Representing tools: how two non-human primate species distinguish between the functionally relevant and irrelevant features of a tool

Few studies have examined whether non-human tool-users understand the properties that are relevant for a tool's function. We tested cotton-top tamarins (Saguinus oedipus) and rhesus macaques (Macaca mulatta) on an expectancy violation procedure designed to assess whether these species make distinctions between the functionally relevant and irrelevant features of a tool. Subjects watched an experimenter use a tool to push a grape down a ramp, and then were presented with different displays in which the features of the original tool (shape, color, orientation) were selectively varied. Results indicated that both species looked longer when a newly shaped stick acted on the grape than when a newly colored stick performed the same action, suggesting that both species perceive shape as a more salient transformation than color. In contrast, tamarins, but not rhesus, attended to changes in the tool's orientation. We propose that some non-human primates begin with a predisposition to attend to a tool's shape and, with sufficient experience, develop a more sophisticated understanding of the features that are functionally relevant to tools.     

Author Index 106, 2001

Authors Index

Author Index 106, 2001     

Gravity biases in a non-human primate?

Pre-school children expect falling objects to travel in a straight line even when there are clear physical mechanisms that deviate the object's path (Hood, 1995). The current study set out to determine whether this expectancy is limited to humans. Cotton-top tamarins (Saguinus oedipus oedipus), a New World monkey species, were tested on Hood's (1995) experimental task where objects are dropped down a chimney connected by an opaque tube to one of three containers. Like human children, there was a significant tendency to search in the container underneath the chimney where the food was dropped on the first trial, even though aligned chimneys and containers were never connected. These search errors suggest that there may be a gravity bias that operates when both primate species fail to understand the constraints operating on object trajectories. Unlike human children however, tamarins were generally more likely to perseverate in making errors even though repeated testing and cost incentives were used.     

Connectionist and diffusion models of reaction time.

Two connectionist frameworks, GRAIN (J. L. McClelland, 1993) and brain-state-in-a-box (J. A. Anderson, 1991), and R. Ratcliff's (1978) diffusion model were evaluated using data from a signal detection task. Dependent variables included response probabilities, reaction times for correct and error responses, and shapes of reaction-time distributions. The diffusion model accounted for all aspects of the data, including error reaction times that had previously been a problem for all response-time models. The connectionist models accounted for many aspects of the data adequately, but each failed to a greater or lesser degree in important ways except for one model that was similar to the diffusion model. The findings advance the development of the diffusion model and show that the long tradition of reaction-time research and theory is a fertile domain for development and testing of connectionist assumptions about how decisions are generated over time.     

Effects of Directed Thinking on Intentions to Engage in Beneficial Activities: Actions Versus Reasons1

An important application of psychological principles involves increasing intentions to engage in activities that, although admittedly beneficial, are often not initially appealing (e.g., studying, quitting smoking, dieting). The present study tests the utility of directed thinking as a tool for eliciting intentions to engage in such activities. Undergraduate students were directed to think either about the reasons why people should find studying enjoyable or about the actions that people might take to make studying enjoyable. Regardless of whether they thought as individuals or in cooperating dyads, students who thought about actions later reported greater intentions to spend time studying than did students who thought about reasons. The results have both theoretical and practical significance.     

Mothers’ attuned responses to infant affect expressivity promote earlier achievement of language milestones

To investigate infants’ affective expressivity and maternal attuned responsiveness to infant expressivity in relation to early language achievement, 77 dyads were visited in their homes at 9 and 13 months, and mothers were interviewed about their children’s language between 9 and 21 months. Maternal responses that were attuned to infant affect, by selectively matching either the gradient features or the valence of infants’ affective expressions, were more predictive of children’s language achievement than maternal nonmatching responses; and maternal matching responses at 9 months were more predictive of children’s language achievements than maternal responses at 13 months. Moreover, maternal matching responses at 9 months predicted second-year language achievements over and above infant affect expressivity at 9 and 13 months, and over and above maternal matching responses at 13 months. Infants’ affective expressivity per se was not predictive.     

A Death in the Family: Report of a Single-Session Trauma Group for Nursing Home Residents and Staff

This article describes a single-session trauma-debriefing group conducted at a nursing home following the death of a resident on an outing. The group had as its core an existing weekly therapy group in the facility, with the addition of affected staff, family, and other residents who were on the outing. The treatment illustrates four principles relevant to counseling and psychotherapy in nursing homes: 1) recognition of death; 2) treatment in and of the milieu; 3) flexibility and structure; and 4) dealing with countertransference. Along the way, we see how the residents are capable of giving, and not merely receiving.     

The Uncanny Self in Love: Divorced Catholic Women Remember Abortion in Romania

This essay presents an ethnographic account of two divorced Catholic women's memories of praying to the Virgin Mary while seeking illegal abortions under the Romanian socialist regime. These women's stories focused on troubling memories of being in love, reflections that were retrospectively shaped by divorce. Drawing on Sigmund Freud's notion of the uncanny, I call these recollections uncanny memories of the self in love. Uncannily remembering one's self in love combines experiential self‐examination and ethical assessment of actions. The notion of the uncanny self in love thus helps bridge the divide between experience‐ and action‐oriented approaches to lived ethics. I argue that the ethical significance of the Virgin Mary's actions depended on my acquaintances’ approach to love. For one woman seeking to stay estranged from her ex‐husband, the Virgin Mary's actions accentuated his ethical immaturity. My other acquaintance harbored more ambivalent feelings toward her ex‐husband; for her, talking about the Virgin Mary helped her relativize feelings of ethical indignation. As a core implication of this argument, I urge greater awareness of the problematic tendency to include the need for greater awareness of tendencies in theories of lived ethics to reify socially situated perspectives on love.     

Structure and content of affective associations with health behaviours: Is the behaviour ‘good OR bad’ or ‘good AND bad’

Objective: The feelings and emotions individuals associate with health-related behaviours influence engagement in those behaviours. However, the structure and the content of these affective associations have not been examined. The studies reported here examined competing hypotheses about the structure (unidimensional or bidimensional) and content (generalised affect or specific emotions) of affective associations with two health-related behaviours: physical activity and fruit/vegetable consumption.

Design: For each behaviour, participants (fruit and vegetable consumption n = 149; physical activity n = 199) completed an assessment of the association of 40 positive and 51 negative affect concepts with the behaviour.

Main outcome measures: Ratings of affective associations with each behaviour.

Results: Confirmatory factor analyses comparing unidimensional and bidimensional affect structure models showed that the structure of individuals’ affective associations was bidimensional for both behaviours – positive and negative affective associations were shown to be separate and distinct constructs. Exploratory factor analyses supported a model of affective associations as generalised affect for both behaviours.

Conclusion: Affective associations with both physical activity and with fruit/vegetable consumption consist of separate positive and negative dimensions of generalised affect. These findings lead to recommendations for research and intervention development based on the implications for how affective associations might operate to influence behavioural decision-making.