Practice Increases the Efficiency of Evidence Accumulation in Perceptual Choice.

Brown, Scott; Heathcote, Andrew · 2005 · Journal of Experimental Psychology Human Perception & Performance

DOI: 10.1037/0096-1523.31.2.289

archive: archived pipeline: cataloged verified

Get this paper ↗ (DOI — opens at the source; we link to it, we don't host it)

Summary

This study investigates how practice influences the efficiency of evidence accumulation during perceptual choice tasks. The authors address a fundamental distinction in response time models: whether evidence accumulation is "lossless" (all evidence weighted equally) or "leaky" (early evidence forgotten over time). Drawing from the self-exciting expert competitor (SEEXC) model of skill acquisition, the paper tests the hypothesis that practice reduces leakage, thereby increasing the weight of early-arriving evidence. This prediction aims to explain the exponential form of the law of practice, which previous neural accumulator models failed to accommodate without assuming changes in input strength rather than accumulation dynamics. To test this hypothesis while avoiding confounds from conscious strategy changes, the authors employed a metacontrast masked priming paradigm. Eight undergraduate participants performed an orientation discrimination task involving square and diamond shapes. Crucially, prime stimuli were presented briefly and masked by the target stimulus, rendering them consciously undetectable to most participants. This design ensured that any observed effects of practice on prime efficacy could not be attributed to deliberate strategic adjustments. The experiment consisted of two one-hour sessions on consecutive days, with response times measured using high-precision serial mouse inputs. The stimuli were presented in rapid succession, with a short interstimulus interval, ensuring that decision processing occurred well before conscious awareness of the prime could influence the response. The results supported the hypothesis that practice decreases leakage in evidence accumulation. The study found that the effects of the subliminal prime stimuli increased significantly with practice. Specifically, as participants gained experience, the influence of the early-arriving prime information on response times and error rates grew stronger. This finding aligns with the prediction that reduced leakage allows earlier evidence to retain more weight in the decision process. The data also demonstrated that the form of the law of practice observed in the participants' performance was consistent with the SEEXC model. By showing that practice enhances the efficacy of unconscious primes, the authors provided empirical evidence that the mechanism of skill acquisition involves a change in the dynamics of evidence integration rather than merely an increase in signal strength or a shift in conscious strategy. The significance of these findings lies in their contribution to the understanding of perceptual decision-making and skill acquisition. The results challenge models that assume static accumulation parameters and support theories where practice modifies the neural or cognitive mechanisms of integration, specifically by reducing leakage through increased self-excitation. This implies that expertise is characterized not just by faster processing or stronger signals, but by a more efficient integration of early sensory information. The use of metacontrast masking successfully isolated these dynamics from conscious control, offering a robust methodological approach for studying the unconscious components of perceptual choice.

Key finding

Practice increases the efficiency of evidence accumulation in perceptual choice by reducing leakage, as evidenced by the increased effect of subliminal prime stimuli on response times after training.

Methodology

lab_experiment

Sample size: 8

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via author_sweep_intake on 2026-05-28.

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• automaticity skill acquisition