Implicit sequence learning in ring‐tailed lemurs (Lemur catta)

Implicit learning involves picking up information from the environment without explicit instruction or conscious awareness of the learning process. In nonhuman animals, conscious awareness is impossible to assess, so we define implicit learning as occurring when animals acquire information beyond what is required for successful task performance. While implicit learning has been documented in some nonhuman species, it has not been explored in prosimian primates. Here we ask whether ring‐tailed lemurs (Lemur catta) learn sequential information implicitly. We tested lemurs in a modified version of the serial reaction time task on a touch screen computer. Lemurs were required to respond to any picture within a 2 × 2 grid of pictures immediately after its surrounding border flickered. Over 20 training sessions, both the locations and the identities of the images remained constant and response times gradually decreased. Subsequently, the locations and/or the identities of the images were disrupted. Response times indicated that the lemurs had learned the physical location sequence required in original training but did not learn the identity of the images. Our results reveal that ring‐tailed lemurs can implicitly learn spatial sequences, and raise questions about which scenarios and evolutionary pressures give rise to perceptual versus motor‐implicit sequence learning.     

Toward quantifying the abuse liability of ultraviolet tanning: A behavioral economic approach to tanning addiction

Many adults engage in ultraviolet indoor tanning despite evidence of its association with skin cancer. The constellation of behaviors associated with ultraviolet indoor tanning is analogous to that in other behavioral addictions. Despite a growing literature on ultraviolet indoor tanning as an addiction, there remains no consensus on how to identify ultraviolet indoor tanning addictive tendencies. The purpose of the present study was to translate a behavioral economic task more commonly used in substance abuse to quantify the "abuse liability" of ultraviolet indoor tanning, establish construct validity, and determine convergent validity with the most commonly used diagnostic tools for ultraviolet indoor tanning addiction (i.e., mCAGE and mDSM‐IV‐TR). We conducted a between‐groups study using a novel hypothetical Tanning Purchase Task to quantify intensity and elasticity of ultraviolet indoor tanning demand and permit statistical comparisons with the mCAGE and mDSM‐IV‐TR. Results suggest that behavioral economic demand is related to ultraviolet indoor tanning addiction status and adequately discriminates between potential addicted individuals from nonaddicted individuals. Moreover, we provide evidence that the Tanning Purchase Task renders behavioral economic indicators that are relevant to public health research. The present findings are limited to two ultraviolet indoor tanning addiction tools and a relatively small sample of high‐risk ultraviolet indoor tanning users; however, these pilot data demonstrate the potential for behavioral economic assessment tools as diagnostic and research aids in ultraviolet indoor tanning addiction studies.     

A two‐part mixed effects model for cigarette purchase task data

The Cigarette Purchase Task is a behavioral economic assessment tool designed to measure the relative reinforcing efficacy of cigarette smoking across different prices. An exponential demand equation has become a standard model for analyzing purchase task data, but its utility is compromised by its inability to accommodate values of zero consumption. We propose a two‐part mixed effects model that keeps the same exponential demand equation for modeling nonzero consumption values, while providing a logistic regression for the binary outcome of zero versus nonzero consumption. Therefore, the proposed model can accommodate zero consumption values and retain the features of the exponential demand equation at the same time. As a byproduct, the logistic regression component of the proposed model provides a new demand index, the “derived breakpoint”, for the price above which a subject is more likely to be abstinent than to be smoking. We apply the proposed model to data collected at baseline from college students (N = 1,217) enrolled in a randomized clinical trial utilizing financial incentives to motivate tobacco cessation. Monte Carlo simulations showed that the proposed model provides better fits than an existing model. We note that the proposed methodology is applicable to other purchase task data, for example, drugs of abuse.     

“You’re on ten,where can you go from there?” Tufnel problems in repeated experiential judgments

We describe a set of Tufnel problems that arise when repeated use of a fixed-point scale precipitates failures to assess a full range of subjective experiences. As empirical evidence, participants in Study 1 periodically reported their depth of mind wandering on either 5- or 7-point Likert scales during a sustained attention task. The proportion of participants providing maximum scale ratings increased quickly over time-on-task and did so more quickly for the 5-point than for the 7-point group. Participants in Study 2 completed the same task using a 10-point scale before indicating whether and where they could have used a scale extended to “11” during the task. Slightly more than 20% of participants reported needing a scale extension. This Need for 11 was associated with differences in both reports of mind wandering depth and task performance. We conclude that Tufnel problems warrant methodological consideration and reflect interesting constraints on human judgment.     

Differentiating technical skill and motor abilities in selected and non-selected 3–5 year old team-sports players

This study examined the difference in 22 3–5 year old boys selected to an advanced or non-advanced group on an English community-based professional club training program. Time to complete 15 m linear sprint and 15 m zig-zag agility tests, with and without a ball, were used to assess the children’s technical skill and motor ability. Age and body mass of both groups were the same, whereas height was greater and BMI was lower in the selected group (p < 0.01). Linear sprint times without and with the ball were 3.98 ± 0.35 and 4.44 ± 0.36 s, respectively for the selected and corresponding times were 4.64 ± 1.04 and 11.2 ± 5.37 s for the non-selected (p < 0.01, ES 0.8, 1.8). Similar results were found when a change of movement was included, both with and without the ball. A model of selection indicated that performance in an agility test with the ball and height had the greatest discriminatory power and explained 95.5% of between group variance. Selected players performed significantly better in tests when ball control was required. These findings suggest that technical proficiency and physical differences may influence team selection in three to five year old children.     

Effects of self-generated versus experimenter-provided cues on the representation of future events

Most experimental studies of prospection focused on episodic forms of future events prompted by means of verbal cues. However, there is evidence suggesting that future events differ considerably according to whether they are produced in response to external, experimenter-provided verbal cues or they are self-generated. In the present study, we compared the quality, the phenomenal characteristics, the temporal distribution, and the content of imagined events prompted by experimenter-provided cues (i.e., cue-words and short verbal sentences) or elicited by means of verbal cues that were self-generated in an autobiographical fluency task. The results showed that future events prompted by means of self-generated cues contained fewer event-specific details than future events prompted by experimenter-provided cues. However, future events elicited by means of self-generated and by experimenter-provided cues did not differ with respect to their phenomenal characteristics. The temporal distribution and the thematic content of future representations were also affected by the type of cue used to elicit prospection. These results offer a holistic view of the properties of future thinking and suggest that the content and the characteristics of envisioned future events may be affected by the method used to elicit prospection.     

Common magnitude representation of fractions and decimals is task dependent

Although several studies have compared the representation of fractions and decimals, no study has investigated whether fractions and decimals, as two types of rational numbers, share a common representation of magnitude. The current study aimed to answer the question of whether fractions and decimals share a common representation of magnitude and whether the answer is influenced by task paradigms. We included two different number pairs, which were presented sequentially: fraction–decimal mixed pairs and decimal–fraction mixed pairs in all four experiments. Results showed that when the mixed pairs were very close numerically with the distance 0.1 or 0.3, there was a significant distance effect in the comparison task but not in the matching task. However, when the mixed pairs were further apart numerically with the distance 0.3 or 1.3, the distance effect appeared in the matching task regardless of the specific stimuli. We conclude that magnitudes of fractions and decimals can be represented in a common manner, but how they are represented is dependent on the given task. Fractions and decimals could be translated into a common representation of magnitude in the numerical comparison task. In the numerical matching task, fractions and decimals also shared a common representation. However, both of them were represented coarsely, leading to a weak distance effect. Specifically, fractions and decimals produced a significant distance effect only when the numerical distance was larger.     

四卡问题解决中的内容与逻辑分析效应

选取条件概率(P(Q|P))由低到高的四个命题作为四卡问题中的检验规则,探讨了大学生被试对四张卡片的逻辑证明作用的推断能力及其对解决四卡问题的影响。结果发现:(1)不同条件概率的命题之间正确选择P-Q的人数百分比不存在显著差异,命题的条件概率因素对四卡问题的正确解决没有影响。(2)逻辑分析过程对四卡问题的正确解决产生了一定的抑制作用,这可能是因为被试不能从整体上思考四张卡片在命题检验中的逻辑作用的缘故。(3)一些被试即使在逻辑分析过程中表现出知道-Q卡片的证伪作用,仍然倾向于选择卡片Q而非-Q,这一现象再次证实了人类思维的非形式逻辑的一面。     

Complexity effects on the children's gambling task

The children's gambling task (CGT [Kerr, A., & Zelazo, P. D. (2004). Development of “Hot” executive function: The children's gambling task. Brain and Cognition, 55, 148–157]) involves integrating information about losses and gains to maximize winnings when selecting cards from two decks. Both cognitive complexity and control (CCC) theory and relational complexity (RC) theory attribute younger children's difficulty to task complexity. In CCC theory, identification of the advantageous deck requires formulation of a higher-order rule so that gains and losses can be considered in contradistinction. According to RC theory, it entails processing the ternary relation linking three variables (deck, magnitude of gain, magnitude of loss). We designed two less complex binary-relational versions in which either loss or gain varied across decks, with the other held constant. The three closely matched versions were administered to 3–5-year-olds. Consistent with complexity explanations, children in all age groups selected cards from the advantageous deck in the binary-relational versions, but only 5-year-olds did so on the ternary-relational CGT.     

汉字识别侧抑制效应的实验研究

以汉字作为实验材料,采用侧抑制任务范式,考察了不同性质冲突任务下的汉字识别情况.结果发现:反应冲突条件下的反应时显著长于无冲突条件,侧抑制效应非常明显;刺激冲突任务中,只有字音干扰条件表现出了侧抑制效应,字形和字义干扰条件下的反应时与无冲突条件均无显著差异.实验结果说明,侧抑制效应可能受认知加工阶段的影响;汉字字音与形、义特征的加工过程可能并不相同,语音的激活可能要早于语义和字形的激活.