Professional Education

  • Master of Arts, Middle Tennessee State University (2008)
  • Doctor of Philosophy, Utah State University (2013)
  • Bachelor of Arts, New Mexico State Univ, Las Cruces (2005)

Stanford Advisors

Research & Scholarship


Journal Articles

  • Multiple visual quantitative cues enhance discrimination of dynamic stimuli during infancy JOURNAL OF EXPERIMENTAL CHILD PSYCHOLOGY Baker, J. M., Mahamane, S. P., Jordan, K. E. 2014; 122: 21-32


    Infants possess basic capabilities to assess various quantitative properties such as number, size, and time. Preverbal discriminations are approximate, however, and are similarly limited across these dimensions. Here, we present the first evidence that multiple sources of quantitative unisensory information about dynamic stimuli-namely, simultaneous visual cues to changes in both number and surface area-may accelerate 6-month-olds' quantitative competence. Using a habituation-dishabituation paradigm, results from Experiment 1 demonstrate that, when provided with such visual cues to multiple quantitative properties that occur in the same direction, infants make more precise discriminations than has been shown when they receive information about either cue alone. Moreover, Experiment 2 demonstrates that infants' discrimination also benefits from simultaneous visual cues to quantitative changes that occur in opposite directions. Finally, Experiment 3 demonstrates that these findings are not driven by infants' ability to discriminate a 2:3 ratio change in surface area of a dynamic stimulus alone. Thus, we hypothesize that enhanced quantitative discrimination occurs because simultaneous visual quantitative changes may be more salient than single-source information, which could better recruit attention and result in more precise learning and remembering.

    View details for DOI 10.1016/j.jecp.2013.12.007

    View details for Web of Science ID 000334900700002

    View details for PubMedID 24518049

  • The evolution of self-control. Proceedings of the National Academy of Sciences of the United States of America MacLean, E. L., Hare, B., Nunn, C. L., Addessi, E., Amici, F., Anderson, R. C., Aureli, F., Baker, J. M., Bania, A. E., Barnard, A. M., Boogert, N. J., Brannon, E. M., Bray, E. E., Bray, J., Brent, L. J., Burkart, J. M., Call, J., Cantlon, J. F., Cheke, L. G., Clayton, N. S., Delgado, M. M., DiVincenti, L. J., Fujita, K., Herrmann, E., Hiramatsu, C., Jacobs, L. F., Jordan, K. E., Laude, J. R., Leimgruber, K. L., Messer, E. J., Moura, A. C., Ostojic, L., Picard, A., Platt, M. L., Plotnik, J. M., Range, F., Reader, S. M., Reddy, R. B., Sandel, A. A., Santos, L. R., Schumann, K., Seed, A. M., Sewall, K. B., Shaw, R. C., Slocombe, K. E., Su, Y., Takimoto, A., Tan, J., Tao, R., van Schaik, C. P., Virányi, Z., Visalberghi, E., Wade, J. C., Watanabe, A., Widness, J., Young, J. K., Zentall, T. R., Zhao, Y. 2014; 111 (20): E2140-8


    Cognition presents evolutionary research with one of its greatest challenges. Cognitive evolution has been explained at the proximate level by shifts in absolute and relative brain volume and at the ultimate level by differences in social and dietary complexity. However, no study has integrated the experimental and phylogenetic approach at the scale required to rigorously test these explanations. Instead, previous research has largely relied on various measures of brain size as proxies for cognitive abilities. We experimentally evaluated these major evolutionary explanations by quantitatively comparing the cognitive performance of 567 individuals representing 36 species on two problem-solving tasks measuring self-control. Phylogenetic analysis revealed that absolute brain volume best predicted performance across species and accounted for considerably more variance than brain volume controlling for body mass. This result corroborates recent advances in evolutionary neurobiology and illustrates the cognitive consequences of cortical reorganization through increases in brain volume. Within primates, dietary breadth but not social group size was a strong predictor of species differences in self-control. Our results implicate robust evolutionary relationships between dietary breadth, absolute brain volume, and self-control. These findings provide a significant first step toward quantifying the primate cognitive phenome and explaining the process of cognitive evolution.

    View details for DOI 10.1073/pnas.1323533111

    View details for PubMedID 24753565

  • The impact of emotion on numerosity estimation FRONTIERS IN PSYCHOLOGY Baker, J. M., Rodzon, K. S., Jordan, K. 2013; 4


    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.

    View details for DOI 10.3389/fpsyg.2013.00521

    View details for Web of Science ID 000331187700001

    View details for PubMedID 23950754

  • A study comparing virtual manipulatives with other instructional treatments in third- and fourth-grade glassrooms Journal of Education Moyer-Packenham, P., Baker, J. M., Westenskow, A., Anderson, K., Shumway, J., Rodzon, K., Jordan, K. E. 2013; 193 (2): 25-39
  • A shared system of representation governing quantity discrimination in canids. Frontiers in psychology Baker, J. M., Morath, J., Rodzon, K. S., Jordan, K. E. 2012; 3: 387-?


    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.

    View details for DOI 10.3389/fpsyg.2012.00387

    View details for PubMedID 23060847

  • Tracking of food quantity by coyotes (Canis latrans) BEHAVIOURAL PROCESSES Baker, J. M., Shivik, J., Jordan, K. E. 2011; 88 (2): 72-75


    Previous studies have demonstrated that Weber's Law mediates quantitative discrimination abilities across various species. Here, we tested coyotes' (Canis latrans) ability to discriminate between various quantities of food and investigated whether this ability conforms to predictions of Weber's Law. We demonstrate herein that coyotes are capable of reliably discriminating large versus small quantities of discrete food items. As predicted by Weber's Law, coyotes' quantitative discrimination abilities are mediated by the ratio between the large and small quantities of food and exhibit scalar variability. Furthermore, in this task coyotes were not discriminating large versus small quantities based on olfactory cues alone.

    View details for DOI 10.1016/j.beproc.2011.08.006

    View details for Web of Science ID 000295996700002

    View details for PubMedID 21856389

  • Multisensory information boosts numerical matching abilities in young children DEVELOPMENTAL SCIENCE Jordan, K. E., Baker, J. 2011; 14 (2): 205-213


    This study presents the first evidence that preschool children perform more accurately in a numerical matching task when given multisensory rather than unisensory information about number. Three- to 5-year-old children learned to play a numerical matching game on a touchscreen computer, which asked them to match a sample numerosity with a numerically equivalent choice numerosity. Samples consisted of a series of visual squares on some trials, a series of auditory tones on other trials, and synchronized squares and tones on still other trials. Children performed at chance on this matching task when provided with either type of unisensory sample, but improved significantly when provided with multisensory samples. There was no speed–accuracy tradeoff between unisensory and multisensory trial types. Thus, these findings suggest that intersensory redundancy may improve young children’s abilities to match numerosities.

    View details for DOI 10.1111/j.1467-7687.2010.00966.x

    View details for Web of Science ID 000287489500005

    View details for PubMedID 22213895

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