Can object affordances impact on human social learning of tool use?

The author describes "higher" and "uniquely human" sociocognitive skills that he argues as being necessary for tool use. We propose that those skills could be based on simpler detection systems humans could share with other animal tool users. More specifically, we discuss the impact of object affordances on the understanding and the social learning of tool use.     

One hand, two objects: emergence of affordance in contexts

Studies on affordances typically focus on single objects. We investigated whether affordances are modulated by the context, defined by the relation between two objects and a hand. Participants were presented with pictures displaying two manipulable objects linked by a functional (knife-butter), a spatial (knife-coffee mug), or by no relation. They responded by pressing a key whether the objects were related or not. To determine if observing other's actions and understanding their goals would facilitate judgments, a hand was: (a) displayed near the objects; (b) grasping an object to use it; (c) grasping an object to manipulate/move it; (d) no hand was displayed. RTs were faster when objects were functionally rather than spatially related. Manipulation postures were the slowest in the functional context and functional postures were inhibited in the spatial context, probably due to mismatch between the inferred goal and the context. The absence of this interaction with foot responses instead of hands in Experiment 2 suggests that effects are due to motor simulation rather than to associations between context and hand-postures.     

Learning to Manipulate and Categorize in Human and Artificial Agents

This study investigates the acquisition of integrated object manipulation and categorization abilities through a series of experiments in which human adults and artificial agents were asked to learn to manipulate two‐dimensional objects that varied in shape, color, weight, and color intensity. The analysis of the obtained results and the comparison of the behavior displayed by human and artificial agents allowed us to identify the key role played by features affecting the agent/environment interaction, the relation between category and action development, and the role of cognitive biases originating from previous knowledge.     

The role of bystanders in students' perception of bullying and sense of safety

Two studies employing a mixed experimental design were conducted to determine if perceptions of bullying, attitudes towards victims, and students' sense of safety at school were influenced by bystanders' reactions to different types of bullying. In Study 1, 217 middle-school children were randomly assigned to read a hypothetical scenario describing a direct bullying episode. In Study 2, 376 primary-school children and 390 middle-school children were presented with scenarios describing a direct bullying episode and an indirect bullying episode. In all scenarios, the bystanders' reactions to the bullying and the gender of the victim were manipulated. Participants endorsed the prosocial behavior in favor of the victims and did not endorse pro-bullying behavior. Furthermore, they perceived passive reactions to the bullying as negative behavior. Participants showed positive attitudes towards victims, which were significantly higher at younger grade levels and among girls. Bystanders' behavior influenced both participants' perceptions of the victims and their perceived sense of safety at school. Implications for anti-bullying programs based upon the group ecology are discussed.     

Emotive concept nouns and motor responses: Attraction or repulsion?

We carried out three experiments aimed at testing whether hand posture affects the compatibility effect that Chen and Bargh (1999) found between a word’s emotional connotation and arm movement direction. In the present study, participants responded by pressing two buttons: one placed near their body, the other far away. In Experiment 1, in which they pressed the response button with their hand open, RTs were shorter when participants pressed the far button for positive words and the near button for negative words, as if they simulated reaching for something good and avoiding something bad. However, in Experiments 2 and 3, in which participants pressed the response button with a tennis ball in their hand, RTs were shorter when participants pressed the near button for positive words and the far button for negative words, as if they simulated drawing a good thing closer and pushing a bad thing away. Results are discussed within the framework of theories on concept grounding in emotion and action systems.     

Language comprehension and dominant hand motion simulation

In five experiments participants were presented with pairs of nouns and verbs. They were asked to decide whether the combinations made sense or not. Half of the participants responded "yes" with the dominant hand, half with the left hand. When pairs referred to manual and mouth actions, participants responded faster with the dominant than with the left hand with sensible sentences. When pairs referred to manual and foot actions the result was opposite. Results suggest that language processing activates an action simulation that is sensitive to both the effector involved and the goal expressed by the sentence.     

Clamped Corticosterone (B) Reveals the Effect of Endogenous B on Both Facilitated Responsivity to Acute Restraint and Metabolic Responses to Chronic Stress

To determine the effects of both corticosterone (B) and chronic stressors on acute ACTH responses to restraint, young male rats were exposed to streptozotocin-induced diabetes, cold (5-7 degreesC) or intracerebroventricular (icv) neuropeptide Y (NPY) for 5 d and then exposed to restraint within 2 h after lights on. Two groups of rats were studied: intact and adrenalectomized replaced with B pellets that maintained plasma B in the normal mean 24-h range of intact rats. In addition to ACTH and B responses to restraint on d 5, body weight, food intake, fat depots, glucose and other hormones were measured to determine the role of stress-induced elevations in B on energy balance. ACTH responses to restraint were normal in intact rats subjected to diabetes or cold. By contrast, there was no ACTH or B response to restraint in NPY-infused intact rats. All 3 groups of chronically stimulated adrenalectomized rats with clamped B had facilitated ACTH responses to restraint compared to their treatment controls. Overall food intake increased in all groups of stressed rats; however, augmented intake occurred only during the light in intact rats and equally in the light and dark in B-clamped rats. White adipose depot weights were decreased by both diabetes and cold and increased by NPY in intact rats; the decreases with cold and increases with NPY were both blunted and changes in fat stores were not significant in adrenalectomized, B-clamped rats. We conclude that: 1. diabetes- and cold-induced facilitation of restraint-induced afferent input to hypothalamic control of the hypothalamo-pituitary-adrenal (HPA) axis is opposed in intact rats by the elevated feedback signal of B secretion; 2. NPY does not induce facilitation of afferent stress pathways; 3. chronic stimulation of the HPA axis induces acute hyperresponsiveness of hypothalamic neurons to restraint provided that the afferent input of this acute stimulus is not prevented by B feedback; 4. stimulus-induced elevations in B secretion result in day-time feeding; 5. insensitivity of both caloric efficiency and white fat stores to chronic stress in adrenalectomized, B-clamped rats results from loss of normally variable B levels.     

Depression,Positive and Negative Affect,Optimism and Health-Related Quality of Life in Recently Diagnosed Multiple Sclerosis Patients: The Role of Identity,Sense of Coherence,and Self-efficacy

The study aimed to describe the levels of depression, positive and negative affect, optimism and health-related quality of life (HRQOL) in a group of recently diagnosed multiple sclerosis (MS) patients (up to 3 years since the diagnosis), taking into account gender, age, and disease duration differences, and to investigate the possible role of identity, sense of coherence (SOC), and self-efficacy in MS (SEMS) on patients’ depression, positive and negative affect, optimism, and HRQOL. The cross-sectional study involved 90 MS patients (61% women; age: M = 37, SD = 12) with an Expanded Disability Status Scale score between 1 and 4 (mild to moderate disability). Patients completed measures of depression (CESD-10), positive and negative affect (PANAS), optimism (LOT-R), HRQOL (SF-12), identity motives, SOC, and SEMS. Depression scores were near the cut-off level for clinically significant depressive symptoms, and negative affect was higher and HRQOL was lower than those in the general population. Women and younger patients reported better adjustment as time passes since the diagnosis. Results of multiple regressions indicated that higher SOC was related to higher mental health, lower negative affect and lower depression. Higher SEMS was predictive of greater positive affect and lower negative affect, whereas higher identity satisfaction was predictive of higher positive affect and optimism and lower depression. The results suggest the usefulness of addressing identity redefinition, SOC and self-efficacy in psychological interventions aimed at promoting patients’ adjustment to MS.     

When objects are close to me: Affordances in the peripersonal space

In the present study, we investigated, using language, which motor information is automatically activated by observing 3-D objects (i.e., manipulation vs. function) and whether this information is modulated by the objects' location in space. Participants were shown 3-D pictures of objects located in peripersonal versus extrapersonal space. Immediately after, they were presented with function, manipulation, or observation verbs (e.g., "to drink," "to grasp," "to look at") and were required to judge whether the verb was compatible with the presented object. We found that participants were slower with observation verbs than with manipulation and function verbs. With both function and manipulation verbs, participants were faster when objects were presented in reachable space. Interestingly, the fastest response times were recorded when participants read function verbs while objects were presented in the accessible space. Results suggest that artifacts are first conceived in terms of affordances linked to manipulation and use, and that affordances are differently activated, depending on context.