High Cognitive Load is Associated with Increased Associative Interference
Post by Shireen Parimoo
The takeaway
Associative interference occurs when our prior knowledge interferes with our memory for newly learned associative information. This effect is enhanced when processing resources are reduced under high cognitive load.
What's the science?
Our brain functions by linking related items in memory - otherwise known as associative memory. Sometimes, our prior knowledge or associations can hinder our ability to learn new associations, an effect known as associative interference. How our brain reacts to associative interference when cognitive resources are low, is not clear. This week in Scientific Reports, Baror and Bar conducted a series of associative memory tests with varying levels of cognitive load and memory demands to investigate the impact of reduced processing capacity on associative interference.
How did they do it?
The authors conducted several memory experiments that assessed associative interference under different levels of cognitive load using explicit (Exp. 1-3) and implicit (Exp. 4) memory paradigms. In Exp. 1a and 1b, participants first intentionally learned word pairs (learning phase) that consisted of semantically related (e.g., Salt-Pepper) or unrelated words (e.g., Salt-Mouse). They then completed a cued recognition test in which a cue word (e.g., Salt) was followed by a target and distractor. There were three conditions based on the semantic relatedness of the cue-distractor pair: (i) related target, unrelated distractor (Pepper/Tree), (ii) unrelated target, unrelated distractor (Mouse/Tree), and (iii) unrelated target, related distractor (Mouse/Cheese). During the test phase, participants also performed a working memory task ranging from low to high cognitive load. High cognitive load was hypothesized to reduce the processing resources available for memory encoding. Exp. 1b included an additional block of learning and test phase trials that were expected to further reduce processing resources over time.
In Exp. 2 and 3, rather than relying on prior knowledge, the authors assessed associative interference from incidentally learned associations. In Exp. 2, individual words were sequentially presented in different colored fonts and participants were instructed to associate consecutive words that appeared in the same color (cue-target pair; intentional learning). These word pairs appeared four times throughout the learning phase and were always preceded by the same word in a different color (pre-cue word), forming an incidental association with the cue word. In the cued recognition test, the distractor was either the pre-cue word or an unrelated word. As before, participants completed a working memory task with low and high cognitive load during the test phase. Exp. 3 was similar, except participants learned associations between pairs of pictures (intentional learning) that were always preceded by the same pre-cue picture (incidental learning).
Lastly, the authors used a contextual priming task to assess associative interference under implicit memory conditions (Exp. 4). They used prime-target pairs that were unrelated or were weakly, moderately, or strongly related to each other. Participants provided object/non-object judgments for the targets while concurrently performing the digit span task under low and high cognitive load. Reaction times to target object recognition were examined as a function of cognitive load and prime-target relatedness.
What did they find?
Target recognition was generally higher under low cognitive load than high cognitive load (Exp. 1 and 2). However, the effect of cognitive load was only present when the distractor was related to the cue word. Thus, reduced processing capacity under high load led to interference from previously learned associations between the cue and distractor. Similarly, reduced processing resources from completing an additional block of the experiment (Exp. 1b) only affected memory when the distractor was related to the cue, but not when the distractor was unrelated to the cue. Together, these results indicate that reducing processing resources by increasing cognitive load and time on task independently contribute to associative interference during recognition.
A similar pattern of results emerged when cue-distractor associations were incidentally learned during the learning phase (Exp. 2 and 3). There was no load effect on target memory with unrelated distractors, but memory accuracy was reduced under high load when the distractor was incidentally associated with the cue. High cognitive load, therefore, interfered with associative retrieval and generalized to both words and pictures. Finally, participants were faster to identify objects that were related to the prime than those that were unrelated (Exp. 4). Interestingly, object recognition for strongly related targets was fastest under low load but slowest under high load, suggesting that reduced cognitive processing capacity also delays the perceptual processing of strongly related information.
What's the impact?
The results of this study provide evidence in favor of the idea that decreasing the available processing resources increases associative interference in memory. These findings are important for informing social and educational domains, where increased stress or too much cognitive load might result in biasing towards previously learned, and potentially misleading information.