Exploring the effect of testing on forgetting in vocabulary learning: an examination of the bifurcation model

ABSTRACT

Research on the testing effect demonstrated a stronger decrease in performance for repeated studying compared to repeated testing. The bifurcation model attributes this test-delay interaction to different distributions of item memory strength. The present study tested the assumptions of the bifurcation model for learning foreign language vocabulary. We hypothesised an elimination or reduction of the interaction in a test/feedback condition because feedback prevents the bifurcation of item memory strength. Our experiment based on a 3 (Learning Method within: Test, test/feedback, copy)?×?3 (Retention Interval between: Immediate, 1-week, 2-weeks) mixed factorial design with a sample of N = 122. The greatest long-term retention was achieved in the test/feedback condition. The bifurcation model was supported by a reduced test-delay interaction for the test/feedback condition. Further evidence for the bifurcation model is needed as interpretations on the dropout rates of items with different recall success were limited due to a floor effect.     

Using neural response properties to draw the distinction between modal and amodal representations

ABSTRACT

Barsalou has recently argued against the strategy of identifying amodal neural representations by using their cross-modal responses (i.e., their responses to stimuli from different modalities). I agree that there are indeed modal structures that satisfy this “cross-modal response” criterion (CM), such as distributed and conjunctive modal representations. However, I argue that we can distinguish between modal and amodal structures by looking into differences in their cross-modal responses. A component of a distributed cell assembly can be considered unimodal because its responses to stimuli from a given modality are stable, whereas its responses to stimuli from any other modality are not (i.e., these are lost within a short time, plausibly as a result of cell assembly dynamics). In turn, conjunctive modal representations, such as superior colliculus cells in charge of sensory integration, are multimodal because they have a stable response to stimuli from different modalities. Finally, some prefrontal cells constitute amodal representations because they exhibit what has been called ‘adaptive coding’. This implies that their responses to stimuli from any given modality can be lost when the context and task conditions are modified. We cannot assign them a modality because they have no stable relation with any input type.

Abbreviatons: CM: cross-modal response criterion; CCR: conjuntive cross-modal representations; fMRI: functional magnetic resonance imaging; MVPA: multivariate pattern analysis; pre-SMA: pre-supplementary motor area; PFC: prefrontal cortex; SC: superior colliculus; GWS: global workspace