Further Exploration of Verbal Influence on Memory

This page describes the second experiment in Loftus and Palmer's study, which delved deeper into how question wording can affect memory recall over time. The researchers expanded their investigation to examine not just speed estimates, but also the creation of false memories.

In this experiment, 150 participants watched a one-minute film showing multiple car accidents. They were then divided into three groups of 50 each:

1. One group was asked about the speed of cars that "smashed" into each other
2. Another group was asked about cars that "hit" each other
3. A control group was not asked about speed at all

Highlight: A week after viewing the film, all participants were asked if they had seen any broken glass in the accident scenes, even though no broken glass was actually present.

The results were striking:

• 16 out of 50 participants in the "smashed" condition reported seeing broken glass
• Only 7 out of 50 in the "hit" condition reported seeing glass
• 6 out of 50 in the control group reported seeing glass

Definition: A chi-squared test is a statistical method used to determine if there is a significant difference between the expected frequencies and the observed frequencies in one or more categories.

The researchers used a chi-squared test to confirm that these differences were statistically significant, meaning they were unlikely to have occurred by chance.

Quote: "Loftus and Palmer states there's 2 types of info that goes into person's memory after complex event: Info obtained from witnessing event [and] Info given AFTER event (post-event info)"

This experiment led to the conclusion that there are two sources of information that contribute to a person's memory of an event:

1. The information obtained from actually witnessing the event
2. Information provided after the event (post-event information)

Over time, these two sources of information merge, creating one overall memory. This process is referred to as the reconstructive hypothesis, highlighting how memory is not a perfect recording but a reconstruction influenced by various factors, including the language used in questioning.

Vocabulary: Eyewitness testimony (EWT) refers to an account given by an individual of an event they have witnessed, often used as evidence in legal proceedings.

The study conclusively demonstrates that leading questions can significantly influence eyewitness testimony, emphasizing the need for careful and neutral questioning in legal and investigative contexts to preserve the accuracy of eyewitness accounts.

Loftus and Palmer's 1974 Study on Eyewitness Testimony

This page details the first experiment in Loftus and Palmer's influential study on the impact of leading questions on eyewitness testimony. The researchers aimed to investigate how the choice of verbs in questions could influence participants' estimates of vehicle speed in accident scenarios.

The procedure involved showing short clips of traffic accidents to groups of US students. Each group was then asked to estimate the speed of the cars using a question that varied only in the verb used to describe the collision. The verbs ranged from "smashed" to "contacted," with "collided," "bumped," and "hit" in between.

Highlight: The choice of verb in the question significantly affected the speed estimates given by participants.

Results showed a clear pattern: stronger verbs like "smashed" led to higher speed estimates, while milder verbs like "contacted" resulted in lower estimates. This demonstrates the power of language in shaping memory and perception.

Example: When asked about cars that "smashed" into each other, participants estimated an average speed of 40.8 mph, compared to just 31.8 mph when the verb "contacted" was used.

The researchers concluded that the wording of questions can influence eyewitness testimony in two ways:

1. By creating bias when participants are uncertain about details
2. By altering the witness's memory of the event, making it seem more severe than it actually was

Vocabulary: Reconstructive memory refers to the process by which people fill in gaps in their memory with information that seems plausible, often influenced by suggestions or expectations.

This experiment highlights the importance of careful questioning in legal and investigative contexts to avoid inadvertently influencing eyewitness accounts.