Feature-positive discriminations during a spatial-search task with humans

Abstract

During feature-positive operant discriminations, a conditional cue, X, signals whether responses made during a second stimulus, A, are reinforced. Few studies have examined how landmarks, which can be trained to control the spatial distribution of responses during search tasks, might operate under conditional control. We trained college students to search for a target hidden on a computer monitor. Participants learned that responses to a hidden target location signaled by a landmark (e.g., A) would be reinforced only if the landmark was preceded by a colored background display (e.g., X). In Experiment 1, participants received feature-positive training (+←YB/ XA→+/A-/B-) with the hidden target to the right of A and to left of B. Responding during nonreinforced transfer test trials (XB-/YA-) indicated conditional control by the colored background, and spatial accuracy indicated a greater weighting of spatial information provided by the landmark than by the conditional cue. In Experiments 2a and 2b, the location of the target relative to landmark A was conditional on the colored background (+←YA/ XA→+/ ZB→+/ +←C /A-/B-). At test, conditional control and a greater weighting for the landmark's spatial information were again found, but we also report evidence for spatial interference by the conditional stimulus. Overall, we found that hierarchical accounts best explain the observed differences in response magnitude, whereas spatial accuracy was best explained via spatial learning models that emphasize the reliability, stability, and proximity of landmarks to a target.

Cue integration in spatial search for jointly learned landmarks but not for separately learned landmarks.

“…Therefore, only the horizontal orientation of the stimuli was used in subsequent experiments. The unequal weighting given to the two landmarks supports the suggestion that cue reliability is influenced by proximity to the goal (Ruprecht et al, 2014) and also indicates that our manipulation of the cue reliability was successful. The integration found in Experiment 1 is consistent with other evidence for cue combination in humans and animals (Byrne & Crawford, 2010; Cheng et al, 2007; Legge et al, 2016).…”

“…Based on previous studies, we speculated that if humans combine information from multiple landmarks, the information from each landmark would be weighted based on the landmark’s “certainty” in specifying the goal location. Ruprecht, Wolf, Quintana, and Leising (2014) have suggested that spatial accuracy is a function of a landmark’s proximity to the goal, its stability (in terms of the variance of the landmark-goal vector across trials), as well as the reward probability signaled by the landmark. In other words, proximity, stability, and reward probability can all be seen as determinants of the certainty of the landmarks with respect to finding the goal.…”

“…In our studies, the landmarks were far enough from the goal that they could not serve as beacons (i.e., beacons are cues located near enough to the goal that distance and direction from the cues does not need to be encoded). Moreover, in contrast to some other studies that used multiple cues (Ruprecht et al, 2014; Sturz & Bodily, 2010), we used a continuous search space (along a single dimension) rather than discrete response locations; this provided more spatial response resolution so that we could detect evidence of compromise during conflict situations.…”

Pavlovian occasion setting in human fear and appetitive conditioning: Effects of trait anxiety and trait depression

“…Additionally, occasion setting has received very little attention in human research (Baeyens et al, 2001(Baeyens et al, , 2004Balea et al, 2020;De Houwer et al, 2005;Declercq & De Houwer, 2008;Dibbets et al, 2002;Franssen et al, 2017;Ruprecht et al, 2014;van Vooren et al, 2012). Most of the occasion setting experiments in humans are done with aversive conditioning (Baeyens et al, 2001(Baeyens et al, , 2004Balea et al, 2020;Dibbets et al, 2002;van Vooren et al, 2012), and even the "aversive" stimuli are usually fairly mild (e.g., losing points or playing a flashing screen with sound pattern, as opposed to electric shocks; De Houwer et al, 2005).…”

“…Most of the occasion setting experiments in humans are done with aversive conditioning (Baeyens et al, 2001(Baeyens et al, , 2004Balea et al, 2020;Dibbets et al, 2002;van Vooren et al, 2012), and even the "aversive" stimuli are usually fairly mild (e.g., losing points or playing a flashing screen with sound pattern, as opposed to electric shocks; De Houwer et al, 2005). There are very few appetitive occasion setting experiments in humans; the existing ones utilize gaining or losing points (Dibbets et al, 2002) or obtaining treasure chests (Ruprecht et al, 2014) based on an instrumental response.…”