Training experts: individuation without naming is worth it.

There is growing evidence that individuation experience is necessary for development of expert object discrimination that transfers to new exemplars. Individuation training in human studies has primarily used label association tasks where labels are learned at both the individual and more abstract (basic) level, and expertise criterion requires that individual-level judgments become as fast as basic-level judgments. However, there are training situations when the use of labels is not practical (e.g., with animals or some clinical populations). Moreover, labeling itself can facilitate object discrimination, thus it is unclear what role labels play in the acquisition of expertise in such training paradigms. Here, participants completed an online game that did not require labels in which they interacted with novel objects (Greebles) or control objects (Yufos). Games either required individuation or categorization. We then assessed the impact of this exposure on an abridged Greeble training paradigm. As expected, participants who played Yufo games or Greeble categorization games showed a significant basic-level advantage for Greebles in the abridged training paradigm, typical of novices. However, participants who played the Greeble identity game showed a reduced basic-level advantage, suggesting that individuation without labels may be sufficient to acquire perceptual expertise.

Antidepressant treatment can normalize adult behavioral deficits induced by early-life exposure to methylphenidate.

BACKGROUND: Methylphenidate (MPH) is prescribed for the treatment of attention-deficit/hyperactivity disorder. Exposure to MPH before adulthood causes behavioral deficits later in life, including anxiety- and depression-like behaviors and decreased responding to natural and drug rewards. We examined the ability of fluoxetine (FLX), a selective serotonin reuptake blocker, to normalize these MPH-induced behavioral deficits. METHODS: Male rats received MPH (2.0 mg/kg) or saline (VEH) during preadolescence (postnatal day [PD] 20-35). When adults, rats were divided into groups receiving no treatment, acute or chronic FLX, and behavioral reactivity to several emotion-eliciting stimuli were assessed. RESULTS: The MPH-treated rats were significantly less responsive to natural (i.e., sucrose) and drug (i.e., morphine) rewards and more sensitive to stress- and anxiety-eliciting situations. These MPH-induced deficits were reversed by exposure to FLX. CONCLUSIONS: These results indicate that exposure to MPH during preadolescence leads to behavioral alterations that endure into adulthood and that these behavioral deficits can be normalized by antidepressant treatment. These results highlight the need for further research to better understand the effects of stimulants on the developing nervous system and the potential enduring effects resulting from early-life drug exposure.