Reconstruing the "reconstruction" of psychopathy: a comment on Cooke, Michie, Hart, and Clark

In this comment we highlight critical problems in the estimation of parameters for their hierarchical three-factor model of psychopathy, as assessed with the Hare Psychopathy Checklist, and their interpretation of these factors as causally related to socially deviant behavior. We argue that there is nothing "causal" about a model in which cross-sectional data are used to assert that antisocial tendencies are consequences of other more fundamental psychopathic traits. We present an equally viable model, based on the PCL-R four-factor solution, in which antisocial tendencies play a fundamental role in the construct of psychopathy, consistent with previous research and clinical tradition.     

Human-like social skills in dogs?

Domestic dogs are unusually skilled at reading human social and communicative behavior--even more so than our nearest primate relatives. For example, they use human social and communicative behavior (e.g. a pointing gesture) to find hidden food, and they know what the human can and cannot see in various situations. Recent comparisons between canid species suggest that these unusual social skills have a heritable component and initially evolved during domestication as a result of selection on systems mediating fear and aggression towards humans. Differences in chimpanzee and human temperament suggest that a similar process may have been an important catalyst leading to the evolution of unusual social skills in our own species. The study of convergent evolution provides an exciting opportunity to gain further insights into the evolutionary processes leading to human-like forms of cooperation and communication.     

Chimpanzees deceive a human competitor by hiding

There is little experimental evidence that any non-human species is capable of purposefully attempting to manipulate the psychological states of others deceptively (e.g., manipulating what another sees). We show here that chimpanzees, one of humans' two closest primate relatives, sometimes attempt to actively conceal things from others. Specifically, when competing with a human in three novel tests, eight chimpanzees, from their first trials, chose to approach a contested food item via a route hidden from the human's view (sometimes using a circuitous path to do so). These findings not only corroborate previous work showing that chimpanzees know what others can and cannot see, but also suggest that when competing for food chimpanzees are skillful at manipulating, to their own advantage, whether others can or cannot see them.     

Chimpanzees understand psychological states - the question is which ones and to what extent

New data suggest that relatively drastic revisions are needed in our theoretical accounts of what other animal species understand about the psychological states of others. Specifically, chimpanzees seem to understand some things about what others do and do not see, or have and have not seen in the immediate past, as well as some things about others' goal-directed activities. This is especially so in competitive situations. They clearly do not have a human-like theory of mind, however, and so the challenge is to specify precisely how ape and human social cognition are similar and different.     

Chimpanzee Use of Human and Conspecific Social Cues to Locate Hidden Food

Two studies are reported in which chimpanzees attempted to use social cues to locate hidden food in one of two possible hiding places. In the first study four chimpanzees were exposed to a local enhancement cue (the informant approached and looked to the location where food was hidden and then remained beside it) and a gaze/point cue (the informant gazed and manually pointed towards the location where the food was hidden). Each cue was given by both a human informant and a chimpanzee informant. In the second study 12 chimpanzees were exposed to a gaze direction cue in combination with a vocal cue (the human informant gazed to the hiding location and produced one of two different vocalizations: a ‘food-bark’ or a human word-form). The results were: (i) all subjects were quite skillful with the local enhancement cue, no matter who produced it; (ii) few subjects were skillful with the gaze/point cue, no matter who produced it (most of these being individuals who had been raised in infancy by humans); and (iii) most subjects were skillful when the human gazed and vocalized at the hiding place, with little difference between the two types of vocal cue. Findings are discussed in terms of chimpanzees’ apparent need for additional cues, over and above gaze direction cues, to indicate the presence of food.     

Acoustic Distinctions in the Speech of Male Psychopaths

A key feature of psychopathy is the ability to deceive, manipulate, and con the unwary, while seeming to be perfectly sincere. Is this impression of sincerity achieved solely through body gestures and facial expression, or is there also something different about the voice quality of psychopaths? We analyzed the acoustic characteristics of speech in 20 male offenders (10 psychopaths and 10 nonpsychopaths), assessed with the Psychopathy Checklist—Revised (Hare, 1991). We used a computer program developed by Alpert, Merewether, Homel, Martz, and Lomask (1986) to measure variations in amplitude and prosody. Results indicated that psychopaths spoke more quietly than controls and did not differentiate, in voice emphasis, between neutral and affective words. These findings are consistent with the developing view that psychopaths are insensitive to the emotional connotations of language. In addition, their vocal characteristics may be part of a self-presentation mode designed to manipulate and control interpersonal interactions.     

Chimpanzee gaze following in an object-choice task

Many primate species reliably track and follow the visual gaze of conspecifics and humans, even to locations above and behind the subject. However, it is not clear whether primates follow a human’s gaze to find hidden food under one of two containers in an object-choice task. In a series of experiments six adult female chimpanzees followed a human’s gaze (head and eye direction) to a distal location in space above and behind them, and checked back to the human’s face when they did not find anything interesting or unusual. This study also assessed whether these same subjects would also use the human’s gaze in an object-choice task with three types of occluders: barriers, tubes, and bowls. Barriers and tubes permitted the experimenter to see their contents (i.e., food) whereas bowls did not. Chimpanzees used the human’s gaze direction to choose the tube or barrier containing food but they did not use the human’s gaze to decide between bowls. Our findings allowed us to discard both simple orientation and understanding seeing-knowing in others as the explanations for gaze following in chimpanzees. However, they did not allow us to conclusively choose between orientation combined with foraging tendencies and understanding seeing in others. One interesting possibility raised by these results is that studies in which the human cannot see the reward at the time of subject choice may potentially be underestimating chimpanzees’ social knowledge. Received: 16 February 1998 / Accepted after revision: 5 July 1998     

The ethics of morphing

Here’s one piece of practical reasoning: “If I do this then a person will reap some benefits and suffer some costs. On balance, the benefits outweigh the costs. So I ought to do it.” Here’s another: “If I do this then one person will reap some benefits and another will suffer some costs. On balance, the benefits to the one person outweigh the costs to the other. So I ought to do it.” Many influential philosophers say that there is something dubious about the second piece of reasoning. They say that it makes sense to trade-off costs and benefits within lives, but not across lives. In this paper I make a case for the second piece of reasoning. My case turns on the existence of morphing sequences—sequences of possible states of affairs across which people transform smoothly into other people.