Benefits of fading in perceptual learning are driven by more than dimensional attention

Abstract

Individuals learn to classify percepts effectively when the task is initially easy and then gradually increases in difficulty. Some suggest that this is because easy-to-discriminate events help learners focus attention on discrimination-relevant dimensions. Here, we tested whether such attentional-spotlighting accounts are sufficient to explain easy-to-hard effects in auditory perceptual learning. In two experiments, participants were trained to discriminate periodic, frequency-modulated (FM) tones in two separate frequency ranges (300–600 Hz or 3000–6000 Hz). In one frequency range, sounds gradually increased in similarity as training progressed. In the other, stimulus similarity was constant throughout training. After training, participants showed better performance in their progressively trained frequency range, even though the discrimination-relevant dimension across ranges was the same. Learning theories that posit experience-dependent changes in stimulus representations and/or the strengthening of associations with differential responses, predict the observed specificity of easy-to-hard effects, whereas attentional-spotlighting theories do not. Calibrating the difficulty and temporal sequencing of training experiences to support more incremental representation-based learning can enhance the effectiveness of practice beyond any benefits gained from explicitly highlighting relevant dimensions.

The Visual Acuity of Rats in Touchscreen Setups

“…All averages are expressed as mean ± SEM. A gradual increase in task difficulty was used as this has been shown to improve learning as opposed to training with difficult stimuli [19].…”

Learning-related improvements in auditory detection sensitivities correlate with neural changes observable during active and passive sound processing

“…Data analyses associated with this metacognitive portion of the task will not be presented here, but will be reported in a separate paper. This fading from easy to hard SNRs was employed so that: 1) the demands of the task were made obvious to participants; and 2) perceptual learning would be effectively produced (for review, see Orduña et al; 24 Wisniewski et al 7 ). All of the training took place in a single session.…”

“…For instance, practice can improve detection thresholds, 2,3 increase sensitivities to differences between simple 4 and complex sounds 5 , and alter spatial acuities (for review, see Wright & Zhang 6 ). Given the variety of tasks that show this perceptual learning, it is perhaps unsurprising that the processes behind experience-related changes in perception have been hotly debated (for review, see Wisniewski, Radell, Church, & Mercado 7 ). Explanations vary between selective attention views (i.e., learners determine the correct features to attend), 8 and views that posit relatively long-term changes to sensory representations and their read-out connections.…”

Easy-to-hard effects in perceptual learning depend upon the degree to which initial trials are “easy”

“…This phenomenon has been referred to as the easy-to-hard effect. It occurs in several modalities and species (for review, see Wisniewski, Radell, Church, & Mercado, 2017).…”

“…The debate between attentional spotlighting and incremental learning theories continues. In one recent study, people were trained to discriminate auditory frequency modulation (FM) rates in two different frequency ranges (300-600 Hz or 3000-6000 Hz; Wisniewski, et al, 2017). In one frequency range, difficulty faded from easy to hard.…”