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. Author manuscript; available in PMC: 2019 Nov 14.

Published in final edited form as: Cognition. 2016 Jun 20;155:8–22. doi: 10.1016/j.cognition.2016.05.020

Fig. 3 — Task rules (A) and example trial events for the four different conditions (B–E). (A) A second order rule related three contextual elements, a digit (1, 2, 3), a letter (A, B), and a symbol ( ,❄), to a response. As depicted, the digit acts as higher order context such that its identity determines whether the symbol (digit = 1), the letter (digit = 2), or both (digit = 3) determines the response. (B–E) On each trial of the experiment, a digit, letter, and symbol are presented in an unpredictable order. At the end of each trial, participants use response mappings presented at the bottom of the screen to indicate whether the target item, as specified by the rule, is shown on the left or right side of the screen. Left or right is indicated by a button press. The correct response in all example trials is “left”. (B) When the “1” appears first (context first-selective), participants know that they need only input the “ ” into working memory and can ignore the “A”. Thus, an input gating strategy is available. (C) When the “1” appears last, (context last-selective), participants have to input both “ ” and “A” into working memory, as they do not know which will be relevant. Then, at the final context presentation, they select the “ ” from working memory to guide their response. Hence, they must use an output gating strategy. (D and E) In order to control for differences in working memory load in context first vs. context last conditions, a global context cue (the digit “3”) specifies that a conjunction of both lower-level items determines the correct response. In contrast to the selective context cues (the digits “1” or “2”), a global context cue always requires holding two items in working memory, irrespective of whether it appears first (D) or last (E).

Inline graphic — Task rules (A) and example trial events for the four different conditions (B–E). (A) A second order rule related three contextual elements, a digit (1, 2, 3), a letter (A, B), and a symbol ( ,❄), to a response. As depicted, the digit acts as higher order context such that its identity determines whether the symbol (digit = 1), the letter (digit = 2), or both (digit = 3) determines the response. (B–E) On each trial of the experiment, a digit, letter, and symbol are presented in an unpredictable order. At the end of each trial, participants use response mappings presented at the bottom of the screen to indicate whether the target item, as specified by the rule, is shown on the left or right side of the screen. Left or right is indicated by a button press. The correct response in all example trials is “left”. (B) When the “1” appears first (context first-selective), participants know that they need only input the “ ” into working memory and can ignore the “A”. Thus, an input gating strategy is available. (C) When the “1” appears last, (context last-selective), participants have to input both “ ” and “A” into working memory, as they do not know which will be relevant. Then, at the final context presentation, they select the “ ” from working memory to guide their response. Hence, they must use an output gating strategy. (D and E) In order to control for differences in working memory load in context first vs. context last conditions, a global context cue (the digit “3”) specifies that a conjunction of both lower-level items determines the correct response. In contrast to the selective context cues (the digits “1” or “2”), a global context cue always requires holding two items in working memory, irrespective of whether it appears first (D) or last (E).