The Jena Voice Learning and Memory Test (JVLMT): A standardized tool for assessing the ability to learn and recognize voices.

The ability to recognize someone's voice spans a broad spectrum with phonagnosia on the low end and super-recognition at the high end. Yet there is no standardized test to measure an individual's ability of learning and recognizing newly learned voices with samples of speech-like phonetic variability. We have developed the Jena Voice Learning and Memory Test (JVLMT), a 22-min test based on item response theory and applicable across languages. The JVLMT consists of three phases in which participants (1) become familiarized with eight speakers, (2) revise the learned voices, and (3) perform a 3AFC recognition task, using pseudo-sentences devoid of semantic content. Acoustic (dis)similarity analyses were used to create items with various levels of difficulty. Test scores are based on 22 items which had been selected and validated based on two online studies with 232 and 454 participants, respectively. Mean accuracy in the JVLMT is 0.51 (SD = .18) with an empirical (marginal) reliability of 0.66. Correlational analyses showed high and moderate convergent validity with the Bangor Voice Matching Test (BVMT) and Glasgow Voice Memory Test (GVMT), respectively, and high discriminant validity with a digit span test. Four participants with potential super recognition abilities and seven participants with potential phonagnosia were identified who performed at least 2 SDs above or below the mean, respectively. The JVLMT is a promising research and diagnostic screening tool to detect both impairments in voice recognition and super-recognition abilities.

Voices to remember: Comparing neural signatures of intentional and non-intentional voice learning and recognition.

Recent electrophysiological evidence suggests a rapid acquisition of novel speaker representations during intentional voice learning. We investigated effects of learning intention on voice recognition, using a variant of the directed forgetting paradigm. In an old/new recognition task following voice learning, we compared performance and event-related brain potentials (ERPs) for studied voices, half of which had been prompted to be remembered (TBR) or forgotten (TBF). Furthermore, to assess incidental encoding of episodic information, participants indicated for each recognized test voice the ear of presentation during study. During study, TBR voices elicited more positive ERPs than TBF voices (from ∼250 ms), possibly reflecting deeper voice encoding. In parallel, subsequent recognition performance was higher for TBR than for TBF voices. Importantly, above-chance recognition for both learning conditions nevertheless suggested a degree of non-intentional voice learning. In a surprise episodic memory test for voice location, above-chance performance was observed for TBR voices only, suggesting that episodic memory for ear of presentation depended on intentional voice encoding. At test, a left posterior ERP OLD/NEW effect for both TBR and TBF voices (from ∼500 ms) reflected recognition of studied voices under both encoding conditions. By contrast, a right frontal ERP OLD/NEW effect for TBF voices only (from ∼800 ms) possibly reflected additional elaborative retrieval processes. Overall, we show that ERPs are sensitive 1) to strategic voice encoding during study (from ∼250 ms), and 2) to voice recognition at test (from ∼500 ms), with the specific pattern of ERP OLD/NEW effects partly depending on previous encoding intention.