Why worry about theory‐dependence? Circularity,minimal empiricality and reliability

It is a widely shared view among philosophers of science that the theory‐dependence (or theory‐ladenness) of observations is worrying, because it can bias empirical tests in favour of the tested theories. These doubts are taken to be dispelled if an observation is influenced by a theory independent of the tested theory and thus circularity is avoided, while (partially) circular tests are taken to require special attention. Contrary to this consensus, it is argued that the epistemic value of theory‐dependent tests has nothing to do with the circularity or non‐circularity of the test, but is instead based on the minimal empiricality and reliability of observations. Since theory‐dependence does not in general prevent observations fulfilling these requirements, it should not be regarded as a phenomenon that is basically detrimental, but as neutral with respect to successful scientific knowledge gathering.     

Aging and the discrimination of 3-D shape from motion and binocular disparity

Two experiments evaluated the ability of younger and older adults to visually discriminate 3-D shape as a function of surface coherence. The coherence was manipulated by embedding the 3-D surfaces in volumetric noise (e.g., for a 55?% coherent surface, 55?% of the stimulus points fell on a 3-D surface, while 45?% of the points occupied random locations within the same volume of space). The 3-D surfaces were defined by static binocular disparity, dynamic binocular disparity, and motion. The results of both experiments demonstrated significant effects of age: Older adults required more coherence (tolerated volumetric noise less) for reliable shape discrimination than did younger adults. Motion-defined and static-binocular-disparity-defined surfaces resulted in similar coherence thresholds. However, performance for dynamic-binocular-disparity-defined surfaces was superior (i.e., the observers?? surface coherence thresholds were lowest for these stimuli). The results of both experiments showed that younger and older adults possess considerable tolerance to the disrupting effects of volumetric noise; the observers could reliably discriminate 3-D surface shape even when 45?% of the stimulus points (or more) constituted noise.     

Retention and extinction of delay eyeblink conditioning are modulated by central cannabinoids

Rats administered the cannabinoid agonist WIN55,212-2 or the antagonist SR141716A exhibit marked deficits during acquisition of delay eyeblink conditioning, as noted by Steinmetz and Freeman in an earlier study. However, the effects of these drugs on retention and extinction of eyeblink conditioning have not been assessed. The present study examined the effects of WIN55,212-2 and SR141716A on retention and extinction of delay eyeblink conditioning in rats. Rats were given acquisition training for five daily sessions followed by one session of retention training with subcutaneous administration of 3 mg/kg of WIN55,212-2 or 5 mg/kg of SR141716A and an additional session with the vehicle. Two sessions of extinction training were then given with WIN55,212-2, SR141716A, or vehicle. Retention and extinction were impaired by WIN55,212-2, whereas SR141716A produced no deficits. The extinction deficit in rats given WIN55,212-2 was observed only during the first session, suggesting a specific impairment in short-term plasticity mechanisms. The current results and previous findings indicate that the cannabinoid system modulates cerebellar contributions to acquisition, retention, and extinction of eyeblink conditioning.     

Systemic 5-bromo-2-deoxyuridine induces conditioned flavor aversion and c-Fos in the visceral neuraxis

5-bromo-2-deoxyuridine (BrdU) is often used in studies of adult neurogenesis and olfactory learning, but it can also have toxic effects on highly proliferative tissue. We found that pairing Kool-Aid flavors with acute systemic injections of BrdU induced strong conditioned flavor aversions. Intermittent injections during Kool-Aid-glucose conditioning interfered with learning of a conditioned flavor-nutrient preference. Acute injection of BrdU also elevated plasma corticosterone levels and induced c-Fos in the visceral neuraxis. Thus, acute or intermittent systemic injections of BrdU (50-200 mg/kg) have aversive effects that may interfere with learning.     

Emotion enhanced retention of cognitive skill learning

Ample evidence suggests that emotional arousal enhances declarative/episodic memory. By contrast, there is little evidence that emotional enhancement of memory (EEM) extends to procedural skill based memory. We examined remote EEM (1.5-month delay) for cognitive skill learning using the weather prediction (WP) probabilistic classification task. Participants viewed interleaved emotionally arousing or neutral pictures during WP acquisition. Arousal retarded initial WP acquisition. While participants in the neutral condition showed substantial forgetting of WP learning across the 1.5-month delay interval, the arousal condition showed no evidence of forgetting across the same time period. Thus, arousal during encoding determined the mnemonic fate of cognitive skill learning. Emotional enhancement of WP retention was independent of verbally stated knowledge of WP learning and EEM for the picture contexts in which learning took place. These results reveal a novel demonstration of EEM for cognitive skill learning, and suggest that emotional arousal may in parallel enhance the neural systems that support procedural learning and its declarative context.     

Hot or cold: is communicating anger or threats more effective in negotiation?

Is communicating anger or threats more effective in eliciting concessions in negotiation? Recent research has emphasized the effectiveness of anger communication, an emotional strategy. In this article, we argue that anger communication conveys an implied threat, and we document that issuing threats is a more effective negotiation strategy than communicating anger. In 3 computer-mediated negotiation experiments, participants received either angry or threatening messages from a simulated counterpart. Experiment 1 showed that perceptions of threat mediated the effect of anger (vs. a control) on concessions. Experiment 2 showed that (a) threat communication elicited greater concessions than anger communication and (b) poise (being confident and in control of one's own feelings and decisions) ascribed to the counterpart mediated the positive effect of threat compared to anger on concessions. Experiment 3 replicated this positive effect of threat over anger when recipients had an attractive alternative to a negotiated agreement. These findings qualify previous research on anger communication in negotiation. Implications for the understanding of emotion and negotiation are discussed.