Knowledge that Transforms

The Commentary by Sherlock and Zietsch (2018) raises important questions about how the science of human psychological development moves forward as researchers make dramatic strides in understanding the role of genetics. In this response, we return to these larger questions, but we begin by addressing Sherlock and Zietsch’s specific argument that “genetic contributions should almost always be considered when dealing with associations between parents’ behavior and their children’s behavior” (p. 156). In our 60-year study of the association between warmth of the childhood family environment and late-life security of attachment (Waldinger & Schulz, 2016), we did not mention the potential influence of genetic factors, and we regret this omission. Moreover, we acknowledge that in some places in the article, we used causal language that was not justified by the design of the study. Although we explicitly stated that the association between warmth of the childhood family environment and late-life security of attachment is correlational and not causal, we went on to interpret these findings as indications of support for the influence of childhood environment on well-being in adulthood. Although this is a plausible interpretation, Sherlock and Zietsch are justified in arguing that genetic influences could contribute to this link and that our article should have noted this. The editorial review process encourages investigators to highlight the implications of their work, and in our enthusiasm to convey the importance of an association that spans six decades, we did not adequately address possible alternative explanations for this association. Waldinger, R. J., & Schulz, M. S. (2016). The long reach of nurturing family environments: links with midlife emotion-regulatory styles and late-life security in intimate relationships. Psychological Science. 27.11. http://doi.org/10.1177/0956797616661556

How do individuals compare images-for example, two graphs or diagrams-to identify differences between them? We argue that categorical relations between objects play a critical role. These relations divide continuous space into discrete categories, such as "above" and "below," or "containing" and "overlapping," which are remembered and compared more easily than precise metric values. These relations should lead to categorical perception, such that viewers find it easier to notice a change that crosses a category boundary (one object is now above, rather than below, another, or now contains, rather than overlaps with, another) than a change of equal magnitude that does not cross a boundary. We tested the influence of a set of topological categorical relations from the cognitive-modeling literature. In a visual same/different comparison task, viewers more accurately noticed changes that crossed relational category boundaries, compared with changes that did not cross these boundaries. The results highlight the potential of systematic exploration of the boundaries of between-object relational categories.

Inexistente

We tested whether affiliating beer brands with universities enhances the incentive salience of those brands for underage drinkers. In Study 1, 128 undergraduates viewed beer cues while event-related potentials (ERPs) were recorded. Results showed that beer cues paired with in-group backgrounds (logos for students' universities) evoked an enhanced P3 ERP component, a neural index of incentive salience. This effect varied according to students' levels of identification with their university, and the amplitude of the P3 response prospectively predicted alcohol use over 1 month. In Study 2 ( N = 104), we used a naturalistic advertisement exposure to experimentally create in-group brand associations and found that this manipulation caused an increase in the incentive salience of the beer brand. These data provide the first evidence that marketing beer via affiliating it with students' universities enhances the incentive salience of the brand for underage students and that this effect has implications for their alcohol involvement.

The human body navigates the environment via locomotory movements that leverage gravity and limb biomechanics to propel the body in a particular direction. This process creates a causal link between limb movements and whole-body translation. However, it is unknown whether humans use this causal relation as a constraint in perception and inference with body movements. In the present study, participants rated actions of other individuals as more natural when limb movements (as a cause) occurred before body displacements (as an effect) than when limb movements temporally lagged behind body displacements. This causal expectation for human body movements not only affected perceptual impressions regarding the naturalness of observed actions but also guided the interpretation of motion cues within a more generalized causal context. We interpret these results within a framework of causality as evidence that the constraint of causal action plays an important role in perception and inference with body movements.

Using generic language to describe groups (applying characteristics to entire categories) is ubiquitous and affects how children and adults categorize other people. Five-year-olds, 8-year-olds, and adults ( N = 190) learned about a novel social group that separated into two factions (citizens and noncitizens). Noncitizens were described in either generic or specific language. Later, the children and adults categorized individuals in two contexts: criminal (individuals labeled as noncitizens faced jail and deportation) and noncriminal (labeling had no consequences). Language genericity influenced decision making. Participants in the specific-language condition, but not those in the generic-language condition, reduced the rate at which they identified potential noncitizens when their judgments resulted in criminal penalties compared with when their judgments had no consequences. In addition, learning about noncitizens in specific language (vs. generic language) increased the amount of matching evidence participants needed to identify potential noncitizens (preponderance standard) and decreased participants' certainty in their judgments. Thus, generic language encourages children and adults to categorize individuals using a lower evidentiary standard regardless of negative consequences for presumed social-group membership.

Abel and Kruger (2010) found that the smile intensity of professional baseball players who were active in 1952, as coded from photographs, predicted these players' longevity. In the current investigation, we sought to replicate this result and to extend the initial analyses. We analyzed (a) a sample that was almost identical to the one from Abel and Kruger's study using the same database and inclusion criteria ( N = 224), (b) a considerably larger nonoverlapping sample consisting of other players from the same cohort ( N = 527), and (c) all players in the database ( N = 13,530 valid cases). Like Abel and Kruger, we relied on categorical smile codings as indicators of positive affectivity, yet we supplemented these codings with subjective ratings of joy intensity and automatic codings of positive affectivity made by computer programs. In both samples and for all three indicators, we found that positive affectivity did not predict mortality once birth year was controlled as a covariate.

Formal theories of learning suggest that associations between events are determined by the internal representations of those events. Thus, learning should depend on perceived reward value-even when perceptions differ from objective values. We examined this prediction in flavor-preference learning in rats. In two experiments, simultaneous contrast either increased perceived reward value, which was paired with a distinctive flavor cue (the positive conditioned stimulus, CS+), or decreased the perceived value of the same reward, which was then paired with a second flavor (the negative conditioned stimulus, CS-). Even though the CS+ and CS- were paired with the same objective reward, there was a preference for the CS+ in subsequent tests. Moreover, the size of contrast-produced changes in reward value during training predicted the preference for the CS+ at test. This contrast-produced learning effect illustrates the mechanisms by which associations, which normally track veridical relationships between events in the world, are formed.

Visual performance of human observers depends not only on the optics of the eye and early sensory encoding but also on subsequent cortical processing and representations. In two experiments, we demonstrated that motion adaptation can enhance as well as impair visual acuity. Observers who experienced an expanding motion aftereffect exhibited improved letter recognition, whereas observers who experienced a contracting motion aftereffect showed impaired letter recognition. We conclude that illusory enlargement and shrinkage of a visual stimulus can modulate visual acuity.

Some theories propose that tools become incorporated into the neural representation of the hands (a process known as tool embodiment; Maravita & Iriki, 2004). Others suggest that conceptual body representation is rigid and that experience with one’s own body is insufficient for adapting bodily cognition, as shown in individuals born without hands (Vannuscorps & Caramazza, 2016) and in amputees with persistent phantom hand representation (Kikkert et al., 2016). How sharp is the conceptual boundary between hands and tools? This question is particularly relevant for individuals who have lost one hand and use prosthetic hands as tools to supplement their missing hand function. Although both congenital one-handers (i.e., amelia patients) and one-handed amputees are encouraged to use prostheses, the former show a greater tendency than the latter to use prosthetic hands in daily tasks (Jang et al., 2011). One-handers have a fully functional remaining hand (allowing them to use handheld tools, etc.), which makes them less likely to show semantic distortions in hand and tool representation. However, their bodies and their interactions with their environment are fundamentally altered by their disability (Makin et al., 2013; Makin, Wilf, Schwartz, & Zohary, 2010). To determine how real-world experience shapes conceptual categorization of hands, tools, and prostheses, we recruited one-handers with congenital or acquired unilateral hand loss to take part in a study involving a priming task. We predicted that one-handers, particularly congenital one-handers, would show more conceptual blurring between hands and tools than control participants would, as a result of less experience with a hand and more reliance on prostheses (which are essentially tools) for typical hand functions. We further predicted that individual differences in prosthesis usage would be reflected in implicit categorization of hands, manual tools, and prostheses.