period varied between 26 and 80 days. Two senior physicians (40%) remained proficient across the duration of the study, while two physicians (40%) had one statistically “suboptimal” OR, and one physician (20%) had two suboptimal retrievals. Conclusion There is a large variability in the duration of the learning period and the number of procedures needed for a resident to master OR. Senior physicians maintain an adequate performance.

The effect of conditioned inhibitors and preexposed cues on the outcome-specific Pavlovian-to-instrumental transfer effect in humans

Using a human Pavlovian-to-instrumental transfer (PIT) task, Alarcón and Bonardi showed that the selective elevation of instrumental responding produced by excitatory transfer cues was reduced when these cues were presented with a conditioned inhibitor (CI), relative to a control cue that was simply preexposed. However, previous research has shown that preexposed cues might also acquire inhibitor-like properties. This study aimed to contrast the inhibitory properties of CIs and preexposed cues, using novel stimuli as controls, in summation and PIT tests. Participants were trained to perform two actions, each reinforced with a distinct outcome (O1 or O2). Two images were trained as CIs, each signalling the absence of one of the outcomes, by presenting them with a cue that was otherwise followed by that outcome (e.g., A→O1, AI→no O1). In contrast, the preexposed cues were simply presented in the absence of the outcomes. In the summation test, participants rated the likelihood of the outcomes in the presence of two independently trained excitatory cues, each presented with a CI, a preexposed cue, or a novel stimulus. Similarly, in the PIT test, participants performed both actions in the presence and absence of these compounds. In the summation test, the CIs and the preexposed cues reduced participants’ expectations of the outcomes more than the novel stimuli. However, in the PIT test, only the CIs reduced the selective elevation of responding produced by the transfer cues. These results might reflect distinct properties of stimuli trained as CIs and those simply preexposed.