Asymmetry of generalization decrement in causal learning

Abstract

Two experiments required volunteers to learn which of various "planes" caused high levels of pollution. Novel test items were then rated as causes of pollution. Items created by adding novel features were rated at the same level as that of the original training items but items created by removing features received reduced ratings. This asymmetry of generalization decrement was not predicted by a well-known configural model of stimulus representation (Pearce, 1987, 1994) but was predicted by a recently proposed model of stimulus representation, the replaced-elements model (Brandon, Vogel, & Wagner, 2000).

Symmetrical generalization decrements: Configural stimulus processing in human contingency learning

“…Up to now, studies that have investigated generalization decrement explicitly have routinely observed asymmetrical generalization decrements (Brandon, Vogel, & Wagner, 2000;Glautier, 2004;González, Quinn, & Fanselow, 2003;Wheeler, Amundson, & Miller, 2006 Glautier's (2004) experiments, participants had to rate the amount of air pollution produced by airplanes. Stimuli created by adding novel features (such as markings or guns) to the previously trained airplanes were rated at the same level as the original training stimuli, but stimuli created by removing features led to reduced ratings.…”

Generalization decrements: Further support for flexibility in stimulus processing

“…It doesn't matter how fast you answer; therefore, take the time you need. If ies of Wheeler et al (2006) and Glautier (2004), which had observed asymmetrical decrements. Furthermore, this would be in line with the suggestion of Pineño et al (2005) that there is greater susceptibility to cue competition in causal than in predictive attribution.…”

“…Previously, experiments intended to compare these decrements reported only asymmetrical decrements in human (Glautier, 2004;Wheeler et al, 2006), as well as in nonhuman learning (Brandon et al, 2000;González et al, 2003) 1 . Guided by the question "Under which conditions is processing best described by configural theories, and under which conditions is it best described by elemental theories?…”

“…of Glautier (2004), are causal scenarios. The participants had to rate the likelihood that the meals caused food poisoning, or how much pollution was caused by an airplane, respectively.…”

“…First, for certain discrimination problems, these theories clearly differ in their predictions about which discriminations should be acquired more rapidly (see, e.g., Harris, Livesey, Gharaei, & Westbrook, 2008;Kinder & Lachnit, 2003;Lachnit, Schultheis, König, Üngör, & Melchers, 2008;Redhead & Pearce, 1995;. Second, these theories differ with respect to responding to new stimuli in a test after acquisition (e.g., summation-Glautier, Redhead, Lachnit, 1988;Myers, Vogel, Shin, & Wagner, 2001;Pearce, Aydin, & Redhead, 1997;generalization decrement-Brandon, Vogel, & Wagner, 2000;Glautier, 2004;González, Quinn, & Fanselow, 2003;Wheeler, Amundson, & Miller, 2006). Most current theories of associative learning assume that stimuli are invariably processed in the same way.…”