Different procedures are often used across experiments to estimate the degree of delay discounting, a common measure of impulsivity. In all procedures, participants indicate their choice between a reward available immediately and one available after a delay. The present experiment determined whether there are differences in the degree of discounting for a hypothetical $100 produced by a procedure that titrates the immediate amount (titrating sequence procedure) versus a procedure that presents a fixed sequence of immediate amounts (fixed sequence procedure) using a within-subject design. The adult human participants showed no significant differences in degree of discounting between procedures as assessed by a hyperboloid model and the Area Under the Curve. Furthermore, the Area Under the Curve values from the two procedures showed a strong positive correlation. These findings suggest there may be no systematic difference between the degree of delay discounting as estimated by the titrating sequence and fixed sequence procedures. Given the apparent similarities in the results, it appears researchers may be justified in basing their choice of which procedure to use on convenience.

Both time and numerosity can be represented continuously as analog properties whose discrimination conforms to Weber’s Law, suggesting that the two properties may be represented similarly. Recent research suggests that the representation of time is influenced by the presence of emotional stimuli. If time and numerosity share a common cognitive representation, it follows that a similar relationship may exist between emotional stimuli and the representation of numerosity. Here, we provide evidence that emotional stimuli significantly affect humans’ estimation of visual numerosity. During a numerical bisection task, enumeration of emotional stimuli (angry faces) was more accurate compared to enumeration of neutrally valenced stimuli (neutral faces), demonstrating that emotional stimuli affect humans’ visual representation of numerosity as previously demonstrated for time. These results inform and broaden our understanding of the effect of negative emotional stimuli on psychophysical discriminations of quantity.

One way to investigate the evolution of cognition is to compare the abilities of phylogenetically related species. The domestic dog (Canis lupus familiaris), for example, still shares cognitive abilities with the coyote (Canis latrans). Both of these canids possess the ability to make psychophysical “less/more” discriminations of food based on quantity. Like many other species including humans, this ability is mediated by Weber’s Law: discrimination of continuous quantities is dependent on the ratio between the two quantities. As two simultaneously presented quantities of food become more similar, choice of the large or small option becomes random in both dogs and coyotes. It remains unknown, however, whether these closely related species within the same family – one domesticated, and one wild – make such quantitative comparisons with comparable accuracy. Has domestication honed or diminished this quantitative ability? Might different selective and ecological pressures facing coyotes drive them to be more or less able to accurately represent and discriminate food quantity than domesticated dogs? This study is an effort to elucidate this question concerning the evolution of non-verbal quantitative cognition. Here, we tested the quantitative discrimination ability of 16 domesticated dogs. Each animal was given nine trials in which two different quantities of food were simultaneously displayed to them. The domesticated dogs’ performance on this task was then compared directly to the data from 16 coyotes’ performance on this same task reported by Baker et al. (2011). The quantitative discrimination abilities between the two species were strikingly similar. Domesticated dogs demonstrated similar quantitative sensitivity as coyotes, suggesting that domestication may not have significantly altered the psychophysical discrimination abilities of canids. Instead, this study provides further evidence for similar non-verbal quantitative abilities across multiple species.

Advances in Web technology and widespread use of the Internet have provided survey researchers with an inexpensive and efficient method of accessing a vast participant pool and the ability to target specific populations that might otherwise be difficult to locate. Buchanan and Smith (1999) argued that online or Internet surveys might have better psychometric properties than do identical paper-and-pencil (PP) or computer-based (CB) surveys. Past research has shown that those taking Internet surveys provide longer, more detailed answers to open-ended questions than do those taking PP surveys (Denscombe, 2008). To date, there have been numerous studies examining the equivalence of PP, CB, and Internet surveys. For the most part, past research has shown that the results from PP, CB, and Internet surveys are similar. For example, past research has demonstrated the comparability of PP, CB, and Internet personality surveys (Birnbaum, 2004;Bliven, Kaufman, & Spertus, 2001;Buchanan & Smith, 1999;Chuah, Drasgow, & Roberts, 2006;Gosling, Vazire, Srivastava, & John, 2004;Reimers & Stewart, 2007;Riva, Teruzzi, & Anolli, 2003;Williams, McGraw, & Tew, 1999). Further support for the comparability between PP, CB, and Internet-administered surveys has been demonstrated in several areas, including methodology (Birnbaum, 2004;Gosling et al., 2004;McGraw, Tew, & Williams, 2000;Riva et al., 2003), health (Bliven et al., 2001), training (Luthans, Avey, & Patera, 2008), transformational leadership (Cole, Bedeian, & Field, 2006), associative learning (Vadillo, Bárcena, & Matute, 2006), and reaction time (Reimers & Stewart, 2007).Although the Internet presents many benefits to survey methodology (Gosling et al., 2004), an equivalent response across survey methods does not necessarily indicate that the samples are interchangeable. For example, whereas the Internet might provide access to a more diverse sample, Internet surveys may be biased toward participants who are young, educated, and of middle to high socioeconomic status. Internet samples might be volunteering solely out of curiosity or interest in the research topic, compared with those recruited by traditional methods who might be motivated by course credit or other compensation. Furthermore, the environmental and physi- Internet research is appealing because it is a cost-and time-efficient way to access a large number of participants; however, the validity of Internet research for important subjective well-being (SWB) surveys has not been adequately assessed. The goal of the present study was to validate the Satisfaction With Life Scale (SWLS; Diener, Emmons, Larsen, & Griffin, 1985), the Positive and Negative Affect Schedule (PANAS-X; Watson & Clark, 1994), and the Subjective Happiness Scale (SHS; Lyubomirsky & Lepper, 1999) for use on the Internet. This study compared the quality of data collected using paper-based (paper-and-pencil version in a lab setting), computer-based (Web-based version in a lab setting), and Internet (Web-based version on a computer of the participant's ...

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