Featured Research

from universities, journals, and other organizations

Like Humans, Monkey See, Monkey Plan, Monkey Do

Date:
December 10, 2007
Source:
Association for Psychological Science
Summary:
How many times a day do you grab objects such as a pencil or a cup? We perform these tasks without thinking, however the motor planning necessary to grasp an object is quite complex. For example, waiters will pick up an inverted glass with their thumb pointing down if they plan to pour water into the glass. Is this something that other animals, non-tool users, would do?

A tamarin grasping the stem of a plastic champagne glass to pull the glass from the apparatus in order to extract a marshmallow stuck inside the glass. In (a), the monkey exhibits the thumb-up grasp orientation, and in (b), the monkey exhibits the thumb-down grasp orientation.
Credit: Dan Weiss, Pennsylvania State University

How many times a day do you grab objects such as a pencil or a cup? We perform these tasks without thinking, however the motor planning necessary to grasp an object is quite complex. The way human adults grasp objects is typically influenced more by their knowledge of what they intend to do with the objects than the objects' immediate appearance. Psychologists call this the “end-state comfort effect,” when we adopt initially unusual, and perhaps uncomfortable, postures to make it easier to actually use an object.

For example, waiters will pick up an inverted glass with their thumb pointing down if they plan to pour water into the glass. While grabbing thumb-down may feel awkward at first, it allows the waiter to be more comfortable when the glass is turned over and water poured inside.

Does this occur because motor planning abilities were crucial in facilitating the evolution of complex tool use in humans? If so, then we might predict that only humans would show this ability. Or perhaps this ability would be evidenced in humans and other tool-using species. The way to test this hypothesis, then, is to test whether this is something that other animals, non-tool users, would do.

Pennsylvania State University psychologists, Dan Weiss, Jason Wark, and David Rosenbaum decided to see if cotton-top tamarins (non-tool users) would show the end-state comfort effect. In the first experiment, Weiss and colleagues presented the monkeys with a small cup containing a marshmallow. The cup was either suspended upright or upside down. Would these monkeys, a non-tool using species, adopt an unusual grasping pattern while removing the cup from the apparatus to retrieve the marshmallow?

The results, which appear in the December issue of Psychological Science, a journal of the Association for Psychological Science, are fascinating. The monkeys grabbed the inverted cup with their thumb pointing down, thereby behaving much like human adults. In the second experiment, the monkeys were confronted with a new handle shape and still displayed grasps that were consistent with end-state comfort.

This research is the first to provide evidence for more sophisticated motor planning than has previously been attributed to a nonhuman species. The authors suggest that formulating relatively long-term motor plans is a necessary but not sufficient condition for tool use. “Our results may be taken to suggest that the reason tamarins don’t use tools in the wild is not that they lack the ability to plan ahead, but rather that the scope of their planning is limited,” say the researchers.


Story Source:

The above story is based on materials provided by Association for Psychological Science. Note: Materials may be edited for content and length.


Cite This Page:

Association for Psychological Science. "Like Humans, Monkey See, Monkey Plan, Monkey Do." ScienceDaily. ScienceDaily, 10 December 2007. <www.sciencedaily.com/releases/2007/12/071206102256.htm>.
Association for Psychological Science. (2007, December 10). Like Humans, Monkey See, Monkey Plan, Monkey Do. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2007/12/071206102256.htm
Association for Psychological Science. "Like Humans, Monkey See, Monkey Plan, Monkey Do." ScienceDaily. www.sciencedaily.com/releases/2007/12/071206102256.htm (accessed September 18, 2014).

Share This



More Plants & Animals News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chimp Violence Study Renews Debate On Why They Kill

Chimp Violence Study Renews Debate On Why They Kill

Newsy (Sep. 17, 2014) The study weighs in on a debate over whether chimps are naturally violent or become that way due to human interference in the environment. Video provided by Newsy
Powered by NewsLook.com
Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins